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NOUS41 KWBC 221253
PNSWSH
Technical Implementation Notice 11-09
National Weather Service Headquarters Washington DC
853 AM EDT Tue Mar 22 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: Hurricane Weather and Research Forecast (HWRF) Model
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 HWRF -
Princeton Ocean Model (POM) coupled system. The scientific
enhancements include the following:
- Upgrade WRF NMM dynamic core from v2.0 to v3.2
- Modify vortex size corrections based on radius of
outermost closed isobar (ROCI) and radius of 34kt winds
- Upgrade HWRF Grid point Statistical Interpolation (gsi)
analysis scheme to community version 2.5
- Upgrade Simplified Arakawa-Schubert (SAS) deep convection
parameterization to new version implemented in the NCEP
Global Forecast System (GFS)
- Modify surface enthalpy exchange coefficient at high
wind speeds
- Expand coupled region in the Eastern Atlantic domain to
prevent storms from loosing coupling effect with the ocean
due to insufficient overlap with the Western Atlantic region
- Upgrade HWRF post-processing to new NCEP Unified Post
Processor (UPP)
Test results from the combination of these upgrades showed
improved track and intensity forecast skill, reduced initial
growth of errors (spin-up and spin-down) and reduced intensity
bias for the Atlantic and a majority of the eastern North
Pacific basins.
Product Changes:
The following elements will be added to the HWRF model output
GRIB files:
- Angle corrected simulated goes satellite imagery products
/infrared and water vapor channels/
- Simulated microwave satellite imagery products
- Additional vertical pressure levels for three-dimensional
variables
The frequency of model output will be increased from 6 hourly to
3 hourly for all variables
The HWRF 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 an increase of roughly 2GB in product size due to
the additional elements.
More details about the HWRF-POM are available at:
http://www.emc.ncep.noaa.gov/HWRF/index.html
NCEP encourages 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 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:
Dr. Vijay Tallapragada
NCEP/Environmental Modeling Center
Hurricane Forecast Project
Camp Springs, Maryland
301-763-8000 x 7232
vijay.tallapragada@xxxxxxxx
NWS National Technical Implementation Notices are online at:
http://www.nws.noaa.gov/os/notif.htm
$$
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