003
NOUS41 KWBC 241455
PNSWSH
SERVICE CHANGE NOTICE 25-47
NATIONAL WEATHER SERVICE HEADQUARTERS SILVER SPRING MD
1055 AM EDT TUE JUN 24 2025
TO: SUBSCRIBERS:
-NOAA WEATHER WIRE SERVICE
-EMERGENCY MANAGERS WEATHER INFORMATION NETWORK
-NOAAPORT
OTHER NWS PARTNERS, USERS AND EMPLOYEES
FROM: DAVID MICHAUD, DIRECTOR
NCEP CENTRAL OPERATIONS
SUBJECT: UPGRADE OF THE REAL-TIME OCEAN FORECAST SYSTEM (RTOFS)
TO VERSION 2.5: EFFECTIVE JULY 24, 2025
EFFECTIVE ON OR ABOUT THURSDAY, JULY 24, 2025 WITH THE 1200
COORDINATED UNIVERSAL TIME (UTC) CYCLE, THE NATIONAL CENTERS FOR
ENVIRONMENTAL PREDICTION (NCEP) CENTRAL OPERATIONS (NCO) WILL
UPGRADE RTOFS TO VERSION 2.5. IN THE EVENT THAT THE
IMPLEMENTATION DATE IS DECLARED A CRITICAL WEATHER DAY (CWD), AN
ENHANCED CAUTION EVENT (ECE), OR OTHER SIGNIFICANT WEATHER IS
OCCURRING OR IS ANTICIPATED TO OCCUR, IMPLEMENTATION OF THIS
CHANGE WILL TAKE PLACE AT 1200 UTC ON THE NEXT WEEKDAY NOT
DECLARED A CWD AND WHEN NO SIGNIFICANT WEATHER IS OCCURRING.
RTOFS CONSISTS OF HYBRID COORDINATE OCEAN MODEL (HYCOM),
COMMUNITY ICE CODE (CICE) VERSION 4 AND DATA ASSIMILATION (DA)
FOR BOTH SEA ICE AND OCEAN.
RTOFS VERSION 2.5 INTRODUCES THE FOLLOWING CHANGES:
1. ADD CLIMATOLOGICAL CONSTRAINTS TO THE ASSIMILATION OF SEA
SURFACE HEIGHT (SSH);
2. UPDATE CONVERSION OF DA INCREMENTS APPLIED TO HYCOM;
3. ADD ASSIMILATION OF VELOCITY OBSERVATIONS FROM DRIFTING
BUOYS AND HIGH-FREQUENCY (HF) RADAR INSTALLATIONS.
THE ABOVE CHANGES ARE EXPECTED TO:
- REDUCE SUBSURFACE NEGATIVE SALINITY BIAS IN THE CARIBBEAN SEA
- PRESERVE HYCOM LAYER STRUCTURE
- PROVIDE ADDITIONAL OBSERVATIONAL CONSTRAINTS FOR DA
NO PRODUCT CHANGES ARE INTRODUCED BY THIS UPGRADE.
CURRENT MODEL DATA IS AVAILABLE HERE:
HTTPS://NOMADS.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/RTOFS/PROD/
FTP://FTP.NCEP.NOAA.GOV/DATA/NCCF/COM/RTOFS/PROD/
PARALLEL DATA WILL BE AVAILABLE ON THE NCEP SITES AT THE
FOLLOWING URLS:
HTTPS://NOMADS.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/RTOFS/PARA/
FTP://FTP.NCEP.NOAA.GOV/DATA/NCCF/COM/RTOFS/PARA/
NCEP ENCOURAGES USERS TO ENSURE THEIR DECODERS ARE FLEXIBLE AND
ARE ABLE TO ADEQUATELY HANDLE CHANGES IN CONTENT ORDER, CHANGES
IN THE SCALING FACTOR COMPONENT WITHIN THE PRODUCT DEFINITION
SECTION (PDS) OF THE GRIDDED BINARY (GRIB) FILES, AND 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.
PLEASE SUBMIT COMMENTS, QUESTIONS, OR REQUESTS PERTAINING TO
THIS UPGRADE TO:
DARYL KLEIST
NWS/NCEP ENVIRONMENT MODELING CENTER
DARYL.KLEIST@NOAA.GOV
FOR QUESTIONS ABOUT THE DATAFLOW ASPECTS, PLEASE CONTACT:
MARGARET CURTIS
NCEP CENTRAL OPERATIONS HPC DATAFLOW TEAM LEAD
NCEP.PMB.DATAFLOW@NOAA.GOV
NATIONAL SERVICE CHANGE NOTICES ARE ONLINE AT:
HTTPS://WWW.WEATHER.GOV/NOTIFICATION/
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