METEOROLOGY FLIGHT PLANNING
crossing. A letter "L" or "H" after the RH value will indicate to which altitude the RH
corresponds. A single slash after these altitudes indicates that more than three crossings occur,
and the number of additional crossings is noted after the slash. When a "00" appears for the RH,
this indicates an RH of 100%. If "20" is coded, this indicates that the RH is the lowest that can
be obtained. Two slashes, "//", indicate RH data is missing.
Freezing level at 1700 feet MSL with 63% RH
Freezing levels at 2800, 3900, and 6100 feet MSL
with 91%RH at 2800 feet
Freezing levels at 800, 2500, and 8500 feet MSL
with 84% RH at 8500 feet, and one additional
Freezing level at the surface
Unable to obtain, high winds, or equipment failure
Balloon iced up at 8900 feet MSL
THE TERMINAL AERODROME FORECAST
Terminal Aerodrome Forecasts (TAF) Use for Flight Planning
Any aviator planning a flight should know both the destination's existing and forecasted weather.
Previously we learned the METAR provides existing weather. Now, we will discuss the surface
forecasted weather conditions by learning how to read TAFs. This teletype information will also
aid you in planning for the type of flight (IFR/VFR), type of approach you require, determining if
an alternate is required, and selection of the best alternate.
Although there are many differences in TAF reporting between the military and civilian weather
offices, as well as throughout the world, we will focus this discussion on the U.S. military TAF
since the bulk of your training flights will commence from military bases. Once this has been
accomplished, it will be much easier to point out differences existing among the TAFs of the
U.S. military, civilian, and international communities.
It will become readily apparent that each line of the TAF forecast will follow the same basic
sequence: message heading or change group, time, wind, visibility, weather and obstructions to
vision, clouds, altimeter, and remarks. The only deviation that occurs is the addition of wind
shear, temperature, icing, and turbulence groups when applicable. Figure 1-18 shows an example
of a single line forecast with a breakdown of each group. Figure 1-19 shows an actual forecast
for Navy Whiting Field.
AVIATION ROUTINE WEATHER REPORTS AND TERMINAL AERODROME