NOUS41 KWBC
101145
PNSWSH
Service Change
Notice 17-86
National Weather
Service Headquarters Silver Spring MD
910 AM EDT Mon
Jul 10 2017
To: Subscribers:
-NOAA Weather Wire Service
-Emergency Managers Weather Information
Network
-NOAAPORT
Other NWS Partners, Users and
Employees
From: Dave Myrick
NWS Office of Science and Technology
Integration
Subject: Sea Surface Temperature change to the RAP
and HRRR
Effective July 12, 2017
Effective on or
about July 12, 2017, beginning with the 0100
Coordinated
Universal Time (UTC) run, the National Centers for
Environmental
Prediction (NCEP) will make a change to the Sea
Surface
Temperature (SST) analysis within the Rapid Refresh
(RAP) and the
High Resolution Rapid Refresh (HRRR) models
Currently, the
RAP and HRRR combine two SST analyses, the
Real-Time Global
(RTG) and a Two-Dimensional Variational
(2D-Var),
in making their respective daily 01 UTC SST updates.
The temperatures
of resolved rivers and small inland lakes are
present in both SST analyses, but only the 2D-Var
analysis is
used to determine the small lake and river
temperatures
ultimately initialized in the RAP and HRRR.
It has recently
come to the attention of NCEP that small inland
lake temperatures are much too cold in the RAP
and HRRR as a
result of poor 2D-Var analyses. NCEP is proposing
to discard the
2D-Var analysis
and rely solely on the RTG analysis for
determining all initial water temperatures in the RAP
and HRRR
(except for a few larger inland lake temperatures which are
and
will continue to be specified by climatology). As
a result of
discarding the 2D-Var analysis, users can expect
resolved river
and small inland lake temperatures to be
significantly improved
in the RAP and HRRR and in all downstream
models. The largest
downstream impacts will occur within the Real-Time
Mesoscale
Analysis
(RTMA) and Unrestricted RTMA (URMA). For the full list
of downstream models, please email the contacts
below.
These changes
will impact all model output on NCEP web services
and NOAAPORT/SBN. Users do not need to take any
action and will
continue to receive the data as they are currently.
Any questions, comments
or requests regarding this change should
be directed to the contacts below. We will review any feedback
and decide whether to proceed.
For questions
regarding these model changes, please contact:
Geoff Manikin
NCEP/Environmental Modeling Center
College Park, Maryland
301-683-3695
For questions
regarding the dataflow aspects of these data sets,
please contact:
Carissa Klemmer
NCEP/NCO Dataflow Team Lead
College Park, Maryland
301-683-0567
ncep.list.pmb-dataflow@noaa.gov
NWS Service
Change Notices are online at:
http://www.nws.noaa.gov/os/notif.htm
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