SAN JUAN, Puerto Rico, (Reuters) – Tropical Storm  Erika weakened to a tropical depression in the northeast  Caribbean yesterday but still threatened Puerto Rico and  neighboring islands with heavy rainfall, the U.S. National  Hurricane Center said.

Most government offices and schools closed early yesterday afternoon and Puerto Rican Governor Luis Fortuno urged  residents to leave flood-prone areas before the storm struck  the U.S. territory.

“We know from past experience, that this can have a  significant impact for Puerto Ricans,” Fortuno said.

Erika’s top sustained winds dropped to 35 miles per hour  (55 km per hour), putting it below the 39 miles-per-hour  (63-km-per-hour) threshold for a tropical storm.

The centre of the ragged mass of thunderstorms was about  130 miles (205 km) east-southeast of San Juan, Puerto Rico, at  5 p.m. EDT (2100 GMT).
It was moving west but was expected to turn west-northwest  on a course that would take it south of Puerto Rico last  night and over the Dominican Republic and Haiti in the next two  days.

Forecasters warned that the system could dump 2 to 4 inches  (5 to 10 cm)  of rain on those in its path, with up to 6 inches  (15 cm) in isolated areas.

The depression was expected to continue weakening and was  not expected to affect oil and natural gas operations in the  Gulf of Mexico.