Update: Flood advisory downgraded to flood watch for Big Island

This story was updated at at 12:29 p.m. on Jan. 29.

The National Weather Service has canceled the flood advisory for the Big Island due to weather radar showing that the heavy rain has diminished. But a flood watch remains in effect until 6 p.m. Monday.

This story was updated at 3:21 a.m. Jan. 29.

A flood watch is now in effect for the Big Island until 6 p.m. Monday. The National Weather Service in Honolulu early Sunday morning extended the advisory for another day.

A flood watch means conditions are favorable for flash flooding, which can be life threatening; do not cross fast flowing water in a vehicle or on foot.

The National Weather Service in Honolulu says a surface trough will act as a focus for heavy showers and thunderstorms over the Big Island through the weekend. The bulk of the rainfall is expected to fall over windward slopes and coasts, but some heavy showers could spread to leeward areas, where stream flow could also become elevated.

Flood prone roads and other low lying areas could be closed because of elevated runoff and overflowing streams. Urban areas could receive more significant flooding and property damage because of rapid runoff.

The public should monitor later forecasts and be prepared to take action should flash flood warnings be issued.

Hawai‘i County Civil Defense on Saturday issued the following advice:

• All Residents in flood prone areas are asked to remain alert for flooding conditions.
• Be aware that road closures could occur without notice.
• Do not attempt to cross flowing water in your vehicle or by foot; turn around don’t drown.
• Be on the alert for malfunctioning traffic signals.
• Please treat flashing traffic lights as a four-way stop.
• Remember, if lightning threatens your area, the safest place to be is indoors.

The National Weather Service also extended a winter storm warning in effect for the summits of Maunakea and Mauna Loa on the Big Island until 6 p.m. Monday.

The National Weather Service says deep moisture and instability will spread over the Big Island through Monday, while temperatures over the summits remain below freezing. This will bring periods of wintry precipitation. While most of the precipitation will fall as snow, freezing rain will also be possible.

Periods of heavy snow with freezing rain are forecast, with additional snow accumulations in excess of 6 inches and some ice accumulations. Travel could be very difficult or even impossible. Snow will also significantly reduce visibility at times.