NOUS41 KWBC 111553


Public Information Statement, Comment Request

National Weather Service Headquarters Washington DC

1155 AM EDT Mon Aug 11 2014

To:††††† Subscribers:

†††††††† -Family of Services

†††††††† -NOAA Weather Wire Service

†† ††††††-Emergency Managers Weather Information Network

†††††††† -NOAAPORT

†††††††† Other NWS users and employees

From:††† Mark Tew

†††††††† Chief, Marine and Coastal Services Branch

Subject: Comments Solicited from August 19, 2014, through

†††† ††††November 30, 2014 on Experimental Tropical Cyclone

†††††††† Threat Grids Added to the National Digital Forecast

†††††††† Database

Effective August 19, 2014, NWS Weather Forecast Offices (WFO)

will begin providing, on an experimental basis, four Tropical

Cyclone Threat grids in the National Digital Forecast Database



The following four Tropical Cyclone (TC) Threat grids will be

added to the NDFD experimentally; wind, storm surge, flooding

rain, and tornado.


There are five levels to describe each TC Threat grid: None, Low,

Moderate, High and Extreme.The TC Threat elements provide the

reasonable worst case scenario, taking into account the forecast

magnitude of the hazard along with the associated uncertainty of

the forecast. The elements are produced only by coastal WFOs

along the Atlantic and Gulf coasts as well as San Juan, PR,

whenever tropical cyclone watches and warnings are in effect for

their area of responsibility (AOR).

The grids are valid for the duration of the event because they do

not convey specific timing. The WFOs will provide updates at

least every 6 hours shortly after the National Hurricane Centerís

advisory and will cease sending updates when tropical cyclone

watches and warnings are no longer in effect for a WFOs AOR.


More details regarding these grids are available in the

Product Description Document in the online catalog of

Experimental NWS products and services available at:


With this implementation, the TC Threat grids will be

available from NDFD in the following 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)

- Graphics via web browser


Graphics and XML services for the TC Threat grids will become

available within 30 days of the experimental release of GRIB2

files into the NDFD.


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

Internet or via the Family of Services (FOS) server, may need to

update their procedures and scripts to access these new elements.

The GRIB2 files are available online at:


CONUS Sector


Puerto Rico Sector


with the following file names used:


Wind††††††††††††††† ds.tcwt.bin

Storm Surge†††††††† ds.tcsst.bin

Flooding Rain†††††† ds.tcfrt.bin

Tornado†††††††††††† ds.tctt.bin


For customers who key on the World Meteorological Organization

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


Geographical Area†† Threat Element†† WMO Header


CONUS†††††††††††††† Wind†††††††††††† ZWUZ98 KWBN

CONUS†††††††††††††† Storm Surge††††† ZSUZ98 KWBN

CONUS†††††††††††††† Flooding Rain††† ZFUZ98 KWBN

CONUS†††††††††††††† Tornado††††††††† ZYUZ98 KWBN

Puerto Rico†††††††† Wind†††††††††††† ZWAZ98 KWBN

Puerto Rico†††††††† Storm Surge††††† ZSAZ98 KWBN

Puerto Rico†††††††† Flooding Rain††† ZFAZ98 KWBN

Puerto Rico†††††††† Tornado††††††††† ZYAZ98 KWBN


Information on accessing and using NDFD elements is online at:


Comments and feedback on these experimental TC Threat elements,

are welcome through November 30, 2014, at:


GRIB2 users:


Users OF XML SOAP service:


NDFD online graphics:


These new elements will remain experimental until NWS assesses

feedback and completes a Technical Analysis. At that time, the

NWS will determine whether to move these experimental elements to

operational status, discontinue them, or revise and extend the

experimental feedback period.

If August 19, 2014, is declared a Critical Weather Day this

implementation date will be postponed.Users will be notified of

that decision via another Public Information Statement and a new

implementation date will be established.


If you have questions regarding this notice, please contact:

John F. Kuhn

Marine and Coastal Weather Services†††

National Weather Service Headquarters

Silver Spring Maryland 20910

301-713-1677 X121


For general questions regarding NDFD data, please email:

For technical questions regarding NDFD data, please contact:

David Ruth

Mesoscale Prediction Branch Chief

NOAA/NWS Office of Science and Technology

Silver Spring, Maryland



NDFD Public Information Statements are online at:


All National Technical Implementation Notices are online at: