NOUS41 KWBC 121620
PNSWSH
Technical Implementation Notice 10-50
National Weather Service Headquarters
120 PM EDT Tue Oct 12 2010
To: Subscribers:
-Family of Services
-NOAA Weather Wire Service
-Emergency Managers Weather Information Network
-NOAAPORT
Other NWS Partners, Users and Employees
From: Timothy McClung
Chief, Science Plans Branch
Office of Science and Technology
Subject: Changes to the North American Ensemble Forecasting
Effective Tuesday, January 11, 2011,
beginning with the 1200 Coordinated Universal Time (UTC) run, the National
Centers for Environmental Prediction (NCEP) will make modifications to the
North American Ensemble Forecasting System (NAEFS). The current NAEFS output is derived by
combining the NCEP Global Ensemble Forecast System (GEFS) and the
The NAEFS
output is disseminated only via the NCEP server. Products are available for http and ftp
download at the following URLs:
http://www.ftp.ncep.noaa.gov/data/nccf/com/gens/prod/
and
ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/gens/prod/
In addition to including the FNMOC data in
the NAEFS ensemble calculations, NCEP will also be modifying the output available from the NCEP GEFS, CMC GEFS, and the NAEFS. These modifications include:
Adding the following 13 bias-corrected
elements to the NCEP
GEFS and NAEFS output for all probabilistic
products:
10 hPa(mb) geopotential height
10 hPa(mb) temperature
10 hPa(mb) u component of wind
10 hPa(mb) v component of wind
50 hPa(mb) geopotential height
50 hPa(mb) temperature
50 hPa(mb) u component of wind
50 hPa(mb) v component of wind
100 hPa(mb) geopotential height
100 hPa(mb) temperature
100 hPa(mb) u component of wind
100 hPa(mb) v component of wind
850 hPa(mb) vertical velocity
The
directory location of the raw CMC GEFS data will be changed. Starting on January 11, the GRIB2 output for
the individual member and ensemble means and spreads will be online in the
following directories, where YYYYMMDD is the date and CC is the model cycle:
http://www.ftp.ncep.noaa.gov/data/nccf/com/gens/prod/cmce.YYYYMMDD/CC/pgrb2a
and
ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/gens/prod/cmce.YYYYMMDD/CC/pgrb2a/
In
addition, the following 28 variables will be added to the CMC output:
10 hPa(mb) geopotential height
10 hPa(mb) temperature
10 hPa(mb) relative humidity
10 hPa(mb) u component of wind
10 hPa(mb) v component of wind
50 hPa(mb) geopotential height
50 hPa(mb) temperature
50 hPa(mb) relative humidity
50 hPa(mb) u component of wind
50 hPa(mb) v component of wind
100 hPa(mb) geopotential height
100 hPa(mb) temperature
100 hPa(mb) relative humidity
100 hPa(mb) u component of wind
100 hPa(mb) v component of wind
850 hPa(mb) vertical velocity
Convective inhibition (CIN 180-0 hPa)
Latent heat net flux
Sensible heat net flux
Downward shortwave radiation flux at
surface
Downward longwave radiation flux at surface
Upward shortwave radiation flux at surface
Upward longwave radiation flux at surface
Upward longwave radiation flux at top of
atmosphere
Volumetric soil moisture (0-10cm)
Water
equivalent of accumulated snow depth
Snow depth (surface)
Soil temperature (0-10cm down)
Data
delivery timing is not expected to be impacted by the implementation. There
will only be a minor increase in the data volumes of existing files due to the
addition of new variables.
A sample
dataset for this NAEFS implementation is available at:
ftp://ftp.emc.ncep.noaa.gov/gc_wmb/yzhu/1q2011
Specific
information regarding the NAEFS and scientific implementation is online at:
http://www.emc.ncep.noaa.gov/gmb/yzhu/html/imp/201012_imp.html
By early
December, once the model is running in parallel on the NCEP Central Computing
System, a consistent parallel feed of data will be available on the NCEP
server. The parallel data will be
available via the following URLs:
http://www.ftp.ncep.noaa.gov/data/nccf/com/gens/para
and
ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/gens/para
NCEP urges
all users to ensure their decoders can handle changes in content order, changes
in the scaling factor component within the product definition section (PDS) of
the GRIB files, and volume changes. These elements may change with future NCEP
model implementations. NCEP will make every attempt to alert users to these
changes before implementation.
For
questions regarding these changes, please contact:
Yuejian Zhu
NCEP/Global Modeling Branch
301-763-8000 X 7052
Yuejian.Zhu@noaa.gov
For
questions regarding the dataflow aspects of these datasets, please contact:
Rebecca Cosgrove
NCEP/NCO Dataflow Team
301-763-8000 X 7198
ncep.pmb.dataflow@noaa.gov
NWS National Technical Implementation
Notices are online at:
http://www.nws.noaa.gov/os/notif.htm
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