Hilo

Tonight: Partly cloudy with isolated showers in the evening, then mostly cloudy with scattered showers after midnight. Lows 61 to 68 near the shore to 48 to 54 at 4000 feet. West winds up to 10 mph. Chance of rain 30 percent.

Christmas Day: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs 75 to 82 near the shore to around 67 at 4000 feet. North winds up to 10 mph shifting to the east in the afternoon. Chance of rain 20 percent.

Wednesday Night: Partly cloudy with isolated showers. Lows 62 to 68 near the shore to 48 to 54 at 4000 feet. Southwest winds up to 15 mph. Chance of rain 20 percent.

Kona

Tonight: Partly cloudy with isolated showers. Haze. Lows around 70 near the shore to 43 to 51 near 5000 feet. Light winds. Chance of rain 20 percent.

Christmas Day: Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Haze through the day. Highs 81 to 86 near the shore to around 69 near 5000 feet. West winds up to 10 mph. Chance of rain 20 percent.

Wednesday Night: Partly cloudy. Isolated showers in the evening. Lows around 70 near the shore to 42 to 51 near 5000 feet. Light winds. Chance of rain 20 percent.

Waimea

Tonight: Breezy. Partly cloudy with isolated showers. Lows 61 to 69 near the shore to 52 to 58 near 3000 feet. Southeast winds up to 20 mph. Chance of rain 20 percent.

Christmas Day: Breezy. Mostly sunny with isolated showers. Highs 73 to 80 near the shore to 69 to 76 near 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Wednesday Night: Breezy. Partly cloudy with isolated showers. Lows 60 to 69 near the shore to 52 to 58 near 3000 feet. Southeast winds up to 20 mph. Chance of rain 20 percent.

Kohala

Tonight: Breezy. Partly cloudy with isolated showers. Lows 61 to 69 near the shore to 52 to 58 near 3000 feet. Southeast winds up to 20 mph. Chance of rain 20 percent.

Christmas Day: Breezy. Mostly sunny with isolated showers. Highs 73 to 80 near the shore to 69 to 76 near 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Wednesday Night: Breezy. Partly cloudy with isolated showers. Lows 60 to 69 near the shore to 52 to 58 near 3000 feet. Southeast winds up to 20 mph. Chance of rain 20 percent.

South Big Island

Tonight: Mostly clear. Breezy and haze. Lows around 70 near the shore to around 48 near 5000 feet. Northeast winds 10 to 20 mph.

Christmas Day: Mostly sunny in the morning then becoming partly sunny. Breezy. Isolated showers. Haze. Highs around 83 near the shore to around 67 near 5000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Wednesday Night: Breezy. Partly cloudy with isolated showers. Lows around 70 near the shore to around 49 near 5000 feet. Northeast winds 10 to 25 mph. Chance of rain 20 percent.

Puna

Tonight: Partly cloudy with isolated showers in the evening, then mostly cloudy with scattered showers after midnight. Lows 61 to 68 near the shore to 48 to 54 at 4000 feet. West winds up to 10 mph. Chance of rain 30 percent.

Christmas Day: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs 75 to 82 near the shore to around 67 at 4000 feet. North winds up to 10 mph shifting to the east in the afternoon. Chance of rain 20 percent.

Wednesday Night: Partly cloudy with isolated showers. Lows 62 to 68 near the shore to 48 to 54 at 4000 feet. Southwest winds up to 15 mph. Chance of rain 20 percent.

Waikoloa

Tonight: Partly cloudy. Haze. Lows 68 to 73 near the shore to 47 to 53 above 4000 feet. Southeast winds up to 10 mph.

Christmas Day: Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Haze through the day. Highs 81 to 86 near the shore to 65 to 73 above 4000 feet. South winds up to 10 mph shifting to the northwest in the afternoon. Chance of rain 20 percent.

Wednesday Night: Partly cloudy. Isolated showers in the evening. Lows 68 to 73 near the shore to 47 to 53 above 4000 feet. Light winds becoming south up to 10 mph after midnight. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Winds will weaken veer east southeasterly Wednesday and become light and variable Thursday into Friday, invoking sea breezes and land breezes. A shallow cold front and upper level disturbance will move into the islands this weekend and may bring a period of more active weather.

Discussion

A 1027 mb surface high centered northeast of Hawaii with a ridge extending southwest passing within 300 miles north of Kauai. A weakening front moving away from the islands lies to the east northeast with an approaching front to the northwest. Visible satellite shows mostly clear skies this morning, while the winds will be mainly trades.
Winds will gradually taper off through Thursday and veer east southeasterly as the ridge moves closer to the islands in response to the approaching front from the northwest. Rainfall amounts will be minimal through Friday with highest chances across windward Big Island. Winds will become light and variable Thursday and Friday and likely invoke daytime sea breezes and nighttime land breezes.
The shallow front is forecast to arrive on Kauai on Saturday and stall near the Big Island Sunday night into early next week. An upper low or trough will form near or east of the Big Island. Still too early to tell if there will be impacts to the eastern end of the state given the differences in the long range GFS and ECMWF. Breezy trade winds will fill in behind the front through the weekend.

Aviation

Moderate to locally breezy east-southeast trades will continue through this afternoon, then weaken heading into tomorrow. The slight southerly component to the trades will result in better terrain blocking across the island chain, which may lead to wind direction and speed fluctuations across wind-protected areas throughout the rest of the afternoon and again tomorrow. Light showers will favor windward slopes and coasts, with brief MVFR conditions possible. Elsewhere, VFR conditions are expected to prevail…with the exception of leeward Big Island, where vog may lead to MVFR visibilities.
No AIRMETs are expected to be needed through tomorrow.

Marine

Winds have decreased and veered slightly out of the southeast today. The Small Craft Advisory (SCA) for waters around Oahu has been dropped, with the remaining SCA area decreased to include a smaller subset of waters around Maui and the Big Island through tonight. Winds will become light and variable for the western half of the state by Wednesday night into Friday. East to southeast winds will persist over the eastern half of the state and become gentle to moderate Thursday into Friday.
A large, long period northwest swell (310 degrees) will fill in late Wednesday night, then peak Thursday before gradually trending down Friday into the weekend. This swell will produce warning- level surf along north and west facing shores, albeit smaller than the event this past weekend. This large swell will also elevate seas to above SCA thresholds as it fills in Wednesday night. Surf along east facing shores will remain rough and choppy tonight, but expect a downward trend during the second half of the week as winds weaken locally and upstream.

Fire weather

No critical fire weather conditions are expected for the next seven days. Mostly dry weather are forecast across the state with limited shower activity as the dry spell continues through Friday. Shower trends increase starting Friday night with trade wind showers.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 AM HST Wednesday for Maui County Leeward Waters, Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Windward Waters, Big Island Leeward Waters.

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Data Courtesy of NOAA.gov