ASAN, Guam (April 10, 2026) – Together with the Government of Guam and Joint Task Force- Micronesia, Joint Region Marianas continues to closely monitor Tropical Storm Sinlaku, formerly known as Tropical Depression 04W, as it tracks toward the Marianas.
JRM receives ongoing updates from the Joint Typhoon Warning Center (JTWC), the Department of War’s official source for tropical cyclone forecasts in the region. Products used for these updates are contained at the JTWC link below.
The latest forecast shows an intensifying system with potential to reach Category 3 or 4 strength, with winds around 104 knots (120 mph), near Guam. Damaging winds of 34 knots (39 mph) or more are possible as early as Monday morning, with destructive typhoon-force winds of 64 knots (74 mph) or more possible for Guam Monday night or early Tuesday morning.
To best prepare for this event, JRM set Tropical Cyclone Condition of Readiness (TCCOR) Storm Watch today at 10 a.m. ChST, enabling base commanders to take preparatory actions.
The next announcement, which will be determined at a later time, will be for TCCOR 3, indicating sustained winds greater than 50 knots (57 mph) are possible within 48 hours. As the storm continues to progress, JRM will announce TCCOR 2 when sustained winds greater than 50 knots are anticipated within 24 hours, followed by TCCOR 1, which is when those winds are occurring or anticipated within 12 hours.
It is important to note a key difference in storm condition thresholds.
The Government of Guam typically sets Conditions of Readiness (COR) based on the onset of damaging winds of 34 knots or more, which does not always align with the DoW threshold. All parties remain in close coordination.
Service members and their families are advised to begin taking precautionary measures, including ensuring households have sufficient food, water, and necessary medication for 7 to 10 days; clearing drainage areas to reduce flooding risk; securing windows, doors, and other items that could become airborne with heavy winds.
JRM will continue to provide updates as the storm progresses.
For the latest advisory information, visit
- NWS Website: https://www.weather.gov/gum
- JTWC Website: https://www.metoc.navy.mil/jtwc/jtwc.html
- JRM Facebook: https://www.facebook.com/jrmguam/
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For more information, contact the Joint Region Marianas Public Affairs Office at jrmpublicaffairs@us.navy.mil.