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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/