Cat 5 Super Typhoon Sinlaku poses a major threat to Guam

Super Typhoon Sinlaku is continuing its approach toward the northern Mariana Islands, packing sustained winds of up to 180 mph, equivalent to a powerful Category 5 system, as of Monday morning. While the likelihood of Guam experiencing the most severe impacts has decreased, the possibility has not been completely ruled out.

Super typhoon Sinlaku threats Guam

Super typhoon Sinlaku

As of Monday morning, Guam remains under Condition of Readiness 2, indicating that damaging winds are expected within the next 24 hours.

Forecasts from the National Weather Service indicate the island could experience tropical storm-force winds between 40–50 mph, with gusts reaching up to 60 mph, along with periods of heavy rainfall from Monday night through Wednesday. A high surf warning and flash flood watch are also in place.

Current weather models suggest Sinlaku is likely to track closer to Saipan and Tinian. However, a slight shift southward could still bring typhoon-strength winds exceeding 74 mph to Guam, according to NWS projections.

Saipan and Tinian are forecast to bear the brunt of the storm by Tuesday, with peak winds potentially reaching 145 mph.

As of Monday morning, Sinlaku was located approximately 340 miles east-southeast of Guam, moving toward the Mariana Islands at around 10 mph. Tropical storm-force winds of up to 45 mph could begin affecting Guam as early as tonight.

A tropical storm warning remains in effect for Guam, along with a typhoon watch—meaning winds of up to 74 mph are expected within 24 hours, while stronger typhoon-force winds remain possible within 48 hours.

NWS reports also indicate that Sinlaku may continue to strengthen as it nears the Mariana Islands.

In preparation for the storm, President Donald Trump approved a request from Guam Governor Lou Leon Guerrero for a federal emergency declaration, according to a statement from the Joint Information Center.

Is Guam expected to get the worst of Sinlaku?

As of Monday morning, forecasters said it remains too early to determine whether Guam will avoid the most severe impacts of Super Typhoon Sinlaku, according to NWS general forecaster Taelor Mesa.

“Typhoons often exhibit small track fluctuations that aren’t fully captured in forecast models,” Mesa explained. “If the system shifts slightly to the south, stronger winds could reach the southern Mariana Islands.”

She added that typhoon-strength winds are still a possibility for Guam. Current projections show Sinlaku moving out of the region by Thursday.

Mesa noted that if the threat of typhoon-force winds increases for Guam, an official warning will be issued.

According to NWS data, Sinlaku developed a well-defined eye about 17 miles wide overnight, with maximum winds reaching up to 175 mph.

The most intense winds are clustered around the eyewall, which, as of Monday morning, is forecast to track near or over Tinian based on Joint Typhoon Warning Center guidance

Meanwhile, NWS meteorologist-in-charge Brandon Aydlett said the chances of the storm shifting far enough south to directly impact Guam are “very unlikely.”

Schools and government offices are closed

According to Adelup, public schools and non-essential government offices will stay closed until Guam is declared safe and downgraded to Condition of Readiness 4 (COR 4).

COR 4 represents the lowest alert level, indicating that all storm threats have passed.

As of Monday morning, Adelup deputy spokesperson Daylin Pelletier said it is “unlikely” that Guam will return to COR 4 by Tuesday.

A flash flood watch

A flash flood watch remained in place for Guam through Wednesday morning.

Forecasts called for up to 2.4 inches of rain on Monday, with the Joint Information Center warning that flooding risks will increase significantly as Sinlaku approaches.

“Typhoon Sinlaku is expected to move across the Marianas on Tuesday, with rainfall near the core potentially reaching 15 to 20 inches,” JIC said in a statement. “For Guam, current projections indicate totals of 6 to 12 inches, with isolated areas possibly receiving higher amounts.”

Stay updated on Typhoon Sinlaku with the latest reports from Weather365.com.