035
NOUS41 KWBC 112020
PNSWSH

Service Change Notice 26-79
National Weather Service Headquarters Silver Spring MD
420 PM EDT Fri Sep 11 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
 National Ocean Service/Center for Operational
 Oceanographic Products and Services

Subject: NOAA`s Center for Operational Oceanographic Products
and Services will Update Sea Level Information for Water Level
Stations Beginning October 01, 2026

Effective on Thursday, October 1, 2026, NOAA`s Center for
Operational Oceanographic Products and Services (CO-OPS) will
change the sea level trend information provided for water level
stations with at least thirty years of data into a new product.
The legacy sea level trend product that provides a single rate
of change across the full history of observations will be
discontinued on October 1, 2026.

Users will now see:
- The total amount of sea level change for the full period of
 record,
- The amount of change since the most recent National Tidal
 Datum Epoch (NTDE 1983-2001),
- The rate of change since the midpoint of the last NTDE (July
 1992), and
- 30-year variations in sea levels.

The new sea level products are currently being made available
via a beta website integrating Sea Level and Extreme Water Level
data products, https://tidesandcurrents.noaa.gov/trends-and-
extremes/index.html.

Users of the legacy CO-OPS sea level change information
available at https://tidesandcurrents.noaa.gov/sltrends/ should
update their bookmarks to:
https://tidesandcurrents.noaa.gov/trends-and-extremes/index.html
starting on October 1, 2026.

Additionally, all sea level data and products will be available
through the CO-OPS Derived Product APIs.
https://api.tidesandcurrents.noaa.gov/dpapi/prod/

Any questions, comments, or requests should be directed to the
contacts below.

If you have feedback or questions regarding these changes,
please contact:

David Wolcott
Oceanographer
240-533-0614
David.Wolcott@noaa.gov

For general questions about CO-OPS data and products, please
contact:

tide.predictions@noaa.gov

For technical issues outside of normal business hours, please
contact:

Continuously Operational Real-time Monitoring System (CORMS)
301-713-2540
corms@noaa.gov

National Service Change Notices are available here:

https://www.weather.gov/notification/