Today: Partly sunny. Isolated showers in the morning, then scattered showers and slight chance of thunderstorms in the afternoon. Highs around 81 near the shore to 64 to 69 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.
Tonight: Mostly cloudy with scattered showers and slight chance of thunderstorms early in the evening, then partly cloudy with scattered showers in the late evening and overnight. Lows around 65 near the shore to around 51 at 4000 feet. Southeast winds up to 10 mph in the evening becoming light. Chance of rain 50 percent.
Friday: Mostly sunny with scattered showers in the morning, then mostly cloudy with numerous showers and slight chance of thunderstorms in the afternoon. Highs around 80 near the shore to 63 to 68 at 4000 feet. Southeast winds up to 10 mph shifting to the east in the afternoon. Chance of rain 70 percent.
Kona
Today: Partly sunny. Scattered showers and slight chance of thunderstorms in the afternoon. Highs 79 to 84 near the shore to around 70 near 5000 feet. Light winds. Chance of rain 50 percent.
Tonight: Mostly cloudy early in the evening then becoming partly cloudy. Scattered showers and slight chance of thunderstorms early in the evening, then isolated showers in the late evening and overnight. Lows 65 to 72 near the shore to around 52 near 5000 feet. Light winds. Chance of rain 50 percent.
ARTICLE CONTINUES BELOW AD
ARTICLE CONTINUES BELOW AD
Friday: Mostly sunny with isolated showers in the morning, then mostly cloudy with scattered showers and slight chance of thunderstorms in the afternoon. Highs 78 to 83 near the shore to around 69 near 5000 feet. Light winds becoming west up to 10 mph in the afternoon. Chance of rain 50 percent.
Waimea
Today: Partly sunny. Isolated showers in the morning, then scattered showers and slight chance of thunderstorms in the afternoon. Highs around 80 near the shore to 70 to 77 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.
Tonight: Mostly cloudy early in the evening then becoming partly cloudy. Scattered showers and slight chance of thunderstorms early in the evening, then scattered showers in the late evening and overnight. Lows around 64 near the shore to 50 to 58 near 3000 feet. Southeast winds up to 10 mph in the evening becoming light. Chance of rain 50 percent.
Friday: Breezy. Mostly sunny with scattered showers in the morning, then mostly cloudy with scattered showers and slight chance of thunderstorms in the afternoon. Highs around 79 near the shore to 69 to 76 near 3000 feet. East winds up to 20 mph. Chance of rain 50 percent.
Kohala
Today: Partly sunny. Isolated showers in the morning, then scattered showers and slight chance of thunderstorms in the afternoon. Highs around 80 near the shore to 70 to 77 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.
ARTICLE CONTINUES BELOW AD
Tonight: Mostly cloudy early in the evening then becoming partly cloudy. Scattered showers and slight chance of thunderstorms early in the evening, then scattered showers in the late evening and overnight. Lows around 64 near the shore to 50 to 58 near 3000 feet. Southeast winds up to 10 mph in the evening becoming light. Chance of rain 50 percent.
Friday: Breezy. Mostly sunny with scattered showers in the morning, then mostly cloudy with scattered showers and slight chance of thunderstorms in the afternoon. Highs around 79 near the shore to 69 to 76 near 3000 feet. East winds up to 20 mph. Chance of rain 50 percent.
South Big Island
Today: Partly sunny. Breezy. Scattered showers and slight chance of thunderstorms in the afternoon. Highs around 82 near the shore to around 71 near 5000 feet. East winds up to 20 mph. Chance of rain 50 percent.
Tonight: Mostly cloudy with scattered showers and slight chance of thunderstorms early in the evening, then partly cloudy with isolated showers in the late evening and overnight. Lows around 67 near the shore to around 51 near 5000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.
Friday: Breezy. Mostly sunny with isolated showers in the morning, then mostly cloudy with scattered showers and slight chance of thunderstorms in the afternoon. Highs around 81 near the shore to around 70 near 5000 feet. East winds up to 20 mph. Chance of rain 50 percent.
Puna
ARTICLE CONTINUES BELOW AD
Today: Partly sunny. Isolated showers in the morning, then scattered showers and slight chance of thunderstorms in the afternoon. Highs around 81 near the shore to 64 to 69 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.
Tonight: Mostly cloudy with scattered showers and slight chance of thunderstorms early in the evening, then partly cloudy with scattered showers in the late evening and overnight. Lows around 65 near the shore to around 51 at 4000 feet. Southeast winds up to 10 mph in the evening becoming light. Chance of rain 50 percent.
Friday: Mostly sunny with scattered showers in the morning, then mostly cloudy with numerous showers and slight chance of thunderstorms in the afternoon. Highs around 80 near the shore to 63 to 68 at 4000 feet. Southeast winds up to 10 mph shifting to the east in the afternoon. Chance of rain 70 percent.
Waikoloa
Today: Partly sunny. Slight chance of thunderstorms and isolated showers in the afternoon. Highs around 81 near the shore to 65 to 72 above 4000 feet. Northeast winds up to 10 mph shifting to the northwest in the afternoon. Chance of rain 20 percent.
Tonight: Partly cloudy. Slight chance of thunderstorms and isolated showers early in the evening, then isolated showers in the late evening and overnight. Lows 67 to 72 near the shore to 47 to 55 above 4000 feet. Light winds. Chance of rain 20 percent.
Friday: Sunny with isolated showers in the morning, then partly sunny with scattered showers and slight chance of thunderstorms in the afternoon. Highs around 80 near the shore to 64 to 71 above 4000 feet. South winds up to 10 mph shifting to the north in the afternoon. Chance of rain 50 percent.
