Today: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 77 to 82 near the shore to 63 to 69 at 4000 feet. North winds 10 to 15 mph decreasing to up to 15 mph in the afternoon. Chance of rain 50 percent.
Tonight: Mostly cloudy with scattered showers. Lows 61 to 68 near the shore to around 54 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 50 percent.
Wednesday: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Highs 76 to 82 near the shore to 62 to 68 at 4000 feet. North winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.
Kona
Today: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Highs 82 to 87 near the shore to around 68 near 5000 feet. Light winds. Chance of rain 40 percent.
Tonight: Partly cloudy. Lows around 70 near the shore to 46 to 52 near 5000 feet. Light winds.
ARTICLE CONTINUES BELOW AD
ARTICLE CONTINUES BELOW AD
Wednesday: Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs 81 to 86 near the shore to around 66 near 5000 feet. Light winds. Chance of rain 20 percent.
Waimea
Today: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 77 near the shore to 66 to 75 near 3000 feet. East winds 10 to 25 mph. Chance of rain 40 percent.
Tonight: Breezy. Mostly cloudy with scattered showers. Lows 61 to 70 near the shore to 52 to 59 near 3000 feet. East winds 10 to 25 mph with gusts to 45 mph. Chance of rain 50 percent.
Wednesday: Breezy. Sunny with scattered showers. Highs around 77 near the shore to 65 to 74 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.
Kohala
Today: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 77 near the shore to 66 to 75 near 3000 feet. East winds 10 to 25 mph. Chance of rain 40 percent.
ARTICLE CONTINUES BELOW AD
Tonight: Breezy. Mostly cloudy with scattered showers. Lows 61 to 70 near the shore to 52 to 59 near 3000 feet. East winds 10 to 25 mph with gusts to 45 mph. Chance of rain 50 percent.
Wednesday: Breezy. Sunny with scattered showers. Highs around 77 near the shore to 65 to 74 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.
South Big Island
Today: Mostly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Highs around 84 near the shore to around 66 near 5000 feet. East winds 10 to 15 mph decreasing to up to 15 mph in the afternoon. Chance of rain 40 percent.
Tonight: Partly cloudy. Lows around 72 near the shore to around 49 near 5000 feet. Northeast winds up to 15 mph in the evening becoming light.
Wednesday: Sunny in the morning then becoming partly sunny. Breezy. Highs around 82 near the shore to around 64 near 5000 feet. East winds up to 20 mph.
Puna
ARTICLE CONTINUES BELOW AD
Today: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 77 to 82 near the shore to 63 to 69 at 4000 feet. North winds 10 to 15 mph decreasing to up to 15 mph in the afternoon. Chance of rain 50 percent.
Tonight: Mostly cloudy with scattered showers. Lows 61 to 68 near the shore to around 54 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 50 percent.
Wednesday: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Highs 76 to 82 near the shore to 62 to 68 at 4000 feet. North winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.
Waikoloa
Today: Sunny and breezy. Highs 81 to 86 near the shore to 64 to 70 above 4000 feet. East winds 10 to 25 mph shifting to the northeast up to 25 mph in the afternoon.
Tonight: Mostly clear. Breezy. Lows around 71 near the shore to 48 to 54 above 4000 feet. East winds up to 25 mph with gusts to 45 mph.
Wednesday: Sunny and breezy. Highs around 83 near the shore to 63 to 69 above 4000 feet. Northeast winds up to 25 mph.
Detailed Forecast
Synopsis
Moderate to breezy easterly trade winds will back to a more northeasterly direction today as a front moves over Kauai late this afternoon, increasing clouds and showers. A strong high far northwest of the state will shift north of the state Wednesday through Thursday, driving the front southeast over the rest of the state. Expect wet conditions along the front and very windy northeasterly trade winds to follow behind the front. Drier than normal air will fill in across the state by Thursday afternoon. A more typical easterly trade wind pattern will then gradually return over the weekend and persist into early next week as the high weakens north of the state.
Discussion
A ridge of high pressure far north of the state that has been producing moderate to breezy easterly trades has weakened and shifted east overnight as a front inches closer to state from the northwest. ASCAT and surface observations show winds have already started to shift out of the northeast near Kauai from a strong 1038 mb high located roughly 1500 miles northwest of the state. Current radar and satellite imagery show scattered clouds and showers riding in with the easterly trades and along and area of convergence positioned from Kauai to nearly 200 miles north northeast of Kauai. Latest model guidance suggests winds will continue to shift out of the northeast today ahead of the front, clouds and showers will briefly become more limited along windward and mauka areas with some showers spilling over to leeward locales. The front will move over Kauai late this afternoon into the evening increasing clouds and shower coverage once again over windward and mauka areas. Very wind conditions are expected for Kauai tonight as the momentum and strength of the leading edge of the front is at the maximum. These very windy conditions may prompt a wind advisory for Kauai tonight.
The strong high is expected to shift north of the state Wednesday and Thursday, tightening the gradient over the state and driving the front and associated clouds and showers southeast down the island chain. Thus a wind advisory may be needed for other parts of the state as very windy conditions spread across the state. The wet weather associated with the front will continue to favor windward and mountain areas with some showers spilling over to leeward locations.
Dewpoints are expected to drop in the mid to upper 50's first for the western half of the state late Wednesday then for the rest of state by Thursday afternoon and persist into the weekend. This will make for drier conditions and seemingly cooler temperatures. Northeasterly trades will gradually ease Friday and may shift out of the east as the high weakens just north of the state and persist into early next week. Clouds and showers will be limited if any along windward and mauka areas. Dewpoint will return to more normals values late in the weekend into early next week.
Aviation
Moderate to breezy trade winds will become locally strong by the afternoon or evening as a cold front approaches Kauai from the northwest. Clouds and showers will continue to favor windward and mauka areas resulting in periods of MVFR conditions. Deeper moisture will move into the western end of the state and increase clouds and showers near Kauai and Oahu this morning. Otherwise, expect VFR to generally prevail across the state.
AIRMET Sierra is in effect for mountain obscuration across north through east sections of Kauai and Oahu this morning due to increased lower clouds and showers. Conditions should improve during the day today.
AIRMET Tango for tempo mountain lee turbulence will likely become necessary by this afternoon or evening as the trade winds strengthen.
Marine
A cold front will push southward through Kauai late this afternoon, then stall out just north of Oahu tonight into early Wednesday. The front will get driven southeastward down the island chain by a strong building high to the distant northwest late Wednesday and Wednesday night. Behind the front, northeast trades will ramp up to strong and near Gale force, with these winds then remaining steady through Friday. The trades will ease back to moderate and locally strong levels over the weekend as the high to the north weakens.
The combination of strengthening northeast trades and large rough seas will bring Small Craft Advisory conditions to most waters through Friday. The winds are expected to be particularly strong over the waters west of Kauai, and a Gale Warning is now in effect beginning 6 PM this evening and continuing through 6 AM Thursday.
A small medium-period north swell will continue to decline today. Long-period forerunners from in incoming long-period northwest swell have reached Kauai and Oahu, and will continue to build down the island chain through the day and peak around 10 feet tonight and Wednesday. While the resulting surf will easily exceed High Surf Advisory levels on north and west facing shores, the peak of the swell will coincide with fresh to near gale northeasterly winds, leading to rough conditions along some east facing shores due to large wind waves. Late Thursday into Friday, the swell will be reinforced and shift out of the north-northwest, likely keeping surf elevated above advisory levels. Another northerly swell reinforcement is possible on Saturday, potentially extending the advisory level surf for north facing shores. This swell is then forecast to lower Sunday into early next week.
Small short-period wind waves and wrapping northerly swell will produce small east shore surf today, followed by a rise around Kauai and Oahu tonight and Wednesday as strengthening northeast trade winds produce large wind waves. Above average east shore surf and rough conditions can be expected Thursday and Friday due to fresh to near gale trade winds and additional wrapping northerly swell. Tiny south shore surf will prevail through the weekend, followed by a small pulse from the south- southwest early next week.
HFO Watches/Warnings/Advisories
High Surf Advisory from noon today to 6 AM HST Thursday for north and west facing shores of Niihau and Kauai.
High Surf Advisory from 6 PM this evening to 6 AM HST Thursday for north and west facing shores of Oahu and Molokai and north facing shore of Maui.
Small Craft Advisory from noon today to 6 PM HST this evening for Kauai Northwest Waters, Kauai Leeward Waters.
Gale Warning from 6 PM this evening to 6 AM HST Thursday for Kauai Northwest Waters, Kauai Leeward Waters.
Small Craft Advisory from noon today to 6 PM HST Friday for Kauai Windward Waters.
Small Craft Advisory from 6 PM this evening to 6 PM HST Friday for Kauai Channel, Oahu Windward Waters, Oahu Leeward Waters, Kaiwi Channel, Maui County Windward Waters, Maui County Leeward Waters.
Small Craft Advisory until 6 PM HST Friday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Windward Waters, Big Island Leeward Waters, Big Island Southeast Waters.
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