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480
NOUS41 KWBC 211130
PNSWSH
TECHNICAL IMPLEMENTATION NOTICE 07-59
NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC
730 AM EDT TUE AUG 21 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/ USERS AND
OTHER PARTNERS...NWS EMPLOYEES
FROM: PAUL HIRSCHBERG
CHIEF...SCIENCE PLANS BRANCH
OFFICE OF SCIENCE AND TECHNOLOGY /OST/
SUBJECT: UPGRADE TO NCEP GLOBAL FORECAST SYSTEM /GFS/:
EFFECTIVE SEPTEMBER 25 2007
EFFECTIVE TUESDAY SEPTEMBER 25 2007...WITH THE 1200 COORDINATED
UNIVERSAL TIME /UTC/ RUN...THE NATIONAL CENTERS FOR ENVIRONMENTAL
PREDICTION /NCEP/ WILL UPGRADE THE GFS POST PROCESSOR.
THE PRIMARY EFFORT BEHIND THIS UPGRADE WILL BE TO UNIFY THE POST
PROCESSING CODE FOR THE NORTH AMERICAN MESOSCALE /NAM/ MODEL AND
THE GFS INTO THE NEW NCEP POST. AFTER THE UPGRADE...BOTH THE NAM
AND GFS MODELS WILL BE ABLE TO GENERATE FIELDS ORIGINALLY CREATED
FOR EACH UNIQUE MODEL.
THE PRIMARY IMPACT TO CUSTOMERS RECEIVING THE GFS WILL BE THAT
THE DEFAULT PRECIPITATION TYPE ALGORITHM WILL CHANGE FROM THE
BALDWIN METHOD TO THE DOMINANT PRECIPITATION TYPE. THE DOMINANT
PRECIPITATION TYPE IS DETERMINED BY TAKING THE PREDICTED
TEMPERATURE AND MOISTURE PROFILES AND RUNNING THEM THROUGH FIVE
ALGORITHMS: BALDWIN /NCEP/...REVISED NCEP...RAMER...BOURGOUIN
...AND AN EXPLICIT MICROPHYSICS ALGORITHM. AT EACH POINT...THE
CODE DETERMINES WHICH PRECIPITATION TYPE WAS PREDICTED BY THE
MAJORITY OF THE ALGORITHMS AND USES THAT AS THE DOMINANT TYPE.
TIES ARE BROKEN IN FAVOR OF THE MORE DANGEROUS WEATHER
/ZR>SN>IP>RA/.
IN ADDITION THE SAME ALGORITHMS WILL BE USED TO DERIVE MOST
FIELDS FOR THE TWO MODELS.
THE PRODUCTS/GRIDS WHICH ARE DISSEMINATED TO NOAAPORT AND/OR THE
SATELLITE BROADCAST NETWORK /SBN/ WILL NOT BE CHANGED IN VOLUME
OR CONTENT.
NCEP CENTRAL OPERATIONS IS CURRENTLY RUNNING A REAL-TIME
PARALLEL. RESULTS FROM THESE PARALLEL RUNS CAN BE VIEWED AT /USE
LOWER CASE LETTERS/:
HTTP://WWW.NCO.NCEP.NOAA.GOV/PMB/NWPARA/ANALYSIS/
IF YOU HAVE ANY QUESTIONS CONCERNING THESE CHANGES...PLEASE
CONTACT:
DR MARK IREDELL
NCEP/EMC...CHIEF GLOBAL MODELING BRANCH
CAMP SPRINGS MARYLAND
PHONE: 301 763 8000 X7231
EMAIL: MARK.IREDELL@xxxxxxxx
OR
KEN CAMPANA
NCEP/EMC...GLOBAL MODELING BRANCH
CAMP SPRINGS MARYLAND
PHONE: 301 763 8000 X7228
EMAIL: KENNETH.CAMPANA@xxxxxxxx
THIS AND OTHER NWS TECHNICAL IMPLEMENTATION NOTICES ARE AVAILABLE
ONLINE AT /USE LOWER CASE LETTERS/:
HTTP://WWW.NWS.NOAA.GOV/OM/NOTIF.HTM
$$