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Preview Meteorology Questions
A warm air mass is characterized by __________. | good visibility | gusty winds | instability | stability |
Warm air masses will generally have __________. | stratiform clouds | turbulence within the mass | good visibility | heavy precipitation |
Temperature and moisture characteristics are modified in a warm or cold air mass due to __________. | movement of the air mass | pressure changes in the air mass | the heterogeneous nature of the air mass | upper level atmospheric changes |
An air mass is termed "warm" if __________. | it originated in a high pressure area | it is above 70°F | it originated in a low pressure area | the ground over which it moves is cooler than the air |
Air temperature varies with __________. | the season of the year | the latitude or distance from the equator | the altitude above sea level | All of the above. |
A source of an air mass labeled mTw is __________. | the equator | the Gulf of Mexico | Alaska | Canada |
The process by which the temperature and/or moisture characteristics of an air mass changes is called __________. | consolidation | sublimation or condensation | association | modification |
An air mass that has moved down from Canada would most likely have the symbols __________. | cPk
|
cTw
|
mPk
|
cTk |
Hot air can hold __________. | more moisture than cold air | the same amount of moisture as cold air | moisture independent of air temperature | less moisture than cold air |
In North America the majority of the weather systems move from __________. | south to north | east to west | north to south | west to east |
Which of the listed properties does warm air possess? | Atmospheric pressure drops as warm air rises. | Moisture in warm air condenses as the air is cooled. | It rises above cooler air and cools as it rises. | All of the above. |
Weather systems in the middle latitudes generally travel from __________. | west to east | north to south | east to west | None of the above |
Ascending and descending air masses with different temperatures is part of an important heat transmitting process in our atmosphere called __________. | barometric inversion | conduction | radiation | convection |
Air masses near the earth's surface __________. | move from areas of high pressure to areas of low pressure | are deflected by the earth's rotation in both hemispheres | are deflected by the "Coriolis effect" | All of the above. |
According to Buys Ballot's Law, when an observer in the Southern Hemisphere experiences a northwest wind, the center of the low pressure is located to the __________. | east-southeast | east-northeast | west-southwest | south-southwest |
You are steaming west in the South Atlantic in an extratropical cyclonic storm, and the wind is dead ahead. According to the law of Buys Ballot, the center of low pressure lies __________. | to the north of you | dead ahead of you | to the south of you | dead astern of you |
If a weather bulletin shows the center of a low pressure system to be 100 miles due east of you, what winds can you expect in the Southern Hemisphere? | South-southwesterly | South-southeasterly | North-northeasterly | North-northwesterly |
According to Buys Ballot's law, when an observer in the Northern Hemisphere experiences a northeast wind the center of low pressure is located to the __________. | west-southwest | northwest | south-southeast | northeast |
If an observer in the Northern Hemisphere faces the surface wind, the center of low pressure is to his __________. | right, slightly in front of him | left, slightly in front of him | left, slightly behind him | right, slightly behind him |
If your weather bulletin shows the center of a low pressure area to be 100 miles due east of your position, what winds can you expect in the Northern Hemisphere? | South to southeast | East to southeast | North to northwest | East to northeast |
You are steaming eastward in the North Atlantic in an extratropical cyclonic storm and the wind is dead ahead. According to the law of Buys Ballot, where does the center of the low pressure lie? | astern of you | to the north | to the south | ahead of you |
What enables you to estimate the bearing of a storm's center? | An educated guess | The left-hand rule | Pascal's Law | Buys Ballot's Law |
You are steaming west in the North Atlantic in an extratropical cyclonic storm, and the wind is dead ahead. According to the law of Buys Ballot, the center of low pressure lies to the __________. | north | east | south | west |
According to Buys Ballot's law, when an observer in the Northern Hemisphere experiences a northwest wind, the center of low pressure is located to the __________. | northeast | west-southwest | northwest | south-southeast |
The probability of a sudden wind may be foretold by __________. | the formation of cumulus clouds in the sky | an overcast sky | a fast approaching line of dark clouds | a partly cloudy sky |
Which cloud type is normally associated with thunderstorms? | Cumulonimbus | Cumulus | Cirrus | Stratus |
In many areas "atoll" clouds (clouds of vertical development) are produced over small islands. These are the result of __________. | rising air currents produced by the warm islands | warm air from the sea rising over higher land areas | descending air over the islands | cool land air mixing with warm sea air |
A cloud of marked vertical development (often anvil-shaped) would be classified as __________. | cirrocumulus | cumulonimbus | cirrus | altocumulus |
On a clear, warm day, you notice the approach of a tall cumulus cloud. The cloud top has hard well defined edges and rain is falling from the dark lower edge. Should this cloud pass directly overhead __________. | the wind speed will not change as it passes | the wind will back rapidly to left in a counterclockwise direction as it passes | it will be preceded by a sudden decrease in wind speed | it will be preceded by a sudden increase in wind speed |
Which type of cloud formation should be of immediate concern to small craft operators? | cirrus | altostratus | cumulonimbus | nimbostratus |
All of the following are associated with cumulonimbus clouds EXCEPT __________. | steady rainfall | hail storms | thunderstorms | tornadoes or waterspouts |
Cumulonimbus clouds can produce __________. | dense fog and high humidity | clear skies with the approach of a cold front | gusty winds, thunder, rain or hail, and lightning | a rapid drop in barometric pressure followed by darkness |
Cumulus clouds that have undergone vertical development and have become cumulonimbus in form, indicate __________. | clearing weather | an approaching hurricane or typhoon | that a warm front has passed | probable thunderstorm activity |
Cumulonimbus clouds are formed by __________. | vertical air movements | horizontal air movements | heavy rainstorms | any movement of moist air |
Which type of cloud is the classic "thunderhead"? | Altostratus | Cumulonimbus | Cirrus | Stratus |
A sign of thunderstorm development is a cumulus cloud __________. | creating cold downdrafts that are felt on the ground | darkening, growing in size and forming an anvil top | that shows extensive vertical development | All of the above. |
From which type of cloud can a tornado or waterspout develop? | Nimbostratus | Altostratus | Cirrus | Cumulonimbus |
Small, visible mound-like protuberances on the bottom of cumulonimbus clouds, that are potential breeding grounds for waterspouts and tornadoes, are called __________. | ice prisms | rime | mamma | thunderheads |
The appearance of nimbostratus clouds in the immediate vicinity of a ship at sea would be accompanied by which of the following conditions? | Dropping barometric pressure and backing wind in the Northern Hemisphere | Severe thunderstorms | Rain and poor visibility | High winds and rising sea |
The low, dark, sheet-like cloud which is associated with continuous precipitation for many hours is a __________. | cirrus cloud | cumulus cloud | nimbostratus cloud | cumulonimbus cloud |
How are cumulonimbus clouds formed? | By vertical air movements | In heavy rainstorms | By horizontal air movements | By any movement of moist air |
Clouds with the prefix "nimbo" in their name __________. | have undergone great vertical development | are middle or high altitude clouds | are sheet or layer clouds | are rain clouds |
Uniform, grayish-white cloud sheets that cover large portions of the sky, and are responsible for a large percentage of the precipitation in the temperate latitudes, are called __________. | altocumulus | altostratus | cirrostratus | cirrocumulus |
Altocumulus clouds are defined as __________. | vertical development clouds | high clouds | low clouds | middle clouds |
If the sky was clear, with the exception of a few cumulus clouds, it would indicate __________. | fair weather | fog setting in | hurricane weather | rain |
The form of cloud often known as "mackerel sky" which is generally associated with fair weather is __________. | cumulonimbus | cirrocumulus | stratus | nimbostratus |
High clouds, composed of small white flakes or scaly globular masses, and often banded together to form a "mackerel sky", would be classified as __________. | cumulonimbus | altostratus | cirrus | cirrocumulus |
A thin, whitish, high cloud popularly known as "mares' tails" is __________. | altostratus | cirrus | stratus | cumulus |
Cirrus clouds are composed primarily of __________. | nitrogen | ice crystals | snow crystals | water droplets |
Which cloud commonly produces a halo about the Sun or Moon? | Altostratus | Altocumulus | Cirrocumulus | Cirrostratus |
Which type of cloud is composed entirely of ice crystals and is found at very high altitudes? | Cirrus | Nimbostratus | Cumulus | Stratus |
The bases of middle clouds are located at altitudes of between __________. | 3,000 to 6,500 feet (914 to 1981 meters) | 6,500 to 20,000 feet (1981 to 6096 meters) | 10,000 to 35,000 feet (3048 to 10,668 meters) | 20,000 to 60,000 feet (6096 to 18,288 meters) |
Which list of clouds is in sequence, from highest to lowest in the sky? | Cirrostratus, altostratus, stratus | Altostratus, stratus, cirrostratus | Stratus, cirrostratus, altostratus | Altostratus, cirrostratus, stratus |
A low, uniform layer of cloud resembling fog, but not resting on the ground, is called __________. | nimbus | stratus | cirrus | cumulus |
Cloud formations are minimal when the __________. | barometric pressure is very low | surface temperature and temperature aloft differ greatly | relative humidity is very high | surface temperature and temperature aloft are equal |
Clouds form __________. | when the relative humidity of the atmosphere is low | dry air compresses moisture from the atmosphere into clouds | as a mass of warm, humid air rises into the atmosphere and cools, condensing moisture into small droplets | as winds blow across bodies of water, the sun causes the moisture to be absorbed and move upward forming clouds |
Clouds are classified according to their __________. | altitude and how they were formed | moisture content | size | location in a front |
Which type of cloud is among the most dependable for giving an indication of an approaching weather system? | Cumulus | Altostratus | Nimbus | Cumulostratus |
Which type of weather could you expect soon after seeing "hook" or "comma" shaped cirrus clouds? | Clearing with the approach of a cold front | The formation of a tropical depression | Continuing fog and rain | Rain with the approach of a warm front |
What occurs when rising air cools to the dew point? | Humidity decreases | Advection fog forms | Winds increase | Clouds form |
The presence of stratus clouds and a dying wind will usually result in __________. | heavy rain | heavy snow | clearing skies | thick fog |
In illustration D039NG below, what type of cloud is indicated by the number five? | Altocumulus | Nimbostratus | Cirrocumulus | Cirrostratus |
In illustration D039NG below, what type of cloud is indicated by the number four? | Altostratus | Cirrostratus | Cumulus | Altocumulus |
In illustration D039NG below, which number indicates cirrus clouds? | 1 | 4 | 5 | 7 |
In illustration D039NG below, what type of cloud is indicated by the number one? | Cirrus | Altocumulus | Altostratus | Nimbostratus |
Fog forms when the air __________. | is 50% water saturated | temperature is greater than the dew point temperature | temperature is equal to, or below the dew point temperature | is 90% water saturated |
What will act to dissipate fog? | Rain that is warmer than air | Downslope motion of an air mass along a coast | Advection of warm air over a colder surface | Upwelling cold water |
Fog is formed when __________. | the moisture in the air is condensed into small droplets | air is cooled to its dew point | the base of a cloud is on the ground | All of the above. |
Radiation fog __________. | is thinnest at the surface | dissipates during the evening | is formed by a temperature inversion | always forms over water |
