NOAA NWS / Event history

Special Marine Warning issued October 18 at 6:26PM ChST until October 18 at 6:45PM ChST by NWS Tiyan GU

Special Marine Warning · Guam Coastal Waters. Severe; likely; urgency: immediate.

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Bulletin issued: 18 October 2026 at 08:26 UTC
First saved by us: 18 October 2026 at 08:32 UTC
Last included in a daily record: 18 October 2026
The linked daily edition preserves what we captured that UTC day; this event page is not a live warning.
Source classification: Severe · Source alert

A recent feed check does not mean a new observation. This page preserves source records; it does not establish current safety or warning status.

Issuer / area: NWS Tiyan GU · Guam Coastal Waters
Certainty / urgency: Likely / Immediate
Message expiry (not hazard end): 18 October 2026 at 08:45 UTC
Forecast onset / end: 18 October 2026 at 08:26 UTC / 18 October 2026 at 08:45 UTC

Archived official description

SMWGUM THE NATIONAL WEATHER SERVICE IN TIYAN HAS ISSUED A * SPECIAL MARINE WARNING FOR... SOUTHEASTERN GUAM COASTAL WATERS... * UNTIL 645 PM CHST. * AT 626 PM CHST, A SEVERE THUNDERSTORM PRODUCING WATERSPOUTS WAS LOCATED 30 NM SOUTHEAST OF IPAN BUOY, MOVING NORTH AT 30 KNOTS. HAZARD...WATERSPOUTS. SOURCE...RADAR INDICATED. IMPACT...WATERSPOUTS CAN EASILY OVERTURN BOATS AND CREATE LOCALLY HAZARDOUS SEAS. * LOCATIONS IMPACTED INCLUDE... MAINLY OPEN WATERS OF GUAM COASTAL WATERS.

Instructions in this archived message

MOVE TO SAFE HARBOR UNTIL HAZARDOUS WEATHER PASSES.

The saved record

What changed

0 updates · 1 first record

Each update compares two versions we saved. This may not include every update from the source. A missing report does not mean an event has ended.

First saved record · 18 October 2026 at 08:32 UTC

Saved by us

18 October 2026 at 08:32 UTC

Starting point

First saved record

Our first saved version of Special Marine Warning issued October 18 at 6:26PM ChST until October 18 at 6:45PM ChST by NWS Tiyan GU. We have no earlier saved version to compare.

Bulletin issued: 18 October 2026 at 08:26 UTC

View saved version 1

Original saved fields, unchanged. This is our record, not an archived copy of the external webpage.

{
  "id": "nws:d7aa69ab1678254cb9b4629e",
  "authorityId": "urn:oid:2.49.0.1.840.0.80f2f127c9c7abfed7904ad06c52844882707e33.001.1",
  "sender": "w-nws.webmaster@noaa.gov",
  "references": [],
  "category": "weather",
  "title": "Special Marine Warning issued October 18 at 6:26PM ChST until October 18 at 6:45PM ChST by NWS Tiyan GU",
  "eventType": "Special Marine Warning",
  "occurredAt": "2026-10-18T08:26:00.000Z",
  "issuedAt": "2026-10-18T08:26:00.000Z",
  "timeBasis": "Bulletin issued",
  "effectiveAt": "2026-10-18T08:26:00.000Z",
  "onsetAt": "2026-10-18T08:26:00.000Z",
  "expiresAt": "2026-10-18T08:45:00.000Z",
  "forecastEndAt": "2026-10-18T08:45:00.000Z",
  "severity": "Severe",
  "urgency": "Immediate",
  "certainty": "Likely",
  "messageType": "Alert",
  "status": "Source alert",
  "place": "Guam Coastal Waters",
  "coordinates": null,
  "issuer": "NWS Tiyan GU",
  "summary": "Special Marine Warning · Guam Coastal Waters. Severe; likely; urgency: immediate.",
  "description": "SMWGUM\n\nTHE NATIONAL WEATHER SERVICE IN TIYAN HAS ISSUED A\n\n* SPECIAL MARINE WARNING FOR...\nSOUTHEASTERN GUAM COASTAL WATERS...\n\n* UNTIL 645 PM CHST.\n\n* AT 626 PM CHST, A SEVERE THUNDERSTORM PRODUCING WATERSPOUTS WAS\nLOCATED 30 NM SOUTHEAST OF IPAN BUOY, MOVING NORTH AT 30 KNOTS.\n\nHAZARD...WATERSPOUTS.\n\nSOURCE...RADAR INDICATED.\n\nIMPACT...WATERSPOUTS CAN EASILY OVERTURN BOATS AND CREATE LOCALLY\nHAZARDOUS SEAS.\n\n* LOCATIONS IMPACTED INCLUDE...\nMAINLY OPEN WATERS OF GUAM COASTAL WATERS.",
  "instruction": "MOVE TO SAFE HARBOR UNTIL HAZARDOUS WEATHER PASSES.",
  "url": "https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.80f2f127c9c7abfed7904ad06c52844882707e33.001.1",
  "source": "nws",
  "sourceName": "NOAA NWS"
}

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