Weather

Question 1

Tropopause

Answer 1

• thin layer above the troposphere

- abrupt change in temperature lapse rate

Question 2

Stratosphere

Answer 2

• small change in temperature with increasing altitude

Question 3

The Jet Stream

Answer 3

• “river” of high speed winds (50 knots +)
• winter = south and increased velocity
• summer = north and slower velocity

Question 4

Standard temperature

Answer 4

15* C at sea level

Question 5

Average lapse rate

Answer 5

2*C per 1000’

Question 6

Troposphere

Answer 6

• Surface to 37,000’ (20,000-65,000)
• higher over the equator
• higher in the summer
• Decrease in temperature with increasing alt

Question 7

Wind rules northern hemisphere

Answer 7

• air circles clockwise around high pressure systems
• air circles counterclockwise around low pressure systems
• closer the isobars together, stronger the wind
• due to surface friction, to about 2000’ winds move outwards from the center of high pressure to low pressure
• coriolis effect deflects wind to the right

Question 8

Relative humidity

Answer 8

• how much water vapor thats present in the air vs. how much it can actually hold
• 100% is considered “saturated
• warm air can hold more water vapor than cold air

Question 9

Dew point

Answer 9

The temperature air must cool too to become saturated (100%) by the water already present in the air

Question 10

Wet snow

Answer 10

• temperature is above freezing at your altitude

Question 11

Atmospheric stability

Answer 11

The resistance of the atmosphere to vertical motion.

Question 12

Characteristics of unstable air

Answer 12

Cumuliform clouds, showery precipitation, rough air (turbulence), and good visibility

Question 13

Characteristics of stable air

Answer 13

Stratiform clouds and fog, continuous precipitation, smooth air, and fair to poor visibility in haze and smoke

Question 14

Dry adiabatic lapse rate

Answer 14

3*C per 1,000’

Question 15

Family’s of clouds

Answer 15

• high clouds
• middle clouds
• low clouds
• clouds with extensive vertical development

Question 16

Radiation Fog

Answer 16

(ground fog) is formed when the ground cools the air to its dew point.
- typically in warm, moist air over low, flatland areas on clear, calm nights.

Question 17

Advertise Fog

Answer 17

• (sea fog)

- formed when warm, moist air moves over colder ground or water

Question 18

Upslope Fog

Answer 18

• formed when moist stable air is cooled to its dew point as it moves up sloping terrain
• dry adiabatic rate (3*C per 1000’)

Question 19

Thunderstorm

Answer 19

• sufficient water vapor
• unstable lapse rate
• initial upward boost (lifting)

Question 20

Cumulus stage

thunderstorm

Answer 20

Continuous updrafts, creating low pressure areas

Question 21

Mature stage

thunderstorm

Answer 21

• Up and downdrafts inside the cloud
• start of rain at the base
• most intense stage of the storm

Question 22

Dissipating stage

thunderstorms

Answer 22

Mostly consists of downdrafts

Question 23

Microbursts

Answer 23

Small scale intense downdrafts which spread outward as they near the ground.

• downdrafts can be as great as 6,000 fpm
• usually Las less than 15 minutes

Question 24

Wind Sgear

Answer 24

A change in wind direction and/or speed in a very short distance

• can occur at any level of the atmosphere
• detected by the pilot as a sudden change in airspeed

Question 25

Low-level wind shear

Answer 25

• All sides of a thunderstorm and directly under the cell

- Also found near frontal activity

Question 26

Warm front wind schear

Answer 26

• most critical before the front passes
• may exist below 5,000’ for about 6 hours before the surface passage of the front
• more extreme than cold front wind schear

Question 27

Cold front wind schear

Answer 27

Usually found behind the front, if the front is moving greater than 30 knots
- schear zone 5,000’ agl 3 hours after the front passes