The National Weather Service has issued a flash flood watch for Hawaii Island through 6 p.m. Wednesday.
Heavy rain is in the forecast for through Wednesday night, with scattered showers on Thursday and Thursday night.
Hilo has experienced lightning and thunder this afternoon.
According to the weather service, heavy rains may persist long enough for runoff to produce flash flooding and conditions may develop that lead to torrential rain. Where torrential rains occur, flash flooding of poor drainage areas, streams, and low lying areas will be possible.
Flash flooding is very dangerous.
If you observe heavy rain, or if a flash flood warning is issued, move to higher ground. Do not try to cross fast flowing or rising water in your vehicle or on foot.
Be prepared for closures of roads, parks and other facilities because of the weather.
According to the Mauna Kea Weather Center, the atmosphere near the Big Island will remain fairly saturated and unstable, allowing fog, ice, high humidity and/or light flurries to plague the summit of Maunakea through at least Wednesday evening. There is also a possibility for convection in the area and periods of heavy snow, particularly through this evening and again between tomorrow afternoon and Wednesday evening.
As of late Monday afternoon, the Maunakea summit access road was open to four-wheel drive vehicles. Two-wheel drive vehicles will not be allowed past the end of the paved portion of the road.