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NOUS41 KWBC 261245
PNSWSH
PUBLIC INFORMATION STATEMENT 25-41
NATIONAL WEATHER SERVICE HEADQUARTERS SILVER SPRING, MD
845 AM EDT THU JUN 26 2025
TO: SUBSCRIBERS:
NOAA WEATHER WIRE SERVICE
EMERGENCY MANAGERS WEATHER INFORMATION NETWORK
NOAAPORT
OTHER NWS PARTNERS, USERS AND EMPLOYEES
FROM: RICHARD BANDY
ACTING DIRECTOR
NCEP/ENVIRONMENTAL MODELING CENTER
SUBJECT: SOLICITING COMMENTS ON PROPOSED DISCONTINUATION OF THE
NORTH AMERICAN MESOSCALE (NAM) MODEL AND OTHER REGIONAL MODELING
SYSTEMS TO BE REPLACED BY THE RAPID REFRESH FORECAST SYSTEM
(RRFS) THROUGH JULY 26, 2025.
THE ENVIRONMENTAL MODELING CENTER (EMC) AT THE NATIONAL CENTERS
FOR ENVIRONMENTAL PREDICTION (NCEP) IS WORKING TOWARDS REPLACING
THE NORTH AMERICAN MESOSCALE (NAM) MODEL, THE HIGH RESOLUTION
WINDOW (HIRESW) ASIDE FROM THE GUAM DOMAIN, THE HIGH RESOLUTION
ENSEMBLE FORECAST (HREF) AND THE NORTH AMERICAN RAPID REFRESH
ENSEMBLE (NARRE) SYSTEMS WITH THE IMPLEMENTATION OF THE RAPID
REFRESH FORECAST SYSTEM (RRFS) IN EARLY 2026. THE NWS IS
SEEKING COMMENTS ON THIS PROPOSED CHANGE THROUGH JULY 26, 2025.
THIS TRANSITION TO RRFS WOULD PROVIDE AN HOURLY UPDATING
MODELING SYSTEM OVER A NORTH AMERICA REGION AT 3 KM HORIZONTAL
GRID SPACING, WHICH, COMBINED WITH THE MODEL RETIREMENTS, WOULD
GREATLY UNIFY AND SIMPLIFY THE “CONVECTIVE SCALE” (APPROXIMATELY
3 KM GRID SPACING) REGIONAL MODELS WITHIN THE NWS OPERATIONAL
MODELING SUITE.
AS A DETERMINISTIC SYSTEM RUNNING TO 84 H, THE RRFS WOULD FULLY
RETIRE THE NAM, AND NEARLY FULLY RETIRE THE HIRESW (ASIDE FROM
THE GUAM DOMAIN). AS AN ENSEMBLE FORECAST SYSTEM, THE RRFS
ENSEMBLE FORECAST SYSTEM (REFS) WOULD FULLY RETIRE THE HREF AND
NARRE SYSTEMS.
THE DETERMINISTIC RRFS GENERATES FULL DOMAIN OUTPUT AT 3 KM GRID
SPACING, AND SUBSET GRID OUTPUT OVER THE CONTIGUOUS UNITED
STATES (CONUS) AND ALASKA (AK) (AT 3 KM GRID SPACING), AND
HAWAII (HI) AND PUERTO RICO (PR) (AT 2.5 KM GRID SPACING). THE
RRFS WILL ALSO PROVIDE OUTPUT FROM A SEPARATE 1.5 KM RRFS FIRE
WEATHER RUN, WITH OUTPUT PROVIDED OVER A 5 X 5 DEGREE ROTATED
LATITUDE LONGITUDE REGION. DETAILS OF THE RRFS OUTPUT GRIDS ARE
AVAILABLE IN
HTTPS://WWW.EMC.NCEP.NOAA.GOV/MMB/MPYLE/RRFS_INFO/RRFS_GRIDS.TXT
RELATIVE DIFFERENCES BETWEEN RRFS OUTPUT PRODUCTS AND THE
PROPOSED-TO-BE-RETIRED SYSTEM PRODUCTS WILL BE DISCUSSED
INDIVIDUALLY BY THE MODELING SYSTEM PROPOSED FOR RETIREMENT.
FOR THE PROPOSED RETIREMENT OF THE NAM:
BOTH THE 12 KM PARENT DOMAIN AND THE 3 KM NESTED DOMAINS (CONUS,
AK, HI, PR) WOULD BE TERMINATED. THE NAM FIRE WEATHER NEST WOULD
ALSO CEASE TO RUN.
LIST OF NAM OUTPUT GRIDS BEING RETIRED (NOT BEING UTILIZED BY
THE RRFS):
HTTPS://WWW.EMC.NCEP.NOAA.GOV/MMB/MPYLE/RRFS_INFO/NAM_RETIREDGRI
DS.TXT
LIST OF NAM NEST OUTPUT GRIDS THAT WILL NOT BE RETIRED (BEING
UTILIZED BY RRFS):
HTTPS://WWW.EMC.NCEP.NOAA.GOV/MMB/MPYLE/RRFS_INFO/NAMNEST_GRIDS.
TXT
LIST OF NAM PRODUCTS NOT GENERATED BY THE RRFS AND DISCONTINUED:
HTTPS://WWW.EMC.NCEP.NOAA.GOV/MMB/MPYLE/RRFS_INFO/NAM_RETIREMENT
S.TXT
FOR THE PROPOSED RETIREMENT OF THE HIRESW:
THE GUAM DOMAIN OF HIRESW WILL CONTINUE TO RUN AS IN CURRENT
OPERATIONS.
HIRESW DOMAINS ENCOMPASSED BY THE RRFS DOMAIN (CONUS, AK, HI,
PR) WILL BE DISCONTINUED.
LIST OF HIRESW OUTPUT GRIDS BEING RETIRED (NOT BEING PRODUCED BY
THE RRFS):
HTTPS://WWW.EMC.NCEP.NOAA.GOV/MMB/MPYLE/RRFS_INFO/HIRESW_GRIDS.T
XT
LIST OF HIRESW PRODUCTS NOT GENERATED WITHIN RRFS AND
DISCONTINUED:
HTTPS://WWW.EMC.NCEP.NOAA.GOV/MMB/MPYLE/RRFS_INFO/HIRESW_RETIREM
ENTS.TXT
PRODUCTS PRODUCED BY THE HIRESW, BUT WHICH WILL BE GENERATED BY
THE SMARTINIT SYSTEM PROCESSING RRFS OUTPUT RATHER THAN DIRECTLY
GENERATED BY THE RRFS:
HTTPS://WWW.EMC.NCEP.NOAA.GOV/MMB/MPYLE/RRFS_INFO/SMARTINIT_PROD
UCTS.TXT
NEW PRODUCTS IN DETERMINISTIC RRFS NOT GENERATED BY NAM OR
HIRESW, AND NOT DESCRIBED IN PRODUCT RETIREMENT/CHANGES TO
EITHER SYSTEM EARLIER:
HTTPS://WWW.EMC.NCEP.NOAA.GOV/MMB/MPYLE/RRFS_INFO/RRFS_NEWITEMS.
TXT
PRODUCTS IN THE RRFS “SUBH” OUTPUT FILE AT 15 MINUTE INTERVALS
FROM 15 MINUTES INTO THE FORECAST TO 18 HOURS INTO THE FORECAST:
HTTPS://WWW.EMC.NCEP.NOAA.GOV/MMB/MPYLE/RRFS_INFO/RRFS_15MIN.TXT
FOR THE PROPOSED RETIREMENT OF THE HREF:
THE ENTIRE HREF SYSTEM WOULD BE REPLACED BY RRFS ENSEMBLE
FORECAST SYSTEM (REFS) PRODUCTS COVERING CONUS, AK, HI, AND PR.
LIST OF HREF OUTPUT GRIDS BEING RETIRED DUE TO CHANGE IN GRID
SPACING AND GEOGRAPHIC COVERAGE:
HTTPS://WWW.EMC.NCEP.NOAA.GOV/MMB/MPYLE/RRFS_INFO/HREF_GRIDS.TXT
CHANGES IN TIMING:
- THE REFS GENERATES PRODUCTS TO 60 H, WHILE HREF ONLY MAKES
FORECASTS TO 48 H
- WHILE HREF GENERATES PRODUCTS TWICE DAILY FOR NON-CONUS
DOMAINS (AK & PR AT 06Z/18Z, AND HI AT 00Z/12Z), REFS PRODUCTS
WILL BE GENERATED AT 00Z/06Z/12Z/18Z FOR ALL REGIONS
HREF TO REFS PRODUCT CHANGES BY OUTPUT FILE TYPE:
HTTPS://WWW.EMC.NCEP.NOAA.GOV/MMB/MPYLE/RRFS_INFO/HREF_PRODUCT_C
HANGES.TXT
FOR THE PROPOSED RETIREMENT OF THE NORTH AMERICAN RAPID REFRESH
ENSEMBLE (NARRE):
THE ENTIRE SYSTEM WOULD BE TERMINATED AND REPLACED BY REFS
PRODUCTS COVERING CONUS, AK, HI, AND PR. THE OUTPUT FROM THE
REFS SYSTEM WILL BE ON THE SAME SUBSET GRIDS PRODUCED BY THE
RRFS (CONUS 3 KM, AK 3 KM, HI 2.5 KM, PR 2.5 KM).
NARRE OUTPUT GENERATED ON GRID 130 (CONUS 13 KM) AND GRID 242
(AK 11.25 KM) WILL BE RETIRED.
CHANGES IN TIMING:
WHILE NARRE GENERATES HOURLY UPDATED ENSEMBLE PRODUCTS EXTENDING
TO 12 H, THE REFS GENERATES PRODUCTS TO 60 H, BUT ONLY UPDATES
EVERY 6 H.
NARRE PRODUCTS DEFINED DIFFERENTLY WITHIN REFS OR RETIRED DUE TO
NOT BEING GENERATED BY REFS:
HTTPS://WWW.EMC.NCEP.NOAA.GOV/MMB/MPYLE/RRFS_INFO/NARRE_REPLACEM
ENT.TXT
IN ADDITION, ALL LEGACY SYSTEM VERIFICATION GRAPHICS WILL BE
REMOVED FROM THE FOLLOWING WEBSITE:
HTTPS://EMC.NCEP.NOAA.GOV/USERS/VERIFICATION/REGIONAL/
A NEW RRFS VERIFICATION WEBSITE WILL BE CREATED AND AVAILABLE
WHEN THE RRFS IS OFFICIALLY IMPLEMENTED INTO OPERATIONS.
PLEASE SUBMIT COMMENTS REGARDING THE PROPOSAL TO DISCONTINUE
THESE PRODUCTS TO:
EMAIL: RRFS.FEEDBACK@NOAA.GOV
GOOGLE FORM: SOLICITING COMMENTS ON THE RAPID REFRESH FORECAST
SYSTEM REPLACING LEGACY SYSTEMS
NATIONAL PUBLIC INFORMATION STATEMENTS ARE ONLINE AT:
HTTPS://WWW.WEATHER.GOV/NOTIFICATION/
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