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PNSWSH

 

Technical Implementation Notice 10-45 Amended

National Weather Service Headquarters Washington DC

810 AM EST Tue Nov 16 2010

 

To:          Subscribers:

               -Family of Services

               -NOAA Weather Wire Service

               -Emergency Managers Weather Information Network

               -NOAAPORT

               Other NWS Partners, Users and Employees

 

From:      Tim McClung

               Science Plans Branch Chief

               Office of Science and Technology

 

Subject:  Amended: Addition of GEFS/NAEFS Products for Alaska:    

               Rescheduled for December 7, 2010

 

NCEP is rescheduling this implementation from November 30 to December 7 to allow more time for evaluation. The original message is below.

 

Effective December 7, 2010, beginning with the 1200 Coordinated

Universal Time (UTC) run, the National Centers for Environmental

Prediction (NCEP) will generate downscaled probabilistic

products for Alaska from the Global Ensemble Forecast System

(GEFS) and the North American Ensemble Forecast System (NAEFS).

There will be no change to the GEFS and NAEFS models.  This

implementation is only to create new output products for Alaska .

These new products will be disseminated on the NCEP server via

http and ftp.

 

The following describes the new Alaskan products:

 

1. Geographic coverage is the 6km NDFD grid (grid 198),

   which covers all of Alaska

2. Products will be in GRIB2 format

3. Output produced four times per day (0000, 0600, 1200,

   and 1800 UTC)

4. Output available every 6 hours out to 384 hours

5. Output available for eight variables: 

     surface pressure

     2-meter temperature

     2-meter maximum temperature

     2-meter minimum temperature

     10-meter u-wind

     10-meter v-wind

     10-meter wind speed

     10-meter wind direction

6. Ensemble products for each of the 8 variables listed above

include:

     10% probability forecast (filename ge10pt)

     50% probability forecast (filename ge50pt)

     90% probability forecast (filename ge90pt)

     Ensemble mean forecast   (filename geavg)

     Ensemble mode forecast   (filename gemode)

     Ensemble spread forecast (filename gesprd)

 

Test data is currently available at:

 

ftp://ftp.emc.ncep.noaa.gov/gc_wmb/yzhu/alaska_q4fy2010/

  

Specific information regarding the GEFS/NAEFS model and

associated products can be found at:

 

http://www.emc.ncep.noaa.gov/gmb/yzhu/html/imp/201004_imp.html

 

A consistent parallel feed of data will become available on the

NCEP server once the model is running in parallel on the NCEP

Central Computing System by mid-October.  The parallel data will

be available via the following URLs:

 

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

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

 

The products will be available in the ndgd_gb2 directories under

gefs and naefs. The files will have alaska in the filename. 

After the implementation, the operational products will be

available on the same server but the URLs above will end in

prod rather than para.

 

NCEP encourages all users to ensure their decoders are flexible

and are able to adequately handle changes in content order,

changes in the scaling factor component within the product

definition section (PDS) of the GRIB files, and also any volume

changes which may be forthcoming. These elements may change with

future NCEP model implementations. NCEP will make every attempt

to alert users to these changes prior to any implementations.

 

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 data

Sets, please contact:

 

     Rebecca Cosgrove

     NCEP/NCO Dataflow Team

     Camp Springs , Maryland 20746

     301-763-8000 X 7198

     ncep.list.pmb-dataflow@noaa.gov

 

NWS National Technical Implementation Notices are online at:

 

     http://www.weather.gov/os/notif.htm

 

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