517
NOUS41 KWBC 032020
PNSWSH
Service Change Notice 25-68
National Weather Service Headquarters Silver Spring MD
420 PM EDT Wed Sep 3 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: Deprecating TLS 1.1: Effective October 6, 2025

Effective Monday, October 06, 2025, NCEP will deprecate Transport
Layer Security (TLS) protocol 1.1, at which time only TLS 1.2 and 1.3
will be allowed. This upgrade will not affect the file paths, but
users who rely on command line tools (e.g., cURL, wget) or other
customized scripts will need to ensure that they are using a recent
version of these tools with TLS v1.2 and/or 1.3 enabled.

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.

This change will affect all paths for
https://nomads.ncep.noaa.gov

For questions about this change 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/