Fog forms when the air temperature is at or below __________. | the dry bulb temperature | 32° F | the dew point | the wet bulb temperature |
While on watch, you notice that the air temperature is dropping and is approaching the dew point. Which type of weather should be forecasted? | Sleet | Hail | Fog | Heavy rain |
When compared to air temperature, which factor is most useful in predicting fog? | Barometric pressure | Absolute humidity | Dew point | Vapor pressure |
The type of fog that occurs on clear nights with very light breezes and forms when the earth cools rapidly ? | frontal fog | advection fog | radiation fog | convection fog |
As the temperature of the air reaches the dew point, __________. | fog may form | rain must develop | water freezes | it begins to snow |
Fog is likely to occur when there is little difference between the dew point and the __________. | relative humidity | barometric pressure | air temperature | absolute humidity |
Fog generally clears when the __________. | temperature increases | wind direction changes | wind speed increases | All of the above. |
Steam smoke will occur when __________. | warm dry air from shore passes over cooler water | extremely cold air from shore passes over warmer water | cool rain passes through a warm air mass | cold ocean water evaporates into warm air |
Which condition would most likely result in fog? | Airborne dust particles | Dew point falling below the air temperature | Warm moist air blowing over cold water | Warm moist air blowing over warm water |
When warm moist air blows over a colder surface and is cooled below its dew point, the result is __________. | radiation fog | frost smoke | advection fog | ice fog |
Fog is most commonly associated with a(n) __________. | anticyclone | warm front at night | low pressure area | cold front in the spring |
The fog most commonly encountered at sea is called __________. | radiation fog | conduction fog | advection fog | frontal fog |
The fog produced by warm moist air passing over a cold surface is called __________. | conduction fog | advection fog | frontal fog | radiation fog |
Advection fog is most commonly caused by __________. | a rapid cooling of the air near the surface of the Earth at night | warm moist air being blown over a colder surface | saturation of cold air by rain | air being warmed above the dew point |
How is an occluded front represented on a weather map? | dashed blue line | blue line | alternate red and blue line | purple line |
Your vessel is enroute from Japan to Seattle and is located at position I on the weather map in illustration D013NG below. You should experience which weather condition? | Clear skies with warm temperatures | Steady precipitation | Overcast skies with rising temperature | Thundershowers |
In the Northern Hemisphere, an observer at point II in illustration D014NG below, should experience a wind shift from what direction? | southwest, clockwise to northwest | northeast, counterclockwise to northwest | northeast, clockwise to west-southwest | east, counterclockwise to south-southwest |
When cold air displaces warm air you have a(n) __________. | warm front | stationary front | occluded front | cold front |
On a working copy of a weather map, a cold front is represented by what color line? | Purple | Alternating red and blue | Red | Blue |
What type of clouds are associated with a cold front? | Altostratus and fracto-cumulus | Cumulus and cumulonimbus | Cirrus and cirrostratus | Altostratus and cirrus |
On a working copy of a weather map what color is the line that represents a stationary front? | Red | Blue | Purple | Alternating red and blue |
What weather change accompanies the passage of a cold front in the Northern Hemisphere? | Wind shift from northeast clockwise to southwest | A line of cumulonimbus clouds | Steady precipitation, gradually increasing in intensity | Steady dropping of barometric pressure |
A cold front moving in from the northwest can produce __________. | lengthy wet weather | increasing cloud cover lasting for several days | low ceilings with thick cirrus clouds | thunderstorms, hail, and then rapid clearing |
On a working copy of a weather map what color is the line that represents a warm front? | Alternating red and blue | Red | Purple | Blue |
A line of clouds, sharp changes in wind direction, and squalls are most frequently associated with a(n) __________. | warm
sector |
cold
front o |
warm
front o |
occluded front |
Which type of frontal passage is associated with a relatively narrow band of precipitation? | A cold front | A warm front | A stationary front | None of the above |
Which weather change accompanies the passage of a cold front in the Northern Hemisphere? | A line of cumulonimbus clouds | Wind shift from northeast, clockwise to southwest | Steady precipitation, gradually increasing in intensity | Steady dropping of barometric pressure |
The steepness of a cold front depends on __________. | the
precipitation generated by the front |
its
velocity |
the
direction of wind around the front |
the temperature of the air behind the front |
Which of the following represents the slope of a warm front? | 1 mile vertically to 150 miles horizontally | 1 mile vertically to 500 miles horizontally | 1 mile vertically to 10 miles horizontally | 1 mile vertically to 50 miles horizontally |
Which condition will occur after a cold front passes? | Pressure decreases | Temperature rises | Humidity decreases | Stratus clouds form |
Which of the following typically happens to the barometric pressure after a cold front passes? | fluctuates | remains the same, with clouds forming rapidly | remains the same | rises, often quite rapidly, with clearing skies |
Which of the following statements concerning frontal movements is TRUE? | A warm front usually has more violent weather associated with it than a cold front. | A cold front generally passes faster than a warm front. | The temperature rises after a cold front passes. | The barometric pressure rises when a warm front passes. |
Which statement is TRUE when comparing cold and warm fronts? | Cold fronts are milder and last longer. | They are very similar with the exception of wind direction. | Warm fronts are more violent and of longer duration. | Cold fronts are more violent and of shorter duration. |
Your facsimile prognostic chart indicates that you will cross the cold front of a low pressure system in about 24 hours. You should __________. | prepare for gusty winds, thunderstorms, and a sudden wind shift | expect to see cirrus clouds followed by altostratus and nimbostratus clouds | alter course to remain in the navigable semicircle | expect clear weather, with steady winds and pressure, until the front passes |
When crossing a front how do isobars tend to change? | change from sharp bends within the air mass to smooth curves at the front | change from smooth curves within the air mass to sharp bends at the front | pass smoothly across the front with no change | become closer together at the front and pass through in straight lines |
A series of brief showers accompanied by strong, shifting winds may occur along or some distance ahead of a(n) __________. | cold front | upper front aloft | cyclone | occluded front |
What happens to the barometric pressure after a cold front passes? | drops, and the temperature rises | drops, and the temperature drops | rises, and the temperature drops | rises, and the temperature rises |
How does the temperature change with the passage of an occluded front? | remains about the same | drops rapidly | depends on whether warm type or cold type occlusion | rises rapidly |
As a cold front passes how do the pressure and the winds change? | pressure drops and winds become gusty | pressure drops and winds become variable | pressure rises and winds become gusty | pressure rises and winds become variable |
Which of the following causes the development of an occluded front? | high pressure area | cold front overtaking a warm front | low pressure area | area of calm air |
Which type of front forms when a cold front overtakes and forces a warm front upwards? | A warm front | A stationary front | A cold front | An occluded front |
In the Northern Hemisphere, gusty winds shifting clockwise, a rapid drop in temperature, thunderstorms or rain squalls in summer (frequent rain/snow squalls in winter) then a rise in pressure followed by clearing skies, indicate the passage of a(n) __________. | cold front | warm front | anticyclone | tropical cyclone |
Brief, violent showers frequently accompanied by thunder and lightning are usually associated with __________. | winds shifting counterclockwise in the Northern Hemisphere | passage of a warm front | stationary high pressure systems | passage of a cold front |
When does a weather front exist? | when two lows are separated by a ridge of higher pressure | when air masses of different temperatures meet | when multiple clouds create a differential in air density | when air masses of the same temperature meet |
In the Northern Hemisphere, what do winds veering sharply to the west or northwest with increasing speed indicate? | stationary front exists | high pressure center has passed | cold front has passed | low pressure center is approaching |
You can expect frontal activity when two air masses collide and __________.
|
there
are significant differences between the temperature of each air mass
|
there
are differences in how they track along the jet stream |
their
barometric pressures and temperatures are the same |
there are no significant differences between their temperatures and moisture content |
Cumulonimbus clouds are most likely to accompany a(n) __________. | high pressure system | cold front | warm front | occluded front |
When a cold air mass and a warm air mass meet, and there is no horizontal motion of either air mass, it is called a(n) __________. | cold front | stationary front | occluded front | warm front |
When a warm air mass is adjacent to a cold air mass, the separation line between the two is called a(n) __________. | front | equipotential line | isotherm | isobar |
How does visibility change after the passage of a cold front? | visibility will improve rapidly | visibility will slightly improve | visibility does not change | visibility becomes poor |
When a warm air mass overtakes and replaces a cold air mass, the contact surface is called a(n) __________. | warm front | occluded front | cold front | line squall |
What is true about a front? | A front is a boundary between two air masses. | There are abrupt temperature differences on opposite sides of a front. | The pressure tendencies are different on opposite sides of a front. | All of the above. |
Which of the following is a boundary between two air masses? | isobar | front | continent | lapse rate |
When a warm air mass overtakes a cold air mass, the contact surface is called a __________. | line squall | warm front | water spout | cold front |
As it approaches, a typical warm front will bring __________. | rising temperatures and falling barometric pressure | rising barometric pressure and temperatures | falling temperature and pressure | falling temperatures and rising pressure |
Which of the following causes a frontal thunderstorm? | a warm air mass rising over a cold air mass | pronounced local heating | wind being pushed up a mountain | an increased lapse rate caused by advection of warm surface air |
Squall lines with an almost unbroken line of threatening dark clouds and sharp changes in wind direction, generally precede a(n) __________. | stationary front | fast-moving cold front | slow-moving warm front | occluded front |
A cloud sequence of cirrus, cirrostratus, and altostratus clouds followed by rain usually signifies the approach of a(n) __________. | stationary front | cold front | warm front | occluded front |
Which is a characteristic of the weather preceding an approaching warm front? | Clearing skies | Steadily falling barometric pressure | Gusty winds | Decreasing relative humidity |
As a warm front approaches how does barometric pressure change? | pressure is steady | pressure falls | pressure is uncertain | pressure rises |
The first indications a mariner will have of the approach of a warm front will be __________. | low dark clouds accompanied by intermittent rain | large cumulonimbus (thunderclouds) building up | fog caused by the warm air passing over the cooler water | high cirrus clouds gradually changing to cirrostratus and then to altostratus |
What is typical of warm front weather conditions? | A wind shift from southwest to northwest | Scattered cumulus clouds | An increase in pressure | Steady precipitation |
The first indications a mariner will have of the approach of a warm front will be __________. | high clouds gradually followed by lower thicker clouds | fog caused by the warm air passing over the cooler water | large cumulonimbus clouds building up | low dark clouds with intermittent rain |
