NOUS41 KWBC 251510



Service Change Notice 11-27

National Weather Service Headquarters Washington DC

1110 AM EDT Tue Jul 26 2011


TO:      Subscribers:

         -Family of Services

         -NOAA Weather Wire Service

         -Emergency Managers Weather Information Network


         Other NWS partners and NWS employees


FROM:    James E. Hoke

         Director Hydrometeorological Prediction Center


SUBJECT: Enhancements to Hydrometeorological Prediction Center
         Medium Range Weather Grids over CONUS Effective 
         October 11 2011

Effective Tuesday, October 11, 2011, the National Centers
for Environmental Prediction’s (NCEP) Hydrometeorological Prediction Center (HPC) will distribute
enhanced CONUS medium range (days 4 through 7) weather grids. The grids have been enhanced to better align with National Digital Forecast Database (NDFD) requirements.


In particular the weather grid temporal resolution has been

increased to 6 hours from 12 hours, additional qualifiers (slight chance, chance) have been added, and the weather type algorithm has been improved to better take into account vertical

temperature profiles. No weather is shown where the Probability

of Precipitation (PoP) is less than 15%.

Graphical representations of the
products are online at:


More details are online at:


If you have questions or feedback, please contact:

    Ed Danaher

    301-763-8000 Ext 7354


National Service Change Notices are online at: