NOUS41 KWBC 201125 AAA



Technical Implementation Notice 15-16 Updated

National Weather Service Headquarters Silver Spring MD

725 AM EDT Mon Mar 20 2017


To:††††† Subscribers:

†††††††† -NOAA Weather Wire Service

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

†††††††† -NOAAPORT

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


From:††† Allison Allen

†††††††† Chief, Marine, Tropical, and Tsunami Services Branch


Subject: Updated: Tropical Cyclone Threat Grids in the National

†††††††† Digital Forecast Database will Transition to

†††††††† Operational Effective June 1, 2017


Updated to add Tropical Cyclone (Hurricane) Threat Grids from

WFO Honolulu to the National Digital Forecast Database (NDFD)

beginning on or around June 1, 2017.


Effective on or around June 1, 2017, the Tropical Cyclone Threat

Grids available on the NWS NDFD will add threat grids issued by

Weather Forecast Office (WFO) Honolulu. Since their initial

implementation, the Tropical Cyclone Threat Grids have been

renamed the Hurricane Threat Grids.

The Hurricane Threat grids consist of four elements:


- Wind

- Storm surge

- Flooding rain

- Tornado


There are five levels to describe each Hurricane Threat grid.

Some minor modifications were made to the names of these threat

levels since their initial implementation based on input from

social scientists:


- Little to None (changed to add Little)

- Elevated (changed from Low)

- Moderate

- High

- Extreme


The Hurricane 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 currently produced by coastal WFOs along the

Atlantic and Gulf coasts, including San Juan, PR, whenever

tropical cyclone watches and warnings are in effect for their

area of responsibility (AOR). WFO Honolulu will begin issuing

Hurricane Threat Grids on or around June 1, 2017, whenever

tropical cyclone watches and warnings are in effect for its area

of responsibility (AOR)


Because the grids do not convey specific timing, they are valid

for the duration of the event. NWS will provide updates at least

every 6 hours shortly after the Central Pacific Hurricane

Center's advisory package is released and will cease when

tropical cyclone watches and warnings are no longer in effect

for WFO Honoluluís AOR.


Additional details regarding these grids are available in the

Product Description Document at:


The Hurricane Threat Grids from WFO Honolulu will be available

from the 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


Users who pull NDFD elements in GRIB2 format may need to

update their procedures and scripts in order to access these new

elements. The GRIB2 files are available online at:


Hawaii Sector


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 users who key on the World Meteorological Organization (WMO)

super heading to access NDFD elements, the super headings are:


Geographical Area†† Threat Element†† WMO Header

Hawaii††††††††††††† Wind†††††††† †† ††ZWSZ98 KWBN

Hawaii††††††††††††† Storm Surge†† ††ZSSZ98 KWBN

Hawaii††††††††† Flooding Rain†††† ZFSZ98 KWBN

Hawaii††††††††† Tornado††††† †††† ††ZYSZ98 KWBN

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


Graphics for the threat grids will be available in the Tropical

grid group at:


Information on accessing and using NDFD elements is online at:


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



If you have questions regarding this notice, please contact:


Jessica Schauer

NWS Marine, Tropical and Tsunami Services Branch

National Hurricane Center

Miami, FL 33165

Telephone: 305-229-4476



Wayne Presnell

NWS Marine, Tropical and Tsunami Services Branch

Silver Spring, MD20910

Telephone: 301-427-9390


Public notifications specifically related to NDFD are online at:

National Technical Implementation Notices, Public Information

Statements, and Service Change Notices are online at: