042  
NOUS41 KWBC 231745  
PNSWSH  
 
SERVICE CHANGE NOTICE 25-46  
NATIONAL WEATHER SERVICE HEADQUARTERS SILVER SPRING MD  
145 PM EDT MON JUN 23 2025  
 
TO: SUBSCRIBERS:  
-NOAA WEATHER WIRE SERVICE  
-EMERGENCY MANAGERS WEATHER INFORMATION NETWORK  
-NOAAPORT  
OTHER NWS PARTNERS, USERS AND EMPLOYEES  
 
FROM: GEORGE JUNGBLUTH  
DIRECTOR, OFFICE OF DISSEMINATION  
 
SUBJECT: UPGRADE OF MULTI-RADAR MULTI-SENSOR (MRMS) TO VERSION  
12.3: EFFECTIVE ON JULY 22, 2025  
 
EFFECTIVE ON OR ABOUT JULY 22, 2025, THE NATIONAL CENTERS FOR  
ENVIRONMENTAL PREDICTION (NCEP) CENTRAL OPERATIONS (NCO) WILL  
UPGRADE THE MULTI-RADAR, MULTI-SENSOR (MRMS) INTEGRATED  
DISSEMINATION PROGRAM (IDP) APPLICATION TO VERSION 12.3.0  
(V12.3).  
 
THE TECHNICAL ENHANCEMENTS WITH V12.3 INCLUDE THE FOLLOWING:  
 
1) SUPPORT FOR NWS RADAR VOLUME COVERAGE PATTERN (VCP) 34  
- THIS CHANGE ENABLES MRMS TO INGEST AND FULLY PROCESS DATA FROM  
WSR-88DS (WEATHER SURVEILLANCE RADAR-1988 DOPPLER) RUNNING IN  
VCP 34.  
 
2) UPGRADE THE PROBSEVERE (PS) PORTION OF MRMS PROBSEVERE  
- PSV3 OUTPUTS ARE MORE STATISTICALLY RELIABLE THAN PSV2 OUTPUTS  
AND EXHIBIT BETTER PROBABILITY OF DETECTION OF SEVERE STORMS AND  
DECREASED FALSE ALARMS. THIS UPGRADE ALSO RE-ENABLES THE  
INCLUSION OF GOES-EAST ABI (ADVANCED BASELINE IMAGER) DATA IN  
THE PROBSEVERE OUTPUT GENERATION PROCESS.  
 
3) MULTI-PRF DEALIASING ALGORITHM (MPDA) SUPPORT  
- MRMS ROTATION TRACKS PRODUCTS WILL BENEFIT FROM IMPROVED  
RADIAL VELOCITY DATA PROCESSING WHEN MPDA IS TURNED ON FOR A  
WSR-88D OPERATING IN EITHER VCP 212 OR 215.  
 
4) LIGHTNING SCALE PARAMETER CHANGES  
- AN INTERNAL PARAMETER USED TO GENERATE MRMS LIGHTNING  
PROBABILITIES IS BEING MODIFIED IN THIS RELEASE TO REDUCE THE  
COMPUTATIONAL FOOTPRINT REQUIRED FOR THESE PRODUCTS. THIS  
CHANGE WILL IMPROVE THE TIMELINESS OF MRMS LIGHTNING PRODUCTS.  
 
5) QUANTITATIVE PRECIPITATION ESTIMATE (QPE) IMPROVEMENTS:  
- MRMS QPES WILL BENEFIT FROM BETTER MELTING LAYER DELINEATION.  
THE RADAR QUALITY INDEX WILL ALSO BE MODIFIED TO IMPROVE THE  
PERFORMANCE OF MULTI-SENSOR QPE PRODUCTS IN THE WARM SEASON.  
 
6) IMPROVEMENTS TO MRMS QUALITY CONTROL (QC)  
- MRMS QC ROUTINES WILL BE UPDATED TO IMPROVE HANDLING OF  
EXCESSIVE GROUND CLUTTER AND BEAM BLOCKAGE AT CERTAIN RADAR  
SITES.NEW WIND FARM LOCATION TABLES WILL ALSO BE IMPLEMENTED  
IN THIS RELEASE.  
 
FOR DETAILS ABOUT FORMAT CHANGES TO PROBSEVERE V3 OUTPUTS (ITEM  
2 ABOVE), PLEASE SEE THE FOLLOWING URL:  
 
HTTPS://WWW.WEATHER.GOV/IDP/MRMS_V12.3_SUPPLEMENTAL  
 
FOR A REAL-TIME FEED OF DATA THAT INCLUDES ALL THE CHANGES  
LISTED IN THIS NOTICE, PLEASE SEE THE FOLLOWING URL:  
 
HTTPS://MRMS-QA.NCEP.NOAA.GOV  
 
TO REPORT PROBLEMS OR OPERATIONAL ISSUES WITH MRMS, PLEASE  
CONTACT:  
NCEP CENTRAL OPERATIONS TECH CONTROL NCO.OPS@NOAA.GOV  
 
FOR QUESTIONS RELATED TO THE UPDATES, PLEASE CONTACT:  
COREY.PIEPER@NOAA.GOV  
 
PLEASE SEND ALL OTHER COMMENTS AND QUESTIONS TO:  
NWS.WEBFEEDBACK@NOAA.GOV  
 
NATIONAL PUBLIC INFORMATION STATEMENTS ARE ONLINE AT:  
HTTPS://WWW.WEATHER.GOV/NOTIFICATION/  
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