Marine Weather

Question 1

What is the primary source of the Earths weather?

Answer 1

the sun

Question 2

Atmospheric pressure at sea level is equal to?

Answer 2

1013.25 millibars; 14.7lbs per square inch or 29.92 inches of mercury

Question 3

What is used to predict the approach of a low pressure system?

Answer 3

barometer

Question 4

A common unit of measurement for atmospheric pressure is?

Answer 4

inches

Question 5

Prior to reading an aneroid barometer you should?

Answer 5

Tap the face lightly with your finger to bring the pointer to its true position

Question 6

The most important information obtained from a barometer is?

Answer 6

The present reading of pressure combined with the changes in pressure observed in the recent past

Question 7

The atmosphere in the vicinity of a high pressure is called?

Answer 7

Anticyclone

Question 8

The wind circulation around a high pressure center in the Northern Hemisphere is?

Answer 8

Clockwise and moving outward from the high

Question 9

Good weather is usually associated with?

Answer 9

A region of high barometric pressure

Question 10

When low pressure area is approaching the weather generally?

Answer 10

worsens

Question 11

a generally circular low pressure is called?

Answer 11

A cyclone

Question 12

the wind direction around low pressure area in the Northern Hemisphere is?

Answer 12

Counterclockwise and inward

Question 13

Weather systems in the middle latitudes generally travel from?

Answer 13

west to east

Question 14

What is the wind pattern that has the most influence over North America?

Answer 14

the prevailing westerlies

Question 15

A sea breeze is?

Answer 15

wind that blows towards an island or beach during the daytime

Question 16

A local wind which occurs during the daytime and is caused by the different rates of warming of the land and water is a

Answer 16

sea breeze

Question 17

A land breeze results from

Answer 17

a land mass cooling more quickly at night than an adjacent water area

Question 18

Hail is a product of?

Answer 18

Violent convection found in thunderstorms

Question 19

When a warm air mass overtakes and replaces a cold air mass the contact surface is called?

Answer 19

a warm front

Question 20

what is typical of a warm front weather condition

Answer 20

steady precipitation

Question 21

Barometric pressure should do what preceding an approaching warm front

Answer 21

steadily fall

Question 22

When cold air displaces warm air you have a?

Answer 22

cold front

Question 23

Whats associated with cold fronts?

Answer 23

A line of clouds, sharp changes in wind direction and squalls

Question 24

A cold front moving in from the northwest can?

Answer 24

Produce thunderstorms, hail then rapid clearing

Question 25

After a cold front passes what happens to barometric pressure?

Answer 25

Usually rises rapidly with clearing skies

Question 26

Which move faster cold or warm fronts?

Answer 26

cold

Question 27

When a cold air mass and warm air mass meet and there is no horizontal motion of either air masses it is called?

Answer 27

stationary front

Question 28

an occluded front is usually caused by?

Answer 28

a cold front overtaking a warm front

Question 29

A line on a weather chart connecting places which have the same barometric pressure is called?

Answer 29

An isobar

Question 30

Pressure gradient is?

Answer 30

The measure of pressure differences over a horizontal distance

Question 31

What enables you to estimate the bearing of a storm's center?

Answer 31

Buys Ballot's Law

Question 32

When facing into the wind in the Northern Hemisphere the center of the low pressure lies?

Answer 32

to your right and behind you

Question 33

Define relative humidity?

Answer 33

the ratio of the actual water vapor content to the current temperature of the air's holding capability

Question 34

The expression, the air is saturated means?

Answer 34

the relative humidity is 100%

Question 35

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?

Answer 35

Dew Point

Question 36

Fog forms when?

Answer 36

The air temperature is at or below the dew point

Question 37

Fog is most commonly associated with?

Answer 37

a warm front at night

Question 38

When warm moist air blows over a colder surface and is cooled below its dew point the result is?

Answer 38

Advection Fog

Question 39

Frost smoke will occur when?

Answer 39

Extremely cold air from shore passes over warmer water

Question 40

What is the classic thunderhead cloud?

Answer 40

Cumulonimbus

Question 41

The wind speed and direction observed from a moving vessel is known as?

Answer 41

Apparent wind

Question 42

In most cases the direction of apparent wind lies?

Answer 42

between the bow and the direction of true wind

Question 43

Apparent wind can be zero only when?

Answer 43

True wind must be from dead astern and the wind speed must equal ships speed

Question 44

A wind vane on a moving vessel shows?

Answer 44

Apparent wind

Question 45

A weather forecast states that the wind will commence backing, in the Northern Hemisphere this means?

Answer 45

it would shift in a counterclockwise manner

Question 46

A veering wind will change direction how in the Northern Hemisphere

Answer 46

clockwise manner

Question 47

The USCG broadcasts weather reports on?

Answer 47

Channel 21A or 22A

Question 48

A message warning of a hurricane will be prefaced by?

Answer 48

Pan-Pan (x3)

Question 49

When do the highest frequency of tropical cyclones occur in the North Atlantic oceans?

Answer 49

August, September and October

Question 50

When is the peak of hurricane season in the Western North Pacific?

Answer 50

July through October

Question 51

Ocean swells originating from a typhoon can move ahead of it at speeds near?

Answer 51

50 knots