Special Marine Warning for Guam Coastal Waters: Waterspouts and High Winds Possible
The National Weather Service has issued a Special Marine Warning for Guam Coastal Waters until 8:30 AM ChST due to a severe thunderstorm capable of producing waterspouts and high wind gusts.
Alert Details
The National Weather Service in Tiyan, Guam, has issued a Special Marine Warning (SMWGUM) for the region. The alert was issued at 7:54 AM ChST on March 2, 2026, following radar detection of hazardous weather conditions.
Affected Areas
The warning specifically covers the Guam Coastal Waters. At the time of the alert, a severe thunderstorm was located over Apra Harbor, moving southwest at approximately 20 knots. The storm is expected to remain primarily over open waters.
What You Should Do
Mariners and residents in the affected area are advised to move to safe harbor immediately. You should remain in a secure location until the hazardous weather passes. Thunderstorms can produce sudden waterspouts that can easily overturn boats and create locally hazardous seas. Small craft are particularly vulnerable and could be damaged by briefly higher winds and suddenly higher waves.
Expected Conditions
- Hazards: Potential waterspouts and wind gusts of 34 knots or greater.
- Seas: Suddenly higher waves and locally hazardous sea conditions are expected near the thunderstorm.
- Movement: The storm system is moving southwest at 20 knots.
Timeline
The Special Marine Warning is effective immediately as of 7:54 AM ChST and is currently scheduled to expire at 8:30 AM ChST on March 2, 2026.
Source: NOAA Official Notice