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-------- Original Message --------
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NOUS41 KWBC 251922
PNSWSH
Technical Implementation Notice 11-35
National Weather Service Headquarters Washington DC
322 PM EDT Mon Jul 25 2011
To: Subscribers:
-Family of Services
-NOAA Weather Wire Service
-Emergency Managers Weather Information Network
-NOAAPORT
Other NWS partners and NWS employees
From: Tim McClung
Chief, Science Plans Branch
Office of Science and Technology
Subject: Changes and Additions to NAM-DNG Products,
Including Distribution of New High-Resolution DNG
Effective October 11, 2011
Effective October 11, 2011, after upgrade of the North American
Mesoscale (NAM) prediction system, and inclusion of high
resolution nests (see TIN 11-16), the National Centers for
Environmental Prediction (NCEP) will modify and enhance the suite
of NAM Downscaled Numerical Guidance (NAM-DNG).
The current NAM-DNG products are distributed to the Continental
U.S. (CONUS), Alaska, Hawaii and Puerto Rico out to 84 hours over
the AWIPS SBN/NOAAPORT and are available on the NCEP server. The
new NAM nests are run only to 60 hours but are run at resolutions
much closer to the National Digital Forecast Database (NDFD)
forecast grids used in the DNG than the 12km NAM, now called the
parent grid.
After the modification of existing NAM-DNG is, as stated in
TIN11-16, the first 60 hours (54 hours) of the current 0000 and
1200 UTC (0600 and 1800 UTC), NAM-DNG will come from the NAM
nests instead of from the 12km NAM parent.
--CONUS: the 4km NAM nest will feed 5km NAM-DNG.
--Alaska: the 6km NAM nest will feed 5.9km NAM-DNG.
--Hawaii, Puerto Rico: 3km NAM nests will feed 2.5km NAM-DNG.
In this way, only slight downscaling (or upscaling in the case of
CONUS) is required. Currently, all systems downscale from 12km.
After the change, there may be some unavoidable amount of
discontinuity between the NAM-nest-based 60 hr (54 hr for 0600
and 1800 UTC) and the NAM-parent-based 63 hr (57 hr for 0600 and
1800 UTC) guidance. These modifications will occur when the NAM
upgrade, detailed in TIN 11-16 linked below, is implemented later
this summer.
www.weather.gov/os/notification/tin11-16nam_changes_aaa.htm
The enhancement of NAM-DNG will come from the addition of
NAM-DNG for CONUS and Alaska at double the present NDFD
resolution through the 60 hours covered by the NAM nests.
For CONUS, the 4km NAM nest will feed a 2.5km NAM-DNG. For
Alaska, the 6km NAM nest will feed a 3km NAM-DNG. Output will be
made available every 3 hours from 0-60 hours for all 4 NAM
cycles.
These new high-resolution NAM-DNG products will be available on
the NCEP server when the NAM upgrade is implemented and will be
made available on NOAAPORT starting with the 1200 Universal
Coordinated Time (UTC) cycle Tuesday, October 11, 2011.
Additionally, simulated composite reflectivity will be added to
output for both the modified and enhanced NAM-DNG.
The grids listed below in Table 1 for CONUS and Table 2 for
Alaska will be available at double NDFD resolutions.
NCEP will remove the coarser 5km CONUS and 5.9km Alaska NAM-DNG
products from NOAAPORT and all other distribution methods once
sufficient time has passed to allow software upgrades. A
separate announcement will be sent before removing these
products.
Table 1: NAM-DNG products available over CONUS at
2.5km resolution and their associated WMO headers
WMO Header NAM-DNG Parameter
[L|M]AJ*** KWBE Dewpoint temperature
[L|M]AJ*** KWBE Cloud Cover
[L|M]AJ*** KWBE Wind Speed
[L|M]AJ*** KWBE Wind Direction
[L|M]AJ*** KWBE Wind Gust Speed
[L|M]DJ*** KWBE Probability of Precipitation (3, 6& 12 hourly)
[L|M]EJ*** KWBE Total Precipitation (3, 6& 12 hourly)
[L|M]HJ*** KWBE Boundary layer height or wet bulb zero height
[L|M]KJ*** KWBE Visibility
[L|M]RJ*** KWBE Minimum/Maximum relative humidity(3& 12 hourly)
[L|M]SJ*** KWBE Snow depth (3& 6 hourly)
[L|M]TJ*** KWBE Temperature
[L|M]TJ*** KWBE Minimum/Maximum temperature (3& 12 hourly)
[L|M]UJ*** KWBE U component of wind
[L|M]VJ*** KWBE V component of wind
[L|M]ZJ*** KWBE simulated composite reflectivity
Table 2: NAM-DNG products available over Alaska at 3km
resolution and their associated WMO headers
WMO Header NAM-DNG Parameter
[L|M]AK*** KWBE Dewpoint temperature
[L|M]AK*** KWBE Cloud Cover
[L|M]AK*** KWBE Wind Speed
[L|M]AK*** KWBE Wind Direction
[L|M]AK*** KWBE Wind Gust Speed
[L|M]DK*** KWBE Probability of Precipitation (3, 6& 12 hourly)
[L|M]EK*** KWBE Total Precipitation (3, 6& 12 hourly)
[L|M]HK*** KWBE Boundary layer height or wet bulb zero height
[L|M]KK*** KWBE Visibility
[L|M]RK*** KWBE Minimum/Maximum relative humidity(3& 12 hourly)
[L|M]SK*** KWBE Snow depth (3& 6 hourly)
[L|M]TK*** KWBE Temperature
[L|M]TK*** KWBE Minimum/Maximum temperature (3 and 12 hourly)
[L|M]UK*** KWBE U component of wind
[L|M]VK*** KWBE V component of wind
[L|M]ZK*** KWBE simulated composite reflectivity
A website outlining all of the NAM-DNG WMO headers is online at:
www.nco.ncep.noaa.gov/pmb/changes/nam_dng_wmoheaders.shtml
The NAM-DNG grids are made available from the NCEP server at:
ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/nam/prod/
or
http://www.ftp.ncep.noaa.gov/data/nccf/com/nam/prod
There are files for the four nests: smartconus, smartak, smarthi
and smartpr followed by the two-digit forecast hour. The CONUS
files will be named smartconus for the 5km and smartconus2p5 for
the 2.5km. Similarly Alaska files will be smartak for the 6km
grids and smartak3 for the 3km grids.
For questions regarding the NAM-DNG, please contact:
Geoff DiMego
NCEP/Environmental Modeling Center
Camp Springs, MD 20746
301-763-8000 x 7221
geoff.dimego@xxxxxxxx
or
Geoff Manikin
NCEP/Environmental Modeling Center
Camp Springs, MD 20746
301-763-8000 x 7263
geoffrey.manikin@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
National Technical Implementation Notices are online at:
http://www.weather.gov/os/notif.htm
$$
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