Tropical Storm Ernesto churns toward Jamaica

Updated 4:20 PM ET

(CBS/AP) KINGSTON, Jamaica - Tropical Storm Ernesto blew across open waters Saturday on a projected path that would skirt Jamaica and hit Mexico after dumping heavy rain on islands in the eastern Caribbean.

The U.S. National Hurricane Center said Ernesto was expected to roll south of Jamaica as a hurricane Sunday evening. The forecast would carry it into the coastal resorts of Mexico's Yucatan Peninsula as a Category 1 hurricane on Wednesday.

Long lines formed at grocery stores in the Jamaican capital of Kingston as people bought water, bread and canned goods.

"We're going to have heavy rains, so I'm stocking up," said Marco Brown, a Kingston resident in his late 50s.

The Jamaican government ordered fishermen who live in outlying cays to evacuate and head to the main island. The storm is expected to pass close to Pedro Cays on Sunday evening, according to the local Meteorological Service Office.

CBS News hurricane consultant Dave Bernard said there is the possibility the storm could enter the Gulf of Mexico, but it's too early to say what, if any, impacts Ernesto could have on the United States' coastline.

"Certainly, if you have plans or cruises going into the western Caribbean Sea, around Cancun or Cozumel, there could be a hurricane threat there in the next 72 hours in the mid-part of next week," Bernard said on "CBS This Morning: Saturday."

The storm earlier forced Dominica to close its airport for two days, and St. Lucia ordered shops to close for several hours, but no damage or flooding was reported on islands affected by the storm.

The hurricane center said Ernesto had maximum sustained winds of about 50 mph (85 kph) Saturday afternoon. It was about 270 miles (440 kilometers) south of Santo Domingo in the Dominican Republic and was moving westward at 18 mph (30 kph).

Meanwhile, a new tropical storm, Florence, formed further out in the Atlantic. It had maximum sustained winds of 45 mph (75 kph) and was about 415 miles (665 kilometers) west of the Cape Verde Islands. The National Hurricane Center said it was not expected to reach hurricane force as it marches generally westward.