test Flashcards
2 Wind direction may be determined by observing all of the following EXCEPT ____
D. swells
4 A local wind which occurs during the daytime and is caused by the different rates of warming of land and water is a __________.
D. sea breeze
6 Which Beaufort force indicates a wind speed of 65 knots?
C. Beaufort force 12
12 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 __________.
A. northeast
#18 The usual sequence of directions in which a tropical cyclone moves in the Southern Hemisphere is \_\_\_\_\_\_\_\_\_\_. A. northwest, west, and south
B. southwest, south, and southeast
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 __________.
A. in the dangerous semicircle
The diurnal pressure variation is most noticeable in the __________.
D. doldrums
34 A line on a weather chart connecting places which have the same barometric pressure is called an __________.
C. isobar
Little or no change in the barometric reading over a twelve hour period indicates __________.
B. that present weather conditions will continue
The daily recurring pattern of pressure changes most noticeable in low latitudes is the ________
B. diurnal variation of pressure
It is desirable that a vessel encountering hurricane or typhoon conditions sends weather reports to the closest meteorological service at least every __________.
B. 3 hours
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 __________.
D. 270°
When reporting wind direction, you should give the direction in __________.
A. true degrees
Temperature and moisture characteristics are modified in a warm or cold air mass due to _________.
B. movement of the air mass
47 A cyclone in its final stage of development is called a(n) __________.
C. occluded cyclone or occluded front
A warm air mass is characterized by __________.
A. stability
A frontal thunderstorm is caused by __________.
C. a warm air mass rising over a cold air mass
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)________.
C. stationary front
When cold air displaces warm air you have a(n) __________.
A. cold front
The fog most commonly encountered at sea is called __________.
D. advection fog
Radiation fog __________.
. is formed by a temperature inversion
Fog is most commonly associated with a(n) __________.
A. warm front at night
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 __________.
A. altostratus
Which cloud type is normally associated with thunderstorms?
D. Cumulonimbus
If the sky was clear, with the exception of a few cumulus clouds, it would indicate __________.
C. fair weather
The form of cloud often known as “mackerel sky” which is generally associated with fair weather
C. cirrocumulus
A thin, whitish, high cloud popularly known as “mares’ tails” is __________.
D. cirrus
70 A low, uniform layer of cloud resembling fog, but not resting on the ground, is called __________.
C. stratus
Which type of cloud is among the most dependable for giving an indication of an approaching weather system?
B. Altostratus
Clouds are classified according to their __________.
C. altitude and how they were formed
Cloud formations are minimal when the __________.
A. surface temperature and temperature aloft are equal
Relative humidity is the percentage of water vapor that is in the air as compared to the maximum amount it can hold at __________.
B. a specific temperature
75 The dew point is reached when the __________.
D. air becomes saturated with water vapor
As the temperature for a given mass of air increases, the __________.
D. relative humidity decreases
79 Relative humidity is defined as __________.
C. the ratio of the actual vapor content at the current temperature to the air’s vapor holding capability
The largest waves (heaviest chop) will usually develop where the wind blows __________.
B. against the flow of the current
Which condition(s) is(are) necessary for the formation of dew?
Clear skies
B. Calm air
C. Earth’s surface cooler than the dew point of the air
D. All of the above
96 The Brazil Current flows in which general direction?
B. Southwesterly
On a voyage from Halifax, N.S., to Dakar, West Africa, the Canary Current will __________.
B. set the vessel to the right
What current flows southward along the west coast of the United States and causes extensive fog in that area?
D. California Current
When a current flows in the opposite direction to the waves, the wave __________.
B. height is increased
114 Generally speaking, a ship steaming across the North Pacific from Japan to Seattle is likely to experience __________.
B. favorable currents for practically the entire crossing
If a hurricane several hundred miles away is moving in your general direction your barometer would
B. start to fall gradually
What is the average speed of movement of a hurricane prior to recurvature?
C. 10 to 12 knots
Atmospheric pressure at sea level is equal to __________.
A. 14.7 pounds per square inch
B. 29.92 inches of mercury
C. 1013.25 millibars
D. All of the above
Lines drawn through points on the Earth having the same atmospheric pressure are known as____.
C. isobars
When within 300 miles of a named tropical storm or hurricane, it is standard practice to send weather reports every __________.
