Tropical Storm Melissa remains almost stationary south of Jamaica, with authorities warning of life-threatening flooding and landslides in parts of southern Haiti and Jamaica through the weekend.

The US National Hurricane Center said Melissa was holding sustained winds of 75 km/h early on Friday. The storm is expected to strengthen steadily and could become a hurricane by Saturday, with forecasters indicating rapid intensification is likely as it moves across warmer waters in the western Caribbean.

Melissa is currently centred about 260 kilometres south southeast of Kingston and 445 kilometres southwest of Port-au-Prince. The storm is expected to drift slowly north and northeast before turning west on Saturday. On its current track, the centre is expected to pass near or just south of Jamaica early next week.

A hurricane watch is in place for Jamaica and the southwestern peninsula of Haiti. A tropical storm warning has also been issued for the same areas, meaning damaging winds could begin within 36 hours.

The most severe threat is from rainfall. Forecast models indicate 20 to 35 centimetres of rain will fall across southern Haiti, the southern Dominican Republic, and eastern Jamaica by late Sunday, with higher local totals possible. Authorities warn this will trigger significant flash flooding and numerous landslides, particularly in mountainous areas already prone to soil instability.

In southern Haiti, where infrastructure and access remain limited in many regions, forecasters described the risk of flooding and landslides as catastrophic. Northern Haiti, northern Dominican Republic, and western Jamaica may receive 7 to 13 centimetres of rain over the same period, with the possibility of flash and urban flooding.

Minor coastal flooding is possible in Jamaica on Saturday as onshore winds increase. However, forecasters noted that a more serious storm surge threat could develop along Jamaica’s south coast early next week depending on Melissa’s eventual track and strength.

Swells generated by the storm are expected to reach the coastlines of Hispaniola, Jamaica, and eastern Cuba over the coming days, creating dangerous surf and rip currents.

Authorities in the region have urged residents to monitor updates from national meteorological agencies and to prepare for rapidly deteriorating conditions, particularly in rural and mountainous areas at risk from fast-moving floodwaters.