[nws-changes] 20110325: GFDL hurricane prediction system chgs-Fwd: ADMIN NOTICE NOUS41 KWBC

• To: nws-changes@xxxxxxxxxxxxxxxx
• Subject: [nws-changes] 20110325: GFDL hurricane prediction system chgs-Fwd: ADMIN NOTICE NOUS41 KWBC
• From: Linda Miller <lmiller@xxxxxxxxxxxxxxxx>
• Date: Fri, 25 Mar 2011 08:44:21 -0600

-------- 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

$$