Oct. 21 (UPI) -- Tropical Storm Melissa is moving slowly through the Caribbean Sea on Wednesday, meaning portions of Haiti, the Dominican Republic and Jamaica were expected to see major flooding through the week, the National Hurricane Center said.

Melissa was about 305 miles south-southwest of Port-au-Prince, Haiti, and 335 miles southeast of Kingston, Jamaica, the NHC said in its 8 a.m. EDT update. The storm had remained virtually stationary since the agency's previous update 3 hours earlier.

The storm had maximum sustained winds of 50 mph and was moving west-northwest at 2 mph.

A hurricane watch was in effect for the southwestern peninsula of Haiti from the border with the Dominican Republic to Port-au-Prince. A tropical storm watch was in effect for Jamaica. Those elsewhere in Haiti, the Dominican Republic and Cuba should monitor the progress of Melissa, the NHC said.

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