NOUS41 KWBC 152014
AAC
PNSWSH
Technical
Implementation Notice 11-35, Amended
National Weather
Service Headquarters Washington DC
415 PM EST Thu
Nov 15 2012
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: Amended Changes and Additions to NAM-DNG
Products,
Including Distribution of New
High-Resolution DNG
Effective Date of NOAAPORT
Activation: December 4,
2012.
Amended to set
the implementation date to add these products to
NOAAPORT to
Tuesday, December 4, 2012.
The modifications
to the current NAM DNG, as part of the upgrade
of the NAM prediction system, were implemented
when the NAM
upgrade was completed on October 18, 2011. This
amended TIN
covers the addition of these products to
NOAAPORT. No changes
are being made at this time to the content of
the products.
Much of what
follows is directly from the original phrasing of
TIN
11-35, with some minor wording changes.
Effective with
the 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 implemented, as
stated in TIN 11-16, 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: 4km NAM
nest will feed 5km NAM-DNG
--Alaska: 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_aad.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. In
addition, simulated composite reflectivity will be
added to
output for both the modified and enhanced NAM-DNG.
The new high-
resolution NAM-DNG products will be made available on
NOAAPORT
on Tuesday December 4, 2012.
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
College Park, Maryland
301-683-3764
or
Geoff Manikin
NCEP/Environmental Modeling Center
College Park, Maryland
301-683-3695
For questions
regarding the dataflow aspects of these data
sets please contact:
Rebecca Cosgrove
NCEP/NCO Dataflow Team
College Park, Maryland
301-683-0567
ncep.list.pmb-dataflow@noaa.gov
National
Technical Implementation Notices are online at:
http://www.weather.gov/os/notif.htm
$$