Dr. Stephen Masters Consulting, LLC

Ensemble WRF forecasts based on the GEFS Ensemble

Update to my WRF-GEFS forecast system.

Several important updates and improvements to this system have recently been implemented. Some of these include:

These changes modernize the modeling and scripting aspects of this system and allow for more rapid application to other domains.

How do I create these forecasts? I download a regional subset of the 21 members of the Global Ensemble Forecast System (GEFS). From each GEFS member, I initialize a Weather Research and Forecast (WRF) model simulation covering the southeast United States at medium (20 km) horizontal resolution. From both the GEFS 6-hourly data and the WRF 1-hourly output, I pull point forecasts for each ensemble member. By looking at these plots, you get see both the forecast value and a measure of the uncertainty. Currently, these jobs are run from the 0000 UTC and 1200 UTC data cycles.

A six-month initial verification study of this system was presented at the American Meteorological Society's Annual Meeting in Phoenix, AZ. The poster and more detailed verification statistics are available by clicking on the poster.


GEFS information

A regional subset of the full GEFS data are downloaded from the NCEP NOMADS Server. Data for 21 ensemble members at forecast hours 0, 6, 12,...168 are downloaded and then prepared for WRF.

WRF information

WRF version 3.7.1 The grid is 100x93 points using the Lambert Conformal projection. The grid resolution is 20 km. The jobs start around 0620 and 1820 UTC respectively for the 0000 and 1200 UTC cycles. New graphics are generated hourly as the jobs complete and all members' data are usually available by around 1030 and 2030 UTC.

Status of download and processing

Status of GEFS download and processing:
12Z cycle: Complete at Mon Dec 18 14:12:54 EST 2017.
Status of WRF simulations and processing:
14 ensemble members complete for 12Z cycle.

Point forecasts for GEFS members (6-hr forecasts)

 GEFS 6-hr forecasts
LocationSfc temp, wind, SLPPrecipitation
Melbourne, FL
Pensacola, FL
Atlanta, GA
Nassau, Bahamas
New Orleans, LA
Huntsville, AL
Miami, FL
Greenbelt, MD
Hendersonville, NC

WRF Ensemble forecasts (Hourly forecasts through 168 hrs)

  WRF forecasts   WRF from GEFS c00 member   Hourly probablistic wind roses
Location Max/Min
PoP
Sfc hourly
temp, wind
SLP,
clouds
Precip     Hourly plots by forecast day
Melbourne, FL
 
    1     2     3     4     5     6     7     8  
Pensacola, FL
 
    1     2     3     4     5     6     7     8  
Atlanta, GA
 
    1     2     3     4     5     6     7     8  
Nassau, Bahamas
 
    1     2     3     4     5     6     7     8  
New Orleans, LA
 
    1     2     3     4     5     6     7     8  
Huntsville, AL
 
    1     2     3     4     5     6     7     8  
Miami, FL
 
    1     2     3     4     5     6     7     8  
Hampton, VA
 
    1     2     3     4     5     6     7     7  
Lake Adger, NC
 
    1     2     3     4     5     6     7     7  
Tarpon Springs, FL
 
    1     2     3     4     5     6     7     7  

WRF animations derived from GEFS c00 member

Wind vector and speed
Sea level pressure and precipitation
Surface temperature

Contact Steve at Dr. Stephen Masters Consulting if you would like to discuss the implementation of this WRF forecast ensemble for your specific region.