Michelle a dangerous hurricane

Image of Hurricane Michelle taken at 11:38 a.m. EST on Friday

MIAMI, Florida (CNN) -- Hurricane Michelle, the eighth of the Atlantic storm season, is churning off Cuba with 100 mph winds as forecasters predict it will become a major storm in the next 24 hours.

Michelle is moving toward the north, where it is expected to hit Cuba over the weekend.

Hurricane watches are in effect for the provinces of Pinar del Rio, La Habana, Havana City, Matanzas and the Isle of Youth. The Cayman Islands has issued a tropical storm watch for its territory.

The National Hurricane Center asked residents in South Florida and the Florida Keys to track the storm closely through the weekend. The storm is expected to turn more toward the east late in the weekend although computer models are split as to when and exactly where that may occur.

MICHELLE INFORMATION At 7 p.m. EST Friday STATUS Hurricane POSITION Near 18.5 degrees north latitude, 84.0 degrees west longitude, or about 240 miles (385 kilometers) south-southeast of the western tip of Cuba MOVEMENT North at near 6 mph (10 kilometers per hour) WIND SPEED Near 100 mph (155 kilometers per hour) with stronger gusts OUTLOOK General motion expected to continue in the next 24 hours

"The bottom line is we have a general idea that the storm will turn to the northeast," said Max Mayfield, director of the National Hurricane Center. "When it will turn to the northeast is very uncertain."

At 7 p.m. Friday, the center of the storm was situated about 240 miles south-southeast of the western tip of Cuba and moving erratically toward the north at around 6 mph, the National Hurricane Center said. Similarly slow movement in this direction is expected to continue through Saturday.

Hurricane force winds extended outward 25 miles from the storm's center, with tropical storm force winds extending up to 115 miles out. Intermittent but locally heavy rain is expected to fall in the Cayman Islands, Jamaica and Cuba over the next few days.

Forecasters predict 10 to 20 inches of rain may fall over the duration of the storm in Cuba, where extensive flooding already has occurred, and other locales in Michelle's path.