Aviation Weather Flashcards

Question

What De-Icing measures do we have?

Answer 1

None A/C have: pneumatic boots, weeping wings, bleed air, electrically heated, and electro impulse etc.

Answer 2

Lines of same or similar pressure, tells us about the pressure gradient force

Answer 3

change in pressure over a given distance, measured by the space between isobars closely spaced isobars = strong winds further spaced isobars = light winds

Answer 4

1) Cold front: bad weather, occurs when a mass of cold, dense, and stable air replaces a body of warmer air. B/c the air is so dense it acts like a snowplow, sliding under warmer air & forcing the less dense air aloft. Moves faster than warm fronts. (25 to 30 mph) 2) Warm front: good weather, poor vis. warmer air slowly overtaking the colder air. Brings higher humidity. Depending on the stability of a warm front, after being overtaken by a cold front, if warm front is stable, clouds will form, if air is not stable, thunder storms and squall lines would form. 3) Occluded front: cold front catching up to a warm front. Strong wind heavy precipitation 4) Stationary front: neither air mass overtaking each other hence "stationary", stationary clouds

Answer 5

``` Low = up, inwards, & counter clockwise High = down, outwards, & clockwise ```

Answer 6

Standard: - 2 deg C per 1,000 ft - 1" barometric pressure per 1,000 ft If not standard, this means that there is unstable weather

Answer 7

high temperatures at the equator leading to rising, less dense air, which flows towards the poles, cools, & becomes dense again, sinks back towards the surface

Answer 8

- Rotation of the earth that affects the way air moves - Moves Right at the Northern Hemisphere - Moves Left at the Southern Hemisphere - Strongest at the poles, weakest at the equator

Answer 9

- 15 deg C or 59 deg F - 29.92" Hg or 1013.25 milibars - 1.225 kg/m^3 density

Answer 10

Light - slight changes in attitude & altitudes Moderate - same as light but a bit worse Severe - large loss of attitude & altitude, momentary loss of controls Extreme - violently tossed around, impossible to control, structural damage

Answer 11

1) Mechanical - buildings and objects on the ground 2) Clear Air - above 15,000' associated w/ jetstreams 3) Convective - uneven heating of earth's surface 4) Frontal - caused by two opposing air masses; associated w/ cold fronts

Answer 12

elongated area of low pressure, opposite of a ridge (orange dashed lines)

Answer 13

elongated area of high pressure, opposite of a trough

Answer 14

Cold front

Answer 15

Warm Front

Answer 16

Stationary Front - neither air mass overtaking each other hence "stationary", stationary clouds

Answer 17

Occluded Front - cold front catching up to a warm front. Strong wind heavy precipitation

Answer 18

**Troughs** - elongated area of low pressure, opposite of a ridge (orange dashed lines)

Answer 19

**Squall line** - a line of active thunderstorms

Answer 20

**Dry Line** - a boundary separating moist and dry air masses.

Answer 21

**Tropical Wave -** an area of low pressure troughs, moves from east to west. Associated with cyclones and strong wind shears.

Answer 22

all weather is the result of differences in temperature, weather is caused by heat exchanges in the atmosphere and the surface, when pressure changes it means that the surface is not heated equally, thus causing weather.

Answer 23

1) Pressure gradient force: rate of change in barometric pressure over a given distance 2) Coriolis force: deflection of the wind to the right (can feel the effects in the northern hemisphere) 3) Surface friction: obstruction to windflow by man made or naturally made obstructions

Answer 24

body of air that has uniform moisture & temperature properties

Answer 25

happens when there is a transition between two air masses that are different in temperture, humidity, and wind.

Answer 26

* 731960: 230º @ 119kts (temperature -60º C) * 189960: 180º @ 200kts+ (temperature -60º C) * 751041: 250º @ 110kts (temperature -41º C) * 771150: 270º @ 111kts (temperature -50º C) * 2867-21: 280º @ 67kts (temperature -21º C) * 2842-13: 280º @ 42kts (temperature -13º C) **_Important info:_** * No winds are forecasted within 1,500' of station elevation * Winds are forecasted true, indicated in tens of degrees (two digits) with reference to true north and wind speed is given in knots (two digits) * 2022: 200@22 knots * Above FL240 the negative is removed from temperature, it is always negative] * If forecast speed is less than 5 knots, the coded group is 9900 which means, "light and variable" * If the wind speed forecast to be 200 knots or greater, the wind group is coded as 99 knots

Answer 27

**Issued** – four times daily with 12- and 24-hour forecasts based on 00Z, 06Z, 12Z and 18Z synoptic data. * 12- and 24-hour forecasts for significant weather from the surface 24,000ft * used for outlook purposes. Use to get a general picture of the weather conditions that are in the relatively distant future.

Answer 28

**Issued** – daily for 12-hour progs valid at 12Z and 00Z. _Features:_ · For altitudes 6000, 9000, 12,000, 18,000, 24,000, 30,000, 34,000 and 39,000 feet MSL · Shows wind direction and speed · Shows temperature aloft

Answer 29

* when temperature decreases at 2º C per thousand ft up to 36,000 ft. Above 36,000, the temperature is considered constant up to 80,000 ft.

Answer 30

* when pressure decreases at a rate of approximately 1" Hg per 1,000 ft of altitude gained to 10,000 ft

Answer 31

When temperature of air rises with altitude, a temperature inversion exists. Commonly, shallow layers of smooth, stable air close to the ground. The air at the top of the inversion acts like a lid, keeping weather and pollutants trapped below. If relative humidity is high, cloud, fog, & haze can form, reducing visibility.

Answer 32

Surface based Inversion = occur on clear, cool, nights when the air close to the ground is cooled by the lowering temperature of the ground. Frontal Inversion = occurs when warm air spreads over a layer of cooler air; or cooler air is forced under a layer of warmer air.

Answer 33

Air that, when pushed up, keeps rising. Conversely, stable airresists upward movement.

Answer 34

* Orographic effects (wind moving across mountains and valleys) * Frictional effects (low pressure systems) * Frontal lifting (when less dense warm air is forced to rise over cooler, denser air as a weather fronts move) * buoyancy (uneven heating of surface).

Answer 35

indicates how closely the air is to being saturated

Answer 36

When a volume of air at a given temperature holds the maximum amount of water vapour, has a relative humidity of 100%

Answer 37

temperature to which air must be cooled to become saturated without changing the pressure. (The closer the dew point is to the air temperature, the closer the air is to saturation)

Answer 38

* Clouds are composed of particles of liquid water (cloud droplets), and particles of ice called (Ice crystals). * Clouds are formed when air is cooled and the temperature equals the dew point (100% humidity) resulting in condensation, which produces clouds.

Answer 39

**O - Orographic** (air cannot go through a mountain, so it flows over it) **C - Convection** (heating of the surface, causing air to rise) **C - Convergence** (air at the surface flows together and pushed upwards) **U - Updraft** (rising air from lifting forces)

Answer 40

Cirro - high clouds composed of wispy crystals Alto - cloud in middle of troposphere Nimbus - cloud associated with precipitation Low -stratus, stratocumulus, and cumulus clouds Middle - altostratus and altocumulus clouds High - cirrocumulus, cirrostratus, and cirrus clouds Precipitating - nimbostratus and cumulonimbus clouds

Answer 41

Centrifugal = outwards Centripetal = inwards

Answer 42

**S - Single Cell :** form when atmosphere is unstable, short lived & last less than an hour becoming strong enough to produce lightning **M - Multi cell :** group of cells merging together, lots of gusts & up/downdrafts **S - Super cell :** large severe storms, powerful updrafts, top of clouds can be 15mi wide. Produce destructive tornadoes. **S - Squall Line :** lines of multicell storms with gusts, 100+ miles long, associated with high winds, lightning, tornadoes, heavy rain/hail.

Answer 43

Clouds and fog both form when water vapor condenses or freezes to form tiny droplets or crystals in the air, but clouds can form at many different altitudes while fog only forms near the ground.

Answer 44

the lowest layer of broken, overcast, or obscurated cloud layer. (AGL)

Answer 45

Cool air moving over a warm surface is heated from below, generating instability and showers

Answer 46

Warm air moving over a cool surface is cooled from below, increasing stability. If air is cooled to its dew point, stratus and/or fog forms.