Lesson 16 Weather Services
Private Pilot Ground School
Grant County Wx
762-5082
METAR
Type of Report
Station ID
Time
Wind
Visibility
Weather
Sky condition
Temp / Dew point
Altimeter
Remarks
PIREPS
Denoted by UA or UUA for urgent
All altitudes are MSL unless otherwise noted
Turbulence LGT, MDT, SVR
Icing CLR, RIME
AREA FORECAST
Covers large geographical areas
12 hour forecast with a 6 hour outlook
- Hazards and Flight precautions
- Synopsis
- Icing
- Turbulence
- VFR clouds and Wx
TAF
Issued 4 times a day
Good for 24 hours
- Type
- Location
- Date / time
- Valid period
- Forecast
- Probability forecast
- Temporary conditions
- Forecast change groups
WEATHER DEPICTION CHART
Shows:
- Total sky cover
- Cloud height or ceiling
WEATHER DEPICTION CHART
- Wx and obstructions to vision
- Visibility
less than 6 miles then an entry is made
IFR less than 1000 and 3 mi (hatched)
MVFR 1000 to 3000 3 to 5 mi
VFR greater than 3000 vis greater than 5 mi
RADAR SUMMARY CHART
Shows:
type of precipitation
intensity
trend
configuration
coverage
echo tops and bases
movement
severe wx watch area
- Tornadoes
- Severe thunderstorms
EFAS
122.0
Available everywhere
Seattle Flight Watch
WINDS AND TEMPS ALOFT
Come out twice daily
Good for time specified on the chart
Temps above 24,000 are all negative
No winds forecast within 1500′ AGL
No temps forecast for the 3000′ level or within 2500′ AGL
9900 Light and variable
Decode exercise
LOW LEVEL PROG
Surface to 24,000
4 times a day
Lower panels 12 and 24 hour surface
Upper panels 12 and 24 hour surface to 400 mb (24,000)
SHOWS:
Fronts
Pressure systems
Speed of frontal movement
Isobars
Forecast precip and or thunderstorms
Precipitation type
Dash dot lines encircle showers and T storms
Solid lines encircle continuous or intermittent precip
Shading indicates precip over half or more of area
LOW LEVEL PROG
UPPER PANELS SHOW:
IFR
MVFR
Turbulence- T storms always imply moderate or greater turb.
Fz levels depicted in 4000′ intervals
TWEB
Route forecast and synopsis
Sky cover cloud bases, tops, visibility, wx and obstructions to vision
25 miles either side of route
MSL bases and tops
SIGMET (all aircraft)
Severe icing
Severe or extreme turb
Dust storms, sandstorms, or volcanic ash with vis less than 3 miles
Volcanic eruption
Valid up to 4 hours
AIRMETS (light aircraft)
Moderate icing
Moderate turbulence
Sustained wind of 30 kts or more on surface
Ceilings less than 1000 and vis less than 3 mi over 50% of the area
Mountain obscurement
Valid up to 6 hours
SURFACE ANALYSIS
Provides a ready means for locating pressure systems and fronts