NOUS41 KWBC 161140 AAA
Technical
Implementation Notice 11-09, Amended
National
Weather Service Headquarters Washington DC
740 AM EDT Mon May 16 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:
Amended: Hurricane Weather and Research Forecast
(HWRF) Model Changes: Effective May 24, 2011
Amended to reschedule this implementation from May 17 to
May 24 to avoid upgrading both NCEP hurricane models on the same day.
Effective
Tuesday, May 24, 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 losing 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
NWS
National Technical Implementation Notices are online at:
http://www.nws.noaa.gov/os/notif.htm
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