796
NOUS41 KWBC 231935
PNSWSH
SERVICE CHANGE NOTICE 26-30
NATIONAL WEATHER SERVICE HEADQUARTERS SILVER SPRING MD
335 PM EST MON MAR 23 2026
TO: SUBSCRIBERS:
-NOAA WEATHER WIRE SERVICE
-EMERGENCY MANAGERS WEATHER INFORMATION NETWORK
-NOAAPORT
OTHER NWS PARTNERS AND NWS EMPLOYEES
FROM: PATRICK BURKE
CHIEF, OCEANOGRAPHIC DIVISION
NOS/CENTER FOR OPERATIONAL OCEANOGRAPHIC PRODUCTS AND
SERVICES
SUBJECT: NOS / CO-OPS WILL BEGIN GENERATING ALL WATER LEVEL DATA
IN STANDARD HYDROLOGIC EXCHANGE FORMAT (SHEF) ON OR
ABOUT APRIL 23, 2026
EFFECTIVE ON OR ABOUT APRIL 23, 2026, NOAA'S CENTER FOR
OPERATIONAL OCEANOGRAPHIC PRODUCTS AND SERVICES (CO-OPS) WILL
BEGIN ONLY ISSUING OBSERVED WATER LEVEL DATA AT COASTAL NATIONAL
OCEAN SERVICE (NOS) STATIONS INTO THE STANDARD HYDROLOGIC
EXCHANGE FORMAT (SHEF) FORMATTED DATA FILES THAT ARE PUSHED TO
HTTPS://TGFTP.NWS.NOAA.GOV/DATA/RAW/SO/. THE SHEF CODES OF HMIRP
AND HCIRP WILL NO LONGER BE AVAILABLE AS OF APRIL 23, 2026. ALL
WATER LEVEL DATA WILL NOW BE DISSEMINATED UNDER THE FOLLOWING
SHEF CODES ONLY:
--- HMIRG - WATER LEVELS IN FEET RELATIVE TO MEAN LOWER LOW
WATER (MLLW) AND GREAT LAKES WATER LEVELS IN FEET ABOVE LOW
WATER DATUM (LWD)
- HCIRG - WATER LEVELS IN FEET RELATIVE TO MEAN LOWER LOW
WATER (MHHW)
THESE SHEF CODES ARE ALREADY ACTIVELY BEING USED FOR CO-OPS
WATER LEVEL DATA, HOWEVER AS A RESULT OF THIS CHANGE, WATER
LEVELS WILL NO LONGER BE DISSEMINATED UNDER THE REDUNDANT SHEF
CODES HMIRP AND HCIRP.USERS OF CO-OPS WATER LEVEL DATA ON THE
RETIRED SHEF CODES SHOULD UPDATE THEIR SYSTEMS TO ENSURE THAT
WATER LEVELS WILL BE RECEIVED AND INGESTED USING THE HMIRG AND
HCIRG SHEF CODES ONLY.
SHEF DATA FILES WILL BE UPDATED EVERY 10 MINUTES AND IN MOST
INSTANCES FOLLOWING THIS CHANGE, STATION DATA WILL INCLUDE 3
OBSERVATIONS PER LINE. THIS CHANGE SHOULD RESULT IN FEWER (IF
ANY) GAPS IN 6-MINUTE CO-OPS WATER LEVEL OBSERVATIONS RECEIVED
FROM CO-OPS.
THIS CHANGE ONLY IMPACTS THE SHEF WATER LEVEL BULLETINS COMING
FROM CO-OPS. NO CHANGES ARE BEING MADE TO THE SHEF
METEOROLOGICAL DATA BULLETINS AT THIS TIME.
IN THE EVENT THAT THE IMPLEMENTATION DATE IS DECLARED A CRITICAL
WEATHER DAY (CWD) OR SIGNIFICANT WEATHER IS OCCURRING OR IS
ANTICIPATED TO OCCUR, IMPLEMENTATION OF THIS CHANGE WILL OCCUR
ON THE NEXT WEEKDAY NOT DECLARED A CWD AND WHEN NO SIGNIFICANT
WEATHER IS OCCURRING.
ANY QUESTIONS, COMMENTS OR REQUESTS REGARDING THIS
IMPLEMENTATION SHOULD BE DIRECTED TO THE CONTACTS BELOW. WE
WILL REVIEW ANY FEEDBACK AND DECIDE WHETHER TO PROCEED.
FOR QUESTIONS REGARDING THESE CHANGES, PLEASE CONTACT:
PAUL FANELLI
SENIOR OCEANOGRAPHER
202-680-9165
PAUL.FANELLI@NOAA.GOV
FOR GENERAL QUESTIONS ABOUT CO-OPS DATA FLOW, PLEASE CONTACT:
TIDE.PREDICTIONS@NOAA.GOV
FOR TECHNICAL ISSUES OUTSIDE OF NORMAL BUSINESS HOURS, PLEASE
CONTACT:
CORMS
301-713-2540
CORMS@NOAA.GOV
NWS SERVICE CHANGE NOTICES ARE AVAILABLE HERE:
HTTPS://WWW.WEATHER.GOV/NOTIFICATION/
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