Steady precipitation is typical of __________. | high pressure conditions | coming cold weather conditions | a warm front weather condition | scattered cumulus clouds |
Which of the symbols shown in illustration D018NG below represents a warm front? | A | B | C | D |
Which of the symbols shown in illustration D018NG below represents an occluded front? | A | B | C | D |
If you count 20 seconds between seeing lightning and hearing the thunder, how far is the storm away from you? | 2 miles | 4 miles | 6 miles | 8 miles |
Despite weather predictions for continued good weather, a prudent mariner should be alert for all of the following, EXCEPT a sudden __________. | wind shift | drop in temperature | squall line | drop in barometric pressure |
You are enroute from Puerto Rico to New York. A hurricane makes up and is approaching. If the wind veers steadily, this indicates that your vessel is __________. | in the dangerous semicircle | directly in the path of the storm | in the navigable semicircle | in the storm center |
If it is impossible to avoid a hurricane in the Northern Hemisphere, the most favorable place to be when the storm passes is in __________. | that half of the storm lying to the right of the storm's path | that half of the storm lying to the left of the storm's path | the eye (center) of the storm | the dangerous semicircle |
The dangerous semicircle of a typhoon in the Southern Hemisphere is that area __________. | to the left of the storm's track | measured from due south clockwise 180° | measured from due south counterclockwise 180° | ahead of the typhoon measured from the storm's track to 90° on each side |
The dangerous semicircle of a hurricane in the Northern Hemisphere is that area of the storm __________. | to the right of the storm's track | between the ship's heading and the bearing to the eye | measured from true north counterclockwise to 180°T | measured from true north clockwise to 180°T |
The navigable semicircle of a hurricane in the Northern Hemisphere is that area of the storm measured __________. | from true north clockwise to 180°T | from the direction of the storm's movement counterclockwise 180° | from the bow counterclockwise to 180° relative | from true north counterclockwise to 180°T |
In a tropical cyclone in the Northern Hemisphere, a vessel hove to with the wind shifting counterclockwise would be __________. | in the navigable semicircle | in the dangerous semicircle | ahead of the storm | directly in the path of the center |
You are attempting to locate your position relative to a hurricane in the Northern Hemisphere. If the wind direction remains steady, but with diminishing velocity, you are most likely __________. | in the right semicircle | in the left semicircle | on the storm track behind the center | on the storm track ahead of the center |
In a tropical cyclone in the Northern Hemisphere, a vessel hove to with the wind shifting counterclockwise would be __________. | ahead of the storm center | in the navigable semicircle | in the dangerous semicircle | directly in the approach path of the storm |
That half of the hurricane to the right hand side of its track (as you face
the same direction that the storm is moving) in the Northern Hemisphere
is called the __________. |
dangerous
semicircle |
windward
side |
leeward
side |
safe semicircle |
Where is the dangerous semicircle located on a hurricane in the Southern Hemisphere? | On the south side | To the left of the storm's track | To the right of the storm's track | In the high pressure area |
The navigable semicircle of a tropical storm in the South Indian Ocean is located on which side of the storm's track? | Rear | Right | Front | Left |
The navigable semicircle of a typhoon in the Southern Hemisphere is the area __________. | ahead of the typhoon, measured from the storm's track to 90° on each side | to the right of the storm's track | measured from due south, counterclockwise 180° | behind the typhoon, measured from 90° to 180°From each side of the storm's track |
The approximate distance to a storm center can be determined by noting the hourly rate of fall of the barometer. If the rate of fall is 0.08 - 0.12 inches, what is the approximate distance to the storm center? | 50 to 80 miles | 80 to 100 miles | 100 to 150 miles | 150 to 250 miles |
You have determined that you are in the right semicircle of a tropical cyclone in the Northern Hemisphere. What action should you take to avoid the storm? | Place the wind on the starboard bow and hold that course. | Place the wind on the starboard quarter and hold that course. | Place the wind on the port bow and hold that course. | Place the wind on the port quarter and hold that course. |
Which condition indicates that you are in a hurricane's dangerous semicircle in the Northern hemisphere? | A norther | A veering wind | A backing wind | A strong, gusty wind |
The left half of the storm is called the navigable semicircle because __________. | the wind tends to blow vessels away from the storms track | the wind speed is decreased by the storm's forward motion | Both A and B | Neither A nor B |
In the Northern hemisphere which semicircle of a hurricane is the navigable
semicircle? |
Left
|
Back
|
Front
|
Right |
In the Northern Hemisphere, if your vessel is in a hurricane's navigable semicircle it should be positioned with the wind on the __________. | starboard bow and heave to until the hurricane has passed | port quarter, maintain course and make as much speed as possible | starboard quarter, hold course and make as much speed as possible | port bow, hold course and make as much speed as possible until the hurricane has passed |
Which condition suggests that your present position lies in the navigable semicircle of a tropical storm? | A strong wind that maintains a constant speed and direction | A veering wind | A backing wind | Sustained gale force winds |
In the Northern Hemisphere, your vessel is believed to be in the direct path of a hurricane, and plenty of sea room is available. The best course of action is to bring the wind on the __________. | starboard quarter, note the course, and head in that direction | port quarter, note the course, and head in that direction | starboard bow, note the course, and head in that direction | port bow, note the course, and head in that direction |
If you are caught in the left semicircle of a tropical storm, in the Southern Hemisphere, you should bring the wind __________. | dead ahead and heave to | 2 points on the port quarter, and make as much way as possible | on the starboard quarter, hold course and make as much way as possible | on the port bow, and make as much way as possible |
In the Northern Hemisphere you are caught in the dangerous semicircle of a storm with plenty of sea room available. The best course of action is to bring the wind on the __________. | port quarter and make as much headway as possible | port bow and make as much headway as possible | starboard bow and make as much headway as possible | starboard quarter and make as much headway as possible |
The edge of a hurricane has overtaken your vessel in the Gulf of Mexico, and the northwest wind of a few hours ago has shifted to the west. This is an indication that you are located in the __________. | navigable semicircle | dangerous semicircle | eye of the storm | low pressure area |
When your vessel is on or near the path of an approaching tropical storm the __________. | barometer falls | wind direction remains steady | wind speed increases | All of the above. |
Which statement is FALSE concerning the dangerous semicircle of a hurricane? | The rain is heavier | The seas are higher | The actual wind speed is increased by the forward movement of the storm along its track | the direction of the wind and the sea might carry a vessel directly into the storm's path |
You can determine if your vessel's position is in the dangerous or navigable semicircle of a hurricane by __________. | observing whether the wind is veering or backing | plotting two or more recent storm positions from weather bulletins | Both A and B | Neither A nor B |
In the Northern Hemisphere, the right half of the storm is known as the dangerous semicircle because __________. | the seas are higher because of greater wind speed | The wind speed is greater here since the wind is traveling in the same general direction as the storm's track | the direction of the wind and seas might carry a vessel into the path of the storm | All of the above. |
When navigating coastwise and hurricane warnings are received, you should __________. | have battened down and be heading for the nearest port of refuge | call the NWS for further information | just begin to react and make plans | call the Coast Guard to request further information |
The safest and most prudent procedure to follow while navigating in the vicinity of a tropical cyclone is to __________. | continue to navigate farther from the coast | take positive steps to avoid it if possible | batten down and prepare to ride out the storm | always navigate towards the coast by the most direct route |
When your vessel is on the storm track but behind the storm's center the __________. | wind speed decreases | barometer rises | wind direction remains steady | All of the above. |
If a hurricane several hundred miles away is moving in your general direction your barometer would __________. | remain steady | start to fall gradually | start to rise rapidly | rise slowly, begin "pumping" and then start a slow, steady fall |
The National Weather Service differentiates between small craft, gale, whole gale, and hurricane warnings by the __________. | wave heights forecasted | amount of rain forecasted | amount of cloud cover forecasted | wind speed forecasted |
When a hurricane passes over colder water or land and loses its tropical characteristics, the storm becomes a(n) __________. | tropical storm | extratropical low-pressure system | easterly wave | high pressure area |
The first cloud formations you can use to indicate the bearing of the center of a hurricane or tropical storm are __________. | the darkest point of the clouds in the "bar" of the storm | the direction of movement of thunderstorms on radar | the point of origin of the altostratus clouds | the point of convergence of the cirrus clouds |
When a tornado moves over the water from land it is called a __________. | waterspout | cyclone | hurricane | tornado |
A hurricane moving northeast out of the Gulf passes west of your position. You could expect all of the following EXCEPT __________. | gradual pressure gradient | high winds | winds veering from south, through west, to northwest | higher than normal swells |
What is the direction of rotation of tropical cyclones, tropical storms and hurricanes in the Northern Hemisphere? | Counterclockwise and outward | Counterclockwise and inward | Clockwise and inward | Clockwise and outward |
The usual sequence of directions in which a tropical cyclone moves in the Southern Hemisphere is __________. | southwest, south, and southeast | northwest, west, and south | west, northwest, and north | north, northwest, and east |
Which condition exists in the eye of a hurricane? | Wind rapidly changing direction | An extremely low barometric pressure | A temperature much lower than that outside the eye | Towering cumulonimbus clouds |
In the relatively calm area near the hurricane center, the seas are __________. | moderate but easily navigated | mountainous and confused | calm | mountainous but fairly regular as far as direction is concerned |
The dense black cumulonimbus clouds surrounding the eye of a hurricane are called __________. | funnel clouds | cloud walls | cyclonic spirals | spiral rainbands |
The strongest winds and heaviest rains in a hurricane are found in the __________.
|
cloud
walls |
eye
|
outer
bands |
spiral rainbands |
Which kind of conditions would you observe as the eye of a storm passes over your vessel's position? | Flat calm seas, heavy rain, light winds, and high pressure | Huge waves approaching from all directions, clearing skies, light winds, and high pressure | Flat calm seas, heavy rain, light winds, and an extremely low barometer | Huge waves approaching from all directions, clearing skies, light winds, and an extremely low barometer |
The eye of a hurricane is surrounded by dense black cumulonimbus clouds which are called the __________. | nimbostratus cloud | bar | wall cloud | funnel |
A vessel entering the eye of a hurricane should expect __________. | the barometer to reach the lowest point | moderating winds and heavy confused seas to strike his vessel from all directions | the winds to increase to hurricane force and strike from a different direction as the eye passes | All of the above. |
Tropical cyclones normally form within which of the following belts of latitude? | 45° to 60° | 30° to 45° | 5° to 15° | 15° to 30° |
Tropical cyclones do not form within 5° of the Equator because __________.
|
of
negligible Coriolis force |
it
is too hot |
it
is too humid |
there are no fronts in that area |
Severe tropical cyclones (hurricanes, typhoons) occur in all warm-water oceans except the __________. | South Atlantic Ocean | North Pacific Ocean | South Pacific Ocean | Indian Ocean |
Tropical cyclones are classified by form and intensity. Which system does not have closed isobars? | Tropical depression | Hurricane | Tropical disturbance | Cyclone |
What classification of tropical cyclone would have closed isobars, counter clockwise rotary circulation, and sustained winds between 34 and 63 knots? | A tropical depression | A tropical storm | A tropical disturbance | A hurricane |
What level of development of a tropical cyclone has a hundred mile radius of circulation, gale force winds, less than 990 millibars of pressure and vertically formed cumulonimbus clouds? | A tropical depression | A typhoon | A tropical storm | A tropical disturbance |
Which condition would NOT indicate the approach of a tropical storm? | Long, high swells | Decrease in wind velocity | Halos about the Sun or Moon | Cirrus clouds |
Early indications of the approach of a hurricane may be all of the following EXCEPT __________. | continuous fine mist-like rain | pumping barometer | short confused swells | gradually increasing white clouds (mare's tails) |
What indicates the arrival of a hurricane within 24 to 36 hours? |
The
barometer drops 2 millibars between 1000 and 1600 |
The
normal swell becoming lower and from a steady direction |
Unusually good weather with above average pressures followed by a slow fall of 4 millibars in six hours | Long bands of nimbostratus clouds radiating from a point over the horizon |
What is the FIRST sign of the existence of a well developed tropical cyclone? | Steep, short-period waves and light wind | An unusually long ocean swell | Thunderstorms and higher than usual humidity | Gale force winds from the north |
Which change in the condition of the seas could indicate the formation of a tropical storm or hurricane several hundred miles from your location? | A lengthy lull in the wind and seas | A brisk chop from the southeast | A long swell from an unusual direction | Large seas coming from different directions |
In the Northern Hemisphere, the largest waves or swells created by a typhoon or hurricane will be located __________. | in the southeast quadrant of the storm | directly behind the storm center | behind and to the left of its course | forward and to the right of its course |
What indicates that a tropical cyclone may be within 500 to 1,000 miles of your position? | A pumping of the barometer up and down a few millibars | The normal swell pattern becoming confused, with the length of the swell increasing | An overcast sky with steadily increasing rain from nimbostratus clouds | A sudden wind shift from southwest to northwest followed by steadily increasing winds |
What kind of pressure systems travel in tropical waves? | Low pressure | Terrastatic pressure | Subsurface pressure | High pressure |
Low pressure disturbances, which travel along the intertropical convergence zone, are called __________. | tropical storms | tidal waves | tropical waves | permanent waves |
A easterly wave is located 200 miles due west of your position, which is north of the equator. Where will the wave be in 24 hours? | In the same place | Closer and to the west | Farther away to the west | Farther away to the east |
You are in the Northern Hemisphere and a tropical wave is located 200 miles due west of your position. Where will the wave be located 24 hours later? | In the same place | Closer and to the east | Farther away to the west | Closer and to the west |
You are in the Northern Hemisphere and a tropical wave is located 200 miles due east of your position. Where will the wave be located 12 hours later? | Nearby to the east | Farther away to the east | Farther away to the west | In the same position |
What kind of weather would you expect to accompany the passage of a tropical wave? | Good weather | Heavy rain and cloudiness | Dense fog | A tropical storm |
In the Northern Hemisphere, what type of cloud formations would you expect to see to the west of an approaching tropical wave? | Cirrostratus clouds lined up in rows extending in a north to south direction | High altostratus clouds in the morning hours | Cumulus clouds lined up in rows extending in a northeast to southwest direction | Cirrostratus clouds lined up in rows extending in a northeast to southwest direction |
A tropical wave is usually preceded by __________. | heavy seas | good weather | heavy rain and cloudiness | tropical storms |
Ocean swells originating from a typhoon can move ahead of it at speeds near __________. | 10 knots | 20 knots | 30 knots | 50 knots |
What is the first visible indication of the presence of a tropical cyclone or hurricane? | An exceptionally long swell | Stratocumulus clouds or strange birds | Dark clouds and the "bar" of the storm | Rain and increasing winds |
Your present weather is sunny with a steady barometer. A low swell approaches your vessel from the south with crests passing at relatively long periods of about four per minute. This usually indicates __________. | a tropical cyclone south of your vessel | a hurricane about 100 miles south of your vessel and heading in your direction | a warm front from the south | an extra-tropical cyclone |
The highest frequency of tropical cyclones in the North Atlantic Ocean occurs during __________. | July, November and December | January, February and March | August, September and October | April, May and June |
When is the peak of the hurricane season in the western North Pacific? | July through October | November through December | January through March | April through June |
Tropical storms and hurricanes are most likely to form in the Southern hemisphere during __________. | April through May | January through March | June through August | September through November |
The hurricane season in the North Atlantic Ocean reaches its peak during the month of __________. | November | June | July | September |
Hurricanes may move in any direction. However, it is rare and generally of short duration when a hurricane in the Northern Hemisphere moves toward the __________. | northeast | north | west or northwest | southeast |
The intensity of a hurricane as it reaches higher latitudes and cooler waters __________. | decreases | remains the same | Increases | None of the above |
Recurvature of a hurricane's track usually results in the forward speed __________. | increasing | remaining the same | varying during the day | decreasing |
What is the average speed of movement of a hurricane prior to recurvature? | 4 to 6 knots | 6 to 8 knots | 10 to 12 knots | 15 to 20 knots |
What is the average speed of the movement of a hurricane following the recurvature of its track? | Over 60 knots | 40 to 50 knots | 5 to 10 knots | 20 to 30 knots |
The wind velocity is higher in the dangerous semicircle of a tropical cyclone because of the __________. | direction of circulation and pressure gradient | recurvature effect | wind circulation and forward motion of the storm | extension of the low pressure ridge |
How can you estimate the position of a tropical storm's center? | With a radio weather bulletin or weather fax | using shipboard radar | observe the wind direction and apply Buys Ballot's law | All of the above. |
A storm's track is characterized by all of the following except __________. | the direction the storm has come from | the path taken by the storm | the speed at which the storm is moving | the direction in which the storm is moving |
Cyclones tend to move __________. | parallel to the isobars in their warm sectors | parallel to the line of the cold front | perpendicular to the isobars in their warm sectors | perpendicular to the line of the cold front |
In a cyclone the lowest pressure is found in the __________. | center | warm front | outer edge | cold front |
You are underway on course 050°T and your maximum speed is 13 knots. The eye of a hurricane bears 120°T, 100 miles from your position. The hurricane is moving towards 265°T at 25 knots. What course should you steer at 13 knots to have the maximum CPA? | 306°T | 276°T | 324°T | 299°T |
You are underway on course 050°T and your maximum speed is 10 knots. The
eye of a hurricane bears 100°T, 90 miles from your position. The hurricane
is moving towards 285°T at 19 knots. If you maneuver at 10 knots to avoid
the hurricane, what could be the maximum CPA? |
39
miles |
45
miles |
53 miles | 59 miles |
You are underway on course 050°T and your maximum speed is 12 knots. The eye of a hurricane bears 080°T, 100 miles from your position. The hurricane is moving towards 265°T at 22 knots. What course should you steer at 12 knots to have the maximum CPA? | 219° | 190° | 199° | 208° |
You are underway on course 050°T and your maximum speed is 13 knots. The eye of a hurricane bears 100°T, 120 miles from your position. The hurricane is moving towards 275°T at 25 knots. If you maneuver at 13 knots to avoid the hurricane, what could be the maximum CPA? | 78 miles | 83 miles | 72 miles | 89 miles |
You are underway on course 050°T and your maximum speed is 13 knots. The eye of a hurricane bears 100°T, 120 miles from your position. The hurricane is moving towards 275°T at 25 knots. What course should you steer at 13 knots to have the maximum CPA? | 326° | 320° | 339° | 333° |
You are underway on course 050°T and your maximum speed is 10 knots. The eye of a hurricane bears 100°T, 90 miles from your position. The hurricane is moving towards 285°T at 19 knots. Which course should you steer at 10 knots to have the maximum CPA? | 221° | 226° | 233° | 238° |
You are underway on course 120°T and can make 12 knots. The eye of a hurricane bears 150°T at 120 miles. The hurricane is on course 295° at 20 knots. What course should you steer at 12 knots to have the maximum CPA? | 348° | 312° | 001° | 330° |
You are underway on course 120°T and your maximum speed is 12 knots. The eye of a hurricane bears 150°T, 120 miles from your position. The hurricane is moving towards 295°T at 20 knots. If you maneuver at 12 knots to avoid the hurricane, what could be the maximum CPA? | 89 miles | 96 miles | 105 miles | 117 miles |
You are underway on course 050°T and your maximum speed is 11 knots. The eye of a hurricane bears 070°T, 80 miles from your position. The hurricane is moving towards 270°T at 19 knots. What course should you steer at 11 knots to have the maximum CPA? | 250° | 227° | 234° | 215° |
You are underway on course 050°T and your maximum speed is 11 knots. The eye of a hurricane bears 070°T, 80 miles from your position. The hurricane is moving towards 270°T at 19 knots. If you maneuver at 11 knots to avoid the hurricane, what could be the maximum CPA? | 66 miles | 79 miles | 74 miles | 84 miles |
You are underway on course 050°T and your maximum speed is 12 knots. The eye of a hurricane bears 120°T, 110 miles from your position. The hurricane is moving towards 285°T at 25 knots. What course should you steer at 12 knots to have the maximum CPA? | 332° | 339° | 346° | 357° |
You are underway on course 050°T and your maximum speed is 12 knots. The eye of a hurricane bears 120°T, 110 miles from your position. The hurricane is moving towards 285°T at 25 knots. If you maneuver at 12 knots to avoid the hurricane, what could be the maximum CPA? | 77 miles | 82 miles | 87 miles | 93 miles |
You are underway on course 050°T and your maximum speed is 12 knots. The eye of a hurricane bears 080°T, 100 miles from your position. The hurricane is moving towards 265°T at 22 knots. If you maneuver at 12 knots to avoid the hurricane, what could be the maximum CPA? | 56 miles | 76 miles | 63 miles | 69 miles |
Mechanical lifting of air by the upslope slant of the terrain is called __________. | vertical lifting | convective lifting | topographic lifting | advective lifting |
The region containing 3/4 of the mass of the atmosphere and the region to which are confined such phenomena as clouds, storms, precipitation and changing weather conditions is called __________. | stratopause | stratosphere | tropopause | troposphere |
The Earth's irregular heating is caused by __________. |
the
time of day |
the
seasons |
geography
|
All of the above. |
What is the primary source of the earth's weather? | The oceans | The moon | The solar system | The sun |
The climate of the northern Gulf coast __________. |
varies
from warm to subtropical |
is
humid and subtropical throughout the year |
is a warm marine type of climate | has an east coast marine type of climate |
The climate of the eastern Gulf coast __________. |
varies
from warm to subtropical |
has
a Mediterranean type of climate |
has
an east coast marine type of climate |
is humid and subtropical throughout the year |
Weather patterns in the Gulf area of the United States are __________. | tropical over Florida and subtropical over the rest of the Gulf Coast area | extremely hot in summer | those of a tropical region | those of a transition zone between tropical and a temperate area |
What natural feature is responsible for the rather even climate found on the Florida peninsula throughout the year? | The cool waters of the Sargasso sea | The Gulf Stream | Strong masses of continental air | The Bermuda high |
Which meteorological feature controls the climate of the Gulf and the Gulf Coast area during late spring and summer? | Tropical cyclones | The Bermuda High | The horse latitudes | The doldrums |
A type of precipitation that occurs only in thunderstorms with strong convection currents that convey raindrops above and below the freezing level is known as __________. | freezing
rain |
sleet | hail |
rime |
A light, feathery deposit of ice caused by the sublimation of water vapor directly into the crystalline form, on objects whose temperatures are below freezing, is called __________. | snow | dew | glaze | frost |
Which type of precipitation is a product of the violent convection found in thunderstorms? | Hail | Freezing Rain | Sleet | Snow |
Which of the following is NOT a form of precipitation? | sleet | snow | rain | frost |
Which condition(s) is(are) necessary for the formation of dew? | Earth's surface cooler than the dew point of the air | Clear skies | Calm air | All of the above. |
A slow, gradual fall of the barometer indicates approaching __________. | deteriorating or unsettled weather | blizzard conditions | heavy, wind driven rain | gale force winds within 12 hours |
In the Northern Hemisphere, when the center of a high pressure system is due east of your position, you can expect winds from the __________. | north to west | south to west | south to east | north to east |
A millibar is a unit of __________. | precipitation | pressure | temperature | humidity |
A rapid rise or fall of the barometer indicates __________. | a change in the present weather conditions | a decrease in wind velocity | heavy rain within six hours | that fog will soon set in |
When a high pressure system is centered north of your vessel in the Northern Hemisphere __________. | the winds should be from the southwest at your location | the winds should be brisk | the wind direction is generally easterly | you should experience hot, moist, clear weather |
A slow rise in the barometric pressure forecasts __________. |
rainy
weather for the next 48 hours |
high
seas |
improving
weather conditions |
deteriorating weather conditions |
Atmospheric pressure may be measured with a(n) __________. | 29.92 inches of mercury | 14.7 pounds per square inch | 1013.25 millibars | All of the above. |
The flow of air around an anticyclone in the Southern Hemisphere is __________. | clockwise and outward | clockwise and inward | counterclockwise and outward | counterclockwise and inward |
Anticyclones are usually characterized by __________. | overcast skies | gustiness and continuous precipitation | dry, fair weather | high winds and cloudiness |
The standard atmospheric pressure in millibars is __________. | 760 | 938.9 | 1000 | 1013.2 |
If you observe a rapid fall of barometric pressure you should __________. | call the Coast Guard to verify the change | prepare for the onset of stormy weather with strong winds | contact the NWS or a local radio station | know the barometer is not working properly |
As a high pressure system approaches, the barometer reading __________. | stays the same | rises | falls rapidly | falls |
In the Southern Hemisphere winds in a low pressure system rotate in a __________. | northeasterly direction | clockwise direction | northerly direction | counterclockwise direction |
The standard atmospheric pressure measured in inches of mercury is __________. |
29.92 |
500.0 |
760.0 |
1013.2 |
A generally circular low pressure area is called a(n) __________. | anticyclone | occluded front | cold front | cyclone |
When observing a rapid rise in barometric pressure, you may expect __________. | clearing weather, possibly accompanied by high winds | heavy rain or severe thundershowers | deteriorating weather with rain or snow | clear weather with no wind, but the possibility of rain or snow within 24 hours |
What is a common unit of measure for atmospheric pressure? | Inches | centimeters | Degrees | Feet |
The wind direction around a low pressure area in the Northern Hemisphere is __________. | counterclockwise and outward | clockwise and outward | clockwise and inward | counterclockwise and inward |
In the Northern Hemisphere, an area of counterclockwise wind circulation surrounded by higher pressure is a __________. | high | warm front | low | cold front |
The pressure gradient between the horse latitudes and doldrums runs __________. | northeast to southwest | north to south | northwest to southeast | east to west |
When a low pressure area is approaching, the weather generally __________. | worsens | is unpredictable | improves | remains the same |
A barometer showing falling pressure indicates the approach of a __________. | high dew point | low dew point | high pressure system | low pressure system |
Stormy weather is usually associated with regions of __________. | changing barometric pressure | steady barometric pressure | low barometric pressure | high barometric pressure |
Pressure gradient is a measure of __________. | pressure difference over horizontal distance | a high-pressure area | pressure difference over time | vertical pressure variation |
The diurnal pressure variation is most noticeable in the __________. | polar regions | doldrums | roaring forties | horse latitudes |
Little or no change in the barometric reading over a twelve hour period indicates __________. | increasing wind strength | that present weather conditions will continue | stormy weather is imminent | a defect in the barometer |
The daily recurring pattern of pressure changes most noticeable in low latitudes is the __________. | pressure tendency | daily lapse reading | diurnal variation of pressure Center | synoptic pressure |
In low latitudes the range of the diurnal variation of pressure is up to __________. | 0.5 millibar | 3.0 millibars | 6.0 millibars | 10.0 millibars |
In low latitudes, the high(s) of the diurnal variation of pressure occur(s) at __________. | noon | 1000 and 2200 | noon and midnight | 1600 |
In low latitudes, the low(s) of the diurnal variation of pressure occur(s) at __________. | noon and midnight | noon | 1000 and 2200 | 0400 and 1600 |
The diurnal variation of pressure is most noticeable __________. | in a low pressure area | during periods of low temperatures | in the doldrums | above the polar circles |
The diurnal variation of pressure is not visible in the middle latitudes in winter because __________. | the increased Coriolis force disperses the pressure variation | it is masked by the pressure changes of moving weather systems | the decreased gravitational effect from the sun causes the variation to fade | the decreased average temperature is less than the critical temperature |
Generally speaking, in the Northern Hemisphere, when winds are blowing from between SE and SW the barometric reading __________. | is somewhat lower than it would be for winds from a northern quadrant | is uncertain and may fluctuate by increasing and decreasing | makes no change at all | is somewhat higher than it would be for winds from the northern quadrant |
A decrease in barometric pressure is associated with all of the following except __________. | clear dry weather | proximity to a low pressure area | inward spiraling circulation | rising warm air |
When your barometer reading changes from 30.25 to 30.05 in a 12-hour period it indicates __________. | rapidly changing weather | improving weather | high winds within the next six hours | little or no immediate change |
Two well-developed high pressure areas may be separated by a __________. | ridge of low pressure | hill of low pressure | valley of low pressure | trough of low pressure |
Generally speaking, you should expect to find low atmospheric pressure prevailing in the earth's __________. | mid-latitudes | equatorial area | polar regions | All of the above. |
Which general weather conditions should you expect to find in a low pressure system? | Fair weather | Scattered clouds at high elevations | Precipitation and cloudiness | Gradual clearing and cooler temperatures |
Two well-developed low pressure areas may be separated by a __________. | hill of higher pressure | valley of higher pressure | trough of higher pressure | ridge of higher pressure |
A cyclone in its final stage of development is called a(n) __________. | occluded cyclone or occluded front | tornado | polar cyclone | anticyclone |
The wind circulation around a high pressure center in the Northern Hemisphere is __________. | clockwise and moving outward from the high | counterclockwise and moving towards the high | counterclockwise and moving outward from the high | clockwise and moving towards the high |
Good weather is usually associated with a region of __________. |
falling
barometric pressure |
high
barometric pressure |
low
barometric pressure |
pumping barometric pressure |
Most high pressure areas in the United States are accompanied by __________. | cool fogs | humid, sticky weather | clear, cool weather | precipitation |
The atmosphere in the vicinity of a high pressure area is called a(n) __________. | occluded front | anticyclone | cold front | cyclone |
A phenomenon where the atmospheric pressure is higher than that of other surrounding regions is called __________. | the "doldrums" | a low front or an occluded front | a high pressure area; an anticyclone; or a "high" | the "trade winds" |
In the Southern Hemisphere the wind circulation in a high pressure system rotates __________. | counterclockwise and outward | counterclockwise and inward | clockwise and outward | clockwise and inward |
Compared to a low pressure system, generally the air in a high is __________. | extremely moist with high relative humidity | muggy and cloudy | cool, more dense, and drier | warmer, less dense, and less stable |
Which weather system produces strong cold winds called "Northers" during the winter months in the Gulf of Mexico? | A cyclone | An anticyclone | A high pressure system | Both A and B |
You are located within a stationary high pressure area. Your aneroid barometer is falling very slowly. This indicates a(n) __________. | wind shift of 180° | increase in the intensity of the system | decrease in the pressure of the system | large increase in wind velocity |
The dry-bulb temperature is 78°F and the wet-bulb temperature is 62°F. What
is the relative humidity? illustration D008DG |
16
(%) |
24
(%) |
39
(%) |
79 (%) |
The dry-bulb temperature is 78°F (26°C) and the wet-bulb temperature is 68°F (20°C). What is the relative humidity? illustration D008DG | 10 (%) | 24 (%) | 56 (%) | 60 (%) |
Relative humidity is the percentage of water vapor that is in the air as compared to the maximum amount it can hold at __________. | a specific temperature | a specific barometric pressure | a specific wind speed | any time |
The dew point is reached when the __________. | temperature of the air equals the temperature of the seawater | air becomes saturated with water vapor | atmospheric pressure is 14.7 lbs. per square inch | relative humidity reaches 50% |
The expression "the air is saturated" means __________. | cloud cover is 100% | the vapor pressure is at its minimum for the prevailing temperature | precipitation has commenced | the relative humidity is 100% |
The temperature at which the air is saturated with water vapor and below which condensation of water vapor will occur is referred to as the __________. | absolute humidity | precipitation point | dew point | vapor point |
The dew point temperature is __________. | always lower than the air temperature | equal to the difference between the wet and dry bulb temperatures | the temperature at which the air is saturated with water vapor | always higher than the air temperature |
As the temperature for a given mass of air increases, the __________. | relative humidity decreases | dew point increases | relative humidity increases | dew point decreases |
As the temperature of an air mass decreases, the __________. | dew point rises | absolute humidity decreases | specific humidity decreases | relative humidity increases |
Relative humidity is defined as __________. |
the
maximum vapor content the air is capable of holding |
the
ratio of the actual vapor content at the current temperature to the air's
vapor holding capability |
the
minimum vapor content the air is capable of holding |
the relation of the moisture content of the air to barometric pressure |
On the Mississippi and Ohio Rivers, there is a special type of fog known as steam fog. It is caused by __________. | a rapid cooling of the ground on a clear night | cold air passing over much warmer water | warm air passing over much colder water | rain coming out of a warm air mass aloft |
Steam fog is most likely to occur on the Mississippi and Ohio Rivers in __________. | fall, around midday | spring, around late evening | fall, around early morning | spring, around early evening |
While upbound through Memphis, the weather report on the TV news indicates that a cold front will cross western Kentucky and Tennessee the next morning. What weather should accompany this front? | Light, southerly winds; high humidity and possibly fog | Scattered clouds with light to moderate southeasterly winds and possibly fog | Overcast with steady, light rain or drizzle | Gusting winds shifting to the northwest with thunderstorms |
While passing through Memphis, the weather report on the TV news indicates that a cold front is crossing western Kentucky and Tennessee. Tomorrow's weather will be dominated by a high pressure area. What weather should you expect tomorrow? | Moderate winds from the northwest, clear visibility and cooler temperatures | Scattered clouds with light, southeasterly winds; high humidity and possibly fog | Light, southerly winds; high humidity and possibly fog | Low overcast; mild temperatures with light, steady rain or drizzle |
While upbound through Memphis, the weather report on TV news indicates that a warm front is stationary over the Kentucky - Missouri - Tennessee areas. What weather conditions should you expect? | Southerly winds with steady rain; fog or overcast | Strong, gusting winds from the NW with thundershowers | Light winds from the northeast with clear skies | A "blue norther" |
Wind direction may be determined by observing all of the following EXCEPT __________. | whitecaps | low clouds | swells | waves |
The best estimate of the wind direction at sea level can be obtained from observing the direction of the __________. | cloud movement | swells | waves | vessel heading |
While taking weather observations, you determine that the wind is blowing from the northeast. You would record the wind direction in the weather log as __________. | 045° | 090° | 135° | 225° |
When reporting wind direction, you should give the direction in __________. | isobaric degrees | relative degrees | true degrees | magnetic compass degrees |
When recording the wind direction in the weather log, you would report the __________. | wind chill factor | direction the wind is blowing toward | direction the wind is blowing from | duration of the maximum gust of wind |
Your ship is proceeding on course 320°T at a speed of 25 knots. The apparent wind is from 30° off the starboard bow, speed 32 knots. What is the relative direction, true direction and speed of the true wind? | Relative 80°, true 060°T, 15.2 knots | Relative 80°, true 040°T, 16.2 knots | Relative 40°, true 080°T, 16.4 knots | Relative 60°, true 040°T, 18.6 knots |
Your vessel is on course 270°T, speed 10 knots. The apparent wind is from 10° off the port bow, speed 30 knots. From which direction is the true wind? | 075°T | 345°T | 165°T | 255°T |
A ship is on course 195° at a speed of 15 knots. The apparent wind is from 40° on the port bow, speed 30 knots. The direction and speed of the true wind are __________. | 068°T, 30 knots | 127°T, 21 knots | 263°T, 42 knots | 292°T, 42 knots |
Your vessel is on course 150°T, speed 17 knots. The apparent wind is from 40° off the starboard bow, speed 15 knots. What is the speed of the true wind? | 9.0 knots | 10.2 knots | 11.0 knots | 12.0 knots |
Your vessel is on course 180°T speed 22 knots. The apparent wind is from 70° off the port bow, speed 20 knots. The true direction and speed of the wind are __________. | 45°T, 21.0 knots | 51°T, 24.0 knots | 58°T, 21.2 knots | 64°T, 26.0 knots |
Your vessel is participating in the Voluntary Observing Ship Program, at 1800 ZT on 31 October your position is LAT 24°50'N, LONG 92°37'W. You are preparing WS Form B-80 as seen in illustration D041NG below. How should you encode the first three groups after the call sign if you estimate the wind? | 31243, 99249, 70926 | 31123, 99929, 70249 | 01003, 99248, 70926 | 31183, 99249, 79237 |
Your vessel is participating in the Voluntary Observing Ship Program, at 0600 ZT on 31 January your position is LAT 00°49'S, LONG 84°27'E. You are preparing WS Form B-80 as seen in illustration D041NG below. How should you encode the first three groups after the call sign if you estimate the wind? | 30243, 90008, 30848 | 31003, 99049, 38427 | 31003, 99008, 30844 | 31063, 99049, 58427 |
Your vessel is participating in the Voluntary Observing Ship Program, you are preparing WS Form B-80 as seen in illustration D041NG below. The dry bulb thermometer reads 34°F and the wet bulb thermometer reads 31°F. How would you encode the air temperature groups in the report? | 10011, 2104/ | 10340, 2031/ | 10340, 2127/ | 10111, 2104/ |
Your vessel is participating in the Voluntary Observing Ship Program, you are preparing WS Form B-80 as seen in illustration D041NG below. The dry bulb thermometer reads 30°F (-1°C) and the wet bulb thermometer reads 28°F (-2°C). How would you encode the air temperature groups in the report? | 11300, 2124/ | 10011, 2003/ | 11011, 2104/ | 11011, 2124/ |
Your vessel is participating in the Voluntary Observing Ship Program, you are preparing WS Form B-80 as seen in illustration D041NG below. The dry bulb thermometer reads 78°F and the wet bulb thermometer reads 75°F. How would you encode the air temperature groups in the report? | 10256, 2074/ | 00256, 0023/ | 10256, 2023/ | 10780, 2074/ |
Your vessel is participating in the Voluntary Observing Ship Program, you are preparing WS Form B-80 as seen in illustration D041NG below. The dry bulb thermometer reads 54°F and the wet bulb thermometer reads 50°F. How would you encode the air temperature groups in the report? | 1054/, 2047/ | 1054/, 2050/ | 10122, 2008/ | 054//, 047// |
Your vessel is participating in the Voluntary Observing Ship Program, you are preparing WS Form B-80 as seen in illustration D041NG below. Your position is LAT 64°42'N, LONG 02°28'W. How would this be encoded? | 9064N, 9025W | 99647, 70025 | 0647N, 00025 | 90647, 90024 |
Your vessel is participating in the Voluntary Observing Ship Program, you are preparing WS Form B-80 as seen in illustration D041NG below. You are hove to in a hurricane on a heading of 328°T. The wind is from 030° true at 119 knots. How should this be encoded on the weather report form? | 83099 | 80399 | 83011 | 80312 |
Your vessel is participating in the Voluntary Observing Ship Program, at
1200 ZT on 31 July, your position is LAT 24°33'N, LONG 173°05'W. You are
preparing WS Form B-80 as seen in illustration D041NG below. How should
you encode the first three groups after the call sign if you estimate the
wind? |
31003,
92433, 71730 |
31243,
99245, 71731 |
01243,
92433, 71731 |
01003, 99245, 71731 |
Your vessel is participating in the Voluntary Observing Ship Program, at 1200 ZT on 31 August, your position is LAT 43°14'S, LONG 175°44'E. You are preparing WS Form B-80 as seen in illustration D041NG below. How should you encode the first three groups after the call sign if you estimate the wind? | 31003, 99432, 31757 | 01003, 94314, 51757 | 31243, 94314, 31757 | 31123, 99432, 31754 |
Your vessel is participating in the Voluntary Observing Ship Program, you are preparing WS Form B-80 as seen in illustration D041NG below. Twenty-five percent of the sky is covered with clouds, and the anemometer indicates that the apparent wind is from 062° relative at 13 knots. You are on course 238°T at 22 knots. How should you encode group Nddff? | 20220 | 20613 | 30219 | 32413 |
Your vessel is participating in the Voluntary Observing Ship Program, you are preparing WS Form B-80 as seen in illustration D041NG below. The sky is overcast, and the anemometer indicates that the apparent wind is from 144° relative at 8 knots. You are on course 162°T at 15 knots. How should you encode group Nddff? | 81408
|
91521 | 83322 | 01615 |
Your vessel is participating in the Voluntary Observing Ship Program, you are preparing WS Form B-80 as seen in illustration D041NG below. One-half of the sky is covered with clouds, and the anemometer indicates that the apparent wind is from 340° relative at 14 knots. You are on course 307°T at 12.6 knots. How should you encode group Nddff? | 43013 | 42205 | 53414 | 54013 |
Your vessel is participating in the Voluntary Observing Ship Program. You are preparing WS Form B-80 as seen in illustration D041NG below. Three-quarters of the sky is covered with clouds, and the anemometer indicates that the apparent wind is from 226° relative at 17.7 knots. You are on course 020°T at 8 knots. How should you encode group Nddff? | 80208 | 72218 | 62324 | 72318 |
Using the surface analysis in illustration D049NG below, what weather conditions would you expect to find at position A? | winds SW-S at 20 knots, heavy rain, and rough seas | Winds calm, light rain, and calm seas | Winds NW-W at 15 knots, partly cloudy, and slight seas | Winds NE-E at 20 knots, heavy rain, and rough seas |
Using the surface analysis in illustration D049NG below, what change in
the wind direction could be expected at position "D" if the low
were moving northeasterly? |
Backing
to the east |
Backing
to the north |
Veering
to the north |
Veering to the west |
Using the surface analysis in illustration D049NG below, what wind speed is reported in position C? | 3 knots | 10 knots | 20 knots | 30 knots |
Using the surface analysis in illustration D049NG below, which wind speeds are reported at position A? | 10 knots | 15 knots | 20 knots | 25 knots |
Above-normal tides near the center of a hurricane may be caused by the __________. | torrential rains | high barometric pressure | storm surge | jet stream |
A tsunami is caused by a(n) __________. | earthquake on the ocean's floor | tornado | tidal wave | storm surge caused by a hurricane or tropical storm |
If the current and wind are in opposite directions, the sea surface represents __________. | a greatly reduced wind speed | a higher wind speed than what really exists | a lower wind speed than what really exists | more turbulent winds |
If the current and wind are in the same direction, the sea surface represents a wind speed __________. | lower than actually exists | higher than actually exists | that has no proportional relationship | that actually exists |
You are anchored in the Aleutian Island chain and receive word that a tsunami is expected to strike the islands in six hours. What is the safest action? | Plant both anchors with about a 60° angle between them, and let out a long scope to each anchor. | Get underway and be in deep, open-ocean water when the tsunami arrives. | Increase the scope of the anchor cable and drop the second anchor underfoot at short stay. | Get underway and be close inshore on the side of the island away from the tsunami. |
What should you expect when you encounter a tsunami in the open ocean? | Violent seas from mixed directions | A major wave of extreme height and length | No noticeable change from the existing sea state | Winds increasing to gale force from the northwest in the Northern Hemisphere |
You are steaming in the open ocean of the North Pacific between the Aleutian Chain and Hawaii. A warning broadcast indicates that an earthquake has occurred in the Aleutians and has generated a tsunami that is predicted to hit Hawaii. What action is necessary for the ship's safety? | Securely stow all loose gear, check deck lashings, and prepare for extreme rolls. | Calculate the tsunami's ETA at your position and turn to a course that will head into the Tsunami. | Prepare for sudden, high-velocity wind gusts from rapidly changing directions. | No special action as tsunamis are inconspicuous in the open ocean |
The height of a wave is the vertical distance __________. | between water levels at one-quarter of the wave's length | from the still water plane to the trough | from the still water plane to the crest | from crest to trough |
The length of a wave is the length __________. | of the wave's trough | measured from crest to crest | measured from crest to trough | of the wave's crest |
What is the distance from the bottom of a wave trough to the top of a wave crest? | Wave depth | Wave breadth | Wave height | Wave length |
On mid-ocean waters, the height of a wind-generated wave is not affected by the __________. | wind's velocity | duration of the wind | water depth exceeding 100 feet | fetch |
Fetch is the __________. | measurement of a wave's steepness | time in seconds required for two crests to pass a given point | distance a wave travels between formation and decay | stretch of water over which a wave-forming wind blows |
In mid-ocean, the characteristics of a wave are determined by three factors. What is NOT one of these factors? | Length of time a wind has been blowing | Fetch | Wind velocity | Effect of the moon's gravity |
The speed at which an ocean wave system advances is called __________. | wave length | ripple length | group velocity | wave velocity |
The velocity of the wind, its steady direction, and the amount of time it has blown determines a wind driven current's __________. | speed | deflection | temperature | density |
Swells that have outrun the storm are produced in the __________. | directly ahead on the storms projected track | rear | right front quadrant | left front quadrant |
The largest waves (heaviest chop) will usually develop where the wind blows __________. | at right angles to the flow of the current | in the same direction as the flow of the current | over slack water | against the flow of the current |
The time interval between successive wave crests is called the __________. | period | frequency | epoch | trough |
In shallow water, waves that are too steep to be stable, causing the crests to move forward faster than the rest of the wave, are called __________. | rollers | breakers | surfers | white caps |
The rise and fall of the ocean's surface due to a distant storm is known as __________. | swell | fetch | waves | sea |
Swell is the rise and fall of the ocean's surface due to __________. | the pull of the moon | fetch | local storms | distant winds |
Three or four feet of the total height of a storm surge in a hurricane can be attributed to __________. | the wind velocity | the decrease in atmospheric pressure | an increase in the wave period | an increase in temperature |
The chart of a beach area shows a very steep slope to the underwater beach bottom. Which type of breakers can be expected when trying to land a boat on this beach? | Plunging | Spilling | Converging | Surging |
The ocean bottom that extends from the shoreline out to an area where there is a marked change in slope to a greater depth is the __________. | continental shelf | offshore terrace | borderland | abyssal plain |
Swell is the rise and fall of the ocean's surface due to __________. | local storms | the pull of the moon | distant winds | fetch |
The chart of a beach area shows a very flat slope to the underwater beach bottom. What type of breakers can be expected when trying to land a boat on this beach? | Converging | Surging | Plunging | Spilling |
Freezing salt water spray should be anticipated when the air temperature drops below what temperature? | 0°F (-17.8°C) | -40°F (-28.9°C) | 32°F (0.0°C) | 28°F (-2.2°C) |
An instrument designed to maintain a continuous record of atmospheric pressure is a(n) __________. | barograph | aneroid barometer | thermograph | mercurial barometer |
A microbarograph is a precision instrument that provides a __________. | graphic record of combustible gases measured in an atmosphere | graphic record of vapor pressure from a flammable/combustible liquid | charted record of atmospheric temperature over time | charted record of atmospheric pressure over time |
A mercurial barometer at sea is subject to rapid variations in height ("pumping") due to the pitch and roll of the vessel. To avoid this error, measurements of atmospheric pressure at sea are usually measured with a(n) __________. | aneroid barometer | fortin barometer | syphon barometer | cistern barometer |
An instrument that maintains a continuous record of humidity changes is called a __________. | thermometer | barometer | hygrograph | thermograph |
An instrument which maintains a continuous record of temperature changes is called a __________. | thermograph | hygrograph | thermometer | barometer |
An anemometer on a moving vessel measures __________. | true wind speed and true wind direction | apparent wind speed only | apparent wind speed and true wind direction | true wind speed only |
Apparent wind speed blowing across your vessel while underway can be measured by a(n) __________. | wind vane | anemometer | thermometer | barometer |
An aneroid barometer is an instrument __________. | in which the pressure of the air is measured | used to measure the speed of wind | used to measure the height of waves | that tells which direction a storm is coming from |
An aneroid barometer on a boat should always be __________. | protected by a collision bulkhead | permanently mounted | located in an air-conditioned area | mounted in the passenger compartment |
A sylphon cell is a part of a __________. | thermograph | maximum thermometer | hygrometer | barograph |
A wind vane on a moving vessel shows __________. | dead reckoning wind direction | estimated wind direction | apparent wind direction | true wind direction |
A sling psychrometer is a(n) __________. | instrument used to measure relative humidity | instrument used in celestial navigation | instrument used to measure specific gravity | type of cargo gear |
An instrument useful in predicting fog is the __________. | anemometer | sling psychrometer | aneroid barometer | microbarograph |
A sling psychrometer is used to measure __________. | engine temperature | barometric pressure | seawater temperature | dry bulb and wet bulb temperatures |
A hygrometer is a device used for determining __________. | atmospheric pressure | relative humidity | the absolute temperature | wind velocity |
What instrument measures wind velocity? | Hydrometer | Barometer | Psychrometer | Anemometer |
What is TRUE concerning an anemometer on a moving vessel? | It
measures true wind speed. |
It
measures apparent wind speed. |
It
measures true wind speed and true wind direction. |
It measures apparent wind speed and true wind direction. |
What is used to measure wind velocity? | Barometer | Anemometer | Psychrometer | Wind sock |
An instrument that indicates wind direction is known as a(n) __________. | hygrometer | wind vane | sling psychrometer | hydrometer |
If your mercurial barometer reads 30.50 inches (1033 millibars) and the temperature is 56°F (13°C), what is the correct reading at 55°N, 150°W? | 30.42 inches (1030 millibars) | 30.45 inches (1031 millibars) | 30.50 inches (1032 millibars) | 30.53 inches (1033 millibars) |
The correction(s) which must be applied to an aneroid barometer reading include(s) __________. | height error | gravity error | temperature error | All of the above. |
Barometers are calibrated at a standard temperature of __________. | 0°F | 32°F | 60°F | 70°F |
The barometer is an instrument for measuring the __________. | dew point | temperature | atmospheric pressure | relative humidity |
Which of the following is a standard correction applied to the reading of an aneroid barometer? | wind speed | temperature | elevation | latitude |
In a microbarograph, the pen should be checked and the inkwell filled __________. | once
per month |
daily | once per week | each time the chart is changed |
Which correction(s) must be applied to an aneroid barometer? | Instrument error and height error | Instrument error and latitude correction | Height error only | Instrument error only |
Atmospheric pressure may be measured with a(n) __________. | mercurial barometer | aneroid barometer | barograph | All of the above. |
Which of the following statements is FALSE? | A thermometer measures temperature. | A barometer measures atmospheric pressure. | An anemometer measures wind speed. | A psychrometer measures wind pressure. |
For an accurate barometer check, you would __________. | check it with a barometer on another vessel | take readings from several barometers and average them | check it with the barometer at the ship chandlery | check it against radio or National Weather Service reports of the immediate vicinity |
The purpose of the "set" hand on an aneroid barometer is to __________. | provide a correction for temperature changes | indicate any change in the reading of the barometer | provide a correction for height above sea level | adjust the barometer |
On what does the operation of an aneroid barometer depend? | Curved tube containing alcohol | Thin, metal, air tight cell | Expansion of mercury in a closed tube | Column of mercury supported by atmospheric pressure |
The pressure-sensitive element of an aneroid barometer is called a __________. | sylphon cell | column of mercury | pressure bellows | constant pressure capsule |
Prior to reading an aneroid barometer, you should tap the face lightly with your finger to __________. | expose any loose connections | bring the pointer to its true position | contract and expand the glass face | demagnetize the metal elements |
To avoid error you should read the scale of an aneroid barometer with your eye placed __________. | directly in front of the pointer | to the left of the pointer | slightly above the meniscus | to the right of the pointer |
Which indication on the barometer is most meaningful in forecasting weather? | The words "Fair -- Change -- Rain" | The relative humidity | The direction and rate of change of barometric pressure | The actual barometric pressure |
The most important information to be obtained from a barometer is the __________. | weather indications printed on the dial (such as "cold, wet, etc.") under the pointer | present reading of the pressure, combined with the changes in pressure observed in the recent past | difference between the reading of the two pointers, which shows wind direction | last two figures of the reading of the pointer, such as .87, .76, or .92 |
Which instrument is used to predict the approach of a low pressure system? | Anemometer | Fathometer | Barometer | Thermometer |
The passing of a low pressure system can be determined by periodically checking the __________. | anemometer | hygrometer
|
thermometer | barometer |
Which of the following is the most useful factor for predicting weather? | The difference in the barometric readings within the past 24 hours | The previous reading of the barometer | The rate and direction of change of barometric readings | The present reading of the barometer |
The needle of an aneroid barometer points to 30.05 on the dial. This indicates that the barometric pressure is __________. | 30.05 millimeters of mercury | 30.05 inches of mercury | 30.05 millibars | falling |
Aneroid barometers are usually calibrated to indicate atmospheric pressure in __________. | feet of mercury and millibars | inches of mercury and millimeters | inches of mercury and centimeters | inches of mercury and millibars |
Barometer readings in weather reports are given in terms of pressure at __________. | the weather station | the broadcasting station | sea level | Washington, D.C. |
Scales on aneroid barometers are usually graduated in inches of mercury in the general range of __________. | 26 to 29 inches | 28 to 31 inches | 30 to 33 inches | 32 to 35 inches |
A barometric pressure reading of 29.92 inches of mercury is equivalent to __________. | 1013.25 millibars | 29.92 feet of water | 766 millimeters of mercury | 76 centimeters of water |
A single barometric pressure reading of 28.60 indicates __________. | rapidly improving weather | a severe low pressure system | fair weather and calm | deteriorating weather |
You should log all barometer readings taken at sea __________. | regularly | at least once during each watch | more often under changeable weather conditions | All of the above. |
Which instrument is used to measure the relative humidity of the air? | A hygrometer | A hydrometer | A spectrometer | A barograph |
The instrument most commonly used to gather the data for determining the relative humidity is the __________. | psychrometer | anemometer | barometer | hydrometer |
A psychrometer has two thermometers that provide dry bulb and wet bulb temperatures. By comparing these two temperature readings with a set of tables you can determine the __________. | wind chill factor | relative humidity and dew point | wind speed | atmospheric pressure |
The apparent wind is zero when the true wind is __________. | from astern and equal to the ship's speed | from ahead and equal to the ship's speed | from astern and is twice the ship's speed | zero |
The wind speed and direction observed from a moving vessel is known as __________. | apparent wind | anemometer wind | true wind | coordinate wind |
The apparent wind's speed can be zero, but only when two conditions are present. One condition is that the true __________. | wind's speed must be zero | wind's speed equals the ship's speed | wind must be on the beam | wind must be from dead ahead |
In most cases, the direction of the apparent wind lies between the bow and __________. | the beam on the lee side | the beam on the windward side | the direction of the true wind | true north |
The velocity of the apparent wind can be less than the true wind and from the same direction, if certain conditions are present. One condition is that the __________. | true wind is from dead ahead | true wind is on the beam | ship's speed is more than the true wind velocity | true wind is from dead astern |
The velocity of the apparent wind can be more than the true wind, and come from the same direction, if certain conditions are present. One condition is that the __________. | true wind must be from dead astern | ship's speed must be less than the true wind velocity | true wind velocity must be faster than the ship's speed | true wind must be from dead ahead |
Which weather element cannot be measured accurately while on board a moving vessel? | Visibility | Temperature | Atmospheric pressure | Wind direction |
An isotherm is __________. | a line on a weather map connecting equal points of both temperature and pressure | a line connecting points of equal barometric pressure on a weather map | a line connecting points of equal temperature on a weather map | an instrument that measures the climatological effects of temperature |
In reading a weather map, closely spaced pressure gradient lines would indicate __________. | high winds | fog or steady rain | high overcast clouds | calm or light winds |
Isobars on a weather map are useful in predicting __________. | wind velocity | temperature | relative humidity | dew point |
A steep barometric gradient indicates __________. | precipitation | strong winds | calms | light winds |
A line on a weather chart connecting places which have the same barometric pressure is called an __________. | isallobar | isotherm | isobar | isotope |
Lines drawn through points on the Earth having the same atmospheric pressure are known as __________. | seismics | isothermal | millibars | isobars |
What do the numbers on isobars indicate? | wind speed | barometric pressure | rain in inches | temperature |
At what angle to the isobars do surface winds blow over the open sea? | About 50° | About 25° | About 90° | About 15° |
Widely spaced isobars on a weather map indicate __________. | gentle breezes | ice, snow or frozen rain | high winds | probability of tornados |
When drawing a weather map and an isobar crosses a front, the isobar is drawn __________. | kinked and pointing away from the low | kinked and pointing towards the high for a warm front only | kinked and pointing towards the low | perpendicular to the front |
On a weather map, a large letter "H" means __________. |
horse
latitudes, with rough seas and strong winds |
a
high pressure area with warm, moist air, and inclement weather |
a
heavy squall line near the "H" |
a high pressure area with cool, dry air, and fair weather |
You can follow the approach of a dangerous cyclonic storm by inspecting __________. | the National Weather Service Observing Handbook No.1, Marine Surface Observations | a newspaper, a weather map, a weather fax, or a weather forecast | the Coast Pilot or Sailing Directions | the sky overhead |
While in port, you can follow the approach of a dangerous cyclonic storm by inspecting __________. | a weather map | the National Weather Service Observing Handbook No.1, Marine Surface Observations | the sky overhead | the Coast Pilot or Sailing Directions |
You can follow the approach of a dangerous cyclonic storm by inspecting __________. | a weather fax | the sky overhead | the National Weather Service Observing Handbook No.1, Marine Surface Observations | the Coast Pilot or Sailing Directions |
Which weather element cannot be measured accurately while on board a moving vessel? | Temperature | Atmospheric pressure | Relative humidity | Wave period |
In a weather report, the term "visibility" expresses __________. | how far you can see with a telescope or binoculars | how far you can see with the "naked eye" | how well you can identify an object at night | the distance in miles at which prominent objects are identifiable |
Weather information provided by the National Weather Service (NWS) advisories should be used along with __________. | weather maps and local knowledge | the local Notice to Mariners | any U.S. Coast Pilot | the Tide Tables and Tidal Current Tables |
As a Merchant Marine Officer you are expected to be able to do which of the following? | listen to weather forecasts on the radio while enroute | obtain a weather forecast before setting out from port | understand all broadcast weather warning information | All of the above. |
What benefit is a weather bulletin to a mariner? | It provides a legal reason to cancel a projected voyage. | It allows the mariner to make long term weather forecasts. | It gives the mariner time to prepare for weather changes. | It is of little benefit since the weather changes frequently and rapidly. |
Weather information is available from __________. | VHF-FM continuous marine weather broadcasts provided by the National Weather Service | commercial radio broadcasts | the Coast Guard on scheduled marine information broadcasts | All of the above. |
Static on your AM radio may be __________. | an indication of "clearing" weather | of no meteorological significance | a sign of strong winds | an indication of nearby thunderstorm activity |
While taking weather observations, you determine that the wind is coming from the west. In the weather log, you would record the wind direction as __________. | 000° | 090° | 180° | 270° |
It is desirable that a vessel encountering hurricane or typhoon conditions sends weather reports to the closest meteorological service at least every __________. | 8 hours | 6 hours | hour | 3 hours |
When within 300 miles of a named tropical storm or hurricane, it is standard practice to send weather reports every __________. | hour | 6 hours | 8 hours | 3 hours |
NOAA VHF weather reports are continuously broadcast on VHF channels WX-1, WX-2 and WX-3 on a frequency of __________. | 156.8, 157.1, 162.55 MHz | 162.55, 162.00, 171.5 KHz | 162.55, 162.40, 162.475 MHz | 2182, 2638, 2670 KHz |
Weather forecast messages are usually __________. |
transmitted
only by commercial broadcast stations |
given
only to TV stations |
broadcast
immediately on VHF Channel 16 and 2182 kHz |
broadcast in plain language |
Weather observations provided by each weather station include all of the following except __________. | predicted weather for the next twelve hours | barometric pressure and change in the last three hours | temperature | visibility |
Plain language is usually used on marine weather __________. | observations
|
forecasts
|
analyses
|
synoptic chart |
In illustration D009NG below, your position X is at LAT 35°S. Which winds are you experiencing? | Southwesterly | Northwesterly | Southeasterly | Northeasterly |
Prevailing winds between 30°N and 60°N latitude are from the __________.
