The Extreme Precipitation Forecasting Table: Enhancing Situational Awareness of Extreme Precipitation Events

In 2014, a national team of Science and Operation Officers (SOOs) was assembled by the Office of Science and Technology Integration and the Weather Prediction Center (WPC) to work on projects improving predictions and Impact-based Decisions Support Services (IDSS) of extreme precipitation events (EPEs).  Events of this magnitude are usually associated with rainfall amounts exceeding the 100-yr Average Recurrence Interval (ARI) and can lead to devastating flooding, extensive property damage, and sometimes loss of life.   

Recently, the NOAA Atlas-14 database of ARI precipitation thresholds became available to operational forecasters in AWIPS.  This dataset provides precipitation frequency estimates based on a 90% confidence interval for ARIs ranging from 1 to 1000 years.  This data can be used to assess the “extremity” or “rarity” of a forecasted rain event and may facilitate IDSS between forecasters and emergency managers prior to an EPE.  The WPC-led team of SOOs are taking advantage of the baselined NOAA-14 data to develop forecasting tools that highlight extreme rainfall in the forecast and model-guidance.  The most recent tool developed is called the Extreme Precipitation Forecasting Table (EPFT).  The EPFT compares Quantitative Precipitation Forecasts (QPFs) to various ARI thresholds and uses the 100-yr ARI in the base configuration to draw attention to potential EPEs.  The EPFT is now available to forecasters at WPC, WFOs, and RFCs as a GFE procedure in AWIPS and will soon be featured as a web-based product through WPC.     

This presentation will give an overview of the strengths and limitations of the EPFT and demonstrate how it can be used to enhance situational awareness prior to the onset of an EPE.