771
NOUS41 KWBC 231533
PNSWSH
TECHNICAL IMPLEMENTATION NOTICE 05-40
NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC
1125 AM EDT MON MAY 23 2005
TO: FAMILY OF SERVICES /FOS/ SUBSCRIBERS...NOAA WEATHER WIRE
SERVICE /NWWS/ SUBSCRIBERS...EMERGENCY MANAGERS WEATHER
INFORMATION NETWORK /EMWIN/ SUBSCRIBERS...OTHER NATIONAL
WEATHER SERVICE /NWS/ CUSTOMERS AND PARTNERS...NWS EMPLOYEES
FROM: PAUL HIRSCHBERG
CHIEF...SCIENCE PLANS BRANCH
OFFICE OF SCIENCE AND TECHNOLOGY /OST/
SUBJECT: UPGRADE OF THE RAPID UPDATE CYCLE /RUC/ FORECAST SYSTEM
EFFECTIVE...JUNE 28 2005.
EFFECTIVE JUNE 28 2005...BEGINNING WITH THE 1200 COORDINATED UNIVERSAL
TIME /UTC/ RUN...THE NATIONAL CENTERS FOR ENVIRONMENTAL PREDICTION /NCEP/
WILL UPGRADE THE RAPID UPDATE CYCLE /RUC/ FORECAST SYSTEM TO IMPROVE ITS
ACCURACY AND PRODUCTS. THE UPGRADE IS INTENDED TO PROVIDE IMPROVEMENTS
TO THE FOLLOWING AREAS OF THE FORECAST GUIDANCE:
-CLOUD
-CEILING
-VISIBILITY
-ICING FORECASTS
-TEMPERATURE AND DEWPOINT FORECASTS AT THE SURFACE AND IN THE
LOWER TROPOSPHERE
-PRECIPITATION FORECASTS.
THE FOLLOWING MODIFICATIONS TO THE RUC MODEL WILL BE MADE IN ORDER TO
ACHIEVE THESE IMPROVEMENTS:
- INCREASE THE HORIZONTAL RESOLUTION FROM 20 KM TO 13.3 KM. USE NEW
HIGHER RESOLUTION /ALSO 13 KM/ FIXED FILES FOR TERRAIN ELEVATION/
LAND USE /WITH LAND-SEA MASK/ SOIL TYPE/ AND ROUGHNESS LENGTH.
-MODIFY GRELL-DEVENYI CONVECTIVE PARAMETERIZATION TO USE OPTIMIZED
WEIGHTING FOR MULTIPLE CLOSURES FOR IMPROVED FORECASTS OF CONVECTIVE
PRECIPITATION.
-IMPLEMENT UPDATED VERSION OF RUC/NCAR BULK MIXED-PHASE CLOUD
MICROPHYSICS DESIGNED TO PRODUCE MORE ACCURATE DEPICTION OF SUPERCOOLED
LIQUID WATER NEEDED FOR ICING FORECASTS.
-THE INITIALIZATION OF LOW-LEVEL MOISTURE FIELDS IS GREATLY IMPROVED BY:
1. MODIFYING THE MOISTURE ANALYSIS VARIABLE FROM LOG OF WATER VAPOR MIXING
RATIO TO PSEUDO-RELATIVE-HUMIDITY
2. MODIFYING RUC MODEL DIGITAL FILTER INITIALIZATION
3. ASSIMILATING NEW OBSERVATIONS FROM GPS PRECIPITABLE WATER AND IMPROVING THE
QUALITY CONTROL FOR PRECIPITABLE WATER DATA.
-ADD SOIL TEMPERATURE AND MOISTURE NUDGING IN ANALYSIS, ONLY INCLUDED
UNDER CERTAIN CONSERVATIVE CONDITIONS, BASED ON NEAR-SURFACE ANALYSIS
INCREMENTS OF TEMPERATURE AND MOISTURE. THIS LEADS TO SIGNIFICANT
IMPROVEMENTS IN 2-METER TEMPERATURE AND DEW POINT FIELDS AS WELL AS
INSTABILITY FORECASTS AND RESULTANT CONVECTIVE PRECIPITATION.
-ASSIMILATE NEW OBSERVATIONS MESONET SURFACE STATIONS AND
BOUNDARY-LAYER WIND PROFILERS TO IMPROVE SURFACE ANALYSIS.
-ASSIMILATE METAR OBSERVATIONS OF CLOUD LEVELS AND VISIBILITY TO IMPROVE
INITIAL CONDITIONS FOR RUC 3-D HYDROMETEOR FIELDS.
THE ENVIRONMENTAL MODELING CENTER (EMC) IS CURRENTLY RUNNING A NEAR REAL-TIME
PARALLEL OF THIS NEW VERSION OF THE RUC FOR ALL MODEL CYCLES. EMC HAS A WEB
PAGE DISPLAYING MODEL OUTPUT OF THESE PARALLEL RUNS VS. THE OPERATIONAL RUNS.
THIS WEB PAGE CAN BE FOUND ONLINE AT /USE LOWER CASE LETTERS/:
HTTP://WWW.EMC.NCEP.NOAA.GOV/MMB/RUC2/PARA/
IF YOU HAVE ANY QUESTIONS CONCERNING THESE CHANGES...PLEASE CONTACT:
GEOFF MANIKIN
NCEP...MESOSCALE MODELING BRANCH
CAMP SPRINGS MARYLAND
PHONE: 301 763 8000 X7263
EMAIL: GEOFFREY.MANIKIN@xxxxxxxx
THIS AND OTHER NWS TECHNICAL IMPLEMENTATION NOTICES ARE AVAILABLE
ONLINE AT /USE LOWER CASE LETTERS/:
HTTP://WWW.NWS.NOAA.GOV/OM/NOTIF.HTM
$$
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