NOUS41 KWBC 141539



Public Information Statement

National Weather Service Headquarters Washington DC

1140 AM EDT Wed August 14 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 Weather Services Branch 


Subject: Soliciting Comments on Experimental Probabilistic

         Tropical Cyclone Storm Surge and Tide above Datum

         Through November 30, 2013   


Effective immediately and continuing through November 30, 2013,

NWS is seeking user feedback on experimental Probabilistic

Tropical Cyclone Storm Surge and Tide above Datum. The

experimental product consists of two suites of graphics:


1. Probability of storm surge and tide above datum: Series of

graphics shows probabilities, in percent, of storm surge with

tide exceeding 2 through 25 feet above North American Datum of

1988 (NAVD88), at 1 foot intervals.


2. Exceedance height of storm surge and tide above datum: Series

of graphics which show heights of storm surge with tide, in feet

above NAVD88, which will be exceeded by a given percentage of

storms. The suite of graphics range from 10 to 50 percent, at

10 percent intervals.


The graphics are a statistical output from an ensemble of Sea

Lake and Overland Surges from Hurricanes (SLOSH) model runs.  All

ensemble members are based on the current National Hurricane

Center (NHC) tropical cyclone advisory. Ensemble members take

into account historical error characteristics by varying input

parameters such as forward speed, cross track location, radius of

maximum wind, and hurricane intensity. Each ensemble member has a

specific time associated with it, which allows SLOSH to calculate

a gridded tide the model combines with the surge, thereby

producing overland flooding based on storm surge plus tide, aka

storm tide.


The graphics are available whenever a hurricane watch or warning

is in effect for any portion of the Gulf or Atlantic U.S.

continental coasts. On a case by case basis, the graphics will

also be available when a tropical storm watch or warning is in

effect. The graphics are available online at:


by selecting "Above Datum" under the Datum drop down menu on the

left hand side.


Please provide feedback by using the brief survey and comment

form available on line at:


If you have questions regarding this notice...please contact:


      John Kuhn

      National Weather Service

      Marine and Coastal Weather Services Branch

      Silver Spring Maryland 20910

      Telephone: 301-713-1677 X121



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