The Extreme Precipitation Forecast Improvement Project: Helping Forecasters and the Public Improve Their Situational Awareness When Extreme Rainfall Is a Threat.

In 2015, the Extreme Precipitation Forecast Improvement Project was established to explore and implement methods that could help operational forecasters improve their situational awareness (SA) to the potential for an extreme precipitation event (EPE). In this presentation, an EPE is defined as a storm that produces liquid rainfall amounts that have a 1 in 100 chance of occurring within a specific duration at any location in any given year. These events are also referred to as having a 100-year Average Recurrence Interval (ARI). This project, funded by the Office of Science and Technology Integration, is being completed by a team of Science and Operations Officers from Weather Forecast Offices (WFOs), hydrologists from River Forecast Centers (RFCs), and leadership from the Weather Prediction Center (WPC). The combined efforts of the team has allowed a series of SA tools to be developed and nationally implemented on an AWIPS platform for use by operational forecasters at the National Weather Service. In addition, simplified versions of these tools have been redesigned into a web-based product suitable for public use.

The first and most widely used AWIPS tool developed by the team is called the Extreme Precipitation Forecasting Table (EPFT). The EPFT allows operational forecasters to compare Quantitative Precipitation Forecasts (QPF) from all available AWIPS-based guidance with ARIs from the NOAA Atlas-14, allowing them to quickly identify when extreme or climatologically significant rainfall is a threat within a 10 day period. The EPFT incorporates simple visualization techniques so forecasters at WPC, RFCs, and WFOs can compare each other’s forecast in a climatological context, allowing for improved collaboration and messaging between agencies. Based on user feedback, the Average Recurrence Interval Table (ARIT) and Extreme Precipitation Assessment Table (EPAT) were developed to complement the EPFT. The team also worked with WPC to develop a web-based product utilizing the NOAA Atlas-14 data called “The Extreme Precipitation Monitor”, which displays WPC’s deterministic QPF in the context of the ARIs from 1 to 100 years. This product provides the public with an idea of where climatologically significant (or extreme) rainfall is expected to occur as forecasted by WPC, and is now an experimental product on WPC’s web-page.

This presentation will demonstrate some of the the latest enhancements added to these AWIPS and web-based products along with user accounts of how they have been used in an operational setting to improve situational awareness during impactful rain events.