Weather Flashcards
What is pressure altitude? What’s the formula to calculate it?
field elevation corrected for nonstandard pressure
Pressure alt = field elev + (29.92 - current altimeter setting)1000
What is density altitude? What’s the formula to calculate it?
thickness of air. Pressure alt corrected for non standard temp
Density alt = pressure alt + (OAT-ISA temp)120
(ISA should be corrected for elevation so 13 celcius for MSN)
What is ISA?
international standard atmosphere
15 celcius at sea level
-2 per 1000 msl (mean sea level)
So madison is 13 celcius
Altimeter 29.92 in hg (or 1013 mBar)
1 in hg pressure change = ___ ft elevation
Pressure drops by 1 in hg for every 1000 ft elevation
SKC
0 of 8 pie slices have clouds
BKN
5-7 of 8 pie slices have clouds
SCT
3-4 of 8 pie slices have clouds
OVC
8 of 8 pie slices have clouds
FEW
1-2 of 8 pie slices have clouds
Name the 3 weather cells from equator to pole
Hadley cell, Ferrell cell, Polar cell
Cold air hits warm
Warm air rapidly forced up, bad weather results
Warm air hits cold
Warm air rises gradually and condenses, resulting in slow steady rain
What are the 4 types of air?
mP polar maritime
cP polar continental (arctic)
mT tropical maritime
cT tropical continental
High pressure caused by
Colliding air
Low pressure caused by
Splitting air
What direction do hi and low pressure areas spin?
Hi - clockwise
Low - counterclockwise
(cap analogy)
Temperature drops ___ degrees every 1000’
2 degrees
3 ingredients for bad weather are:
- Moisture
- Lifting mechanism - mountain, cold front, bluffs, tractor
- Unstable air - every 1000’ AGL, 2 deg colder. Instability caused by mixing air due to different temps in the layers
Low clouds: altitude and summary
Low <6k ft
Small clouds, not much rain
Middle clouds: altitude and summary
Mid 6k-20k ft
Rain
High clouds: altitude
High >20k ft
What’s a dry line?
Line between dry and moist air that pushes moist air up.
Radiation Fog
Heat radiating out. Clear night with no clouds - earth’s surface is giving off heat. This fog happens right on the ground.
Advection Fog
Sideways movement of air from water onto land in the morning
Upslope Fog
Wind pushes air up mountain, pressure drops causing the air to cool adiabatically
Steam Fog
Cold air hits warm water, water steams up into air
When the METAR says RMK, it means ___
remark
When the METAR says RAB, it means ___
rain began
Cumulus
Any altitude, cotton ball clumped
Stratus
Layers
Cirrus
High altitude, no rain
Nimbus
Moist - rain
Cumulonimbus
Most likely to rain
VFR: color, ceiling, visibility
Green
Ceiling >3k AGL
Visibility >5 sm
IFR: color, ceiling, visibility
Red
Ceiling 500-1k AGL
Visibility 1-3 sm
mVFR: color, ceiling, visibility
Blue
Ceiling 1-3k AGL
Visibility 3-5 sm
lIFR: color, ceiling, visibility
Magenta
Ceiling <500 AGL
Visibility <1 sm
When does your altimeter lie to you?
High to low, hot to cold, watch out below.
Density affects ___ and pressure affects ___
Airspeed indication, altitude indication
What services do FSS provide?
Weather briefings
enroute weather
recieve and process flight plans
handle PIREPS
relay clearances
issue NOTAMS
WFO (Weather forcast office)
Issues TAFs
(some) issues weather warnings & soaring forcasts
What services does the AWC provide?
AIRMETs
SIGMETs + convective
Area forcasts (FA)
Significant weather Prog charts
more random shit
What do standard briefings contain?
Adverse conditions
VNR (VFR not recommended)
Synopsis (overview)
Current conditions (unless departure is more that 2 hours out)
En route forcast
Destination forcast
Winds aloft
NOTAMs
SFRA (prohibited areas & special flight rules areas)
ATC delays
RAIM availability (if requested)
When is an outlook briefing appropriate?
When departure is 6+ hours away
When is an abbreviated briefing appropriate?
When departure has been delayed
How do you recieve an in-flight weather briefing?
Contact flight service via a frequency found in a VOR box or RCO frequency. Initial call should include tail number and frequency listening on. R next to frequency means it is recieve only so you may have to listen for a responce on the VOR frequency.
Internet briefings
DUATS II (direct user access terminal) Allows anyone to access AWC weather or file flight plans www.duatsii.com or www.duats.com or www.1800wxbrief.com
ADDS (aviation digital data service) FAA, NOAA & NCAR service, provides forecasts & observations
TIBS (telephone information briefing service)
Prepared by flight service
Provides area & route briefings
Airspace procedures
Special announcements
HIWAS (hazardous in-flight weather advisory)
Continuous weather info broadcasted over selected NAVAIDS
Includes-
AIRMETs
SIGMETs + convective
Urgent PIREPS
FIS-B (flight information service - broadcast)
Ground based broadcast provided by ADSB
Properly equipped aircraft can access datalink weather info for recent conditions
