Hilo

Tonight: Mostly cloudy with numerous showers. Lows around 69 near the shore to around 54 at 4000 feet. North winds up to 15 mph. Chance of rain 70 percent.

Saturday: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 81 near the shore to around 73 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Saturday Night: Mostly cloudy with numerous showers. Lows around 68 near the shore to around 52 at 4000 feet. North winds up to 15 mph. Chance of rain 70 percent.

Kona

Tonight: Mostly cloudy with scattered showers early in the evening, then mostly cloudy in the late evening and overnight. Lows 73 to 78 near the shore to 53 to 59 near 5000 feet. Light winds. Chance of rain 30 percent.

Saturday: Sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 84 to 92 near the shore to 70 to 75 near 5000 feet. Light winds. Chance of rain 40 percent.

Saturday Night: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Lows 72 to 78 near the shore to 54 to 61 near 5000 feet. Light winds. Chance of rain 20 percent.

Waimea

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 70 near the shore to around 58 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Saturday: Partly sunny in the morning then becoming mostly sunny. Breezy. Scattered showers. Highs around 83 near the shore to around 75 near 3000 feet. East winds 10 to 25 mph with gusts to 45 mph. Chance of rain 50 percent.

Saturday Night: Breezy. Partly cloudy with scattered showers. Lows around 69 near the shore to around 57 near 3000 feet. East winds 10 to 25 mph with gusts to 45 mph. Chance of rain 50 percent.

Kohala

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 70 near the shore to around 58 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Saturday: Partly sunny in the morning then becoming mostly sunny. Breezy. Scattered showers. Highs around 83 near the shore to around 75 near 3000 feet. East winds 10 to 25 mph with gusts to 45 mph. Chance of rain 50 percent.

Saturday Night: Breezy. Partly cloudy with scattered showers. Lows around 69 near the shore to around 57 near 3000 feet. East winds 10 to 25 mph with gusts to 45 mph. Chance of rain 50 percent.

South Big Island

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Breezy. Lows around 71 near the shore to around 53 near 5000 feet. Northeast winds 10 to 20 mph decreasing to up to 15 mph after midnight.

Saturday: Breezy. Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 86 near the shore to around 70 near 5000 feet. East winds up to 25 mph. Chance of rain 20 percent.

Saturday Night: Breezy. Mostly cloudy with isolated showers in the evening, then partly cloudy after midnight. Lows around 70 near the shore to around 55 near 5000 feet. Northeast winds up to 20 mph. Chance of rain 20 percent.

Puna

Tonight: Mostly cloudy with numerous showers. Lows around 69 near the shore to around 54 at 4000 feet. North winds up to 15 mph. Chance of rain 70 percent.

Saturday: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 81 near the shore to around 73 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Saturday Night: Mostly cloudy with numerous showers. Lows around 68 near the shore to around 52 at 4000 feet. North winds up to 15 mph. Chance of rain 70 percent.

Waikoloa

Tonight: Partly cloudy. Breezy. Lows 70 to 75 near the shore to 52 to 59 above 4000 feet. East winds up to 25 mph.

Saturday: Mostly sunny. Breezy. Isolated showers in the afternoon. Highs 81 to 87 near the shore to 69 to 77 above 4000 feet. East winds up to 25 mph shifting to the north in the afternoon. Gusts up to 45 mph. Chance of rain 20 percent.

Saturday Night: Partly cloudy. Breezy. Isolated showers in the evening. Lows around 72 near the shore to 53 to 60 above 4000 feet. East winds up to 25 mph with gusts to 45 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

A remnant frontal boundary brings increased showers to Molokai and Oahu today and Kauai late tonight into early Saturday. Stable, breezy trades then prevail well into next week.

Discussion

Remnant frontal zone has shifted west into the Kauai Channel this afternoon and presents as a narrow band of shallow moisture existing at the convergent interface of breezy NE trades and building easterlies. Satellite and radar observations confirm model depictions of saturation up to around 8kft in the vicinity of this boundary and low-level forcing remains sufficient to generate widespread light showers along with spotty heavy showers along the convergent boundary itself. As drier conditions develop over Oahu this afternoon and evening in the wake of the departing convergence boundary, showers will increase over Windward Kauai through tonight. As governing high pressure migrates eastward, easterlies will gradually build across the area which will usher this band of showers westward with time. Drier upstream air will begin working into Kauai during Saturday.
Strong 595dm mid-level ridging is already establishing over western portions of the area and will build eastward during the next 24-48 hours. Consensus is strong among the extended guidance that a stable, breezy, and normal to slightly wetter than normal trade wind pattern will continue well into next week. Further amplification of the resident mid-level ridge axis may allow for a period of quite windy trades by the end of next week.

Aviation

A stable and breezy trade wind flow will remain in place through Saturday, with higher chances for MVFR conditions over windward Kauai. Ridging aloft is producing an inversion between 6,000 to 8,000 ft, and the breezy trade wind flow is generating low-level turbulence over and downwind of terrain on all islands, where AIRMET Tango remains in place.
A band of moisture from dissipated front will continue to affect western end of the island chain through Saturday. This feature is clearing Oahu this afternoon and will be affecting windward Kauai with MVFR ceilings and visibility in SHRA by sundown. AIRMET Sierra for mountain obscuration will be dropped on the late afternoon issuance for Oahu and posted for Kauai. Expect the MVFR conditions to remain focused over Kauai through Saturday, though the band could briefly sag over Oahu again. Elsewhere, isolated MVFR conditions will be confined to windward areas, while VFR will dominate leeward.

Marine

High pressure to the northwest of the state will gradually shift to the north this weekend and will maintain fresh to locally strong northeasterly trades through at least early next week. With the high moving north of the state, the wind direction will become more easterly by Sunday. Day time ASCAT pass showed the winds have dropped below Small Craft Advisory (SCA) thresholds in select areas and the SCA has been adjusted. SCA remains in effect for select coastal zones and will likely remain in effect for the windier waters around Maui County and the Big Island for the foreseeable future. In the extended, there is growing confidence for trades to strengthen as a strong high sets up NNE of the state. Widespread strong trades are expected during the second half of next week with even gales possible for select channels.
A reinforcing medium period NW to NNW (320-340 degree) swell has started to fill in this afternoon and should peak tonight into early Saturday, then gradually decline over the weekend. A moderate NW (325 degree) swell is expected to fill in on Monday and will likely peak near advisory levels late Monday. This swell will be followed by a slightly larger NW (320 degree) swell on Wednesday, which should produce advisory level surf for N and W facing shores next week Wednesday.
Surf along east-facing shores will remain rough and choppy through the middle of next week due to the breezy trade winds. Long range models are showing a significant increase of windswell towards the later half of next week due a large fetch of strong trade winds setting up over and upstream of the state. Surf should easily reach advisory thresholds (10 ft) and it may reach warning levels (15 ft) along east facing shores during its peak.
Surf along south-facing shores will remain small and near the seasonal average through the middle of next week. Tiny long-period pulses will be possible over the next few days.
Also with the peak monthly tides coming up towards the later half of next week (Nov 14th to Nov 18th) we should see coastal inundation impacts during the early morning hours along all coastlines. The large windswell combined with the peak monthly tides could cause greater impacts along windward shores.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 AM HST Saturday for Kauai Northwest Waters, Kauai Leeward Waters, Kauai Channel.
Small Craft Advisory until 6 PM HST this evening for Kauai Windward Waters, Oahu Windward Waters, Oahu Leeward Waters, Kaiwi Channel, Maui County Leeward Waters.
Small Craft Advisory until 6 PM HST Sunday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

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Data Courtesy of NOAA.gov