Check Ride Prep C: Weather Flashcards
How to Get Wx
-Check Local Wx
-Wx Brief: STD, outlook, abreviated
-supplement w/ Foreflight
In Flight:
-ATIS/AWOS/ASOS
-Flight Service Station
-in flight wx
- pireps
- flight plans
PA.I.C.K3a Atmospheric Composition and Stability
Composition:
78% nitrogen
21% oxygen
1% trace gasses
Stability: The atmospheres ability to resist vertical development
-little to no turbulence; poor visibility
Stability
Stability: The atmospheres ability to resist vertical development
-little to no turbulence; poor visibility
Surface Analysis Charts
-Fronts
-Pressures
-Isobars: areas of same or like pressure
-close: heavily changing
pressure gradient (windy)
PA.I.C.K3b: Wind
-Windshear: dramatic change in windspeed and direction
-Mountain wave
PA.I.C.K3c: Temperature
-STD Temperature: 15 Celsius 59 F
-STD Pressure: 29.92” hg
-Temperature Inversion: warm air above
- STD Lapse: 2 Celsius per 1000’ 1.8F
- Atmospheric Lapse: 1”hg/1000’
PA.I.C.K3d: Moisture/Precipitation
Dewpoint: Temp @ which the air is completely saturated so visible moisture occurs
PA.I.C.K3e: Wx System Formation, Including Air Masses and Fronts
Pressure:
Low- inward, upward, ccw
High- outward, downward, cw
Trough- elongated area of low pressure
Ridge- elongated area of high pressure
Fronts:
-Warm: warm mass of air overtaking cold mass of air
-Cold: cold mass of air overtaking warm mass of air
-Stationary: two relatively = air masses where weather @ the boundary will prevail for days
-Occluded: when a fast moving cold front catches up to a slow moving warm front wx prevails followed by a cold front
PA.I.C.K3f: Clouds
Low: 6500’ AGL
Middle: 6500’ -20,000’
High: 20,000’+
Stratiform: Layered Clouds
Cumuliform: Puffy
Cirrus: High, Wispy
Nimbo: Rain
Lenticular: High Winds
PA.I.C.K3g: Turbulence
Irregular motion of vertical currents
PA.I.C.K3h: Thunderstorms and Microbursts
For thunderstorms to form:
1. moisture
2. lifting action
3. unstable atmosphere
3 Stages:
-cumulus: updrafts, storm builds
-mature: up + down drafts, rain @ surface
-dissipating: mostly down drafts, storm blowing itself out
VIRGA: rain that doesn’t reach the ground
Microbursts: most severe type of low level wind shear, associated w/ convective precipitation,
-Horizontal diameter 1-2 miles
-Depth 1000’, 5-10 minutes, 6000 FPM
PA.I.C.K3i: Icing and Freezing Level Information
Types of Ice:
-Clear
-Rime
-Mixed
Aircraft Icing:
-Structural
-Instrument
-Induction
To pick up ice:
-freezing level, freezing temp, and visible moisture
PA.I.C.K3j: Fog/Mist
- Advection: ocean -> land
layer of warm moist air passes over cool land, passing dew point - Upslope: moist stable air forced up sloping land fast due to wind
- Steam: land to sea
cool dry air passes over warm water - Ice: -25F water forms directly into ice crytsals
- Radiation: clear nights w/ little to no winds
valleys
warm ground cools overnight, condensing air
PA.I.C.K3k: Frost
-common on planes that have sat overnight when the temp goes below dewpoint & below freezing
-on preflight run hand over every surface
-do not take off w/ any ice
Coriolis Force
-the force caused by rotating of the earth
-why do winds aloft follow isobars: Coriolis force
