Pressures And Winds

Question 1

Isobars

Answer 1

Lines connecting points of equal pressure corrected to sea level

Spaced 4 mb apart

Question 2

Pressure Gradient Force

Answer 2

Rate at which air will accelerate depends on rate at which pressure changes with distance.

Question 3

Isobar Spacing

Answer 3

Isobars closely spaced – strong or steep pressure gradient, moderate to strong winds

Isobars widely spaced – weak or flat pressure gradient, calm or light winds

Question 4

Before Coriolis Force takes effect, in which direction do winds move?

Answer 4

High pressure to low pressure

Question 5

What causes wind speed?

Answer 5

Pressure Gradient Force

Question 6

Coriolis Force

Answer 6

An apparent deflective force resulting from the Earth’s rotation

Question 7

Coriolis Force

Characteristics

Answer 7

Acts perpendicular to wind

Proportional to wind speed

Strongest at poles

Zero at equator

Question 8

High pressure rotates

Answer 8

Clockwise and parallel to the isobars

Below 2000 feet
Diverges approximately 30 degrees from the center

Question 9

Low pressure rotates

Answer 9

Counter-clockwise and parallel to the isobars

Below 2000 feet
Converges approximately 30 degrees from the center

Question 10

Surface Friction

Answer 10

Reduces wind speed

Question 11

All fronts are?

Answer 11

All fronts are low pressures.

Question 12

What is the standard MSL pressure in inches of mercury and millibars?

Answer 12

29.92 Hg and 1013.2 hP/mb

Question 13

What is an isobar?

Answer 13

A line connecting points of equal pressure (spaced 4 mb apart)

Question 14

What is the significance of widely spaced isobars on a weather chart?

Answer 14

Widely spaced isobars indicate a weak or flat pressure gradient force and would produce light or calm wind near those locations.

Question 15

The wind aloft or gradient wind circulation around a high-pressure area is

Answer 15

Clockwise and parallel to the isobars

Question 16

The wind aloft (gradient wind) direction in the southeast quadrant of a low-pressure area will be approximately from the____?

Answer 16

southwest

Question 17

Surface wind that converges to the center is associated with____pressure areas, and surface wind that diverges from the center is associated with ____pressure

Answer 17

low, high

Question 18

What causes the surface wind to flow across the isobars, rather than remain parallel to the isobars?

Answer 18

surface friction

Question 19

True or False
While flying parallel to the isobars above 2000 feet AGL, the wind is approximately a head wind or a tail wind and the pressure remains relatively constant.

Answer 19

true

Question 20

If you are flying directly toward a low pressure area, the crosswind will be from your ____?

Answer 20

left

Question 21

You are flying a course of 045° with steady crosswind from 135°. Based upon the wind direction, what kind of pressure and general weather conditions would you expect ahead?

Answer 21

High pressure area with clear skies and weak pressure gradient force.

Question 22

Flying on an easterly heading, you observe the aircraft drifting to the right. If you do not reset your altimeter as the flight progresses, you can expect the aircraft to be _____ than the indicated altitude.

Answer 22

lower

Question 23

Strong pressure gradient force is usually associated with _____ pressure areas.

Answer 23

low

Question 24

3000’ AGL is from 150°. From which direction is the wind blowing on the surface?

Answer 24

120°

Question 25

Sky conditions associated with low-pressure areas are normally produced by

Answer 25

Rising and cooling of the air