Upper-Air Observation Decoding Guide

Here is the symbolic form of upper air observations worldwide

In this model:

TT	Temperature (°C)
DD	Dew Point Depression (T - Td) °C Note: Some web sites use dew point in the spot. How can you tell the difference? By knowing that the dew point temperature can never be higher than the temperature. Example 1 (500 mb chart from UCAR): This has to be dew point depression since there are values higher than the temperature Example 2 (500 mb chart from NWS Storm Prediction Center): Note that the green numbers to the lower left must be dew point temperatures since they are negative Note 2: This may be coded as "X" if the relative humidity is less than about 5%
HHH	Coded height of the surface above mean sea level (always 3 digits) 925 mb: in meters 850 mb: last three digits of height (meters; leading 1 dropped - Standard Atmosphere Height about 1.5 km) 700 mb: last three digits of height (meters; leading 2 or 3 dropped- Standard Atmosphere Height about 3 km) 500, 400, 300 mb: decameters (tens of meters; units digits assumed to be zero) 250, 200, 100 mb: decameters (tens of meters; units digits assumed to be zero) with 10,000 digit dropped (assumed to be 1)
ddd	Wind direction (degrees) (to nearest 5) See meteorological coordinate system key for more
fff	Wind speed (kt) Always plotted on the clockwise side of the wind shaft System: Pennant 50 kt Full barb 10 kt Half barb 5 kt See description of wind barb in surface station model key for more
hh	Height change in last 12 hours (decameters: 10's of meters)
N	Sky cover at that level

Here's an example of the Upper Air Station Model