Today: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 82 near the shore to 65 to 70 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 30 percent.
Tonight: Mostly cloudy with scattered showers. Lows around 67 near the shore to around 54 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 50 percent.
Tuesday: Partly sunny with scattered showers. Highs around 81 near the shore to 66 to 71 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.
Kona
Today: Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 83 near the shore to around 70 near 5000 feet. West winds up to 10 mph. Chance of rain 20 percent.
Tonight: Mostly cloudy in the evening then becoming mostly clear. Isolated showers. Lows 67 to 72 near the shore to around 54 near 5000 feet. Light winds. Chance of rain 20 percent.
ARTICLE CONTINUES BELOW AD
ARTICLE CONTINUES BELOW AD
Tuesday: Sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs around 84 near the shore to around 71 near 5000 feet. West winds up to 10 mph. Chance of rain 40 percent.
Waimea
Today: Breezy. Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs around 81 near the shore to 70 to 78 near 3000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 40 percent.
Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 67 near the shore to 52 to 60 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.
Tuesday: Windy. Partly sunny with scattered showers. Highs around 80 near the shore to 71 to 78 near 3000 feet. East winds 10 to 30 mph. Chance of rain 50 percent.
Kohala
Today: Breezy. Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs around 81 near the shore to 70 to 78 near 3000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 40 percent.
ARTICLE CONTINUES BELOW AD
Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 67 near the shore to 52 to 60 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.
Tuesday: Windy. Partly sunny with scattered showers. Highs around 80 near the shore to 71 to 78 near 3000 feet. East winds 10 to 30 mph. Chance of rain 50 percent.
South Big Island
Today: Mostly sunny. Highs around 83 near the shore to around 71 near 5000 feet. East winds up to 15 mph.
Tonight: Mostly cloudy with isolated showers in the evening, then mostly clear after midnight. Lows around 69 near the shore to around 53 near 5000 feet. Northeast winds up to 15 mph. Chance of rain 20 percent.
Tuesday: Breezy. Sunny in the morning, then mostly cloudy with isolated showers in the afternoon. Highs around 84 near the shore to around 72 near 5000 feet. East winds up to 25 mph. Chance of rain 20 percent.
Puna
ARTICLE CONTINUES BELOW AD
Today: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 82 near the shore to 65 to 70 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 30 percent.
Tonight: Mostly cloudy with scattered showers. Lows around 67 near the shore to around 54 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 50 percent.
Tuesday: Partly sunny with scattered showers. Highs around 81 near the shore to 66 to 71 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.
Waikoloa
Today: Mostly sunny. Breezy. Highs around 82 near the shore to 66 to 72 above 4000 feet. East winds up to 15 mph shifting to the north in the afternoon.
Tonight: Partly cloudy. Breezy. Isolated showers in the evening. Lows around 71 near the shore to 50 to 56 above 4000 feet. Southeast winds up to 25 mph. Chance of rain 20 percent.
Tuesday: Mostly sunny. Windy. Isolated showers in the afternoon. Highs around 83 near the shore to 67 to 72 above 4000 feet. Northeast winds up to 30 mph. Chance of rain 20 percent.
Detailed Forecast
Synopsis
Dry and stable trade wind conditions are expected through the first half of the week, with the best rainfall chances favoring our windward and mauka locations overnight through the morning periods. A few showers could make it into our leeward areas, especially as the trades become gusty tonight through Tuesday. A return of light winds and increasing moisture associated with an approaching front could bring the rainfall chances up late Thursday through the weekend, especially over the western end of the state as the front begins to weaken and stall.
Discussion
Guidance remains in good agreement and shows the dry and stable trade wind pattern continuing through the first half of the week as a strong ridge noses eastward behind a passing front north of the state. Clouds and showers will favor windward and mauka locations, with the best chances being overnight through the early morning hours. Although the tail-end of the passing front should stall and dissipate nearby to the north Tuesday through Wednesday, the leading edge of the moisture axis could make it as far south as Kauai, which would support better windward shower coverage. Elsewhere, dry and stable conditions will limit rainfall accumulations. Easterly trades are expected to peak in the breezy category Tuesday as strong high pressure builds to our north.
Despite some model differences in timing, a general consensus supports the ridge to the north weakening and shifting southward beginning Thursday as a shortwave trough and surface cold front approach. Surface winds will respond and become light out of the southeast Thursday as the front moves into the area. A combination of light winds, increasing moisture, and lowering upper heights will support better rainfall coverage over the western end of the state where the front will weaken and begin to stall. Light winds may linger into the weekend before trades gradually return Sunday into next week.
Aviation
A high pressure system will build in north of the state through at least Tuesday with increasing trade winds into the moderate to locally breezy range starting on Monday. Brief periods of isolated to scattered showers are expected mainly over windward and mountain areas. Periods of MVFR ceilings and visibility are likely to persist this evening along windward Big Island with pockets of IFR conditions. Windward Big Island weather conditions will begin improving after 10Z.
AIRMET SIERRA remains in effect for north through east sections of the Big Island for tempo mountain obscuration above 1500 feet due to clouds and showers. These conditions will likely to slowly improve after 10Z.
Marine
The weak ridging north of the state that has maintained a loose pressure gradient and resultant gentle trades will give way to a more established area of high pressure northwest of the islands. This new high will build in behind a hurricane force low currently moving into the Gulf of Alaska this morning. This synoptic set up will tighten the pressure gradient down across the region and ultimately restrengthen trades from fresh to locally strong magnitudes by Tuesday morning. These speeds will hang on through Wednesday before backing off again in response to the high north of the islands moving east and being replaced by a relatively small weak area of low pressure. This low may be far enough south to drag a very weak, diffuse boundary into the waters by next weekend. The large swell created by the hurricane force low will reach our offshore waters by tonight. This has prompted an all water Small Craft Advisory for seas through Wednesday afternoon. These high seas will occur just before the period of strong winds commence tonight into early Tuesday across the typical windier waters surrounding Maui County and Big Island.
The High Surf Advisory (HSA) remains in effect for the north and west-facing shores of the smaller islands, except Maui's west shore, through Tuesday afternoon. This is associated with an ongoing passing northwest (320 degree) medium period swell that has been gradually leveling out through the night and to capture the next swell. The next large north northwest (340 degree) swell generated from the hurricane force low mentioned above will begin filling in tonight and peak Tuesday. This large, long period swell will likely drive north and west-facing surf heights to High Surf Warning levels Tuesday morning. This large swell should slowly decline from Tuesday night through the remainder of the week as it veers more northerly by Thursday. Strengthening trades the next couple of days will increase eastern exposure chop and lead to rough surf from Tuesday into the middle of the week.
HFO Watches/Warnings/Advisories
High Surf Advisory until 6 PM HST Tuesday for Niihau, Kauai Leeward, Waianae Coast, Oahu North Shore, Kauai North, Molokai Windward, Molokai North, Molokai West, Maui Central Valley North, Windward Haleakala.
Small Craft Advisory until 6 PM HST Wednesday for Kauai Northwest Waters, Kauai Windward Waters, Oahu Windward Waters, Kaiwi Channel, Maui County Windward Waters, Alenuihaha Channel, Big Island Windward Waters.
Small Craft Advisory until 6 PM HST Wednesday for Kauai Leeward Waters, Kauai Channel, Oahu Leeward Waters, Maui County Leeward Waters, Maalaea Bay, Pailolo Channel, Big Island Leeward Waters, Big Island Southeast Waters.
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