Rain, possible thunderstorms predicted through weekend

JOHN BURNETT/Tribune-Herald A wave crashes over the rocks Thursday afternoon at Hilo Bayfront. An unstable airmass is moving over the islands, bringing an increase in showers across the state but primarily the Big Island and Maui.
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The new year has brought rain to East Hawaii, as well as windy weather and high surf to most of the Big Island.

As of 8 a.m. Thursday, Hilo International Airport had received 3.99 inches of rain since Jan. 1, and more rain fell later in the day.

More than a quarter of that rain, 1.27 inches, arrived during the 24-hour period ending 8 a.m. Sunday.

Glenwood, in the upper Puna rainforest, reported 9.25 inches of rain for the year as of 8 a.m. Thursday. Most of that total, 5.54 inches, fell between 8 a.m. Wednesday and 8 a.m. Thursday.

Most leeward Hawaii Island rain gauges reported little to no rain in the first nine days of the year, and the Kona coffee belt has its rainy season in the summer, unlike the windward side of the island.

Kealakekua, which is where North and South Kona converge, reported 1.22 inches of precipitation in the 24-hour periods ending at 8 a.m. Monday, Tuesday and Thursday.

And Kahua Ranch, in the Kohala Mountains above Waimea, tallied 3.5 inches total, with 2.29 inches of that coming in the 24-hour period ending at 8 a.m. Wednesday.

A flash flood watch is in effect for the Big Island and Maui through 6 p.m. Saturday.

An unstable airmass is moving over the islands, bringing an increase in showers across the state but primarily the Big Island and Maui. While showers are possible in most areas, the areas most susceptible to flooding will be windward locations which have already received rain this week.

The extended period of rain could cause flooding in low spots which could make some roadways impassable. Debris in streams and gulches may clog bridges and culverts. Strong winds may cause tree branches to fall which will potentially add to the amount of debris.

The National Weather Service warns that flash flooding is life threatening and cautions to not try to cross fast-flowing water either in a vehicle or on foot.

Heavy rain is forecast for today, tonight and Saturday in Hilo. Thunderstorms are possible through Saturday night, and showers are expected Sunday and Sunday night. New rainfall could total between 1-2 inches daily through Saturday.

A high surf warning remains in effect for east-facing shores of all islands until 6 p.m. Saturday, with surf predicted between 10 to 15 feet.

Forecasters warn there could be waves occasionally sweeping across portions of beaches and select low-lying roads, very strong breaking waves, and strong longshore and rip currents. Large breaking surf, significant shore break and dangerous currents make entering the water hazardous.

Easterly winds of 25-35 mph, with higher gusts, have buffeted the Big Island for most of the week, and Hawaii Fire Department rescue and ocean safety personnel have had a busy week due to the wind and waves.

An adult and three children clinging to an overturned kayak were rescued Monday morning in waters off Puako Beach Drive in South Kohala after sustained winds of 25 to 30 mph drove the capsized craft away from the shoreline. A paddle-boarder also was rescued that morning off Puako.

And on Tuesday afternoon, a 32-year-old man was swept off a cliff side while picking opihi on the shoreline north of Ha‘ena Beach fronting W.H. Shipman property near Keaau.

A county helicopter dropped a Fire Department rescue swimmer into the water. The victim was lifted to safety in a rescue net with minor injuries and refused medical treatment.

A Fire Department statement advised the public to “be aware of weather/surf conditions and warnings for their own safety.”

Email John Burnett at jburnett@hawaiitribune-herald.com.