Precipitation Events: Probability of Precipitation Bias Statistics

摘要

Bias statistics were generated for four big precipitation events which occurred between January 1 and February 10, 2008. Big events were defined to be periods when the National Precipitation Verification Unit (NPVU) precipitation analysis indicated that precipitation amounts well above the climatological norm occurred over a significant portion of the Pocatello forecast area. These events were identified using a WR/SSD developed web page available on the WR AWIPS network. The BOIVerify2.0 application was used to generate bias statistics for the Probability of Precipitation (PoP) forecasts issued by the Pocatello office and for available model guidance through a forecast lead-time of 72 hours. In addition to generating forecast statistics for the entire forecast area, bias statistics were generated for four distinct sub-regions: the Snake River Plain, the Central Mountains, the Eastern Highlands, and the Southern Highlands. Finally, statistics were generated for the full range of PoP values at 24 and 72 hour forecast lead-times for the 40 day period ending on February 10, 2008. This period included dry (Verified PoP less than or equal to 40%) periods, wet (Verified PoP greater than or equal to 50%) periods and the four 'big' precipitation events, so a full range of expected or verified PoP (VPoP) values could be evaluated.