Decoding Guide
Winds and Temperatures Aloft
Description:
This product depicts the observed winds and temperatures at various altitudes
for reporting stations across the U.S. These observations are obtained daily
at 00Z and 12Z from weather balloon releases. Observations are made at various
pressure levels which approximately correspond to the altitude indicated
on the chart. Since the measurements are made by pressure level instead
of altitude, it is important to note that the altitude is an approximation
only and will vary measurement-to-measurement and reporting station-to-reporting
station.
Issuance:
0000 and 1200 UTC
Data Sources:
Radiosonde-equipped weather balloons
Depiction:
A
wind barb is used
to indicate wind speed and direction. Yellow text next to the barb gives
the station identifier and the temperature in degrees F.
Example:

This example shows an observation made at station OAX (Omaha Nebraska) with 20
knot winds observed from approx 260 degrees. The temperature at this (apparently
high) altitude is -84 degrees F.
Click Here for a Discussion on Wind Barb Notation