NOUS41 KWBC 311725



Service Change Notice 16-36

National Weather Service Headquarters, Washington, DC

125 PM EDT Wed Aug 31 2016


TO:        Subscribers:

           -NOAA Weather Wire Service

           -Emergency Managers Weather Information Network


           Other NWS partners and NWS employees


FROM:      John Ferree

           Acting Chief, Severe, Fire, Public and Winter Weather

           Services Branch


           Tim Oram

           Acting Chief, Marine, Tropical and Tsunami Services



SUBJECT:   Tornado and Severe Thunderstorms Watches May Include

           Outer Marine Zones Effective September 29, 2016


Effective Thursday, September 29, 2016, at 1800 Coordinated

Universal Time (UTC), Continental U.S. Tornado and Severe

Thunderstorm Watches may include outer marine zones. Currently

Tornado and Severe Thunderstorm watches can only include the near-

shore marine zones, out to approximately 20 miles off-shore. This

change allows watches to extend to the outer marine zones, to

approximately 60 miles off-shore.


Inclusion of the outer marine zones in some Tornado and Severe

Thunderstorm Watches will give a more complete understanding of the

severe thunderstorm risk to mariners, particularly in the Gulf of

Mexico and off the Atlantic Coast. Tornado Watches and Severe

Thunderstorm Watches will only include the outer marine zones when

the adjacent near-shore marine zones are included in the watch.


This change only affects Tornado Watches and Severe Thunderstorm

Watches. Warnings are not impacted by this change, and only Special

Marine Warnings will continue to be issued in these outer marine

zones. There is not a change to product formats.



Maps of the inner and outer coastal marine zones around the

CONUS are posted at


(click marine coastal areas for detail).


These zones are described further in NWS Instruction 10-302

found at:

List of additional marine zones potentially included in a tornado

or severe thunderstorm watch:


GMZ170     ANZ070     AMZ170     PZZ170

GMZ175     ANZ071     AMZ172     PZZ173

GMZ270     ANZ170     AMZ174     PZZ176

GMZ275     ANZ172     AMZ176     PZZ270

GMZ370     ANZ174     AMZ178     PZZ275

GMZ375     ANZ270     AMZ270     PZZ370

GMZ470     ANZ271     AMZ272     PZZ376

GMZ472     ANZ272     AMZ274     PZZ470

GMZ475     ANZ273     AMZ276     PZZ475

GMZ570     ANZ370     AMZ370     PZZ570

GMZ572     ANZ373     AMZ372     PZZ571

GMZ575     ANZ375     AMZ374     PZZ575

GMZ577     ANZ470     AMZ470     PZZ576

GMZ670     ANZ471     AMZ472     PZZ670

GMZ675     ANZ472     AMZ474     PZZ673

GMZ770     ANZ473     AMZ570     PZZ676

GMZ775     ANZ475     AMZ572     PZZ775

GMZ870     ANZ670     AMZ575

GMZ873     ANZ672     AMZ670

GMZ876     ANZ674     AMZ671

GMZ676     ANZ676

GMZ033     ANZ678








For more information, please contact:


John Ferree

Severe Storms Services Leader


Telephone: (405) 325-2209


National Public Information Notices are online at: