The Meteorological Service of Jamaica on Thursday afternoon reiterated that a severe weather alert remains in effect for Jamaica because of a tropical wave over the southern Caribbean Sea that continues to move westward.

According to the Met Service, the tropical wave is expected to become more organised as it moves into an area conducive for development in the next 24 hours.

"Unstable weather conditions associated with the tropical wave are expected to spread over the central Caribbean waters south of Jamaica, and fishers on the cays and banks are further advised to evacuate immediately and return to the mainland," the Met Service said in its 4:00 pm news release.

"Other small craft operators in coastal waters are urged to return to port, while those in port are advised not to venture out as conditions are expected to deteriorate," the Met Service added.

Advising that severe weather impacts are likely to be experienced over sections of Jamaica as the system develops and moves closer to the island in the next couple of days, the Meteorological Service said it is continuing to monitor the progress of the system, and encouraged "all interests to pay special attention to further releases".

In its three-day forecast the Met Service said that on Saturday the island will experience isolated morning showers across eastern and north-central parishes, becoming mostly cloudy with scattered afternoon to late evening showers, thunderstorms and gusty winds across most parishes. The forecast also states that there will be lingering night-time showers and thunderstorms.

Sunday, the Met Service said, will be mostly cloudy with periods of showers, thunderstorms and strong gusty winds across most parishes, as well as lingering night-time showers and thunderstorms.

Monday will be mostly cloudy, with morning showers and thunderstorms mainly across southern and north-western parishes. The afternoon will be cloudy and "windy conditions are expected across the island".