HONOLULU (HawaiiNewsNow) - UPDATE AT 12 p.m.:
The Flash Flood Warning has expired for Hawaii Island, but a Flood Watch remains in effect until 6 p.m. Monday. Lingering unstable conditions may produce locally heavy showers and thunderstorms.
Route 19 is now open for travel. Motorists are reminded to drive safely and to be alert as weather conditions may change without notice.
UPDATE AT 10:15 a.m.:
Due to the excessive amount of rainfall, Route 19 at the 25 mile marker, which is located in the Laupahoehoe area, is closed. The road will remain closed for an unknown amount of time.
In addition, all motorists are urged to stay off the roadways and highways in the Hamakua, North Hilo, Hilo, and Puna Districts due to the excessive rains and resulting flooding and ponding on the roadways.
UPDATE AT 9:00 a.m.:
The National Weather Service in Honolulu has issued another Flash Flood Warning for windward areas of the Big Island of Hawaii until 12 noon.
Forecasters said at 8:54 a.m., radar showed areas of heavy showers a thunderstorms in the area. Rain was falling at rates of two to three inches per hour in Hilo and Puna.
Other locations in the warning include but are not limited to Pepeekeo, Papaikou, Paauilo, Ookala, Laupahoehoe, Honomu, Hakalau, Hilo, Pahoa and Keaau.
A Flash Flood Warning means that flash flooding is imminent or already occurring. Move to higher ground now.
The warning may be extended if heavy rain persists.
Meanwhile, a Flash Flood Watch remains in effect for the entire Big Island until 6 p.m.
UPDATE at 8:30 a.m.:
The flash flood WARNING has expired for Hawaii County. Heavy rains have subsided, but runoff is still occurring and streams will remain high for several hours. A flash flood WATCH is now in effect for the island of Hawaii. Lingering unstable conditions may produce locally heavy showers and thunderstorms.
UPDATE at 3:30 a.m.:
A flash flood warning has been issued for the island of Hawaii until 6:30 a.m.
According to the National Weather Service, radar showed heavy rains around the Honoka'a area northwest of Hilo.
Big Island police have closed Highway 19 near the 34-mile marker in Paauilo due to severe flooding. Officials say they are unsure when the road will reopen.
A strong thunderstorm brought penny-sized hail to parts of the Big Island of Hawaii Sunday night.
The hail was reported in the Hilo and Puna areas. The National Weather Service said the storm was reported near Pahoa shortly before 11 p.m., and was moving to the southeast. Forecasters said wind gusts to 30 miles per hour and intense lightning were possible.
Lightning accompanied heavy rain over Hilo earlier in the evening.
Follow the storm with our Interactive Radar Map.