The National Weather Service said that through 4 p.m., a large area of heavy showers and scattered thunderstorms are moving through the region, which will produce brief heavy downpours
Visibility will be reduced to less than 1 mile and could produce local flooding.
Wind gusts to 45 mph are expected. Occasional to frequent lighting is expected as well, the Weather Service reported. Urban and small stream flood advisories are possible over the islands.
A special marine warning is in effect for the coastal waters of Guam, Rota, Tinian and Saipan until 3:45 p.m. Heavy rain, occasional to frequent lightning and wind gusts of 40 knots or greater are expected.
Waterspouts are possible, the Weather Service reported. Waterspouts can easily overturn boats and create locally hazardous seas. Small craft could be damaged in briefly higher winds and suddenly higher waves.
Boaters can expect visibility down to half a mile in heavy showers. Boaters are advised to move to safe harbor immediately as gusty winds and high waves are expected, the Weather Service reported.
A thunderstorm advisory is in effect for the Guam International Airport through 4 p.m. Thunderstorms are expected within 20 nautical miles of the airport during this time, the Weather Service stated.
The Offices of Guam Homeland Security and Civil Defense advise the community to practice extreme caution while traveling in rainy conditions by driving below the speed limit and allowing enough braking distance between vehicles.