KINGSTON, Jamaica—A tropical storm watch remains in effect for Jamaica as Tropical Storm Melissa is moving very slowly across the Caribbean Sea south of Hispaniola.

This means tropical storm conditions pose a possible threat to Jamaica within 48 hours.

According to the Meteorological Service of Jamaica, at 10:00 am the centre of Tropical Storm Melissa was located by Air Force Reserve Reconnaissance aircraft near latitude 14.4 degrees North, longitude 73.6 degrees West.

This is about 485 kilometres (300 miles) south-southwest of Port-au-Prince, Haiti, about 478 kilometres (298 miles) southeast of Morant Point, Jamaica, or about 525 kilometres (325 miles) southeast of the capital, Kingston.

Tropical Storm Melissa is moving very slowly toward the west-northwest near 4 km/h (2 mph). A slow forward speed and a gradual turn to the northwest and north-northwest are expected during the next few days.

Maximum sustained winds are near 85 km/h (50 mph) with higher gusts. Some gradual strengthening is anticipated during the next few days, and Melissa could become a hurricane on Thursday.

On the current forecast track, the tropical storm is now expected to approach Jamaica before turning towards the west on Saturday and passing over the waters south of Jamaica through the start of next week.

As the system nears Jamaica, it is expected to produce periods of moderate to heavy rainfall and strong, gusty winds, possibly reaching tropical storm intensity, particularly over northeastern and southern parishes on Thursday and continuing through the weekend.

Marine interests should expect widespread heavy showers and thunderstorms, along with tropical storm-force winds late Wednesday and Thursday. All small craft operators, including fishers from the cays and banks, should be arriving in port to start preparations for safe harbour.

The Meteorological Service says it continues to closely monitor the progress of Tropical Storm Melissa.