Hilo

Tonight: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Lows 56 to 64 near the shore to 47 to 52 at 4000 feet. Northwest winds up to 10 mph. Chance of rain 50 percent.

Wednesday: Mostly sunny. Isolated showers in the afternoon. Highs 75 to 82 near the shore to 63 to 69 at 4000 feet. North winds up to 15 mph. Chance of rain 20 percent.

Wednesday Night: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows 57 to 65 near the shore to 47 to 53 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 50 percent.

Kona

Tonight: Mostly cloudy with isolated showers in the evening, then mostly clear after midnight. Lows around 66 near the shore to 41 to 47 near 5000 feet. Light winds. Chance of rain 20 percent.

Wednesday: Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs 80 to 86 near the shore to around 68 near 5000 feet. West winds up to 10 mph. Chance of rain 20 percent.

Wednesday Night: Mostly cloudy with isolated showers in the evening, then mostly clear after midnight. Lows around 67 near the shore to 42 to 49 near 5000 feet. Light winds. Chance of rain 20 percent.

Waimea

Tonight: Partly cloudy with isolated showers. Lows 56 to 66 near the shore to 48 to 56 near 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Wednesday: Sunny in the morning then becoming partly sunny. Isolated showers. Highs 63 to 81. Northeast winds up to 15 mph. Chance of rain 20 percent.

Wednesday Night: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Lows 57 to 66 near the shore to 50 to 56 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Kohala

Tonight: Partly cloudy with isolated showers. Lows 56 to 66 near the shore to 48 to 56 near 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Wednesday: Sunny in the morning then becoming partly sunny. Isolated showers. Highs 63 to 81. Northeast winds up to 15 mph. Chance of rain 20 percent.

Wednesday Night: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Lows 57 to 66 near the shore to 50 to 56 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

South Big Island

Tonight: Mostly cloudy with isolated showers in the evening, then mostly clear after midnight. Lows around 68 near the shore to around 47 near 5000 feet. Light winds. Chance of rain 20 percent.

Wednesday: Sunny in the morning, then mostly cloudy with isolated showers in the afternoon. Highs around 82 near the shore to around 66 near 5000 feet. Light winds becoming south up to 10 mph in the afternoon. Chance of rain 20 percent.

Wednesday Night: Mostly cloudy with isolated showers in the evening, then mostly clear after midnight. Lows around 68 near the shore to around 48 near 5000 feet. Light winds. Chance of rain 20 percent.

Puna

Tonight: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Lows 56 to 64 near the shore to 47 to 52 at 4000 feet. Northwest winds up to 10 mph. Chance of rain 50 percent.

Wednesday: Mostly sunny. Isolated showers in the afternoon. Highs 75 to 82 near the shore to 63 to 69 at 4000 feet. North winds up to 15 mph. Chance of rain 20 percent.

Wednesday Night: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows 57 to 65 near the shore to 47 to 53 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 50 percent.

Waikoloa

Tonight: Mostly clear. Lows around 67 near the shore to 44 to 49 above 4000 feet. East winds up to 15 mph.

Wednesday: Breezy. Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs 81 to 87 near the shore to 65 to 71 above 4000 feet. Northeast winds up to 20 mph. Chance of rain 20 percent.

Wednesday Night: Mostly clear. Breezy. Lows 65 to 70 near the shore to around 48 above 4000 feet. East winds up to 20 mph.

Detailed Forecast

Synopsis

Stable and rather dry northerly winds will shift out of the northeast on Wednesday, producing limited showers over mainly north and windward slopes. Winds will strengthen a bit and shift from a more easterly trade wind direction from Thursday into Saturday. Expect a few more clouds and brief passing overnight to early morning showers, mainly over windward and mountain areas as the trade winds return. Trade winds will decline Sunday and may become disrupted early next week.

Discussion

A stable and rather dry northerly flow remains in place as a weak surface ridge remains over the state and a disturbance passes over 550 miles to the northeast. A ridge aloft is maintaining very stable conditions with an inversion based near 5,000 ft, and moisture is lacking. Sea breezes have produced no rainfall during the past several hours, with the exception of the Big Island, where a few showers will linger through the evening along windward and southern slopes.
Winds will increase and shift out of the northeast late tonight and Wednesday as the surface ridge strengthens north of the state. The disturbance passing northeast of the islands will send a narrow and shallow band of showers, leading to a slight boost in showers along windward and north slopes on Kauai late tonight, then down the island chain Wednesday.
Trade winds are expected to build Thursday and Friday as the surface ridge to the north strengthens. Very stable conditions will prevail on Thursday as a ridge aloft passes overhead on Thursday, giving way to a shallow upper-level trough that will bring a period of thin high clouds Friday and Saturday. Modest showers will be focused along windward slopes, and most leeward areas will be dry.
Ensemble guidance suggests the surface ridge will be displaced southward toward the islands Sunday and likely move overhead on Monday and Tuesday. Expect weakening trades on Sunday and light southerly or variable winds by Monday.

Aviation

Dry conditions and high stability prevail as light northerlies and afternoon sea breezes give way to localized land breezes in the most sheltered locales tonight. Elsewhere, winds light winds gradually veer to northeasterly for Wednesday. Shower activity essentially nil through tomorrow afternoon.
No AIRMETs in effect.

Marine

Light to moderate north to northeast winds will gradually veer out of the east northeast and increase into the moderate to fresh category tonight through the second half of the week as high pressure builds north of the area. Winds may ease next weekend and into early next week with a potential front passing to the north. Seas will potentially exceed the 10 ft Small Craft Advisory level Friday through Saturday for waters exposed to large west- northwest swells.
Surf along exposed north and west facing shores will remain up into Thursday, due to a mix of a fresh, long-period west- northwest swell and a couple of fading, shorter period north- northwest and north-northeast swells. The long period west- northwest swell will hold through tonight before lowering Wednesday through Thursday. A developing hurricane force low 1500 NM northwest of the islands will send a large, long-period west- northwest swell Friday into the weekend. Surf heights could reach warning levels late Friday into early Saturday before easing during the remainder of the weekend.
Surf along east facing shores will remain up through the weekend due to a lingering short-period north-northeast swell and a short-period northeast swell expected late Thursday through the weekend. Heights will peak Friday into the weekend below the advisory level as this northeast swell arrives and peaks.
Surf along south facing shores will remain near seasonal averages this week, driven by a mix of short period southeast and background long period south-southwest swells. Early next week, an out-of-season south-southwest swell is possible. This swell is expected to originate from a recent broad gale passing southeast of New Zealand. This active trend may persist through the first week of December as a similar system passing near New Zealand is forecast to follow later this week.

Fire weather

Although daytime relative humidity will be rather low through the weekend, winds will be somewhat weak into tomorrow and will likely remain below the critical level even as stronger trades develop Thursday through Saturday.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov