An approaching cold front from the northwest that is expected to bring heavy rain and possible flooding has prompted forecasters at the National Weather Service to issue a flash flood watch for Kauai and Oahu Sunday and Monday.

Attendees to Sunday’s Pro Bowl may want to pack rain gear. Although current mild weather conditions are expected to prevail through Saturday, the band of heavy rain is expected to hit Oahu Sunday afternoon, weather officials say.

An unstable and moist air mass in front of the approaching cold front could cause heavy rain and possible thunderstorms Sunday and Monday, forecasters say.

The storm system also appears to be slowing, which could mean the rain will linger, making flooding more likely.

The weather system is expected to move over Maui County and Hawaii island late Monday and could bring heavy rain to those islands.