NOUS41 KWBC 261119



Technical Implementation Notice 13-64

National Weather Service Headquarters Washington DC

720 AM EDT Thu Sep 26 2013


To:       Subscribers:

          - Family of Services

          - NOAA Weather Wire Service

          - Emergency Managers Weather Information Network

          - NOAAPORT

          Other NWS Partners and NWS Employees


From:     Eli Jacks

          Chief, Fire and Public Weather Services Branch


Subject:  Experimental Ice Accumulation Grids

          Transition to Operational Status in the National

          Digital Forecast Database for CONUS Only

          Effective November 5, 2013


Effective Tuesday, November 5, 2013, at 1400 Coordinated

Universal Time (UTC), Ice Accumulation grids  will become

operational in the National Digital Forecast Database (NDFD) at a

select number of NWS Weather Forecast Offices (WFOs) in the

Conterminous United States (CONUS) only. The WFOs issuing these

grids, as well as more information regarding these elements, are

in the online Product Description Document (PDD):


The Ice Accumulation grids depict the expected new ice

accumulation on exposed surfaces (in hundredths of inches) during

a 6-hour period. An Ice Accumulation grid will be specified

whenever at least a trace of ice accumulation is forecast for any

hour during a valid period. The Ice Accumulation grids will be

added to the NDFD CONUS sector and to the 16 pre-defined NDFD

CONUS subsectors for each 6-hour period out to 48 hours from 

00 UTC Day 1.


With this implementation, these forecasts will be available from

NDFD in the standard methods:


- GRIdded Binary version 2 (GRIB2) files via Hypertext Transfer

  Protocol (HTTP) and File Transfer Protocol (FTP)


- eXtensible Markup Language (XML) via Simple Object Access

  Protocol (SOAP) and Representational State Transfer (REST)


- Graphics via web browser


Users who pull NDFD elements in GRIB2 format, either via the

Internet or via the Family of Services server access service, may

need to update their procedures and scripts to access these new



For customers who key on the World Meteorological Organization

(WMO) super heading to access NDFD elements, the super headings

for the operational Ice Accumulation grids are:


Geographic Area                 WMO Header

---------------                 ----------

Central Great Lakes             YZFZ98 KWBN

Central Mississippi Valley      YZHZ98 KWBN

Central Plains                  YZKZ98 KWBN

Central Rockies                 YZNZ98 KWBN

CONUS                           YZUZ98 KWBN

Eastern Great Lakes             YZEZ98 KWBN

Mid-Atlantic                    YZCZ98 KWBN

Northeast                       YZBZ98 KWBN

Northern Plains                 YZJZ98 KWBN

Northern Rockies                YZMZ98 KWBN

Pacific Northwest               YZPZ98 KWBN

Pacific Southwest               YZQZ98 KWBN

Southeast                       YZDZ98 KWBN

Southern Mississippi Valley     YZIZ98 KWBN

Southern Plains                 YZLZ98 KWBN

Southern Rockies                YZOZ98 KWBN

Upper Mississippi Valley        YZGZ98 KWBN


Customers who use the NDFD in XML via web service or the online

graphical NDFD images can use the same methods they currently use

to acquire these new operational elements


General information on accessing and using NDFD elements is

online at:


If November 5, 2013, is declared a critical weather day, this

implementation may be postponed.  In that case, partners and

users will be notified of that decision via an updated Technical

Implementation Notice as far in advance as possible.


For general questions regarding NDFD data, please email:


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


For general questions regarding the Ice Accumulation grids or

this notice, please contact:


  Andy Horvitz

  Fire and Public Weather Services Branch

  NOAA/NWS Office of Climate Water and Weather Services

  Silver Spring, Maryland 20910


National Technical Implementation Notices are online at: