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TECHNICAL IMPLEMENTATION NOTICE 08-42
NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC
205 PM EDT TUE MAY 20 2008

TO:       SUBSCRIBERS:
          -FAMILY OF SERVICES
          -NOAA WEATHER WIRE SERVICE
          -EMERGENCY MANAGERS WEATHER INFORMATION NETWORK
          OTHER NWS PARTNERS...USERS AND EMPLOYEES

FROM:     JASON TUELL
          SCIENCE PLANS BRANCH CHIEF
          OFFICE OF SCIENCE AND TECHNOLOGY 

SUBJECT:  ENSEMBLE WAVE MODEL CHANGES: EFFECTIVE JUNE 24 2008

EFFECTIVE TUESDAY JUNE 24 2008...BEGINNING WITH THE 1200 
COORDINATED UNIVERSAL TIME /UTC/ RUN...THE NATIONAL CENTERS FOR
ENVIRONMENTAL PREDICTION /NCEP/ WILL INTRODUCE CHANGES TO THE 
ENSEMBLE WAVE MODEL. THE MODEL CHANGES INCLUDE:

1. USING THE NEW MULTI-GRID WAVEWATCH-III MODEL TO DRIVE THE
   ENSEMBLES. THIS MODEL IS CURRENTLY BEING USED IN THE
   FORECAST WAVE MODEL AND INCLUDES UPGRADES TO MODEL PHYSICS.

2. ADDING A 1 DEGREE X 1 DEGREE GLOBAL GRID THAT EXTENDS FROM
   -80S TO 80N. 

3. EXTENDING ENSEMBLE MEMBERS FROM 10 TO 20.

4. EXTENDING FORECASTS FROM 5 DAYS TO 10 DAYS.

5. INSTEAD OF USING THE SAME RESTART FILE FOR ALL THE ENSEMBLE
   MEMBERS...THE ENSEMBLE MEMBERS WILL NOW RETAIN THEIR OWN
   INDIVIDUAL RESTART FILES. THIS PROVIDES GREATER VARIABILITY
   IN THE ENSEMBLES...MAKING THE STATISTICS MORE MEANINGFUL. 

6. PROVIDING ALL OUTPUT FILES IN GRIB2 FORMAT.

THE COMBINED IMPACT OF THESE CHANGES HAS LED TO AN IMPROVEMENT
IN MODEL PERFORMANCE BECAUSE THERE IS A GREATER SPREAD IN THE
WAVE DATA WHICH ACCURATELY REFLECTS THE SPREAD IN THE WIND
ENSEMBLES. THIS CHANGE IN TURN PROVIDES BETTER STATISTICAL
ESTIMATES.

DATA DELIVERY TIMING/CONTENT/VOLUME CHANGES:

NOAAPORT DATA: THESE DATA SETS ARE NOT AVAILABLE ON NOAAPORT.

NWS FTP SERVER: THESE DATA SETS ARE NOT AVAILABLE ON THE NWS FTP 
SERVER.

NCEP FTP SERVER: A CONSISTENT FEED OF TEST DATA WILL BECOME 
AVAILABLE ON MAY 19 2008 IN THE FOLLOWING LOCATION ON THE NCEP 
FTP SERVER /USE LOWERCASE LETTERS/:

  FTP://FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/WAVE/PARA

FILENAMES AFFECTED BY THIS CHANGE CONTAIN ONE OF THE FOLLOWING 
QUALIFIERS /USE LOWERCASE LETTERS/:

  MENS
  GEP
  MEAN
  SPREAD
  PROBAB

IF YOU HAVE QUESTIONS ABOUT THESE CHANGES...PLEASE CONTACT: 

  HENDRIK TOLMAN
  NCEP/EMC...CHIEF MARINE MODELING BRANCH
  CAMP SPRINGS MARYLAND
  PHONE: 301 763 8000 X7253
  EMAIL: HENDRIK.TOLMAN@NOAA.GOV
 
FOR QUESTIONS REGARDING THE DATAFLOW ASPECTS OF THESE DATA 
SETS...PLEASE CONTACT THE NCEP/NCO/PMB DATAFLOW HELP DESK AT:

   EMAIL: NCEP.PMB.DATAFLOW@NOAA.GOV

NWS TECHNICAL IMPLEMENTATION NOTICES ARE ONLINE AT  
/USE LOWER CASE LETTERS/:

  HTTP://WWW.NWS.NOAA.GOV/OM/NOTIF.HTM

$$
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