|
east
|
south
|
west | north |
Considering the general circulation of the atmosphere, the wind system between latitudes 30°N and 60°N is commonly called the __________. | prevailing westerlies | horse latitudes | trade winds | subpolar low pressure belts |
The direction of the surface wind is __________. | from low pressure toward high pressure deflected by the earth's rotation | directly from low pressure toward high pressure | from high pressure toward low pressure deflected by the earth's rotation | directly from high pressure toward low pressure |
The direction of prevailing winds in the Northern hemisphere is caused by the __________. | Arctic cold fronts | Earth's rotation | Gulf Stream | magnetic field at the North Pole |
"Surface circulation" is another term for __________. | wind in the lower troposphere | cyclones | ocean currents | air in motion at all levels of the atmosphere |
Where are the prevailing westerlies of the Southern Hemisphere located? | Between 60° and 90° latitude | Between 10° and 20° latitude | Between the Equator and 10° latitude | Between 30° and 60° latitude |
The prevailing westerlies of the Southern Hemisphere blow 18 - 30 knots __________. | during the summer months only | during the winter only | all year long | during spring only |
The winds of the "roaring forties" are strongest near __________. | 50°S | 40°S | 50°N | 40°N |
The area of strong westerly winds occurring between 40°S and 60°S latitude is called the __________. | roaring forties | polar easterlies | prevailing westerlies | jet streams |
The direction of the southeast trade winds is a result of the __________. | equatorial current | humidity | rotation of the earth | change of seasons |
Weather conditions in the middle latitudes generally move __________. | northward | eastward | westward | southward |
The wind flow from the horse latitudes to the doldrums is deflected due to __________. | the mid-latitude, semi-permanent high | differing atmospheric pressures | the prevailing westerlies | Coriolis force |
On the pole side of the trade wind belt, there is an area of high pressure with weak pressure gradients and light, variable winds. This area is called the __________. | geostrophic winds | doldrums | horse latitudes | prevailing westerlies |
The region of high pressure extending around the Earth at about 35°N latitude is called the __________. | doldrums | troposphere | prevailing westerlies | horse latitudes |
The greater the pressure difference between a high and a low pressure center, the __________. | greater the force of the wind will be | warmer the temperature will be | dryer the air mass will be | cooler the temperature will be |
Wind velocity varies __________. | inversely with the barometric pressure | directly with the pressure gradient | directly with the temperature of the air mass | inversely with the absolute humidity |
On the pole side of the high pressure belt in each hemisphere, the pressure diminishes. The winds along these gradients are diverted by the Earth's rotation toward the east and are known as the __________. | doldrums | prevailing westerlies | horse latitudes | geostrophic winds |
Which wind pattern has the most influence over the movement of frontal weather systems over the North American continent? | Dominant southwesterly flow | Prevailing westerlies | Northeast trades | Subpolar easterlies |
In the doldrums you will NOT have __________. | high relative humidity | frequent showers and thunderstorms | steep pressure gradients | frequent calms |
The doldrums are characterized by __________. | frequent calms | steady, light to moderate winds | clear skies | low humidity |
In the doldrums you can expect __________. | steep pressure gradients | frequent rain showers and thunderstorms | steady, constant winds | low relative humidity |
The prevailing winds in the band of latitude from approximately 5°N to 30°N are the __________. | doldrums | southeast trade winds | northeast trade winds | prevailing westerlies |
The winds with the greatest effect on the set, drift, and depth of the equatorial currents are the __________. | doldrums | trade winds | horse latitudes | prevailing westerlies |
The consistent winds blowing from the horse latitudes to the doldrums are called the __________. | roaring forties | trade winds | polar easterlies | prevailing westerlies |
During the winter months, the southeast trade winds are __________. | drier than during the summer months | wetter than during the summer months | stronger than during the summer months | weaker than during the summer months |
The southeast trade winds actually blow toward the __________. | east | southeast | northwest | south |
The belt of light and variable winds between the westerly wind belt and the northeast trade winds is called the __________. | subtropical high pressure belt | polar frontal zone | intertropical convergence zone | doldrum belt |
The horse latitudes are characterized by __________. | steady winds generally from the southeast in the Southern Hemisphere | the formation of typhoons or hurricanes in certain seasons | weak pressure gradients and light, variable winds | steady winds in one direction for six months followed by wind reversal for the next six months |
The "horse latitudes" are regions of __________. | abundant blue sea grass vegetation | light airs and calms | brisk prevailing winds | None of the above |
In regions near the poles, the winds are generally described as __________. | northerlies | westerlies | easterlies | southerlies |
Which of the following is associated with consistently high barometric pressure? | The trade winds | The doldrums | The prevailing westerlies | The horse latitudes |
Air circulation is caused or affected by __________. |
the
rotation of the earth on its axis |
mountain
ranges |
convection
currents caused by differences in radiant heating between equatorial and
polar regions |
All of the above. |
The force resulting from the earth's rotation that causes winds to deflect to the right in the Northern Hemisphere and to the left in the Southern Hemisphere is called __________. | aurora borealis | pressure gradient | ballistic deflection | Coriolis effect |
Which statement describes the prevailing wind direction in mid-winter in the Gulf Coast area? | 40% to 50% of mid-winter winds are from a southern quadrant. | 30% to 40% of mid-winter winds are from a northern quadrant. | the winds are variable in speed, but strongest in March. | None of the above |
A gale is characterized by a wind speed of __________. | 48 to 63 knots | 34 to 47 knots | 64 to 83 knots | 10 to 20 knots |
A tropical storm is a tropical cyclone that generates winds of __________. | over 63 knots | between 20 and 33 knots | between 34 and 63 knots | None of the above |
A hurricane is characterized by winds of __________. | up to 33 knots | 34 to 47 knots | 48 to 63 knots | 64 knots or greater |
A weather forecast states that the wind will commence backing. In the Northern Hemisphere, this would indicate that it will __________. | shift in a clockwise manner | decrease in velocity | shift in a counterclockwise manner | continue blowing from the same direction |
A weather forecast states that the wind will commence veering. In the Northern Hemisphere this indicates that the wind will __________. | increase in velocity | continue blowing from the same direction | shift in a clockwise manner | shift in a counterclockwise manner |
A local wind which occurs during the daytime and is caused by the different rates of warming of land and water is a __________. | land breeze | chinook | foehn | sea breeze |
A sea breeze is a wind __________. | caused by cold air descending a coastal incline | caused by the distant approach of a hurricane | that blows towards the sea at night | that blows towards an island during the day |
What wind reverses directions seasonally? | Jet stream | Secondary winds | Monsoon winds | Hooked trades |
A strong, often violent, northerly wind occurring on the Pacific coast of Mexico, particularly during the colder months, is called __________. | Pampero | Papagayo | Norther | Tehuantepecer |
Monsoons are characterized by __________. | light,
variable winds with little or no humidity |
steady
winds that reverse direction semiannually |
strong,
gusty winds that blow from the same general direction all year |
strong, cyclonic winds that change direction to conform to the passage of an extreme low pressure system |
A very light breeze that causes ripples on a small area of still water is a __________. | chinook | hog's breath | cat's paw | williwaw |
What will a veering wind do? | Circulate about a low pressure center in a counterclockwise manner in the Northern Hemisphere | Circulate about a high pressure center in a clockwise manner in the Southern Hemisphere | Change direction in a clockwise manner in the Northern Hemisphere | Vary in strength constantly and unpredictably |
In the Northern Hemisphere, a wind that shifts counterclockwise is a __________. | reverse wind | chinook wind | veering wind | backing wind |
In the Northern Hemisphere a wind is said to veer when the wind __________. | changes direction violently and erratically | remains constant in direction and speed | changes direction clockwise, as from north to east, etc. | changes direction counterclockwise, as from south to east, etc. |
Which wind results from a land mass cooling more quickly at night than an adjacent water area? | Coastal breeze | Land breeze | Sea breeze | Mistral |
What generally occurs when the land is cooler than the nearby water? | A land breeze | A norther | A sea breeze | A prevailing westerly |
A katabatic wind blows __________. | horizontally between a high and a low pressure area | in a circular pattern | down an incline due to cooling of the air | up an incline due to surface heating |
Which Beaufort force indicates a wind speed of 65 knots? | Beaufort force 0 | Beaufort force 6.5 | Beaufort force 12 | Beaufort force 15 |
The Beaufort scale is used to estimate the __________. | wind speed | percentage of cloud cover | barometric pressure | wind direction |
Which scale is used to estimate wind speed by observing sea conditions __________. | Beaufort scale | Metric scale | Wind scale | Coriolis scale |
A "Norther" in the Gulf of Mexico is __________. | a strong northerly wind that generally occurs between November and March | a forcible northerly wind of at least 20 knots | a wind shift to the north accompanied by a drop in temperature | All of the above. |