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-------- Original Message --------
Subject: ADMIN NOTICE NOUS41 KWBC
Date: Fri, 1 Oct 2010 04:57:39 -0600
From: Unidata Local Data Manager <ldm@xxxxxxxxxxxxxxxx>
To: ldmnotices@xxxxxxxxxxxxxxxx
077
NOUS41 KWBC 011057
PNSWSH
Technical Implementation Notice 10-44: Amended
National Weather Service Headquarters Washington DC
657 AM EDT Fri Oct 1 2010
To: Subscribers:
-Family of Services
-NOAA Weather Wire Service
-Emergency Managers Weather Information Network
-NOAAPORT
Other NWS Partners...Users and Employees
From: Tim McClung
Science Plans Branch Chief
Office of Science and Technology
Subject: Amended: Multi-grid Hurricane Wave Model Upgrade:
Rescheduled for October 26, 2010
Due to the need for additional testing, NCEP is postponing this
implementation from October 19 to October 26, 2010.
Effective Tuesday, October 26, 2010, beginning with the 1200
Coordinated Universal Time (UTC) run, the National Centers for
Environmental Prediction (NCEP) will implement a new Hurricane
Wave Model. This multi-grid hurricane wave model will replace
the existing North Atlantic Hurricane (NAH) and North Pacific
Hurricane (NPH) wave models. The model upgrade will result in a
change of 27 minutes to the product dissemination time and the
generation of new products. Details of these changes are
outlined below.
Model Changes:
Instead of two separate models, the hurricane wave model will
now be a single model with multiple two-way nested grids. The
new multi-grid hurricane wave model will use WAVEWATCH-III
v3.14, the same model version as NCEPs Global Multi-grid Wave
Model (the current NAH and NPH use WAVEWATCH-III v 2.22). The
upgrade to version 3.14 will result in the following:
- Upgraded shallow water physics, which accounts for shallow
water processes such as wave breaking. Together with the
increased wave resolution in coastal regions, this change will
provide a better representation of wave physics in land
falling hurricanes.
- Increasing internal model spectral resolution to 50 components
in frequency and 36 components in direction. Spectral output
at the points will continue to be 29 components in frequency
and 24 components in direction.
- Adding a new algorithm to partition the spectral energy into
wind wave, primary and secondary swells. Spectral parameters
for these different fields (wave height, peak period and
direction) will be part of the model output on the new grids
listed below. These fields will not be added to the existing
NAH and NPH products.
Wind forcing for the global, Alaskan and Pacific Island grids
will be from the Global Forecast System (GFS) winds while all
the other grids will be a blend of the GFS and GFDL hurricane
model winds, as is currently done in the NAH and NPH. The only
exception is the Hawaiian Islands, part of the Pacific Island
grid, which also will have a blend of GFS and GFDL hurricane
model wind forcings.
Product Changes
As a result of this upgrade, all of the output products from the
new multi-grid hurricane model will be disseminated 27 minutes
later than the current NAH and NPH output products. Any
concerns with this change in product dissemination time should
be directed to the contact points listed below.
The output grids from the multi-grid hurricane wave model will
be as follows:
Products with 25x24 spectral resolution:
-Current 0.25 degree NAH grids
-Current 0.25 degree NPH grids
Products with 50x36 spectral resolution:
-New 0.5 degree global domain grid
-New 0.25 degree regional domain for North Atlantic (domain
corresponds to current NAH grid)
-New 0.25 degree regional domain for North Pacific (domain
corresponds to current NPH grid)
-New 10 arc min grid for the North Atlantic regional waters
-New 10 arc min grid for the North Pacific regional waters
-New 10 arc min grid for the Pacific Islands and Hawaii
-New 10x15 arc min grid for the Alaskan waters
-New 4 arc min grid for the US East Coast
-New 4 arc min grid for the US West Coast (including the
coastal waters of Hawaii)
-New 8x4 arc min grid for the Alaskan coast
NCEP will continue to produce the current NAH and NPH output
products, including their respective point output files, until
further notice. These products will be generated using output
from the new multi-grid hurricane wave model.
The new grids will be disseminated via the NCEP server and will
be incorporated into AWIPS on a yet-to-be-determined date. More
details about the NCEP Multi-Grid Hurricane Wave Model are
available at:
http://polar.ncep.noaa.gov/waves/index2.shtml
A consistent parallel feed of data will become available on the
NCEP server once the model is running in parallel on the NCEP
Central Computing System, around September 7, 2010. At this
time, the parallel data will be available at::
http://www.ftp.ncep.noaa.gov/data/nccf/com/wave/para
or
ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/wave/para
Users should ensure their decoders are flexible and are able to
adequately handle changes in content, parameter fields changing
order, changes in the scaling factor component within the
Product Definition Section (PDS) of the GRIB files, and any
volume changes that may occur. These elements may change with
future NCEP model implementations. NCEP will make every attempt
to alert users to these changes prior to any implementation.
For questions regarding these model changes, please contact:
Hendrik Tolman
NCEP/Marine Modeling and Analysis Branch
Camp Springs, Maryland
301-763-8000 x 7253
hendrik.tolman@xxxxxxxx
For questions regarding the dataflow aspects of these data sets,
please contact:
Rebecca Cosgrove
NCEP/NCO Dataflow Team
Camp Springs, Maryland 20746
301-763-8000 x 7198
ncep.list.pmb-dataflow@xxxxxxxx
NWS National Technical Implementation Notices are online at:
http://www.nws.noaa.gov/os/notif.htm
$$
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