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Special Marine Warning issued October 18 at 7:03PM ChST until October 18 at 7:30PM 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 09:04 UTC
First saved by us: 18 October 2026 at 09:17 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 09:30 UTC
Forecast onset / end: 18 October 2026 at 09:04 UTC / 18 October 2026 at 09:30 UTC

Archived official description

SMWGUM THE NATIONAL WEATHER SERVICE IN TIYAN GUAM HAS ISSUED A * SPECIAL MARINE WARNING FOR... GUAM COASTAL WATERS... * UNTIL 730 PM CHST. * AT 703 PM CHST...A SHOWER CAPABLE OF PRODUCING WATERSPOUTS WAS LOCATED OVER EASTERN GUAM WATERS MOVING NORTH AT 30 KNOTS. HAZARD...WATERSPOUTS AND WIND GUSTS 34 KNOTS OR GREATER. SOURCE...RADAR. IMPACT...WATERSPOUTS CAN CREATE LOCALLY HAZARDOUS SEAS. SMALL CRAFT COULD BE DAMAGED IN BRIEFLY HIGHER WINDS AND SUDDENLY HIGHER WAVES. * THE SHOWER WILL REMAIN OVER MAINLY OPEN WATERS.

Instructions in this archived message

WATERSPOUTS CAN EASILY OVERTURN BOATS AND CREATE LOCALLY HAZARDOUS SEAS. SEEK SAFE HARBOR IMMEDIATELY.

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 09:17 UTC

Saved by us

18 October 2026 at 09:17 UTC

Starting point

First saved record

Our first saved version of Special Marine Warning issued October 18 at 7:03PM ChST until October 18 at 7:30PM ChST by NWS Tiyan GU. We have no earlier saved version to compare.

Bulletin issued: 18 October 2026 at 09:04 UTC

View saved version 1

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

{
  "id": "nws:816c026ac9c2376ab8450a4b",
  "authorityId": "urn:oid:2.49.0.1.840.0.391af34d6ba259662ef720e0203bb905ae53bd33.001.1",
  "sender": "w-nws.webmaster@noaa.gov",
  "references": [],
  "category": "weather",
  "title": "Special Marine Warning issued October 18 at 7:03PM ChST until October 18 at 7:30PM ChST by NWS Tiyan GU",
  "eventType": "Special Marine Warning",
  "occurredAt": "2026-10-18T09:04:00.000Z",
  "issuedAt": "2026-10-18T09:04:00.000Z",
  "timeBasis": "Bulletin issued",
  "effectiveAt": "2026-10-18T09:03:00.000Z",
  "onsetAt": "2026-10-18T09:04:00.000Z",
  "expiresAt": "2026-10-18T09:30:00.000Z",
  "forecastEndAt": "2026-10-18T09:30:00.000Z",
  "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 GUAM HAS ISSUED A\n\n* SPECIAL MARINE WARNING FOR...\nGUAM COASTAL WATERS...\n\n* UNTIL 730 PM CHST.\n\n* AT 703 PM CHST...A SHOWER CAPABLE OF PRODUCING WATERSPOUTS WAS\nLOCATED OVER EASTERN GUAM WATERS MOVING NORTH AT 30 KNOTS.\n\nHAZARD...WATERSPOUTS AND WIND GUSTS 34 KNOTS OR GREATER.\n\nSOURCE...RADAR.\n\nIMPACT...WATERSPOUTS CAN CREATE LOCALLY HAZARDOUS SEAS. SMALL\n\nCRAFT COULD BE DAMAGED IN BRIEFLY HIGHER WINDS AND\n\nSUDDENLY HIGHER WAVES.\n\n* THE SHOWER WILL REMAIN OVER MAINLY OPEN WATERS.",
  "instruction": "WATERSPOUTS CAN EASILY OVERTURN BOATS AND CREATE LOCALLY HAZARDOUS\nSEAS. SEEK SAFE HARBOR IMMEDIATELY.",
  "url": "https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.391af34d6ba259662ef720e0203bb905ae53bd33.001.1",
  "source": "nws",
  "sourceName": "NOAA NWS"
}

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