NOUS41 KWBC 272014



Service Change Notice 17-90

National Weather Service Headquarters Silver Spring MD

414 PM EDT Thu Jul 27 2017


To:        Subscribers:

           -NOAA Weather Wire Service

           -Emergency Managers Weather Information Network


           Other NWS Partners and NWS Employees


From:      Michelle Hawkins, Chief

           Severe, Fire, Public, and Winter Weather Services



Subject:   Impact Based Warnings (IBW) to Become Operational at

           NWS Pacific Region Offices Effective October 2, 2017


The NWS Pacific Region Weather Forecast Offices (WFOs) and

Weather Service Office Pago Pago, American Samoa, will transition

to the IBW format effective October 2, 2017. Alaska Region WFOs

will transition to the IBW format no later than December 31,

2017. The contiguous United States NWS WFOs transitioned

operationally to the IBW format on May 10, 2017. The NWS has been

experimenting with the IBW format since 2013 at a variety of

WFOs. Successes with this format along with comments received

from the public, partners, and social scientists have all been



Severe Thunderstorm Warning (SVR), Tornado Warning (TOR), and

Severe Weather Statement (SVS) products will be stratified into

categories distinguishing extreme cases from base convective

warnings. Additional enhanced wording will be included to convey

information about associated impacts, specific hazards expected,

and recommended actions, both within the bullet statements and as

part of the tag line codes.


Additional information and product examples are online at:


A Product Description Document (PDD) outlining the products is

online at:


For more information, please contact:


  Greg Schoor

  Acting NWS Severe Storms Services Program Leader

  Norman, OK 73072


National Service Change Notices are online at: