NCEP's Short-Range Ensemble Forecast (SREF) system is a dual-core multi-physics regional ensemble over North America. It consists of 26 members, 13 using the Advanced Research WRF (WRF-ARW) model and 13 members using the NEMS Non-Hydrostatic Multiscale Model on B-grid (NEMS-NMMB). SREF is run to 87-h at 16 km horizontal resolution with 40 vertical layers at 0300, 0900, 1500, and 2100 UTC. To create ensemble diversity a mix of different physics parameterizations, lateral boundary conditions (LBC) from the Global Ensemble Forecast System (GEFS), and initial conditions are used. Table 1 shows the physics configuration used for the 13 NEMS-NMMB members, and Table 2 shows the configurations used for the WRF-ARW members.

The October 2015 SREF implementation was its last upgrade, as future regional ensemble development at NCEP will focus on building a high-resolution convective-allowing ensemble including the FV3 dynamic core. 

Table 1 : Physics, initial conditions, and lateral boundary conditions used in the 13 NEMS-NMMB SREF members; click here for definition of acronyms.

Table 2: Physics, initial conditions, and lateral boundary conditions used in the 13 WRF-ARW SREF members; click here for definition of acronyms.

SREF-Related Web Pages

Official NCEP MAG SREF Site	SPC SREF web site	SPC SREF Plumes
Aviation(CONUS, Alaska, Hawaii)	Cyclone Track

  Information about NCEP SREF  

Oct. 21, 2015 SREF Upgrade	Past Upgrades	References
SREF data on NCEP NOMADS	SREF Verification

  Other Time-lagged Ensemble Products  

North America Rapid Refresh Ensemble -- Time Lagged (NARRE-TL)

High-Resolution Ensemble Forecast (HREF)

SPC HREF site

 

 

PLEASE READ THE DISCLAIMER

 

Environmental Modeling Center (EMC)

For more info about the NCEP SREF, please contact: Jun Du For more info about the NARRE-TL, please contact: Binbin Zhou For more info on the HREF, please contact Matthew Pyle