NOUS41 KWBC 161308 AAA

PNSWSH

 

Public Information Notice: Amended

National Weather Service Headquarters Washington DC

908 AM EDT Tue Jul 16 2013

 

To:       Subscribers:

          - Family of Services

          - NOAA Weather Wire Service

          - Emergency Managers Weather Information Network

          - NOAAPORT

          Other NWS partners and NWS employees

 

From:     Andrew Stern

          Acting Chief, Meteorological Services Division

 

Subject:  Amended: Extending Comment Period on Increasing the

          Resolution in the National Digital Forecast Database

          Until December 31, 2013

 

Amended to extend the comment period to December 31, 2013

 

On August 28, 2012, the spatial resolution in the National

Digital Forecast Database (NDFD) was increased, on an

experimental basis, to 2.5km resolution for all forecast times.

In addition, the temporal resolution was made accessible at one

hour resolution for the first 36 hours from NDFD issuance time in

experimental status. These are the finest spatial and temporal

resolutions at which NWS Weather Forecast Offices (WFOs) in the

conterminous United States (CONUS) provide forecasts.  Forecasts

from WFOs and NWS National Centers that employ coarser

resolutions are mapped onto the finer resolution NDFD grid.

 

The increased spatial and temporal resolution applied to files

containing data for the entire CONUS, but not Alaska, Hawaii,

Guam, Puerto Rico, the Virgin Islands, or the 16 CONUS

subsectors. These subsectors remain at their current operational

resolutions.

 

The NWS will accept comments and feedback on the increase in

resolution during the experimental period through December 31,

2013.  Links to surveys are online at:

 

http://www.nws.noaa.gov/survey/nws-survey.php?code=ndfd-grids25

 

Pending analysis of comments, the NWS will decide whether or not

to proceed to transition the experimental fine resolution to

operational status for the CONUS.  Current operational

resolutions would continue for Alaska, Hawaii, Guam, Puerto Rico,

the Virgin Islands, and the 16 CONUS subsectors.

 

Specifications for operational and experimental NDFD grids can be

viewed at the following URL:

 

http://graphical.weather.gov/docs/ndfdSRS.htm

 

The NDFD continues in parallel in operational phase at current

spatial and temporal resolutions throughout the experimental

period. Experimental fine resolution forecasts are updated

approximately 15 minutes after operational NDFD forecasts. NDFD

graphics and Simple Object Access Protocol/REST/XML services are

provided from operational NDFD grids.

 

To access experimental fine resolution grids use the following

URLs:

 

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 are provided in

individual files for each day in order to limit file sizes. 

Experimental grids for selected elements are more tightly packed

in GRIB format with both decimal and binary scaling applied.  

GRIB 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 GRIB packing for operational NDFD files are

unchanged during the experimental period.  Experimental Ice

Accumulation and daily Maximum and Minimum Relative Humidity

grids also remain unchanged.

 

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

 

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

  1325 East West Highway

  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

  1325 East West Highway

  Silver Spring, Maryland 20910

  Andy.Horvitz@noaa.gov

 

Service Change 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

 

$$