A tropical storm warning and hurricane watch are now in effect for Jamaica as Tropical Storm Melissa moves slowly across the Caribbean Sea and closer to the island.

It means tropical storm conditions pose a possible threat to the island within 36 hours and hurricane conditions are likely to pose a threat within 48 hours, the Meteorological Service of Jamaica stated in its 5am bulletin Thursday.

At 4:00 am, the centre of Tropical Storm Melissa was located near latitude 15.0 degrees North, longitude 74.9 degrees West. This is about 353 kilometres (219 miles) south-southeast of Morant Point, Jamaica or about 390 kilometres (240 miles) south-southeast of the capital Kingston, the agency stated.

“Tropical Storm Melissa is moving very slowly toward the west near 6 km/h (3 mph). A slow forward speed and a gradual turn to the northwest or north-northwest is forecast during the next couple of days, followed by a westward turn.

“Maximum sustained winds are near 85 km/h (50 mph) with higher gusts. Little change in strength is forecast during the next day or so but, Melissa could become a hurricane in a couple of days, with more substantial intensification forecast by late Friday and through the weekend,” the release stated.

On the forecast track, Tropical Storm Melissa is expected to continue in the direction of Jamaica before turning towards the west on Saturday and moving over the waters south of the island. As the system nears Jamaica, showers will begin to affect the island with periods of moderate to heavy rainfall beginning late Thursday afternoon. This will continue through Friday and the weekend, the met office said.

Strong, gusty winds, possibly reaching tropical storm strength, are expected to gradually develop late Thursday and Friday, continuing into the weekend. These winds will initially affect eastern and southern parishes, before gradually spreading across the remainder of the island. Winds reaching hurricane strength are possible over sections of eastern parishes as early as Saturday, as Tropical Storm Melissa continues to move closer to Jamaica.

The Meteorological Service said marine interests should expect widespread heavy showers and thunderstorms, accompanied by tropical-storm-force winds Thursday and continuing through the weekend. Winds reaching hurricane strength are likely on Saturday, particularly over southern and eastern offshore waters, as Tropical Storm Melissa moves closer to the island. All small craft operators including fishers from the cays and banks should by now be in port and are urged to complete their necessary safety precautions without delay.

The met office said it continues to closely monitor the progress of Tropical Storm Melissa, and all interests are encouraged to pay special attention to further releases.