Where NWS Publishes Weather Alert and Forecast Change Notices

The National Weather Service (NWS) announces changes to its alerts and forecast products through one public notification system, indexed at weather.gov/notification and archived at weather.gov/notification/archive. Each notice is one of three types: a Public Information Statement (PNS) for a proposed change still open for comment, a Service Change Notice (SCN) for a change that has been implemented or is about to be, or a Technical Implementation Notice (TIN) — the third type named alongside PNS and SCN in the notification archive (weather.gov/notification/archive). In the worked SCN example below, the document’s issue date/time is stated separately from the date the change actually takes effect.

This original record-reading guide is a general reading aid, not cited evidence. It does not depict a source record; the article text and source links provide the facts.

Key points

• NWS notices are distributed through “the NOAA Weather Wire Service (NWWS), the Emergency Managers Weather Information Network (EMWIN), NOAAPort, and Subscribers” (weather.gov/notification).
• A PNS marks a proposed change still open for public comment (see the current PNS26-65 example below).
• An SCN marks a change that has been implemented or is about to be (see the current SCN26-75 example below).
• Older notices are searchable in the “Archive of PNS/SCN/TIN (1996-2022)” and in a dedicated “Service Change Notices Archive ( 1997 - 2022 )” (weather.gov/notification; weather.gov/notification/archive).
• The worked SCN24-88 example below states both its own issue timestamp and a separately labeled effective date, so readers can tell “when this was announced” apart from “when this actually changes.”

Notice types: PNS, SCN, TIN

NWS routes its alert and forecast product change notices through one index page, weather.gov/notification. The page identifies its own distribution channels as “the NOAA Weather Wire Service (NWWS), the Emergency Managers Weather Information Network (EMWIN), NOAAPort, and Subscribers” (weather.gov/notification). In practice, these are the same feeds broadcasters, emergency managers, and downstream data subscribers already use for warnings and forecasts, so a product change reaches the same audience as the products themselves.

The three notice types answer three different reader questions:

• PNS (Public Information Statement) — is a change being proposed, and can I still comment on it? The current example is “PNS26-65: Soliciting Comments on Proposed Retirement of Significant Weather (SIGWX) Low-Level Forecast Product (LLFP) through October 2, 2026” (weather.gov/notification), which names the specific product under review and the exact date the comment window closes.
• SCN (Service Change Notice) — has a change been implemented, and when? The current example is “SCN26-75: Experimental Probabilistic Precipitation Portal will Transition to Operational Status on or about October 1, 2026” (weather.gov/notification), which names the product moving from experimental to operational status and its target date.
• TIN (Technical Implementation Notice) — what are the technical specifications behind a change? TINs are listed on the same index alongside PNS and SCN documents.

Where to find older notices

Notices don’t disappear once superseded. The index page links to an “Archive of PNS/SCN/TIN (1996-2022)” covering all three notice types together, and the dedicated archive page at weather.gov/notification/archive separately lists the “Service Change Notices Archive ( 1997 - 2022 )” (weather.gov/notification; weather.gov/notification/archive). A reader tracing the history of a specific alert or forecast product — including changes made years before the current notice list — can search these archives by year rather than relying on the current index alone.

Issue-date comparison

The clearest way to see the difference between “when a change was announced” and “when it took effect” is to read one SCN document in full. Service Change Notice 24-88 opens with its own issue header:

“Service Change Notice 24-88 National Weather Service Headquarters Silver Spring MD 215 PM EDT Thu Sep 5 2024” (SCN24-88 PDF)

That header is the issue date and time — the moment NWS Headquarters published the notice: 2:15 PM EDT on Thursday, September 5, 2024. Further down, the same document states a separately labeled effective date for the change itself:

“Subject: Renaming of Excessive Heat Watch and Warning to Extreme Heat Watch and Warning: Effective March 4, 2025” (SCN24-88 PDF)

In other words, this single notice was issued on September 5, 2024, to announce a renaming that would not actually take effect until March 4, 2025 — roughly six months later. A reader who only skims the top of the document could mistake the issue date for the effective date; the two are separately labeled fields, and only the “Effective” line tells you when the change is actually live.

What this article does not answer

An SCN or PNS names the change and its dates, but it typically points to a linked directive or Product Description Document for the full technical specification — this article does not restate that complete specification for any given change. It also does not say whether or when any particular third-party weather app, broadcaster, or phone actually adopted a change by its stated effective date; the NWS notice record covers only what NWS itself published and when, not how quickly downstream products caught up.

Source links

https://www.weather.gov/notification/ https://www.weather.gov/notification/archive https://www.weather.gov/media/notification/pdf_2023_24/scn24-88_heat_haz_simp.pdf