C. 3 hours
When a warm air mass overtakes and replaces a cold air mass, the contact surface is called a(n) __________.
A. warm front
The fog produced by warm moist air passing over a cold surface is called __________.
D. advection fog
While on watch, you notice that the air temperature is dropping and is approaching the dew point. Which type of weather should be forecasted?
D. Fog
In many areas “atoll” clouds (clouds of vertical development) are produced over small islands. These are the result of __________.
A. rising air currents produced by the warm islands
169 Altocumulus clouds are defined as __________.
B. middle clouds
As the temperature of an air mass decreases, the __________.
B. relative humidity increases
Weather observations provided by each weather station include all of the following except ______.
C. predicted weather for the next twelve hours
195 A slow rise in the barometric pressure forecasts __________.
C. improving weather conditions
An isotherm is __________.
D. a line connecting points of equal temperature on a weather map
The type of fog that occurs on clear nights with very light breezes and forms when the earth cools rapidly by radiation is known as __________.
A. radiation fog
Ascending and descending air masses with different temperatures is part of an important heat transmitting process in our atmosphere called __________.
C. convection
The Beaufort scale is used to estimate the __________.
C. wind speed
As a licensed Merchant Marine Officer you are expected to __________.
A. obtain a weather forecast before setting out from port
B. listen to weather forecasts on the radio while enroute
C. understand all broadcast weather warning information
D. All of the above
A sea breeze is a wind __________.
B. that blows towards an island during the day
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, the center of the low pressure lies __________.
D. to the south
Early indications of the approach of a hurricane may be all of the following EXCEPT __________.
A. short confused swells
What do the numbers on isobars indicate?
A. barometric pressure
The standard atmospheric pressure in millibars is __________.
D. 1013.2
A generally circular low pressure area is called a(n) __________.
A. cyclone
Good weather is usually associated with a region of __________.
B. high barometric pressure
An occluded front is caused by a(n) __________.
D. cold front overtaking a warm front
Advection fog is most commonly caused by __________.
D. warm moist air being blown over a colder surface
Fog is likely to occur when there is little difference between the dew point and the __________.
B. air temperature
A cloud of marked vertical development (often anvil-shaped) would be classified as __________.
D. cumulonimbus
258 All of the following are associated with cumulonimbus clouds EXCEPT __________.
A. steady rainfall
The velocity of the wind, its steady direction, and the amount of time it has blown determines a wind driven current’s__________.
D. speed
As the temperature of the air reaches the dew point, __________.
B. fog may form
If you are caught in the left semicircle of a tropical storm, in the Southern Hemisphere, you should bring the wind __________.
C. on the port bow, and make as much way as possible
A boundary between two air masses is a(n) __________.
C. front
When warm moist air blows over a colder surface and is cooled below its dew point, the result is __________.
C. advection fog
The presence of stratus clouds and a dying wind will usually result in __________.
C. thick fog
If you observe a rapid fall of barometric pressure you should __________.
D. prepare for the onset of stormy weather with strong winds
Static on your AM radio may be __________.
A. an indication of nearby thunderstorm activity
Which type of front forms when a cold front overtakes and forces a warm front upwards?
B. An occluded front
Which general weather conditions should you expect to find in a low pressure system?
B. Precipitation and cloudiness
A very light breeze that causes ripples on a small area of still water is a __________.
A. cat’s paw
Which condition would most likely result in fog?
A. Warm moist air blowing over cold water
368 A hurricane is characterized by winds of __________.
D. 64 knots or greater
If an observer in the Northern Hemisphere faces the surface wind, the center of low pressure is to his __________.
B. right, slightly behind him
A millibar is a unit of __________.
C. pressure
A rapid rise or fall of the barometer indicates __________.
C. a change in the present weather conditions
Which type of cloud formation should be of immediate concern to small craft operators?
D. cumulonimbus
Which scale is used to estimate wind speed by observing sea conditions __________.
D. Beaufort scale
Compared to a low pressure system, generally the air in a high is __________.
B. cool, more dense, and drier
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 __________.
B. south-southwest
A barometer showing falling pressure indicates the approach of a __________.
B. low pressure system
Cumulonimbus clouds are most likely to accompany a(n) __________.
B. cold front
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 __________.
B. to the south of you
On a weather map, a large letter “H” means __________.
A. a high pressure area with cool, dry air, and fair weather
