NOUS41 KWBC 271450



Service Change Notice 17-23

National Weather Service Headquarters Washington DC

1050 AM EST Mon Feb 27 2017


To:      Subscribers:

         -NOAA Weather Wire Service

         -Emergency Managers Weather Information Network


         Other NWS Partners and NWS Employees


From:    Allison Allen

         Chief, Marine, Tropical, and Tsunami Services Branch


Subject: Expansion of the tropical cyclone watch/warning

         information available in the National Tropical Cyclone

         Watch/Warning (TCV) products issued for Atlantic

         tropical cyclones Effective on or around June 1, 2017


Effective on or around June 1, 2017, the National Hurricane

Center (NHC) will expand the tropical cyclone watch and warning

information available in its National Tropical Cyclone

Watch/Warning (TCVAT#) products issued for Atlantic tropical

cyclones. In past hurricane seasons, the National TCV products

for the Atlantic basin contained only the tropical cyclone wind

watches and warnings along coastal segments issued by NHC. 

Beginning in the 2017 hurricane season, the national TCV

products from NHC for the Atlantic basin will include all 

NWS-issued zone-based tropical cyclone wind and storm surge

watches and warnings from both NHC and local Weather Forecast

Offices (WFOs) and will no longer contain breakpoint

information. Information about the new NWS storm surge

watch/warning can be found in Service Change Notice 17-16:


The process to compile the complete set of coastal and inland

watches and warnings will result in a modest delay in the

availability of the NHC-issued National TCV, which is expected

to be available within 15 minutes of the nominal advisory time

for routine advisories. In some circumstances, such as for the

issuance of special advisories, it may be delayed as much as 

45 minutes after the advisory time.  Public Information

Statements from NHC (PNSNHC) and social media may be used to

communicate significant issuance delays for any NHC products. 


The national TCV for the Atlantic Basin will contain Universal

Geographic Code (UGC) and the following Valid Time Event Codes (VTEC):


TR.A - Tropical Storm Watch

TR.W - Tropical Storm Warning

HU.A - Hurricane Watch

HU.W - Hurricane Warning

SS.A - Storm Surge Watch

SS.W - Storm Surge Warning


Examples of the National TCV product for the Atlantic Basin can

be found on the NHC website:


Additional information on UGC and VTEC can be found in NWS

Instruction (NWSI) 10-1701 and NWSI 10-1703, respectively at:


These changes to the NHC-issued national TCV do not apply to the

Pacific Basin.  National TCV products issued for the Pacific

basin from NHC (TCVEP#) and the Central Pacific Hurricane Center

(TCVCP#) will continue to use only coastal segment or island

VTEC, as appropriate, at this time. 


For more information, please contact:


Jessica Schauer

NWS Marine, Tropical and Tsunami Services Branch

Miami, FL 33165

Telephone: 305-229-4476



Wayne Presnell

NWS Marine, Tropical and Tsunami Services Branch

Silver Spring, MD 20910

Telephone: 301-427-9390



National Service Change Notices are online at: