::Quantitative precipitation forecast


Forecast::rainfall    Weather::forecast    Models::within    Model::national    Center::radar    Ensemble::observed

Example of a five-day rainfall forecast from the Hydrometeorological Prediction Center

The Quantitative Precipitation Forecast (abbreviated QPF) is the expected amount of melted precipitation accumulated over a specified time period over a specified area.<ref name="SERFC">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> A QPF will be created when precipitation amounts reaching a minimum threshold are expected during the forecast's valid period. Valid periods of precipitation forecasts are normally synoptic hours such as 0000, 0600, 1200 and 1800 GMT. Terrain is considered in QPFs by use of topography or based upon climatological precipitation patterns from observations with fine detail. Starting in the mid-to-late 1990s, QPFs were used within hydrologic forecast models to simulate impact to rivers throughout the United States. Forecast models show significant sensitivity to humidity levels within the planetary boundary layer, or in the lowest levels of the atmosphere, which decreases with height.<ref>Christian Keil, Andreas Röpnack, George C. Craig, and Ulrich Schumann (2008). Sensitivity of quantitative precipitation forecast to height dependent changes in humidity. Geophysical Research Letters. Retrieved on 2008-12-31.</ref> QPF can be generated on a quantitative, forecasting amounts, or a qualitative, forecasting the probability of a specific amount, basis.<ref>P. Reggiani and A. H. Weerts (2008). Probabilistic Quantitative Precipitation Forecast for Flood Prediction: An Application. Journal of Hydrometeorology, February 2008, pp. 76–95. Retrieved on 2008-12-31.</ref> Radar imagery forecasting techniques show higher skill than model forecasts within 6 to 7 hours of the time of the radar image. The forecasts can be verified through use of rain gauge measurements, weather radar estimates, or a combination of both. Various skill scores can be determined to measure the value of the rainfall forecast.

Quantitative precipitation forecast sections
Intro  Use of radar  Use of forecast models  Probability approach  Entities which generate rainfall forecasts  Verification  See also  References  External links  

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