The thirteenth named storm of the 2025 Atlantic hurricane season has formed in the Caribbean, prompting hurricane and tropical storm watches for parts of Haiti and Jamaica.

According to the US National Hurricane Center (NHC), Tropical Storm Melissa was located about 490 kilometres south of Port-au-Prince, Haiti, at 2pm Eastern Time (7pm Irish time) on Tuesday. The storm is moving west at about 22 km/h, with maximum sustained winds near 85 km/h.

A hurricane watch has been issued for the southern coast of Haiti from the border with the Dominican Republic to Port-au-Prince, while a tropical storm watch is in effect for Jamaica. The NHC said hurricane conditions are possible in Haiti from Thursday, and tropical storm conditions could reach Jamaica by late Thursday or Friday.

Forecasters expect Melissa to slow down and gradually turn northwest and north over the coming days, tracking toward the waters near southwestern Haiti and Jamaica later this week. Further strengthening is likely as the system moves over warm Caribbean waters.

Heavy rainfall is forecast to bring significant flooding to parts of Hispaniola. The NHC warned that five to ten inches (125–250 mm) of rain could fall across Haiti and the Dominican Republic through Friday, with the potential for flash floods and landslides in mountainous terrain.

Lighter rainfall of one to three inches (25–75 mm) is expected across Jamaica, Puerto Rico and Aruba, with localised flash and urban flooding possible.

Melissa’s winds currently extend up to 185 kilometres from the storm’s centre, and swells generated by the system are expected to reach Hispaniola, Jamaica and eastern Cuba within the next couple of days, creating hazardous surf and rip currents.

The storm is being monitored by an Air Force Hurricane Hunter aircraft, which is providing updated data on wind speeds and pressure. At 7pm GMT (2PM EDT), Melissa’s minimum central pressure was measured at 1003 millibars (29.62 inches).

The 2025 Atlantic hurricane season has already seen multiple storms affecting the Caribbean and the western Atlantic, with activity expected to continue into November.