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PNSWSH TECHNICAL IMPLEMENTATION NOTICE 10-13 NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC 1240 PM EST THU MAR 11 2010 TO: SUBSCRIBERS:-FAMILY OF SERVICES -NOAA WEATHER WIRE SERVICE
-EMERGENCY MANAGERS WEATHER INFORMATION NETWORK-NOAAPORT OTHER NWS PARTNERS...USERS AND EMPLOYEES
FROM: TIMOTHY MCCLUNG
SCIENCE PLANS BRANCH CHIEF
OFFICE OF SCIENCE AND TECHNOLOGY
SUBJECT: GLOBAL MULTI-GRID WAVE MODEL CHANGES:
EFFECTIVE APRIL 27 2010
EFFECTIVE TUESDAY APRIL 27 2010...BEGINNING WITH THE 1200 COORDINATED UNIVERSAL TIME /UTC/ RUN...THE NATIONAL CENTERS FOR ENVIRONMENTAL PREDICTION /NCEP/ WILL UPGRADE THE GLOBAL MULTI-GRID WAVE MODEL. THE PRIMARY CHANGE IS TO THE ISSUANCE TIME OF THE MULTI-GRID WAVE MODEL GRIB2 PRODUCTS DISSEMINATED VIA NOAAPORT...AWIPS...THE NCEP FTP SERVER AND NCEPS REAL- TIME NOMADS SERVER. MODEL PRODUCTS FOR ALL PROJECTIONS ARE CURRENTLY DISSEMINATED AT APPROXIMATELY 4 HOURS 30 MINUTES AFTER MODEL CYCLE TIME...WITH ALL PROJECTIONS AVAILABLE IN ONE OUTPUT FILE PER MODEL GRID. STARTING ON APRIL 27...THE GRIB2 PRODUCTS WILL BE DISSEMINATED THROUGHOUT THE RUN OF THE MODEL AS EACH FORECAST HOUR COMPLETES. PRODUCTS WILL BEGIN TO BE DISSEMINATED AT APPROXIMATELY 3 HOURS 30 MINUTES AFTER MODEL CYCLE TIME WITH THE LAST FORECAST PROJECTION DISSEMINATED AT 4 HOURS 30 MINUTES AFTER MODEL CYCLE TIME. ON THE FTP SERVERS AND NOMADS...EACH FORECAST HOUR WILL NOW BE PROVIDED IN A SEPARATE FILE FOR EACH MODEL GRID.
THERE WILL BE NO CHANGE IN DISSEMINATION TIME FOR THE POINT-BASED OUTPUT PRODUCTS DISSEMINATED VIA NOAAPORT AND AWIPS. THOSE PRODUCTS WILL CONTINUE TO BE DISSEMINATED AT 4 HOURS 30 MINUTES AFTER MODEL CYCLE TIME.
ADDITIONAL CHANGES TO THE MULTI-GRID WAVE MODEL INCLUDE:-INCREASE THE SPECTRAL RESOLUTION OF THE MODEL TO 50 BINS IN FREQUENCY AND 36 BINS IN DIRECTION. THIS RESOLUTION CHANGE ONLY AFFECTS THE INTERNAL COMPUTATIONS OF THE MODEL. NO OUTPUT PRODUCTS WILL CHANGE RESOLUTION.
-EXTEND THE WAVE DATA COVERAGE ON THE GLOBAL GRID FROM 77.5N TO 82.5N. THE GLOBAL OUTPUT GRID WILL REMAIN THE SAME...THE NUMBER OF POINTS ON THAT GRID WITH NON-MISSING DATA VALUES WILL INCREASE. A VERY SMALL INCREASE IN DATA VOLUME IS EXPECTED DUE TO THIS CHANGE.
-CHANGES WILL BE MADE TO ELIMINATE SMALL INSTABILITIES IN THE CORNER OF THE COASTAL PACIFIC GRID /WC_4M/.
MORE DETAILS ABOUT THE NCEP MULTI-GRID WAVE MODEL ARE AVAILABLE AT /USE LOWERCASE/:
HTTP://POLAR.NCEP.NOAA.GOV/WAVES/INDEX2.SHTMLA CONSISTENT PARALLEL FEED OF DATA IS AVAILABLE ON THE NCEP FTP SERVER FROM THE PARALLEL MODEL RUNNING ON THE NCEP CENTRAL COMPUTING SYSTEM. THE PARALLEL DATA IS AVAILABLE VIA THE FOLLOWING URL /USE LOWERCASE/:
FTP://FTP.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/WAVE/PARANCEP ENCOURAGES ALL USERS TO ENSURE THEIR DECODERS ARE FLEXIBLE AND ARE ABLE OF ADEQUATELY HANDLING CHANGES IN CONTENT...PARAMETER FIELDS CHANGING ORDER...CHANGES IN THE SCALING FACTOR COMPONENT WITHIN THE PRODUCT DESCRIPTION SECTION /PDS/ OF THE GRIB FILES AND ANY VOLUME CHANGES WHICH MAY OCCUR. THESE ELEMENTS MAY CHANGE WITH FUTURE NCEP MODEL IMPLEMENTATIONS. NCEP WILL MAKE EVERY ATTEMPT TO ALERT USERS TO THESE CHANGES PRIOR TO ANY IMPLEMENTATION.
FOR QUESTIONS REGARDING THESE MODEL CHANGES...PLEASE CONTACT:
HENDRIK TOLMAN NCEP/MARINE MODELING AND ANALYSIS BRANCH CAMP SPRINGS MARYLAND 301-763-8000 X 7253 HENDRIK.TOLMAN@xxxxxxxxFOR QUESTIONS REGARDING THE DATAFLOW ASPECTS OF THESE DATA SETS... PLEASE CONTACT
REBECCA COSGROVE NCEP/NCO DATAFLOW TEAM CAMP SPRINGS MARYLAND 20746301-763-8000 X 7198 NCEP.LIST.PMB-DATAFLOW@xxxxxxxx
NWS NATIONAL TECHNICAL IMPLEMENTATION NOTICES ARE ONLINE AT /USE LOWERCASE/:
HTTP://WWW.WEATHER.GOV/OS/NOTIF.HTM
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