Hurricane Maria gains strength, and a watch is issued for Puerto Rico

Hurricane Maria, which continued to strengthen Sunday, maintained a west-northwest track Sunday night toward the already storm-battered Leeward Islands.

As of 5 a.m. Monday, Maria, which became a Category 1 hurricane Sunday afternoon, was located 130 miles east-southeast of Dominica with sustained winds of 90 mph.

Forecasters expect Maria, which was moving west-northwest at 13 mph, to hit the Leeward Islands Monday and become a major hurricane by the time it nears Puerto Rico Tuesday.

A hurricane watch was issued Monday morning for Puerto Rico, Vieques and Culebra.

A “burst of convection” occurred in the storm’s center Sunday afternoon, with an open eyewall forming in the the storm’s core, National Hurricane Center forecasters said. Because the storm is compact, it could quickly intensify as it moves over warm ocean waters and faces weak wind shear, they said.

Maria should become a major storm over the next two days, which could cause wind speeds to vary slightly if it undergoes eyewall replacements, which big storms are prone to do.

Hurricane advisories continue to extend across Caribbean islands battered by Irma as the storm approaches. Forecast models generally agree on a track that takes Maria near Guadalupe and the northern islands of the Lesser Antilles on Monday and near Puerto Rico on Tuesday as a major hurricane.

It’s too soon to tell Maria’s impacts to Florida or the U.S. coast. Early models show the storm moving toward Florida and up the East Coast, but forecasts so far in advance can be hundreds of miles off.

By Sunday night, tropical storm force winds extended 105 miles from Maria’s center. Within three days, forecasters say sustained winds could reach 125 mph.

As the storm approaches, watches and warnings continued to expand, with Guadeloupe, Dominica, St. Kitts, Nevis, Montserrat and Martinique under hurricane warnings, meaning hurricane conditions could strike in 36 hours. St. Martin and St. Bart’s, both pounded by Irma, are among the islands under hurricane watches. Others include Antigua, Barbuda, Saba, St. Eustatius, Anguilla, Barbados and St. Lucia.

Last week, Irma’s ferocious Category 5 winds left a wake of destruction that damaged more than 90 percent of the buildings on Barbuda and forced all its residents to flee. On St. Martin, residents are wondering if it’s even possible to rebuild.

Maria formed much closer to land, giving it less time to grow to Irma’s monster proportions, but it is facing conditions eerily similar to the path Irma took: low wind shear, a warm ocean and very moist air.

Maria is being steered by a high-pressure ridge to the west-northwest. That ridge is expected to weaken in the next three days, which could slow the storm but keep it headed in the same direction.

As it nears the coast, Hurricane Jose, about 305 miles southeast of Cape Hatteras on Sunday and expected to move offshore parallel to the East Coast, could play a factor in where Maria goes. If Jose weakens the ridge steering the storm, it could allow Maria to take a track more to the northwest or north-northwest. If not, the storm will likely keep heading to the west-northwest.

Sunday morning, Jose strengthened slightly, but forecasters say it will likely weaken in the coming days as it faces stronger wind shear, and then moves over colder water. They expect it to weaken again to a tropical storm in three to four days.

Forecasters warned that the islands could again be hit with heavy storm surge, from four to six feet deep. The central and southern Leeward Islands could get between six and 12 inches of rain, with 20 inches possible in some locations. Dangerous waves and rip currents will likely pick up around the Lesser Antilles Sunday night.

Maria became the seventh hurricane this season in what was expected to be an above average year, with five to nine hurricanes and two to five major storms predicted. But 2017 may end up easily beating that forecast with more than two months to go during the busiest part of the Atlantic season.

Forecasters are also watching Tropical Storm Lee, located nearly 910 miles west-southwest of the Cabo Verde Islands. Lee weakened to a depression Sunday, poses no threat to land and is expected to fizzle on Monday.

Miami Herald staff writer Carli Teproff contributed to this report.

This story was originally published September 18, 2017 at 5:54 AM with the headline "Hurricane Maria gains strength, and a watch is issued for Puerto Rico."