-------- Original Message --------
762
NOUS41 KWBC 131240
PNSWSH
TECHNICAL IMPLEMENTATION NOTICE 08-77 AMENDED
NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC
740 AM EST THU NOV 13 2008
TO: SUBSCRIBERS:
-FAMILY OF SERVICES
-NOAA WEATHER WIRE SERVICE
-EMERGENCY MANAGERS WEATHER INFORMATION NETWORK
-NOAAPORT
OTHER NWS PARTNERS...USERS AND EMPLOYEES
FROM: JASON TUELL
CHIEF...SCIENCE PLANS BRANCH
OFFICE OF SCIENCE AND TECHNOLOGY
SUBJECT: AMENDED: RAPID UPDATE CYCLE UPGRADE EFFECTIVE: NOVEMBER
12 2008
REFER TO: TECHNICAL IMPLEMENTATION NOTICE /TIN/ 08-77 TRANSMITTED
ON OCTOBER 6 2008
AMENDED TO POSTPONE THE EFFECTIVE DATE FROM NOVEMBER 12 2008 TO
NOVEMBER 17 2008 DUE TO AN UNEXPECTED POWER FAILURE AT THE BACKUP
SUPERCOMPUTER FACILITY AND NASA SHUTTLE LAUNCH SCHEDULED FOR
NOVEMBER 13. THE ORIGINAL NOTICE...WITH REVISED DATE IS BELOW:
EFFECTIVE MONDAY NOVEMBER 17 2008...BEGINNING WITH THE 1200
COORDINATED UNIVERSAL TIME /UTC/ RUN...SEVERAL CHANGES WILL BE
MADE TO THE RAPID UPDATE CYCLE /RUC/ MODELING-ASSIMILATION
SYSTEM. THESE CHANGES ARE MADE TO IMPROVE MODEL PERFORMANCE.
THE MODEL CHANGES INCLUDE:
1. USE OF RRTM LONGWAVE RADIATION SCHEME...REPLACING PREVIOUS
DUDHIA LONGWAVE RADIATION SCHEME.
2. MODIFICATIONS TO GRELL-DEVENYI CONVECTIVE PARAMETERIZATION TO
REDUCE EXCESSIVE AREAL COVERAGE FOR LIGHT PRECIPITATION.
3. MODIFICATIONS TO RUC LAND-SURFACE MODELSNOW DENSITY CHANGE
TO PREVENT EXCESSIVE COLD 2-M TEMPERATURES OVER FRESH SNOW
AND SNOW MELTING LIMITATION TO IMPROVE 2-M TEMPERATURES FOR
WARM-AIR ADVECTION OVER SNOW COVER.
4. SPECIFICATION OF LATENT HEATING FROM 3-D RADAR REFLECTIVITY
DURING PRE-FORECAST DIABATIC DIGITAL FILTER INITIALIZATION
/DFI/ ALREADY IN THE RUC MODEL.
THE ANALYSIS CHANGES INCLUDE:
1. ASSIMILATION OF 3-D RADAR REFLECTIVITY...COMBINED WITH
SATELLITE AND METAR CLOUD DATA TO MODIFY WATER VAPOR FIELD...
AND PRODUCING RADAR-BASED 3-D LATENT-HEAT SPECIFICATION TO BE
INCLUDED IN RUC MODEL DFI.
2. ASSIMILATION OF TAMDAR AIRCRAFT OBSERVATIONS INCLUDING
MOISTURE OBSERVATIONS.
3. ASSIMILATION OF MESONET WIND DATA USING STATIONS FROM A
MESONET STATION WIND USELIST.
4. REVISION TO OBSERVATION ERROR AND BACKGROUND ERROR FOR
MOISTURE OBSERVATIONS.
5. IMPROVED QC BASED ON MEAN OBSERVATION-BACKGROUND DIFFERENCES
FOR A GIVEN PLATFORM WITHIN A RUC ANALYSIS WINDOW.
OTHER OUTPUT CHANGES INCLUDE:
1. ADD 4 ADDITIONAL 2-D FIELDS TO THE RUC ISOBARIC /PGRB/ FILES:
-THREE REFLECTIVITY FIELDS /MAXIMUM...1-KM...4-KM SIMILAR
TO PRODUCTS ALREADY PRODUCED FOR THE NAM.
-RELATIVE HUMIDITY RELATIVE TO PRECIPITABLE WATER FOR
SATURATED COLUMN.
2. REVISION TO 2-M DEW POINT DIAGNOSTIC TO BETTER ACCOUNT FOR
VERTICAL MIXINGTHIS IS NOT A CHANGE TO THE MODEL...ONLY IN
THE POST-PROCESSING.
3. ERRONEOUS PRECIPITATION FIELDS FOR THE ANALYSIS TIME PERIOD
ARE BEING REMOVED /ALL VALUES ARE SET TO MISSING/.
4. REDUNDANT PRECIPITATION FIELDS AT FORECAST HOURS 1...4...
7...AND 10 ARE BEING REMOVED.
5. NO OTHER OUTPUT CHANGES.
THE COMBINED IMPACT OF THESE CHANGES HAS LED TO THE FOLLOWING
IMPROVEMENTS IN MODEL PERFORMANCE:
1. REDUCES BIAS IN 2-M TEMPERATURE AND 10-M WIND SPEED FOR ALL
TIMES OF DAY AND ALL SEASONS.
2. IMPROVED PRECIPITATION AND CLOUD FORECASTS FOR 1-H TO 12-H
DURATIONS.
3. IMPROVED CEILING AND VISIBILITY FORECASTS
4. IMPROVED LOWER TO MID-TROPOSPHERIC TEMPERATURE AND RH
FORECASTS IN MIDWEST AND EASTERN US.
5. IMPROVED ACCURACY IN TEMPERATURE AND WIND FIELDS FOR CONUS
RTMA /WHICH USES DOWNSCALED 1-H RUC FORECASTS AS RTMA
BACKGROUND/.
THE RUC CHANGES INCLUDED IN THIS PROJECT WILL INCREMENTALLY
IMPROVE THE OVERALL FORECAST SKILL OF THE RUC FORECAST. IN
ADDITION TO THE ASSIMILATION OF NEW OBSERVATION TYPES /RADAR
REFLECTIVITY...TAMDAR...MESONET WINDS/...THE CHANGES ARE INTENDED
TO ADDRESS KNOWN RUC WEAKNESSES AND BIASES AS OBSERVED BY
NOAA/ESRL/GSD STAFF...EMC/MMB STAFF...NCEP SERVICE CENTERS AND
NWS FORECASTERS.
MORE DETAILS ABOUT THESE CHANGES CAN BE SEEN AT /USE LOWERCASE
LETTERS EXCEPT...NCEP-CCB-RUC...BELOW/:
HTTP://RUC.NOAA.GOV/RUC13_DOCS/NCEP-CCB-RUCUPGRADE-12MAY08.PDF
DATA DELIVERY TIMING WILL NOT BE IMPACTED BY THIS IMPLEMENTATION.
THE RUC DELIVERY TIME WILL NOT CHANGE.
DATA VOLUMES WILL INCREASE ONLY SLIGHTLY FROM THE FEW ADDITIONAL
2-D FIELDS DESCRIBED ABOVE.
SIGNFICANT DATA CONTENT CHANGES ARE NOT EXPECTED.
THESE MODEL CHANGES WILL IMPACT ALL DISSEMINATION ROUTES
INCLUDING NOAAPORT... THE NWS PUBLIC FTP SERVER AND THE NCEP
PUBLIC FTP SERVER. A CONSISTENT PARALLEL FEED OF DATA WILL BECOME
AVAILABLE ON THE NCEP FTP SERVER ONCE THE MODEL IS RUNNING IN
PARALLEL ON THE NCEP CENTRAL COMPUTING SYSTEM. THIS CHANGE IS
PLANNED TO OCCUR ABOUT SEPTEMBER 16 2008...AT WHICH TIME THE
PARALLEL DATA WILL BECOME AVAILABLE VIA THE FOLLOWING URL /USE
LOWERCASE LETTERS/:
FTP://FTP.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/RUC/TEST
NCEP ENCOURAGES ALL USERS TO ENSURE THEIR DECODERS ARE FLEXIBLE
AND ARE ABLE TO ADEQUATELY HANDLE CHANGES IN CONTENT
ORDER...PARAMETER FIELDS CHANGING ORDER...CHANGES IN THE SCALING
FACTOR COMPONENT WITHIN THE PDS OF THE GRIB FILES AND ALSO ANY
VOLUME CHANGES WHICH MAY BE FORTHCOMING. THESE ELEMENTS MAY
CHANGE WITH FUTURE NCEP MODEL IMPLEMENTATIONS. NCEP WILL MAKE
EVERY ATTEMPT TO ALERT USERS TO THESE CHANGES PRIOR TO ANY
IMPLEMENTATIONS.
FOR QUESTIONS CONCERNING THESE CHANGES...PLEASE CONTACT:
GEOFF MANIKIN
NCEP...MESOSCALE MODELING BRANCH
CAMP SPRINGS MARYLAND
PHONE: 301-763-8000 X7263
EMAIL: GEOFFREY.MANIKIN@xxxxxxxx
OR
STAN BENJAMIN
NOAA EARTH SYSTEM RESEARCH LABORATORY
BOULDER COLORADO
PHONE: 303-497-6387
EMAIL: STAN.BENJAMIN@xxxxxxxx
TECHNICAL IMPLEMENTATION NOTICES ARE ONLINE AT /USE LOWERCASE/:
HTTP://WWW.WEATHER.GOV/OS/NOTIF.HTM
$$