Metro-02
Meteorology and Flight Planning
(1) Above or below 0 degrees indicated with a
"+" or "-"
(2) All temperatures above 24,000 ft MSL are
below zero so the minus sign is dropped
c.
Exceptions
(1) Variable winds indicated by "99" for
direction
(2) Forecast winds less than 5 kts indicated by
"9900" and read as "light and variable"
(3) If wind speeds exceed 100 kts, 100 is
subtracted from the wind speed and 50 is
added to the direction; e.g., a wind from
230 at 145 kts would be encoded as 7345
(4) Wind speeds in excess of 200 kts would be
encoded at 199 kts; e.g., 7399 would be
230 degrees at 199 kts
3.
Temperature decoding/encoding rules
a.
Temperature and wind are sometimes omitted
from the forecast
(1) Wind information is never forecast for
altitudes within 1,500 ft of the surface
(2) Temperature information is never forecast
at any altitude within 2,500 ft of the surface
(3) Temperature information is never forecast
for the 3,000 ft level
4.
Interpolation--Often the wind information will not be
forecast for the altitude which the pilot wishes to file.
In this case, they must interpolate for the desired
information
(7-97) Original
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