NCEP Modeling Synergy Meeting Highlights: January 28, 2008


This meeting was led by Michael Brennan and attended by Keith Brill, Mary Hart, Geoff DiMego, Ed Danaher, Ken Campana, Vera Gerald, Dave Plummer, and Joe Sienkiewicz. Stephen Jascourt of UCAR/COMET, Rusty Billingsley of Southern Region HQ, David Bright of SPC, and Maj. Eric Dernovish of AFWA attended by remote teleconference.


1. NCO


No representative of NCO was present. A detailed list of all upcoming upgrades and implementations can be found here.




2a. Global Climate and Weather Modeling Branch


Ken Campana reported briefly on the new GFS upgrade that was detailed in an email earlier this week. The charter containing the details of the upgrade can be accessed at:


This upgrade will involve changes to the GSI, a new quality control scheme, upgrades to the shortwave and longwave radiation physics and the enthalpy replacing virtual temperature as the thermodynamic state variable (due to the model extending beyond the mesosphere). Implementation is tentatively scheduled for April. This implementation will begin running in parallel soon.


The current format GFS spectral coefficient file, using virtual temperature, will continue to be generated for downstream users, at least into 2009. This will be transparent to users and will be in addition to the new format GFS spectral file which contains enthalpy.


2b. Mesoscale Modeling Branch


Geoff DiMego reported on a NAM bundle tentatively scheduled for implementation in late March, with a parallel on the production machine beginning by around February 1. This upgrade includes:


  • An increase in the domain size by 18% (in the north, west, and east directions), this will have downstream impacts for users of the native NAM grid output (e.g., SREF, Hi-Res Window, RUC, etc.)
  • An upgrade in the i,j,k WRF-NMM code that will allow the model to run more efficiently and offset most of the increase in run time due to the expanded domain
  • Introduction of gravity-wave drag and mountain blocking
  • An upgrade to the NOAH LSM to match the NCAR version
  • An upgrade of the GSI to the August 2007 version, however the strong balance constraint will not be included
  • A slight modification of the positive definite advection scheme


2c. Global Ensemble Prediction System




2d. Short Range Ensemble Forecast System


A SREF implementation will begin running in parallel later this year to upgrade the WRF members to the latest available version and increase the resolution of the RSM and WRF members to 32 km (to match the Eta members). Also, the components making up the SREF will be adjusted to include more WRF members. The new SREF will be composed of:

6 Eta members

5 RSM members

10 WRF members (5 NMM, 5 ARW)


2e. Marine Modeling and Analysis Branch


Vera Gerald reported on the following MMAB issues:


        A parallel version of the Great Lakes wave model is now available, however the next version using NDFD winds is having data problems.

        A parallel version of the wave model ensemble is running, now with 12 members and a longer run time

        A parallel version of the multi grid wave model is now running with output available to 90N, although currently output north of 76N is bogus.

        A parallel version of RTOFS is running with a new assimilation scheme and forecast results available out to 6 days, this parallel also includes a updated GFS/HYCOM model interface as well as parallelized post processing.



Stephen Jascourt of COMET reported that he had noticed several instances of artificial-looking, stationary narrow zones of enhanced accumulated precipitation and simulated reflectivity in WRF-NMM hi-res-window output. Matt Pyle and others who work on the model are aware of and looking into the problem.


Mike Brennan reported that HPC forecasters had noticed improved performance of the experimental NAM over the operational NAM for two recent events.


4. The next Synergy Meeting will be held Monday, February 25, 2008, at 12:00 pm EST in Room 209 at EMC, with remote conference capability.