The threat of thunderstorms and heavy rain, as well as a half-foot of snow over the Mauna Loa and Maunakea summits, has prompted watches for the entire state, including the Big Island, starting this evening and continuing until early Saturday.
An upper-level low moving in from the west, combined with converging low-level flow and moisture moving in from the east, will bring the potential for thunderstorms and locally heavy rainfall statewide, according to the National Weather Service in Honolulu. Forecasters noted the upper-level low is “already producing lots of thunderstorms.”
All areas of the Big Island are included in the watch.
In addition to the flash flood watch, the summits of Maunakea and Mauna Loa are also under a winter storm watch through late Friday night. Six inches or more of snow are forecast to fall at elevations over 12,000 feet. The Maunakea Access Road was open as of 10:25 a.m. Thursday.
Forecasters cautioned that flood-prone roads and other low-lying areas may be closed due to elevated runoff and overflowing streams. Urban area may receive more significant flooding and property damage due to rapid runoff.
A flash flood watch means that conditions are favorable for flash flooding. Be prepared to take action if a flash flood warning is issued by moving to higher ground immediately.