High-Resolution Rapid Refresh (HRRR) (2024)

Composite Reflectivity

The HRRR is aNOAA real-time 3-km resolution, hourly updated, cloud-resolving,convection-allowingatmospheric model, initialized by 3km grids with 3km radar assimilation.Radar data is assimilated in the HRRR every 15 min over a 1-h period adding further detail to that provided by the hourly data assimilationfrom the 13km radar-enhanced Rapid Refresh.

HRRR implementations at NCEP
• HRRRv1 - 30 Sept 2014
• HRRRv2 - 23 Aug 2016
• HRRRv3 - 12 July 2018
• HRRRv4 - 2 Dec 2020

Information here inHRRRv4/RAPv5 summary - Jan 2020

HRRR Colorado Labs Award video- a 2-minute layperson-level description on the HRRR from late 2015and why it is important. (October 2015)
HRRRv4/RAPv5.

Key features for HRRRv4:
• improved cloud representation for boundary-top clouds, especially for shallow cold-air layers with cold-air retention
• better cloud bands (snow squalls, hurricane bands, lake-effect bands)
• 3km ensemble data assimilation for improved storm prediction for 1-12h
• inline smoke prediction
• improved lake temperatures
• Extension to 48h forecast every 6h.

HRRR Ensemble (HRRRE) prediction - documentation as of March 2020
2022 HRRR description - Dowell et al 2022
HRRRv2 physics description in Benjamin et al. 2016, A North American Hourly Assimilation and Model Forecast Cycle: The Rapid Refresh.Mon. Wea. Rev., 144, 1669-1694.

HRRR Data Archives