Warn on Forecast: NEWS-e

The NOAA Warn-on-Forecast (WoF) research project has developed a convection-allowing ensemble analysis and forecast system designed to provide short-range (0–6 hr) guidance for thunderstorm hazards. This system— the NSSL Experimental Warn-on-Forecast System for ensembles (NEWS-e)—has been run in realtime for Hazardous Weather Testbed experiments since 2016, including the NSSL Spring Forecasting Experiment and Flash Flood and Intense Rainfall Experiment. NEWS-e forecasts provide rapidly-updating, probabilistic forecasts of the likelihood and severity of threats such as tornadoes, severe hail, damaging winds, and flash flooding within thunderstorms.

The current configuration of NEWS-e consists of an ensemble of 36 individual members that are initialized within the Earth System Research Laboratory’s High-Resolution Rapid Refresh Ensemble (HRRRE). The NEWS-e domain is centered over expected areas of severe weather during the day and covers an approximately 1000 x 1000 km region with 3-km grid spacing. Conventional and remotely sensed observations, including radar reflectivity, radial velocity, and GOES-16 cloud water path, are assimilated into NEWS-e every 15 minutes using an ensemble Kalman filter (EnKF). NEWS-e forecasts are issued with 18 members hourly or sub-hourly, depending on the phenomenon of interest, and are up to 6 hours in length with output available every 5 minutes.