A yellow warning for isolated severe thunderstorms is in force from 1pm to 5pm on Friday, with the mountains and southern and eastern areas of the island expected to be hit at times, the Department of Meteorology said.
Rainfall is expected to reach between 35 and 50 millimetres an hour, and hail and strong gusts of wind cannot be ruled out, the department said.
The warning was issued at 10.53am on Friday.