Detailed Forecast
Synopsis
Light winds will allow for sea breeze development in most areas today. Shower coverage will remain highest near Kauai in closest proximity to a surface trough, although we should see an increase in sea breeze showers over the remainder of the state this afternoon as the airmass moistens up. Troughing aloft and unstable conditions will move over the island chain Friday through Saturday, bringing the potential for locally heavy rainfall and thunderstorms to some islands, particularly Kauai and Oahu. Trade winds will increase during this time as well as high pressure slides by well north of the islands, with breezy conditions expected statewide by Saturday. The airmass will stabilize Sunday through the middle of next week, with more typical trade wind weather expected and moderate to breezy trade winds prevailing.
Discussion
Currently at the surface, a west-east oriented trough of low pressure is positioned near Kauai, while a ridge of high pressure is located around 750 miles northwest of Kauai. The trough is cutting of the strongest gradient associated with the high and keeping winds light across the island chain early this morning. Infrared satellite imagery shows partly cloudy conditions in most areas, with a bit more cloud coverage over Kauai as well as Maui and the Big Island. Radar imagery shows scattered showers moving into windward sections of Kauai, with very little shower activity seen elsewhere. Main short term focus revolves around the potential for thunderstorms and some locally heavy rain Friday through the weekend.
The surface trough near Kauai will gradually sharpen up and shift southward into the western islands today through Friday. This will keep a northeasterly flow in place near Kauai, with easterly trades over the eastern end of the state. The winds will be on the increase across each end of the state during this time, while lighter winds prevail over the central islands closer to the trough. The trough will gradually dampen out Friday night and Saturday, while high pressure slides by well north of the state. This will strengthen the trade winds, with breezy conditions expected across the entire island chain by Saturday. Surface ridging will then hold in place north of the state Sunday through the middle of next week, keeping moderate to breezy trade winds in place with only minor fluctuations in strength.
As for the remaining weather details, the deepest moisture will remain near the surface trough which will linger over the smaller islands during the next few days. Shower coverage appears to remain the highest over Kauai today in closest proximity to the surface trough. Across the other islands, the moistening up of the boundary layer should bring a few more showers this afternoon than were seen yesterday, with a thunderstorm not out of the question on the Big Island. With the trough expected to make some slight southward progress tonight, we should see an increase in showers particularly over windward sections of the smaller islands. Troughing aloft will overspread the state Friday through Saturday while the deepest moisture remains over the northwestern islands. Although some locally heavy showers and even a thunderstorm or two will be possible statewide, the models seem to be favoring higher potential for some downpours and a few thunderstorms over Kauai and Oahu during this time. At the moment, confidence in the potential for widespread heavy rainfall and flooding is not high enough to warrant a Flood Watch, but this will continue to be monitored closely during the next few days.
The deeper moisture begins to exit to the southwest Saturday night and Sunday, with mid and upper level ridging beginning to build in from the northwest. This should lead to a gradual stabilization of the airmass and a return to more typical trade wind weather. Building mid and upper level ridging will continue to stabilize the airmass over the islands Monday through the middle of next week, with typical trade wind weather featuring scattered windward showers and a few leeward spillovers expected statewide.
Aviation
Land breezes are supporting mostly clear and VFR conditions for Oahu through the Big Island as cirrus streams overhead. Meanwhile, light to moderate trades are focusing low clouds and a few showers over the windward slopes of Kauai. As the light gradient gives way to sea breezes, interior clouds and showers over the smaller islands are expected to be more robust than in previous days with a few locally heavy showers possible during peak heating. Isolated thunder is probable once again over the Big Island interior. Strengthening trades will bring increasing shower coverage and a higher probability of MVFR to Windward Kauai by late this evening.
An upper trough over the islands is supporting a band of moderate to severe turbulence in the FL280/FL360 layer. This band of turbulence will gradually shift southeast and weaken through today. Reference SIGMET SIERRA series for more information.
AIRMET Tango for moderate mid-and upper-level turbulence remains in effect.
Marine
A surface trough lingering in the area will support moderate northeast winds over the northwest Kauai waters and light to moderate east flow over the Maui and Big Island waters through tonight. The land and sea breeze regime will persist over the central island waters (Molokai waters to the Kauai Channel) closer to the trough. A transition is expected Friday into the weekend as a cold front passes to the north and high pressure builds in behind it. As the tail-end of the frontal boundary settles southward into the area Friday, fresh to strong northeast winds will accompany it, then become easterly Saturday. Expect this pattern to hold through early next week as the ridge sets up north of the islands. Small Craft Advisory conditions due to these strong winds are anticipated beginning sometime between Friday and Friday night for some waters, then may need to be expanded to other areas over the weekend. Seas will respond and may near the 10 ft advisory threshold for exposed waters (windward waters) through the weekend.
Surf along north facing shores will hold at small levels today due to a mix of a medium-period northwest swell and short-period northerly swell moving through. Expect a downward trend from both swell sources Friday into the weekend as they move out. A fresh medium-period north-northwest swell associated with a pocket of strong- to gale-force level winds setting up around 900 nautical miles to the northwest through the day Thursday will arrive at the exposed beaches by the end of the day Saturday, then hold into Sunday before fading. On Monday, an upward trend is expected out of the northwest from a distance source currently developing near the Kurils in the far northwest Pacific (head of the fetch over 2500 nautical miles away from Hawaii). This long-period northwest swell will slowly fill in through the day Monday, then peak sometime between Tuesday and Wednesday before lowering into the latter half of next week. If this materializes, surf could near advisory levels for exposed north and west facing shores of the smaller islands as it peaks.
Surf along south facing shores will hold through today, then ease Friday into the weekend as an out of season long-period south swell moves through.
Surf along east facing shores will trend up this weekend through next week as the aforementioned ridge sets up to the north and a belt of fresh to strong easterly trades develop over and far upstream of the islands over the eastern Pacific.
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