NOUS41 KWBC 071930



Technical Implementation Notice 12-36

National Weather Service Headquarters Washington DC

330 PM EDT Tue Aug 28 2012


To:        Subscribers:

           -Family of Services

           -NOAA Weather Wire Service

           -Emergency Managers Weather Information Network


           Other NWS Partners, Users and Employees


From:      Timothy McClung

           Chief, Science Plans Branch

           Office of Science and Technology


Subject:   Change to GRIB encoding of NCEP Stage II and RTMA

           Precipitation Products: Effective September 18, 2012


Effective on or about Tuesday, September 18, 2012, beginning with

the 1200 Coordinated Universal Time (UTC) run, the National

Centers for Environmental Prediction (NCEP) will make changes to

the Stage II analysis products and the Real Time Mesoscale

Analysis (RTMA)precipitation grids. The subcenter designation in

the GRIB2 encoding will read "4" for Environmental Modeling

Center (EMC).


Currently, the GRIB encoding for the Stage II and RTMA

precipitation analyses have the originating center set to "7"

(for US National Weather Service - NCEP), but the octet for

subcenter has not been set and defaults to zero. To more

accurately designate the data source, NCEP is setting the

subcenter value to "4" for EMC.


NCEP urges all users to ensure their decoder can handle this

change.  Sample Stage II and RTMA precipitation files can be

found at:


The Stage II and RTMA precipitation products are made available

publically on the NCEP FTP server at:


in the nam_pcpcn_anal.YYYYMMDD directories, where YYYYMMDD is the

4-digit year, month and day.  In addition, the RTMA precipitation

products are available on NOAAPORT with the WMO headers LEIA98




For questions regarding these changes, please contact:


    Ying Lin

    NCEP/EMC/Mesoscale Modeling Branch

    Before 16 Aug 2012:

    301-763-8000 x7248

    After 20 Aug 2012:



NWS National Technical Implementation Notices are online at: