Hilo

Tonight: Partly cloudy with isolated showers and thunderstorms in the evening, then mostly cloudy with scattered showers after midnight. Lows 66 to 72 near the shore to 52 to 59 at 4000 feet. Southeast winds up to 10 mph shifting to the southwest after midnight. Chance of rain 50 percent.

Saturday: Sunny. Isolated showers in the morning. Highs 81 to 87 near the shore to 67 to 72 at 4000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Saturday Night: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 65 to 71 near the shore to 51 to 58 at 4000 feet. East winds up to 10 mph in the evening becoming light. Chance of rain 40 percent.

Kona

Tonight: Partly cloudy with isolated showers. Lows around 74 near the shore to around 53 near 5000 feet. Light winds. Chance of rain 20 percent.

Saturday: Sunny. Isolated showers in the afternoon. Highs around 86 near the shore to around 69 near 5000 feet. Northwest winds up to 10 mph. Chance of rain 20 percent.

Saturday Night: Partly cloudy. Isolated showers in the evening. Lows around 73 near the shore to around 52 near 5000 feet. Light winds. Chance of rain 20 percent.

Waimea

Tonight: Partly cloudy with isolated showers. Lows 65 to 73 near the shore to 56 to 63 near 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Saturday: Sunny and breezy. Isolated showers in the morning. Highs around 82 near the shore to 72 to 81 near 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Saturday Night: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 64 to 73 near the shore to 55 to 62 near 3000 feet. East winds up to 15 mph. Chance of rain 40 percent.

Kohala

Tonight: Partly cloudy with isolated showers. Lows 65 to 73 near the shore to 56 to 63 near 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Saturday: Sunny and breezy. Isolated showers in the morning. Highs around 82 near the shore to 72 to 81 near 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Saturday Night: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 64 to 73 near the shore to 55 to 62 near 3000 feet. East winds up to 15 mph. Chance of rain 40 percent.

South Big Island

Tonight: Partly cloudy with isolated showers. Lows around 75 near the shore to around 56 near 5000 feet. Northeast winds up to 15 mph. Chance of rain 20 percent.

Saturday: Sunny and breezy. Highs around 88 near the shore to around 68 near 5000 feet. East winds up to 20 mph.

Saturday Night: Partly cloudy with isolated showers in the evening, then clear after midnight. Lows around 75 near the shore to around 54 near 5000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Puna

Tonight: Partly cloudy with isolated showers and thunderstorms in the evening, then mostly cloudy with scattered showers after midnight. Lows 66 to 72 near the shore to 52 to 59 at 4000 feet. Southeast winds up to 10 mph shifting to the southwest after midnight. Chance of rain 50 percent.

Saturday: Sunny. Isolated showers in the morning. Highs 81 to 87 near the shore to 67 to 72 at 4000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Saturday Night: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 65 to 71 near the shore to 51 to 58 at 4000 feet. East winds up to 10 mph in the evening becoming light. Chance of rain 40 percent.

Waikoloa

Tonight: Mostly clear. Lows around 75 near the shore to 52 to 57 above 4000 feet. Light winds.

Saturday: Sunny. Isolated showers in the afternoon. Highs around 87 near the shore to 66 to 75 above 4000 feet. North winds up to 10 mph. Chance of rain 20 percent.

Saturday Night: Mostly clear. Lows around 74 near the shore to 50 to 56 above 4000 feet. Light winds.

Detailed Forecast

Synopsis

An area of showers south of Oahu has moved northward. Scattered to numerous moderate showers are ongoing across Oahu. Light winds will allow a land/sea breeze pattern to dominate with possible light trades building late this weekend. Winds shift out of the east- southeast next week with a wet and unstable pattern setting up over the islands by midweek.

Discussion

Not many changes were made as the previous forecast remains on track. A low pressure system far north of the islands, combined with an associated trough, will continue to bring a light wind flow pattern to the area through much of the weekend. These should weaken slightly allowing for a slight uptick in winds through tomorrow. With the lighter winds, we should continue to see land and sea breezes over the state.
An area of showers south of Oahu has moved northward. Scattered to numerous moderate showers are ongoing across Oahu. There is still an isolated chance for a thunderstorm of two but those should stay over the waters.
As the aforementioned low weakens, some moderate trades will filter back into the islands late this weekend. An upper level low digging southward, will position itself just west of the state by the middle of next week. This low will induce a surface trough that will veer and strengthen winds out of the east southeast beginning late Monday and continuing through at least mid-week bringing a wetter and more unstable weather pattern. Clouds and scattered showers will focus over windward and southeastern sides of the islands. While there are model differences it is also to far out to see what if any impacts there will be.

Aviation

The general lower level southeast flow across the islands has been weak enough to allow localized sea breezes to kick in early this afternoon. Most sites are experiencing VFR conditions, but the chance for MVFR and isolated IFR within lower clouds and/or showers or thunderstorms still exists into the evening. Thickening clouds with isolated pockets of moderate rain within higher terrain over Oahu has prompted an AIRMET Sierra for tempo mountain obscuration above 2500 feet that will likely continue into this evening. Showers may shift to Kauai later tonight with possible AIRMET Sierra for mountain obscurations. Light winds will back a bit more east and strengthen slightly over the eastern half of the state Saturday.

Marine

A troughing pattern will continue to weaken trade winds near Hawaiian waters into early next week, allowing for daytime onshore sea breezes to continue along nearshore leeward coastal waters. An upper level disturbance lingering north of the island chain will bring periods of enhanced showers through the weekend. Long range guidance shows increasing southeasterly winds by the middle of next week in an unstable weather pattern with the potential for increasing shower coverage and thunderstorms.
A mix of a small medium-period northwest (330 deg) swell and a small short- to medium-period north-northeast (020 deg) swell will maintain small surf along north facing shores through Saturday. The smaller forerunners of a moderate to large long- period northwest (320 deg) swell will build into Hawaiian waters starting Sunday afternoon. This swell energy will build to High Surf Advisory (HSA) levels by Monday, then likely hold through Tuesday before slowly falling below from Wednesday onward. Predicting slightly higher swell heights than the latest swell model guidance indicates, as recent swell model forecasts were too low as compared to nearshore ground truth buoy observations.
Surf along south facing shores will remain small through the weekend with a series of background south and southwest swells. East facing shores will remain tiny to small through Friday. In addition, a small, medium to long period easterly swell from Tropical Cyclone Priscilla in the East Pacific is forecast to arrive late Saturday into Sunday.
Peak high tides associated with the lunar cycle will lead to minor coastal flooding along shorelines and low lying coastal areas during the peak high tide through Saturday morning. A Coastal Flood Statement is in effect for all coastal areas through Saturday, and will likely be cancelled later Saturday morning following the peak high tide cycle.

Fire weather

Light winds and isolated to scattered showers will help maintain fire weather below critical thresholds for the next several days. Inversion heights will range from 8000 to 9,000 feet.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov