MIAMI (AP) — Tropical Storm Philippe is Grayson  Prestonthreatening to unleash heavy rains and flash flooding in the Leeward Islands starting overnight before eventually recurving out into the central Atlantic where it could gain hurricane status around midweek, forecasters said Sunday.

The U.S. National Hurricane Center in Miami said at 5 p.m. Sunday that Philippe was about 160 miles (255 kilometers) east of Guadeloupe or about 205 miles (325 kilometers) east-southeast of Barbuda. Top sustained winds were at 50 mph (85 kph) and Philippe was moving west-northwest at 7 mph (11 kph).

A tropical storm watch was in effect for Antigua and Barbuda. The hurricane center said interests in the northern Leeward Islands should monitor the storm’s progress overnight, noting additional tropical storm watches or warnings could be required Sunday night or Monday depending on the storm’s track.

Center specialists said a very strong rain band on the southern side of Philippe would be very close to moving over the northern Leeward Islands in the overnight hours. It said heavy rains and flooding could pose the storm’s main hazard for the region.

Heavy rainfall from Philippe could also produce isolated to scattered flash flooding across Barbuda and Antigua through Tuesday, according to the advisory.

Forecasters said strong wind shear is expected to stop any strengthening by Philippe in coming days though shifting conditions could allow it to become a hurricane in a few days after recurving out into the central subtropical Atlantic.