Hilo

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows 61 to 68 near the shore to 51 to 56 at 4000 feet. North winds up to 10 mph in the evening becoming light. Chance of rain 50 percent.

Thursday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 75 to 81 near the shore to 61 to 67 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 40 percent.

Thursday Night: Partly cloudy with scattered showers. Lows 61 to 68 near the shore to 51 to 56 at 4000 feet. East winds up to 10 mph shifting to the west after midnight. Chance of rain 40 percent.

Kona

Tonight: Mostly clear with isolated showers. Lows around 71 near the shore to 45 to 52 near 5000 feet. Light winds. Chance of rain 20 percent.

Thursday: Mostly sunny. Isolated showers in the afternoon. Highs 81 to 86 near the shore to around 67 near 5000 feet. Light winds. Chance of rain 20 percent.

Thursday Night: Mostly clear with isolated showers. Lows around 71 near the shore to 46 to 52 near 5000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.

Waimea

Tonight: Partly cloudy with isolated showers. Lows 61 to 70 near the shore to 53 to 61 near 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Thursday: Mostly sunny with isolated showers. Highs 62 to 81. East winds up to 15 mph becoming around 10 mph in the afternoon. Chance of rain 20 percent.

Thursday Night: Partly cloudy with isolated showers. Lows 61 to 70 near the shore to 54 to 61 near 3000 feet. East winds up to 10 mph shifting to the south after midnight. Chance of rain 20 percent.

Kohala

Tonight: Partly cloudy with isolated showers. Lows 61 to 70 near the shore to 53 to 61 near 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Thursday: Mostly sunny with isolated showers. Highs 62 to 81. East winds up to 15 mph becoming around 10 mph in the afternoon. Chance of rain 20 percent.

Thursday Night: Partly cloudy with isolated showers. Lows 61 to 70 near the shore to 54 to 61 near 3000 feet. East winds up to 10 mph shifting to the south after midnight. Chance of rain 20 percent.

South Big Island

Tonight: Mostly clear. Lows around 72 near the shore to around 50 near 5000 feet. Northeast winds 10 to 15 mph.

Thursday: Sunny. Isolated showers in the afternoon. Highs around 83 near the shore to around 66 near 5000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Thursday Night: Mostly clear. Lows around 72 near the shore to around 51 near 5000 feet. Northeast winds 10 to 15 mph.

Puna

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows 61 to 68 near the shore to 51 to 56 at 4000 feet. North winds up to 10 mph in the evening becoming light. Chance of rain 50 percent.

Thursday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 75 to 81 near the shore to 61 to 67 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 40 percent.

Thursday Night: Partly cloudy with scattered showers. Lows 61 to 68 near the shore to 51 to 56 at 4000 feet. East winds up to 10 mph shifting to the west after midnight. Chance of rain 40 percent.

Waikoloa

Tonight: Mostly clear. Lows around 72 near the shore to 49 to 54 above 4000 feet. East winds up to 10 mph.

Thursday: Sunny. Highs 81 to 87 near the shore to 64 to 70 above 4000 feet. Light winds becoming north up to 10 mph in the afternoon.

Thursday Night: Mostly clear. Lows around 72 near the shore to around 52 above 4000 feet. Northeast winds up to 10 mph shifting to the southeast after midnight.

Detailed Forecast

Synopsis

Gradually diminishing trade winds will deliver just a few showers to windward areas of the smaller islands the next day or so, while windward Big Island will continue to receive passing showers. Light and variable winds and mostly dry weather are expected statewide from Thursday night into Sunday. A weak front may move over the islands from the northwest late this weekend, bringing little in the way of rainfall, with winds remaining on the lighter side.

Discussion

Gradually diminishing trade winds will deliver little in the way of rainfall to windward areas of the smaller islands the next day or so, while windward Big Island will continue to receive passing showers. Light and variable winds and mostly dry weather are expected statewide Thursday night into Sunday. Late Sunday into Monday, a weak front is expected to approach from the NW, and deterministic model guidance continues to offer inconsistent solutions for the prognosis of this feature, and the evolution of the weather pattern early next week. Ensemble consensus guidance indicates that we can be confident that winds remain light, and precipitation totals associated with the potential frontal passage will remain on the lower side. While confidence in the details of the forecast is quite reduced for next week, light winds appear likely and significant rainfall unlikely headed into Thanksgiving.
A 1019 mb surface high centered about 400 miles is supporting moderate trade winds this afternoon, with a stable and dry atmosphere resulting in very little rainfall. Afternoon soundings show the inversion has lowered to near 5000' on Kauai, with a low PWAT of .8″, while a deeper mixed-layer on the Big Island has pushed the inversion base to near 9000', with a PWAT of 1.3″. This has allowed windward Big Island to be the exception to the mostly dry regime, at least through mid-day, where persistent showery low clouds brought about .5″ to .75″ of rainfall. The short term should feature little change as moderate trade winds slowly diminish, with just a few (or less) windward showers on the smaller islands, and greater coverage of showers over windward Big Island. Shower coverage and frequency over windward Big Island should taper off by tomorrow night as a land and sea breeze wind pattern develops statewide. This will occur as the high moves S and dissipates, leaving a surface ridge near/over the islands. This pattern will persist into at least Sunday, after which forecast details become increasingly uncertain.

Aviation

Trades will decrease gradually through Friday. Showery weather is expected for windward Big Island through tonight with periods of MVFR conditions expected. Some of the heavier showers may produce brief IFR conditions. Elsewhere, fair trade wind weather is expected with a few light showers possible over windward and mauka areas.
AIRMET SIERRA is in effect for windward Big Island due to mountain obscuration. Conditions may briefly improve during the day, but ceilings will likely lower again during the evening and overnight tonight.

Marine

Moderate to locally fresh trade winds will decline tomorrow as high pressure north of the state weakens and drifts southward. For Thursday night through Saturday, a surface ridge will be stalled roughly 100 nm north of Kauai, producing gentle to locally moderate trades, strongest around the Big Island. Winds are expected become light and variable on Sunday as a weak and shallow front approaches. The weak front may reach the islands as early as Sunday night. Strong winds look unlikely at this time, and disrupted trade winds are expected into early next week.
A series of north-northeast and northwest swells are due this week. A tiny northwest swell of about 1 to 1.5 feet at 15 to 16 seconds is detectable on the PacIOOS Hanalei and Waimea buoys this afternoon, with hints of the swell showing on the Pauwela buoy. This swell will peak at around 2 feet late tonight through Friday. A larger northwest swell of 3 to 6 feet will build late Saturday, peak Sunday, and decline Monday, followed by a smaller pulse on Tuesday. A medium period north swell will slowly build tonight and Thursday, and hold at 4 to 5 feet Friday and Saturday. A very deep storm off the U.S. Pacific Northwest coast will send an overlapping pulse of north-northeast swell late Saturday. This swell will peak Sunday into Monday, then drop off on Tuesday. None of these swells is expected to produce advisory level surf, but we will monitor buoys for the potential of high surf on north and east shores, mainly from the pulse of north-northeast swell.
As trade winds decline, easterly wind wave energy will steadily drop through Friday, then fade out during the weekend. Surf along south facing shores will remain small through the week.

Fire weather

KBDI values remain high in most leeward areas, where a dry weather pattern is anticipated the next several days. Minimum relative humidity values reached the critical 45% threshold this afternoon at PHNL, and will likely occur from late morning through the afternoon each day through Saturday. However, weakening winds will mitigate the potential for critical fire weather conditions.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov