NOUS41 KWBC 161604



Technical Implementation Notice 12-56

National Weather Service Headquarters Washington DC

1105 AM EST Fri Nov 16 2012


To:       Subscribers:

          -Family of Services

          -NOAA Weather Wire Service

          -Emergency Managers Weather Information Network


          -Other NWS Partners, Users and Employees


From:     Tim McClung

          Science Plans Branch Chief

          Office of Science and Technology


Subject:  Bug Fix to Ceiling and Visibility Fields in the      

          Short Range Ensemble Forecast System:    

          Effective December 4, 2012


On December 4, 2012, beginning with the 1500 Coordinated

Universal Time (UTC) cycle, the National Centers for

Environmental Prediction (NCEP) will implement a fix to the Short

Range Ensemble Forecast System (SREF). The fix will address:


-Incorrect calculations of visibility fields for the following

 11 members: 4 NMMB members (n2, p2, n3, p3) and 7 ARW members

 (ctl, n1, p1, n2, p2, n3, p3).


-Incorrect calculations of ceiling fields for the following

 4 NMMB members - n2, p2, n3, p3.


This fix will not affect format or content included in any SREF

output products, and has no impact on the AWIPS products or

ensemble products: mean, spread and probability. 


The Environmental Modeling Center (EMC) Mesoscale Modeling Branch

(MMB) has a publicly available Web site with more information

concerning the SREF modeling system as well as other NCEP

regional modeling systems:


For questions regarding the scientific content of the modeling

system, please contact:


     Geoff Dimego


     College Park, Maryland 20740



     Jun Du


     College Park, Maryland 20740

     phone: 301-763-3704


For questions regarding the dataflow aspects of these data sets,

please contact:


     Rebecca Cosgrove

     NCEP/NCO Dataflow Team

     College Park, Maryland 20746



National NWS Technical Implementation Notices are online at: