In order to report and forecast weather, meteorologists obtain weather information through a variety of sources, which include weather observers, automated weather observation stations, weather radar, weather balloons, and pilots.

Meteorologists use the information from these sources to provide a variety of weather products, which are used by the pilot to build a mental picture of current and expected weather.

These weather products include reports, forecasts, and advisories.


A weather report is history. When you read a report, you are seeing a description of weather as it was at the time of the report. Since the weather is constantly changing, it is important to pay close attention to the time at which a report was made, and to use the most current report available.

Weather reports include:

  • METAR: the aviation routine weather report, which is an hourly text report of local conditions at an airport
  • Radar Weather Reports, which are text reports generated automatically by radar sites
  • Pilot Reports (PIREPs): reports of actual conditions encountered by pilots
  • Surface Analysis Charts: depicting current and past surface weather graphically to provide a general overview of large scale weather systems
  • Weather Depiction Charts: which graphically depict past weather more in terms of visual, marginal visual, or instrument weather conditions
  • Radar Summary Charts: providing a graphical depiction of past locations and movement of precipitation detected by radar


A forecast is a best guess at what the weather will do in the future. Forecasts contain valid time periods for which they may be used.

Weather forecasts include:

  • Terminal Aerodrome Forecast (TAF): a written forecast of local conditions in the vicinity of an airport
  • Area Forecast (FA): a written forecast of conditions expected throughout wider geographic areas
  • Winds and Temperatures Aloft Forecast (FD): which provides expected wind direction, speed, and temperatures at different altitudes
  • Significant Weather Prognostic Charts: graphically depict 12 and 24 hour forecasts to provide an overview of significant weather and surface weather systems.

Weather Advisories

Weather advisories alert pilots to hazardous weather and atmospheric phenomenon.

Weather advisories include airmets, which are reports of hazardous weather which is mainly of interest to smaller aircraft, sigmets, which are reports of hazardous weather significant to all aircraft, and convective sigmets, which are reports of hazardous weather significant to all aircraft, which is associated with convective weather activity.


These weather reports, forecasts, and advisories are primarily written in contractions for words, rather than the entire words. These contractions are supplemented with some non-abbreviated words, which are used when they are self explanatory in nature or reference a specific geographic area. The contractions are meant to be logical and straight forward to decode.