NOAA to implement significant upgrade to storm-scale hourly weather forecast models
Experimental and Operational Models beside the actual rainfall image.
Enhancements to NOAA's hourly storm-scale weather prediction models, the 3-km High Resolution Rapid Refresh (HRRR) and 13-km Rapid Refresh (RAP), are targeted for implementation at NOAA's National Centers for Environmental Prediction (NCEP) on August 23, 2016.
This upgrade is the result of a close collaboration between Earth System Research Laboratory (ESRL) Global Systems Division (GSD) and National Weather Service (NWS) National Centers for Environmental Prediction (NCEP). NWS, Federal Aviation Administration (FAA), and renewable-energy-community (sponsored by NOAA and Dept. of Energy) colleagues have been evaluating these enhancements over the last year.
Improvements to the HRRR and RAP models make timing and placement of weather events more precise, especially for severe thunderstorms, heavy rain events and winter storms. This is critical information for NWS situational awareness but also for aviation/transportation and energy-related users of HRRR/RAP weather guidance.
For the upgrade, GSD researchers developed ways for HRRR and RAP to ingest new data from radar, lightning sensors, surface stations, and cloud observations to improve analyses of the current state of the atmosphere, critical for more accurate thunderstorm and winter storm forecasts. GSD- and NCAR-developed improvements to boundary-layer, cloud physics and land schemes better describe the evolution of the atmosphere, also critical for better storm forecasts.
The upgrade will also significantly increase use of polar orbiting and GOES (geostationary) satellite data, add NCEP's first assimilation of lightning data, and push hourly forecasts out an additional 3h (from 15 to 18h for HRRR, from 18 to 21 hours for RAP) to help the NWS extend lead-times for high-impact events such as thunderstorms.
In April, the experimental HRRR running in real-time at GSD accurately predicted 15-20 inches of rain in a 12-hour period for Houston,Texas that caused deadly flooding. GSD tests of the experimental RAP and HRRR showed improved forecasts of temperature, dewpoint, and winds from near the surface up to jet-stream levels of the atmosphere. The new versions of RAP and HRRR reduce a daytime near-surface warm bias of 2-3 degrees C to near zero.
The upgraded RAP and HRRR package has been running in real-time demonstration mode at GSD since early 2015, and in real-time parallel at NCEP since late July, in preparation for the implementation. Researchers hope to have the next set of advances running in real-time on experimental models by September.
GSD's modeling team includes federal, Cooperative Institute for Research in Environmental Studies (CIRES), and the Cooperative Institute for Research in the Atmosphere (CIRA) researchers.
Images of severe flooding in Houston, TX.
For more information contact: Susan Cobb 303-497-5093
