Hilo

Tonight: Partly cloudy with scattered showers. Lows 64 to 71 near the shore to 54 to 59 at 4000 feet. Northeast winds up to 10 mph shifting to the northwest after midnight. Chance of rain 40 percent.

Monday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 79 to 85 near the shore to 65 to 70 at 4000 feet. East winds up to 10 mph. Chance of rain 40 percent.

Monday Night: Mostly cloudy with scattered showers. Lows 64 to 71 near the shore to around 57 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Kona

Tonight: Partly cloudy. Lows around 73 near the shore to 49 to 54 near 5000 feet. Light winds.

Monday: Mostly sunny. Isolated showers in the afternoon. Highs 83 to 88 near the shore to around 68 near 5000 feet. West winds up to 10 mph. Chance of rain 20 percent.

Monday Night: Partly cloudy. Lows around 74 near the shore to 50 to 55 near 5000 feet. Light winds.

Waimea

Tonight: Partly cloudy with isolated showers. Lows 63 to 72 near the shore to 56 to 62 near 3000 feet. East winds 10 to 15 mph decreasing to up to 15 mph after midnight. Chance of rain 20 percent.

Monday: Mostly sunny with isolated showers. Highs 64 to 84. East winds up to 15 mph. Chance of rain 20 percent.

Monday Night: Partly cloudy with scattered showers. Lows 64 to 72 near the shore to 57 to 63 near 3000 feet. East winds 10 to 15 mph. Chance of rain 40 percent.

Kohala

Tonight: Partly cloudy with isolated showers. Lows 63 to 72 near the shore to 56 to 62 near 3000 feet. East winds 10 to 15 mph decreasing to up to 15 mph after midnight. Chance of rain 20 percent.

Monday: Mostly sunny with isolated showers. Highs 64 to 84. East winds up to 15 mph. Chance of rain 20 percent.

Monday Night: Partly cloudy with scattered showers. Lows 64 to 72 near the shore to 57 to 63 near 3000 feet. East winds 10 to 15 mph. Chance of rain 40 percent.

South Big Island

Tonight: Mostly clear. Lows around 74 near the shore to around 53 near 5000 feet. Northeast winds 10 to 15 mph.

Monday: Sunny. Highs around 86 near the shore to around 69 near 5000 feet. East winds up to 15 mph.

Monday Night: Mostly clear. Lows around 74 near the shore to around 54 near 5000 feet. East winds 10 to 15 mph.

Puna

Tonight: Partly cloudy with scattered showers. Lows 64 to 71 near the shore to 54 to 59 at 4000 feet. Northeast winds up to 10 mph shifting to the northwest after midnight. Chance of rain 40 percent.

Monday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 79 to 85 near the shore to 65 to 70 at 4000 feet. East winds up to 10 mph. Chance of rain 40 percent.

Monday Night: Mostly cloudy with scattered showers. Lows 64 to 71 near the shore to around 57 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Waikoloa

Tonight: Mostly clear. Lows around 74 near the shore to around 54 above 4000 feet. Light winds becoming southeast up to 10 mph after midnight.

Monday: Mostly sunny. Highs 84 to 89 near the shore to 66 to 73 above 4000 feet. North winds up to 10 mph.

Monday Night: Partly cloudy. Lows around 75 near the shore to 52 to 57 above 4000 feet. Light winds.

Detailed Forecast

Synopsis

Moderate trades will remain stable and dry for the remainder of the week, with limited light showers windward and mauka favoring the overnight hours.

Discussion

Visible satellite imagery shows mainly scattered clouds over the islands, with morning low clouds and showers around Oahu and Molokai having dissipated. The local atmosphere is very stable, characterized by relatively strong temperature inversions around 6500-7000 ft with substantial dry and warm air in the mid- levels. This has kept any rainfall very light today, with nothing more than passing light showers windward and mauka. A weak area of moisture upstream of the state, manifested as a broad field of sparse, showery clouds, will move through tonight, which may bring a slight uptick in windward shower coverage, though the dry and stable atmosphere in place will keep rainfall amounts on the light side.
Little change is anticipated for the remainder of the forecast period. The latest model runs indicate the progressive mid-latitude pattern will keep surface and mid-level high pressure firmly in place around 1500 miles northwest of the islands. This will ensure trade wind speeds remain seasonably light to moderate, while delivering a steady feed of mid-level dry air. With no significant upstream moisture sources, either observed or modeled, this pattern will favor continued high stability and mostly dry trades for the remainder of the week.

Aviation

Stable, moderate trades will deliver limited low clouds and light showers to windward and mauka areas through the forecast period. Brief MVFR possible within any heavier showers, otherwise VFR prevails.
No AIRMETs in effect.

Marine

High pressure north and northeast of the islands will keep moderate to locally fresh trades in place through late this week. Although wind speeds may flirt with Small Craft Advisory criteria in the windier channels at times, they will likely not be consistent enough to warrant the issuance of a SCA. Therefore, there are currently no headlines in effect.
A small, medium period north-northwest swell will gradually decline today through Monday as it shifts more northerly. A similar, or slightly larger, medium period northwest swell should arrive late Monday night, peak late Tuesday and Tuesday night, then decline as it shifts more northerly Wednesday and Thursday. Several additional small swells from the north should maintain some small surf along north facing shores Friday through next weekend.
A series of small long-period southwest swells should provide some small but inconsistent surf along south facing shores during the next couple days. A slightly larger south-southwest swell should fill in Tuesday, hold through Wednesday, then gradually decline through the rest of the work week. A small, long period south swell is expected to arrive on Saturday (October 5) and then hold into early next week, giving another boost to surf along south facing shores.
East shore surf will remain small through most of this week, although select spots with more northerly exposure could see some of the north swells throughout the week.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov