NOUS41 KWBC 121620

PNSWSH

 

Technical Implementation Notice 10-50

National Weather Service Headquarters Washington DC

120 PM EDT Tue Oct 12 2010

 

To:        Subscribers:

           -Family of Services

           -NOAA Weather Wire Service

           -Emergency Managers Weather Information Network

           -NOAAPORT

           Other NWS Partners, Users and Employees

 

From:      Timothy McClung

           Chief, Science Plans Branch

           Office of Science and Technology

 

Subject:   Changes to the North American Ensemble Forecasting
           System (NAEFS): Effective January 11, 2011

 

Effective Tuesday, January 11, 2011, beginning with the 1200 Coordinated Universal Time (UTC) run, the National Centers for Environmental Prediction (NCEP) will make modifications to the North American Ensemble Forecasting System (NAEFS).  The current NAEFS output is derived by combining the NCEP Global Ensemble Forecast System (GEFS) and the Canadian Meteorological Center s GEFS.  Starting January 11, the global ensemble system run by the Fleet Numerical Meteorology and Oceanography Center (FNMOC) will also be included in the NAEFS.

 

The NAEFS output is disseminated only via the NCEP server.  Products are available for http and ftp download at the following URLs:

 

http://www.ftp.ncep.noaa.gov/data/nccf/com/gens/prod/

and

ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/gens/prod/

 

In addition to including the FNMOC data in the NAEFS ensemble calculations, NCEP will also be modifying the output available from the NCEP GEFS, CMC GEFS, and the NAEFS.  These modifications include:

 

Adding the following 13 bias-corrected elements to the NCEP

GEFS and NAEFS output for all probabilistic products:

    10 hPa(mb) geopotential height

    10 hPa(mb) temperature

    10 hPa(mb) u component of wind

    10 hPa(mb) v component of wind

    50 hPa(mb) geopotential height

    50 hPa(mb) temperature

    50 hPa(mb) u component of wind

    50 hPa(mb) v component of wind

    100 hPa(mb) geopotential height

    100 hPa(mb) temperature

    100 hPa(mb) u component of wind

    100 hPa(mb) v component of wind

    850 hPa(mb) vertical velocity

 

The directory location of the raw CMC GEFS data will be changed.  Starting on January 11, the GRIB2 output for the individual member and ensemble means and spreads will be online in the following directories, where YYYYMMDD is the date and CC is the model cycle:

 

http://www.ftp.ncep.noaa.gov/data/nccf/com/gens/prod/cmce.YYYYMMDD/CC/pgrb2a

and

ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/gens/prod/cmce.YYYYMMDD/CC/pgrb2a/

 

In addition, the following 28 variables will be added to the CMC output:

    10 hPa(mb) geopotential height

10 hPa(mb) temperature

10 hPa(mb) relative humidity

    10 hPa(mb) u component of wind

    10 hPa(mb) v component of wind

    50 hPa(mb) geopotential height

50 hPa(mb) temperature

50 hPa(mb) relative humidity

    50 hPa(mb) u component of wind

    50 hPa(mb) v component of wind

    100 hPa(mb) geopotential height

100 hPa(mb) temperature

100 hPa(mb) relative humidity

    100 hPa(mb) u component of wind

    100 hPa(mb) v component of wind

    850 hPa(mb) vertical velocity

Convective inhibition (CIN 180-0 hPa)

    Latent heat net flux

    Sensible heat net flux

    Downward shortwave radiation flux at surface

    Downward longwave radiation flux at surface

    Upward shortwave radiation flux at surface

    Upward longwave radiation flux at surface

    Upward longwave radiation flux at top of atmosphere

    Volumetric soil moisture (0-10cm)

    Water equivalent of accumulated snow depth

    Snow depth (surface)

    Soil temperature (0-10cm down)

 

Data delivery timing is not expected to be impacted by the implementation. There will only be a minor increase in the data volumes of existing files due to the addition of new variables.

 

A sample dataset for this NAEFS implementation is available at:

 

ftp://ftp.emc.ncep.noaa.gov/gc_wmb/yzhu/1q2011

 

Specific information regarding the NAEFS and scientific implementation is online at:

 

http://www.emc.ncep.noaa.gov/gmb/yzhu/html/imp/201012_imp.html

 

By early December, once the model is running in parallel on the NCEP Central Computing System, a consistent parallel feed of data will be available on the NCEP server.  The parallel data will be available via the following URLs:

 

http://www.ftp.ncep.noaa.gov/data/nccf/com/gens/para

and

ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/gens/para

 

NCEP urges all users to ensure their decoders can handle changes in content order, changes in the scaling factor component within the product definition section (PDS) of the GRIB files, and volume changes. These elements may change with future NCEP model implementations. NCEP will make every attempt to alert users to these changes before implementation.

 

For questions regarding these changes, please contact:

 

      Yuejian Zhu

      NCEP/Global Modeling Branch

      Camp Springs , Maryland

      301-763-8000 X 7052

      Yuejian.Zhu@noaa.gov

 

For questions regarding the dataflow aspects of these datasets, please contact:

 

     Rebecca Cosgrove

     NCEP/NCO Dataflow Team

     Camp Springs , Maryland 20746

     301-763-8000 X 7198

     ncep.pmb.dataflow@noaa.gov

 

NWS National Technical Implementation Notices are online at:

 

   http://www.nws.noaa.gov/os/notif.htm

 

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