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Technical Implementation Notice

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: