NOUS41 KWBC 071835



Technical Implementation Notice 15-55

National Weather Service Headquarters Washington DC

235 PM EST Mon Dec 7 2015


To:       Subscribers:

          -Family of Services

          -NOAA Weather Wire Service

          -Emergency Managers Weather Information Network


          Other NWS partners and NWS employees


From:     Timothy McClung

          Portfolio Manager

          Office of Science and Technology Integration


Subject:  Short Range Ensemble Forecast (SREF) Ceiling Height

          Change, Effective January 12, 2016


With the last SREF upgrade on October 21, 2015, the cloud

ceiling height was changed from Above Ground Level (AGL) to

Above Sea Level (ASL). Recent feedback from forecasters

indicates the change to ASL has inhibited their use of the

probability of ceiling height exceeding certain thresholds

because those thresholds are inherently AGL. Therefore, ceiling

height will be changed back to AGL. This change will affect the

ceiling height fields in all 26 SREF members and in the SREF

ensemble products: mean, spread and probability.


Output from the SREF is available for North America, the

Contiguous United States, Alaska and Eastern Pacific domains.

The change will impact the following NCEP servers:


*Where CC is the cycle 03, 09, 15, 21


For questions regarding the scientific content of the modeling

system, please contact:


     Geoff DiMego


     College Park, Maryland 20740

     Phone: 301-683-3764


     Jun Du


     College Park, Maryland 20740

     Phone: 301-763-3704


For questions regarding the data flow aspects, please contact:


     Carissa Klemmer

     NCEP/NCO Dataflow Team

     College Park, Maryland 20740

     Phone:  301-683-0567



NWS Technical Implementation Notices are online at: