Upgrade to NOAA WAVEWATCH III Model (Text)

TECHNICAL IMPLEMENTATION NOTICE 07-51...AMENDED
NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC
208 PM EDT MON SEP 17 2007

TO:  FAMILY OF SERVICES /FOS/ SUBSCRIBERS...NOAA WEATHER
     WIRE SERVICE /NWWS/ SUBSCRIBERS...EMERGENCY MANAGERS
     WEATHER INFORMATION NETWORK /EMWIN/SUBSCRIBERS...
     OTHER NATIONAL WEATHER SERVICE /NWS/ PARTNERS
     AND OTHER USERS...NWS EMPLOYEES

FROM:  PAUL HIRSCHBERG
       CHIEF...SCIENCE PLANS BRANCH
       OFFICE OF SCIENCE AND TECHNOLOGY /OST/

SUBJECT:  AMENDED: UPGRADE TO NOAA WAVEWATCH III MODEL:
          EFFECTIVE SEPTEMBER 18 2007

REFER TO: TECHNICAL IMPLEMENTATION NOTICE /TIN/ 07-51 
          TRANSMITTED ON AUG 2 2007

AMENDED TO INFORM USERS THAT THE REGIONAL WAVE PRODUCTS WILL BE DELAYED BY 15 MINUTES ONCE THIS IMPLEMENTATION BECOMES EFFECTIVE. THE TIMELINESS OF THE GLOBAL WAVE PRODUCTS WILL NOT BE IMPACTED.

EFFECTIVE TUESDAY SEPTEMBER 18 2007...WITH THE 1200 COORDINATED UNIVERSAL TIME /UTC/ RUN...THE NATIONAL CENTERS FOR ENVIRONMENTAL PREDICTION /NCEP/ WILL UPGRADE THE NOAA WAVEWATCH III /NWW3/ MODEL.

THE FOLLOWING CHANGES BELOW WILL BE INCORPORATED INTO THE NWW3 MODEL SYSTEM:

1. A MULTI-GRID GLOBAL MODEL THAT PROVIDES FORECAST PRODUCTS ON SEVERAL DIFFERENT GRIDS. ALL THE GRIDS HAVE INTERNAL TWO-WAY COUPLING AND EXCHANGE INFORMATION DURING THE COMPUTATION CYCLE. THE NEW GRIDS ARE:
   1. A 30 MINUTE RESOLUTION GLOBAL GRID.
   2. THREE 10 MINUTE RESOLUTION REGIONAL GRIDS COVERING THE UNITED STATES /US/ EAST/WEST COASTS AND EASTERN PACIFIC ISLANDS INCLUDING HAWAII.
   3. AN ALASKA REGIONAL GRID WITH A 15 MINUTE RESOLUTION IN LONGITUDE AND A 10 MINUTE RESOLUTION IN LATITUDE.
   4. TWO 4 MINUTE RESOLUTION COASTAL GRIDS FOR THE US EAST/WEST COASTS. THE US WEST COAST GRID ALSO INCLUDES THE COASTAL WATERS OF THE HAWAIIAN ISLANDS.
   5. AN ALASKAN COASTAL GRID WITH A RESOLUTION OF 8 MINUTES IN LONGITUDE AND 4 MINUTES IN LATITUDE.
2. FIELD OUTPUT WILL BE AVAILABLE IN GRIB2 FORMAT.
3. THE ENERGY SPECTRUM WILL BE PROPERLY PARTITIONED.
4. THE FOLLOWING ADDITIONAL OUTPUT GRIDS WILL BE AVAILABLE:
   1. PARTITIONED WAVE HEIGHT DATA FOR WIND SEAS-KPDS ID=102 PRIMARY SWELLS-KPDS ID=105-LEVEL 1 SECONDARY SWELLS-KPDS ID=105-LEVEL 2
   2. PARTITIONED PEAK PERIOD DATA FOR WIND SEAS-KPDS ID=103 PRIMARY SWELLS-KPDS ID=106-LEVEL 1 SECONDARY SWELLS-KPDS ID=106-LEVEL 2
   3. PARTITIONED MEAN DIRECTION FOR WIND SEAS-KPDS ID=101 PRIMARY SWELLS-KPDS ID=104-LEVEL 1 SECONDARY SWELLS-KPDS ID=104-LEVEL 2
5. MINOR CHANGES TO THE PHYSICS INCLUDING:
   1. LINEAR WAVE GROWTH TERM TO IMPROVE INITIAL WAVE GROWTH RESULTS
   2. A SURF ZONE BREAKING TERM TO PROVIDE MORE REALISTIC ESTIMATES OF WAVE HEIGHT FOR LAND FALLING TROPICAL SYSTEMS.
6. THE FORECAST RUN WILL NOW START NINE FORECAST HOURS PRIOR TO THE ORIGINATING TIME OF THE CYCLE AS OPPOSED TO SIX HOURS PRIOR ALLOWING FOR THREE ADDITIONAL HOURS OF ASSIMILATION. FORECAST OUTPUT CONTINUES OUT TO 180 HOURS.

THIS UPGRADED FORECAST SYSTEM WILL BE USED TO REPLACE THE CURRENT GRIDDED OUTPUT OF THE NOAA WAVEWATCH III MODELING SYSTEM. THE FOLLOWING GRIDS...WHICH ARE AVAILABLE ON NOAAPORT...WILL BE IMPACTED BY THE UPGRADE MODELING SYSTEM:

• EASTERN NORTH PACIFIC /ENP/
• WESTERN NORTH ATLANTIC /WNA/
• ALASKAN WATERS /AKW/

THE PRODUCTS/GRIDS WHICH ARE DISSEMINATED TO NOAAPORT AND/OR THE SATELLITE BROADCAST NETWORK /SBN/ WILL NOT BE CHANGED IN VOLUME OR CONTENT.

IF YOU HAVE ANY QUESTIONS CONCERNING THESE CHANGES...PLEASE CONTACT:

THIS AND OTHER NWS TECHNICAL IMPLEMENTATION NOTICES ARE AVAILABLE ONLINE AT:

www.nws.noaa.gov/om/notif.htm