-------- Original Message --------
172
NOUS41 KWBC 251418
PNSWSH
Technical Implementation Notice 11-11
National Weather Service Headquarters Washington DC
1017 AM EDT Fri Mar 25 2011
To: Subscribers:
-Family of Services
-NOAA Weather Wire Service
-Emergency Managers Weather Information Network
-NOAAPORT
Other NWS Partners, Users and Employees
From: Timothy McClung
Science Plans Branch Chief
Office of Science and Technology
Subject: GFDL Hurricane Prediction System Changes:
Effective May 17, 2011
Effective Tuesday, May 17, 2011, beginning with the 1200
Coordinated Universal Time (UTC) run, the National Centers for
Environmental Prediction (NCEP) will upgrade the Geophysical
Fluid Dynamics Laboratory (GFDL) Hurricane Prediction System.
The scientific changes to the model include the following:
- Upgrade Simplified Arakawa-Schubert (SAS) deep convection
parameterization to new version implemented in the NCEP
Global Forecast System (GFS)
- Modify the surface enthalpy exchange coefficient and
dissipative heating effect
- Expand coupled region in the Eastern Atlantic domain
to prevent storms from losing coupling effect with the
ocean due to insufficient overlap with the Western Atlantic
region. The new overlap will be 25 degrees.
- Correct several bugs in the model.
In testing, these improvements resulted in an average reduction
of forecast error of about 20 percent in the Atlantic basin for
the 3 to 5 day forecast period for tests of storms from the 2010
Atlantic hurricane season.
Product Changes:
The following will be added to the GFDL model output GRIB files:
Model-predicted 10 meter winds will be outputted in addition to
the lowest model level 35 meter winds.
The GFDL hurricane model GRIB products are disseminated via the
NCEP and NWS FTP servers and are not available on NOAAPORT or
AWIPS. These changes will result in no change in product
dissemination time. There will be only a minor increase in
product size.
Once implemented, the GFDL data will be available on the NWS ftp
server at:
ftp://tgftp.nws.noaa.gov/SL.us008001/ST.opnl/MT.ghm_CY.xx
where xx is the model cycle
and at the NCEP servers at:
www.ftp.ncep.noaa.gov/data/nccf/com/hur/prod/hur.YYYYMMDDHH
and
ftp.ncep.noaa.gov/pub/data/nccf/com/hur/prod/hur.YYYYMMDDHH
where YYYY is year, MM is month, DD is day, and HH is model
cycle.
More details about the GFDL hurricane prediction system are
available at:
http://www.gfdl.noaa.gov/operational-hurricane-forecasting
NCEP encourages all users to ensure their decoders are flexible
and are able to adequately handle changes in content order,
changes in the scaling factor component within the product
definition section (PDS) of the GRIB files, and also any volume
changes which may be forthcoming. These elements may change with
future NCEP model implementations. NCEP will make every attempt
to alert users to these changes prior to any implementations.
For questions regarding these model changes, please contact:
Morris Bender
GFDL/NOAA
Princeton, NJ
Phone: 609-452-6559
morris.bender@xxxxxxxx
Timothy Marchok
GFDL/NOAA
Princeton, NJ
Phone: 609-452-6534
timothy.marchok@xxxxxxxx
NWS National Technical Implementation Notices are online at:
http://www.nws.noaa.gov/os/notif.htm
$$