NOUS41 KWBC 051509



Technical Implementation Notice 13-07

National Weather Service Headquarters Washington DC

1010 AM EST Tue Mar 5 2013


To:      Subscribers:

         -Family of Services

         -NOAA Weather Wire Service

         -Emergency Managers Weather Information Network


         Other NWS Partners...and NWS Employees


From:    Mark Tew

         Chief, Marine and Coastal Services Branch


Subject: NWS Transitioning from Deterministic To Probabilistic

         Storm Surge Forecasts effective with the

         2013 Hurricane Season


Effective with the 2013 hurricane season and thereafter, the NWS

will no longer provide deterministic Sea, Lake, and Overland

Flooding from Hurricanes (SLOSH) model output during tropical

cyclones in an unofficial manner.


The American Meteorological Society and the National Academies of

Science have endorsed greater use of probabilistic forecasts by

NWS. For several years, the National Hurricane Center (NHC) has

been providing probabilistic storm surge products as part of a

long-term, multiyear NWS effort to improve communications on

storm surge. 


SLOSH deterministic guidance was informally provided to some

users over the past several years; however, the deterministic

SLOSH model output has the potential to conflict with the

official NWS forecast for storm surge and to interfere with

evacuation decisions from emergency managers.


A description of the current suite of operational, probabilistic

storm surge guidance products is provided on line at:


The NWS will again provide an experimental suite of probabilistic

storm surge products for 2013 that communicate inundation in

terms of feet above ground level. This information will be

provided on an interactive Google Earth background map and as a

static image. Information on these experimental products is

available at:


A separate Public Information Statement on these experimental

products will be disseminated prior to May 15, 2013.


In addition to the operational and experimental probabilistic

storm surge products, the NWS is also actively developing

inundation graphics and a storm surge watch/warning.


For technical questions regarding this notice, please contact:


      Jamie Rhome

      National Hurricane Center

      Storm Surge Team Lead

      Miami, FL  33165



For policy questions regarding this notice, please contact:


      Timothy Schott

      NWS Marine and Coastal Services Branch

      Silver Spring Maryland 20910

      301-713-1677 X122


National Technical Implementation Notices are online at: