Hilo

Today: Sunny. Highs 82 to 87 near the shore to 70 to 76 at 4000 feet. Southeast winds up to 15 mph.

Tonight: Partly cloudy. Lows 61 to 68 near the shore to around 55 at 4000 feet. West winds up to 10 mph in the evening becoming light.

Tuesday: Mostly sunny. Isolated showers in the afternoon. Highs around 85 near the shore to 70 to 76 at 4000 feet. West winds up to 10 mph shifting to the east in the afternoon. Chance of rain 20 percent.

Kona

Today: Sunny. Highs 81 to 87 near the shore to around 70 near 5000 feet. Southwest winds up to 10 mph.

Tonight: Mostly clear. Lows around 69 near the shore to 42 to 50 near 5000 feet. East winds up to 10 mph in the evening becoming light.

Tuesday: Sunny. Highs around 84 near the shore to around 69 near 5000 feet. Northeast winds up to 10 mph shifting to the west around 10 mph in the afternoon.

Waimea

Today: Sunny with isolated showers. Highs around 81 near the shore to 73 to 78 near 3000 feet. West winds up to 15 mph. Chance of rain 20 percent.

Tonight: Breezy. Mostly clear with isolated showers. Lows 60 to 69 near the shore to 52 to 59 near 3000 feet. Southwest winds up to 20 mph. Chance of rain 20 percent.

Tuesday: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Highs around 81 near the shore to 73 to 78 near 3000 feet. Southwest winds up to 10 mph shifting to the west in the afternoon. Chance of rain 50 percent.

Kohala

Today: Sunny with isolated showers. Highs around 81 near the shore to 73 to 78 near 3000 feet. West winds up to 15 mph. Chance of rain 20 percent.

Tonight: Breezy. Mostly clear with isolated showers. Lows 60 to 69 near the shore to 52 to 59 near 3000 feet. Southwest winds up to 20 mph. Chance of rain 20 percent.

Tuesday: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Highs around 81 near the shore to 73 to 78 near 3000 feet. Southwest winds up to 10 mph shifting to the west in the afternoon. Chance of rain 50 percent.

South Big Island

Today: Mostly sunny. Highs around 82 near the shore to around 71 near 5000 feet. West winds 10 to 15 mph.

Tonight: Partly cloudy. Lows around 70 near the shore to around 49 near 5000 feet. Northwest winds 10 to 15 mph.

Tuesday: Mostly sunny. Isolated showers in the morning. Highs around 83 near the shore to around 70 near 5000 feet. West winds 10 to 15 mph. Chance of rain 20 percent.

Puna

Today: Sunny. Highs 82 to 87 near the shore to 70 to 76 at 4000 feet. Southeast winds up to 15 mph.

Tonight: Partly cloudy. Lows 61 to 68 near the shore to around 55 at 4000 feet. West winds up to 10 mph in the evening becoming light.

Tuesday: Mostly sunny. Isolated showers in the afternoon. Highs around 85 near the shore to 70 to 76 at 4000 feet. West winds up to 10 mph shifting to the east in the afternoon. Chance of rain 20 percent.

Waikoloa

Today: Sunny. Highs 82 to 87 near the shore to 67 to 74 above 4000 feet. West winds up to 15 mph.

Tonight: Mostly clear. Scattered showers in the evening. Lows 67 to 73 near the shore to 46 to 51 above 4000 feet. South winds up to 15 mph. Chance of rain 30 percent.

Tuesday: Sunny. Scattered showers in the morning. Highs around 85 near the shore to 66 to 74 above 4000 feet. South winds around 10 mph shifting to the west up to 10 mph in the afternoon. Chance of rain 40 percent.

Detailed Forecast

Synopsis

A front will move down the island chain through Wednesday, bringing breezy southwesterly winds and rain. A second front will sweep through the islands Thursday night and Friday, introducing another round of rain. Trade winds will return and become strong behind this second front.

Discussion

A front near Kauai is moving slowly eastward and is poised to move across that island within the next few hours. Satellite loop shows a broad but ragged band of low clouds associated with this front extending about 200 miles westward from Kauai. A prefrontal cloud band across Oahu is about to move northeast and away this morning. Southwest winds ahead of the front are locally breezy across the state. Lighter southwest winds and clearer skies persist across Maui and the Big Island. Westerly winds aloft were beginning to decrease, but began to increase again after midnight and remain above warning threshold at this hour. As a result, the High Wind Warning for the Big Island summits has been extended through 6 pm HST this evening.
Models show the front will reach Kauai later this morning, along with increased showers and strengthening southwest winds. Prefrontal showery low clouds may affect Kauai earlier than that. The front will slowly move eastward down the island chain, impacting Oahu and Maui County tonight and Tuesday, then weaken near the Big Island Wednesday into Thursday. Southwest wind gusts up to 45 mph are possible along north and east sides of the islands due to downslope effects, mainly across Kauai and Oahu this afternoon and evening. This is just below advisory threshold. The front will not be quite as strong when it reaches Maui County and the Big Island, so downslope gusts will be somewhat weaker. Expect drier and more stable conditions, along with light north to northeast winds, behind the front.
As the front is dissipating across the Big Island Thursday, another front will approach the main Hawaiian Islands from the northwest. Expect this next front to quickly move across the island chain Thursday night into Friday, with strong trade winds building behind. Winds will easily exceed advisory levels for most of the state in the wake of this next front late Friday into Saturday. Expect a quick bout of rainfall as this next front passes through.

Aviation

Moderate to breezy southwest winds will continue through tonight. A cold front just northwest of the islands will move across Kauai this morning then gradually progress down the island chain through the middle of the week. Expect clouds and showers to increase across western islands today, with widespread MVFR cigs and vsbys along with breezy to windy conditions likely as the front moves eastward.
AIRMET Tango for moderate turbulence below 8000 ft remains in effect for north through east sections of all islands, with conditions continuing through tonight. AIRMET Sierra for mountain obscuration above 2000 ft is in effect for areas west of Molokai.

Marine

Fresh to strong SW winds will continue through tonight as a front approaches. This combined with the arrival of a WNW swell tonight has led to the Small Craft Advisory being expanded down the island chain for exposed waters due to a combination of winds and seas. The winds will quickly ease as the front advances down the island chain and stalls over the eastern end of the state tonight through Tuesday night, likely enough for localized land and sea breeze conditions to form near the coasts (light N background flow trailing the front Tuesday into Tuesday night). Light to moderate E background flow is forecast for a brief period Wednesday as the next front approaches. This next front will move through Thursday through Friday with strong N winds trailing the front Thursday night through Friday. Strong trades are depicted over the weekend as high pressure builds north of the area.
Surf along exposed N and W facing shores will remain rough into tonight due to a mix of building short-period wind waves associated with the increasing SW winds and the arrival of a medium period WNW swell. Surf heights will near advisory levels for N and W facing shores of the smaller islands today. A larger WNW swell arriving tonight into Tuesday will drive the surf to near warning levels Tuesday through Tuesday night as it peaks. Similar to other recent WNW swells during the last few weeks, surf along the leeward side of the Big Island will likely near their warning level Tuesday through Tuesday night.
As this WNW swell eases Wednesday through Thursday, guidance shows a mix of a moderate N to NNE and WNW swell moving through. The NNE component will become the dominant swell Thursday night through Friday in response to a broad gale forming in the northeast Pacific Tuesday through midweek – likely enough for a return to advisory-level surf for exposed coasts (010-020 deg swell).
Surf along E facing shores will remain small through most of the week due to the lack of trades locally and upstream. An upward trend is expected later in the week through next weekend as the large NNE swell and strong trades return.
Surf along S facing shores will remain rough through tonight due to strengthening southwest winds. A downward trend is expected Tuesday through midweek as winds diminish.

HFO Watches/Warnings/Advisories

High Wind Warning until 6 PM HST today for Big Island Summits.
Small Craft Advisory until 6 PM HST Tuesday for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Kauai Channel, Oahu Windward Waters.

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Data Courtesy of NOAA.gov