Weather Quizlet

Composition of the atmosphere...

21% oxygen, 78% nitrogen, 1% other gases

Nearly all weather takes place in what part of the atmosphere?

Troposphere

Tropopause

isothermal layer in between the stratosphere and troposphere

Which layer does temperature stay relatively constant?

Tropopause (Isothermal layer)

What occurs in an inversion layer?

temperature increases, altitude increases

What happens to aerodynamic forces in the troposphere?

as altitude increases wind increases, but pressure and temperature decrease

What is the initiating factor for all winds?

Pressure Gradient Force

Standard Day conditions

29.92 in Hg and 15 degrees C

Lapse Rate for pressure

1 in Hg per 1,000 feet

Lapse rate for temperature

2 degrees per 1,000 feet

When is a PIREP given:

I - IFR approach conditions differ than before

W - wind shear

U - unusual weather

R - requested by ATC

M - missed approach is executed

Weather Watches AKA "Willy Willy"

severe weather watch issued for severe thunderstorms and tornados

AIRMET

MODERATE icing or turbulence, anything not thunderstorm related, LLWS, every 6 hours

Convective SIGMENT

Associated with THUNDERSTORMS:

1. 60 miles long

2. tornado with hail 3/4 of an inch

3. 30 mins or greater duration of a thunderstorm

Non-Convective SIGMET

severe weather conditions NOT related to thunderstorms, can include volcanic ash and dust/sand storms

Definition of an Air Mass

large body of air with the same temperature and moisture characterisitcs

How are air masses named?

location, temperature, moisture

Which air masses are stable?

warm

Which air masses are unstable?

cold

Saturation Definition

when temperature = moisture and the air can no longer hold moisture

Indicated Altitude

Garbage In, Garbage Out

True Altitude

Same as MSL, height above sea level

Absolute Altitude

above ground level

What is the altimeter setting for Class A airspace?

29.92 in Hg

When determining true altitude based off indicated what saying is utilized?

High to Low, look out below.

Low to High, plenty of sky.

Surface winds are below what AGL?

dashed lines, are created because of surface friction, 2,000 ft AGL

Gradient Winds

solid lines, blow parallel to the isobars, above 2,000 ft AGL

Jet Stream Definition

a narrow band of winds that blow from west to east at approx. 100-150 knots, and is located at the top of the troposphere

Pressure Gradient winds spin parallel to the isobars due to what?

the coriolis effect made by the pressure gradient force (PGF)

Sea Breeze

high pressure cool air is pushed inland during the day

Land Breeze

high pressure cool air is pushed outward to the sea during the night

Pressure Gradient Force saying....

Out of the highs, into the lows.

Clouds 6,500 AGL to 20,000 AGL...

Alto

Clouds 20,000 AGL and up....

Cirro

Surface clouds to 6,500 AGL...

Low - normal stratus and cumulus clouds with no prefix

AUTO means...

"made by a robot" automatically generated

Prevailing Visibility (SM)

greatest horizontal visibility throughout at least half a circle, can be non continuous

Runway Visual Range (RVR)

horizontal distance looking down the runway will be in FEET OR METERS

Ceilings are caused...

VV, BKN, OVC

VV

vertical visibility - distance seen directly upward from the ground into a total obscuration

8/8 summation layer

BKN

5/8-7/8 summation layer

OVC

8/8 summation layer

Prognostic Charts show what...

Precipitation in forecasted weather conditions, utilized for "big picture planning" aka XC flights

What is maintained throughout turbulence?

Attitude --> based on the indicator

Fronts are classified by what...

T- temperature

W - wind

D - dew point

P - pressure

Lifting Methods

F - Frontal

O - orographic

C - convergent

T - thermal

Causes of Turbulence

WTF MAN

W- wind shear

T - thermal

F - frontal

M - mechanical

Turbulence Duration

OIC

O - occasional,

How does icing affect aerodynamic factors?

Drag +

Thrust -

Lift -

Weight +

Fuel Consumption +

Stall Speed +

Structural Icing

Clear: -10 to 0 C

Rime: -10 to -20 C

Mixed: -8 to -15 C

Icing Requirments

1. visible moisture

2. free air temp is below freezing

3. aircraft surface is below freezing

Type of ground icing that must be removed prior to flight?

Frost

Engine Icing

Compressor and Induction, will occur at 10C (high moisture, low temp)

Wind Shear Definition

sudden, drastic change in wind speed and direction

LLWS is the most dangerous due to risk of stall at low level altitudes with the inability to recover the aircraft

Occluded fronts are what color?

Purple

Warm fronts are what color?

Red

Cold fronts are what color?

Blue

Turbulence Intensity

Light, Moderate, Severe, Extreme

Icing Intensity

Trace, Light, Moderate, Severe

Fog Characterisitics

50 feet off the ground, greater than 20 ft thick, vis is less than 5/8 SM

Minimizing Icing

1. get out of visible moisture

2. climb above -20C

3. use anti-ice/deicing

Fog formation requirements

1. condensation nuclei

2. low temp/dew point

3. light surface winds

Two types of fog:

Radiation - burns off with the sun, occurs at night

Advection - too thick for the sun to penetrate

Thunderstorm Hazards

H - hail

I - icing

M - microburst (5-6k fpm)

E - extreme turbulence

L - lightning

T -tornados

Gust Front

dangerous gusty winds, 5-20 miles in front of an approaching thunderstorm

Precipitation Characteristics

Showery - sudden start stop with abrupt changes

Continuous - steady with gradual changes

Intermittent - start/stop at least once an hour

Squall Line

line of fast moving thunderstorms developing 50-300 miles in front of cold fronts, depicted by a double-dotted red line on a surface chart

Pressure before a front

Low

Pressure after a front

High

Pressure can also be referred to as....

local altimeter

Thermal Turbulence

an aircraft will climb over a hot field due to thermal turbulence

Stable Air Particles behave how...

colder air settles when the lifting action is removed so it is stable

Unstable Air Particles behave how...

warmer air will tumble and rise when the lifting action is removed so it is unstable

Things to add to Dump Sheet

1. warm, cold, occluded front diagram with wind direction and speed

2. FOCT

3. OIC

4. cloud level with alto, cirro

5. H and L pressure wind gradients

6. Flight Conditions Table

7. sea and land breeze diagrams

8. icing temps

One line on a wind bar represents what...

10 knots

What fronts winds' change 180 degrees?

Stationary and Occluded Front