NOUS41 KWBC 231822
PNSWSH
Public Information Notice
National Weather Service Headquarters Washington DC
120 PM EDT Thu Aug 23 2012
To: Subscribers:
- Family of Services
- NOAA Weather Wire Service
- Emergency Managers Weather Information Network
- NOAAPORT
Other NWS partners and NWS employees
From: Jason Tuell
Chief, Meteorological Services Division
Subject: Seeking Comments on Increasing the Resolution in the
National Digital Forecast Database (NDFD) Effective
August 28, 2012
Effective Tuesday, August 28, 2012, at 10:00 am EDT, 1400
Coordinated Universal Time (UTC), the NDFD spatial resolution
will become available in experimental status at 2.5km resolution
for all forecast times. The NDFD temporal resolution will be
available in experimental status at 1 hour resolution for the
first 36 hours from NDFD issuance time. These are the finest
spatial and temporal resolutions at which Weather Forecast Offices
in the Conterminous United States (CONUS) provide forecasts.
Forecasts from NWS offices and centers employing coarser
resolutions will be mapped onto the finer resolution NDFD grid.
This change will affect files which contain data for the entire
CONUS, but will not include Alaska, Hawaii, Guam, Puerto Rico
and the Virgin Islands, or the 16 CONUS subsectors which will
remain at their current operational resolutions.
Specifications for operational and experimental NDFD grids
can be viewed at the following URL:
http://graphical.weather.gov/docs/ndfdSRS.htm
Operational NDFD data will continue to be provided in parallel at
current spatial and temporal resolutions throughout the experimental
120 day period. Experimental fine resolution forecasts will be updated
approximately 15 minutes after operational NDFD forecasts. NDFD
graphics and SOAP/REST/XML services will continue to be provided from
operational NDFD grids during the experimental 120 day period.
To access experimental fine resolution grids, go to:
ftp://tgftp.nws.noaa.gov/sl.us008001/st.expr/df.gr2/dc.ndfd/ar.conus/
or
http://weather.noaa.gov/pub/sl.us008001/st.expr/df.gr2/dc.ndfd/ar.conus
Experimental grids for forecast days 1 through 3 will be provided in
individual files for each day to limit file sizes. Experimental grids
for selected elements will be more tightly packed in GRIB2 format with
both decimal and binary scaling applied. GRIB2 encoding characteristics
for each NDFD element can be viewed at the following URL:
http://graphical.weather.gov/docs/grib_design.html#element_encoding_lo
File structures and GRIB2 packing for operational NDFD files will remain
unchanged during the experimental period. Experimental Ice Accumulation
and daily Maximum and Minimum Relative Humidity grids will also remain
unchanged, i.e., stay at 5km resolution.
WMO headers and file structures for current operational and experimental
NDFD files can be viewed at:
http://www.nws.noaa.gov/ndfd/resources/NDFDelem_current.xls
WMO headers and files structure for the new experimental fine resolution
files can be viewed at:
http://www.nws.noaa.gov/ndfd/resources/NDFDelem_fullres.xls
At the conclusion of the 120 day period, NWS will evaluate any comments
and decide whether to proceed with operational implementation for the
entire CONUS. Current operational resolutions will continue for Alaska,
Hawaii, Guam, Puerto Rico and the Virgin Islands, and the 16 CONUS subsectors.
The NWS will accept comments and feedback on the increase in resolution
during the experimental period through at least December 31, 2012.
The survey link is online at:
http://www.nws.noaa.gov/survey/nws-survey.php?code=ndfd-grids25
General information on accessing and using NDFD elements is online at:
http://ndfd.weather.gov/technical.htm
For general questions regarding NDFD data, please email:
nws.ndfd@noaa.gov
For technical questions regarding NDFD data, please contact:
David Ruth
Chief, Mesoscale Prediction Branch
NOAA/NWS Office of Science and Technology
Silver Spring, Maryland 20910
David.Ruth@noaa.gov
For questions regarding this notice, please contact:
Andy Horvitz
National Weather Service
Office of Climate Water and Weather Services
Silver Spring, Maryland 20910
Andy.Horvitz@noaa.gov
Technical Implementation Notices specifically related to NDFD are
online at:
http://www.weather.gov/ndfd/tins.htm
National Public Information Notices are online at:
http://www.weather.gov/os/notif.htm
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