Hilo

Tonight: Partly cloudy with scattered showers until early morning, then partly cloudy with numerous showers late in the night. Lows 62 to 69 near the shore to 48 to 56 at 4000 feet. North winds up to 15 mph. Chance of rain 70 percent.

Monday: Mostly sunny with numerous showers in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 76 to 81 near the shore to around 67 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Monday Night: Mostly cloudy in the evening then becoming partly cloudy. Slight chance of thunderstorms and isolated showers. Locally heavy rainfall possible. Lows 63 to 68 near the shore to 49 to 55 at 4000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Kona

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Lows around 70 near the shore to 43 to 52 near 5000 feet. Light winds.

Monday: Mostly sunny in the morning, then mostly cloudy with isolated showers in the afternoon. Highs around 84 near the shore to around 69 near 5000 feet. Light winds becoming west up to 10 mph in the afternoon. Chance of rain 20 percent.

Monday Night: Mostly cloudy in the evening then becoming partly cloudy. Lows around 70 near the shore to 43 to 50 near 5000 feet. East winds up to 10 mph.

Waimea

Tonight: Partly cloudy. Breezy. Isolated showers until early morning, then scattered showers late in the night. Lows 62 to 69 near the shore to 54 to 59 near 3000 feet. East winds up to 15 mph increasing to up to 25 mph after midnight. Chance of rain 40 percent.

Monday: Windy. Mostly sunny with scattered showers in the morning, then mostly cloudy with isolated showers in the afternoon. Highs 73 to 80 near the shore to 69 to 78 near 3000 feet. East winds 10 to 30 mph with gusts to 50 mph. Chance of rain 40 percent.

Monday Night: Partly cloudy. Breezy. Lows 62 to 69 near the shore to 52 to 59 near 3000 feet. East winds 10 to 20 mph.

Kohala

Tonight: Partly cloudy. Breezy. Isolated showers until early morning, then scattered showers late in the night. Lows 62 to 69 near the shore to 54 to 59 near 3000 feet. East winds up to 15 mph increasing to up to 25 mph after midnight. Chance of rain 40 percent.

Monday: Windy. Mostly sunny with scattered showers in the morning, then mostly cloudy with isolated showers in the afternoon. Highs 73 to 80 near the shore to 69 to 78 near 3000 feet. East winds 10 to 30 mph with gusts to 50 mph. Chance of rain 40 percent.

Monday Night: Partly cloudy. Breezy. Lows 62 to 69 near the shore to 52 to 59 near 3000 feet. East winds 10 to 20 mph.

South Big Island

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Breezy. Lows around 71 near the shore to around 49 near 5000 feet. East winds up to 20 mph.

Monday: Windy. Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 84 near the shore to around 67 near 5000 feet. Northeast winds up to 30 mph shifting to the east 10 to 30 mph in the afternoon. Chance of rain 20 percent.

Monday Night: Mostly cloudy in the evening then becoming partly cloudy. Breezy. Lows around 72 near the shore to around 49 near 5000 feet. East winds 15 to 20 mph.

Puna

Tonight: Partly cloudy with scattered showers until early morning, then partly cloudy with numerous showers late in the night. Lows 62 to 69 near the shore to 48 to 56 at 4000 feet. North winds up to 15 mph. Chance of rain 70 percent.

Monday: Mostly sunny with numerous showers in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 76 to 81 near the shore to around 67 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Monday Night: Mostly cloudy in the evening then becoming partly cloudy. Slight chance of thunderstorms and isolated showers. Locally heavy rainfall possible. Lows 63 to 68 near the shore to 49 to 55 at 4000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Waikoloa

Tonight: Partly cloudy. Breezy. Lows 69 to 74 near the shore to 48 to 54 above 4000 feet. East winds up to 20 mph. Gusts up to 40 mph after midnight.

Monday: Breezy. Mostly sunny in the morning, then mostly cloudy with isolated showers in the afternoon. Highs 81 to 87 near the shore to 66 to 74 above 4000 feet. Northeast winds up to 25 mph with gusts to 45 mph. Chance of rain 20 percent.

Monday Night: Partly cloudy. Lows 68 to 73 near the shore to 47 to 53 above 4000 feet. East winds up to 10 mph in the evening becoming light. Gusts up to 30 mph.

Detailed Forecast

Synopsis

Breezy trades return for the first half of the week bringing a modest increase in showers windward and mauka. Light winds then give way to a land and sea breeze pattern with afternoon clouds and isolated showers over island interiors during the second half of the week.

Discussion

Nascent trades have begun building into the forecast area in response to approaching mid-level ridging. This is evidenced by emerging light NNE to NE winds at several windward stations. Elsewhere, however, sea breezes will remain established until this evening. The lead edge of building surface high pressure manifests as a shallow moisture boundary approaching Kauai that will bring increased showers to windward and mauka locales as trades strengthen late tonight. The remainder of the state will remain on the dry side as pressure rises bring a return to breezy trade winds. High pressure then continues its eastward trek eventually returning the islands to a weakened trade wind state for the second half of the week. Winds then veer to the SE in response to a weakening front approaching from the northwest. This will favor a return to a land and sea breeze pattern over the western half of the state. Dry and benign weather prevails for the forseeable future.

Aviation

Light winds continue into tonight, with trade winds returning late tonight. Sea breeze clouds and spotty showers inland will persist through the evening, then clear as land breezes briefly develop. Low clouds and showers will start to favor windward and mauka areas late tonight as trades return. VFR will prevail, but brief MVFR is possible with passing showers.
No AIRMETs in effect.

Marine

Hazardous marine conditions will persist into Monday due to an extra large northwest swell. Observations at the offshore buoys northwest of Kauai show a 17-20 foot swell appearing to have leveled off this morning with the peak of this swell expected to continue through sunset, then gradually ease late tonight through Tuesday. Resulting surf should reach giant levels, in excess of 40 feet (faces) along coastlines with the highest exposure. Heights could hover at or above warning levels into Monday before lowering to advisory levels by Tuesday. Will determine tonight whether to extend the warning through Monday, or go with a High Surf Advisory for those exposed north and west facing shores.
Possible significant coastal impacts will including considerable beach erosion along exposed shorelines and potential overwash onto vulnerable coastal roadways and properties. Mariners should also anticipate hazardous conditions, including strong currents and occasional breaking waves near harbor entrances, making transits potentially dangerous.
A fast-moving surface high approaching from the northwest will lead to a rapid increase in northeast winds tonight, followed by fresh to strong trade winds as the high passes north of the state on Monday. A Small Craft Advisory (SCA) remains in effect for seas exceeding 10 feet, and as winds increase, the SCA will be expanded to include wind-affected zones. Trades are expected to gradually decline and shift southeasterly on Tuesday and Wednesday as the high moves eastward.

Fire weather

Minimal fire weather concerns at this time to relatively light winds and elevated RH.

HFO Watches/Warnings/Advisories

High Surf Warning until 6 AM HST Monday for Niihau, Kauai Leeward, Waianae Coast, Oahu North Shore, Maui Windward West, Kona, Kohala, Kauai North, Molokai Windward, Molokai North, Molokai West, Maui Central Valley North, Windward Haleakala.
High Surf Advisory until 6 AM HST Monday for Big Island East, Big Island North.
Small Craft Advisory until 6 AM HST Monday for all Hawaiian waters except Maalaea Bay,

Big Island Now Weather is brought to you by Blue Hawaiian Helicopters.

Check out their Big Island Helicopter Tours today!

Data Courtesy of NOAA.gov