Typhoon Mawar Expected to Hit Guam by Wednesday

What was Tropical Storm Mawar has strengthened in the Pacific into a typhoon and was expected to make landfall on Wednesday, bringing high winds and possible flooding to the Mariana Islands, including Guam, the National Weather Service said.

Mawar had maximum sustained winds of 80 miles per hour as of early Monday local time, with gusts up to 95 m.p.h., said Patrick Doll, the lead meteorologist of the Weather Service.

The storm is expected to continue strengthening, and forecasts project that it will hit Guam, a U.S. territory, around 10 a.m. on Wednesday local time, Mr. Doll said.

As the storm approaches the islands, its winds are “going to pick up,” said Brandon Bukunt, a meteorologist with the Weather Service, and outer rain bands could bring heavy downpours, increasing the chances of flooding, including in Guam, which is home to Andersen Air Force Base.

Mawar, which formed early on Sunday morning local time, might make landfall as a tropical storm. Mr. Doll said a typhoon watch was being maintained because of variability in the storm’s track.

“The system can do little wobbles, kind of like a snake going through the grass,” he said. “It may travel in a general direction, but you’re going to have a wiggle here and there. And the key will be, when does that wiggle occur and at what strength, which will determine if anyone takes a direct hit.”

Gov. Lou Leon Guerrero of Guam and Rear Adm. Benjamin Nicholson placed the island and its military bases on alert on Saturday for possible destructive winds, according to a statement from the base.

The statement added that “all military installations on Guam are currently securing facilities, and housing residents are urged to commence heavy-weather preparedness efforts.”

Typhoons can form year-round but are most common from May to October.

Mawar, a Malaysian name that means “rose,” is the second named storm in the West Pacific this season. The first, Tropical Storm Sanvu, weakened in less than two days.