SYNOP

SYNOP (surface synoptic observations) is a numerical code (called FM-12 by WMO) used for reporting weather observations made by manned and automated weather stations. SYNOP reports are typically sent every six hours on shortwave using RTTY. A report consists of groups of numbers (and slashes where data is not available) describing general weather information, such as the temperature, barometric pressure and visibility at a weather station.

Message format

This is the general structure of a SYNOP message. Numbers shown here are fixed (group indicators), numbers replacing the x's contain the weather data plus information about the station's position (and speed and direction where applicable).

xxxxx xxxxx 99xxx xxxxx xxxxx xxxxx 00xxx 1xxxx 2xxxx 3xxxx 4xxxx 5xxxx
6xxxx 7xxxx 8xxxx 9xxxx 222xx 0xxxx 1xxxx 2xxxx 3xxxx 4xxxx 5xxxx 6xxxx
70xxx 8xxxx
  333 0xxxx 1xxxx 2xxxx 3xxxx 4xxxx 5xxxx xxxxx 6xxxx 7xxxx 8xxxx 9xxxx

See also

• METAR
• CLIMAT

External links

• Explanation of SYNOP codes
• Weather RTTY schedules of Deutscher Wetterdienst
• A SYNOP decoder Active/X
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