Hilo

Today: Mostly cloudy with showers likely. Highs 78 to 83 near the shore to 64 to 70 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Tonight: Cloudy. Showers likely in the evening, then showers after midnight. Lows 63 to 71 near the shore to 55 to 60 at 4000 feet. North winds up to 15 mph. Chance of rain 90 percent.

Thursday: Cloudy. Showers likely in the morning, then scattered showers in the afternoon. Highs 77 to 83 near the shore to 62 to 68 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Kona

Today: Sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs around 87 near the shore to around 70 near 5000 feet. West winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Lows 70 to 76 near the shore to 52 to 58 near 5000 feet. Light winds. Chance of rain 50 percent.

Thursday: Mostly sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs around 85 near the shore to around 68 near 5000 feet. West winds up to 10 mph. Chance of rain 50 percent.

Waimea

Today: Breezy. Partly sunny with scattered showers. Highs 66 to 85. East winds 10 to 25 mph with gusts to 45 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then showers likely after midnight. Lows 64 to 71 near the shore to 57 to 64 near 3000 feet. East winds 10 to 25 mph with gusts to 45 mph. Chance of rain 70 percent.

Thursday: Breezy. Mostly cloudy with scattered showers. Highs 64 to 84. East winds 10 to 25 mph with gusts to 45 mph. Chance of rain 50 percent.

Kohala

Today: Breezy. Partly sunny with scattered showers. Highs 66 to 85. East winds 10 to 25 mph with gusts to 45 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then showers likely after midnight. Lows 64 to 71 near the shore to 57 to 64 near 3000 feet. East winds 10 to 25 mph with gusts to 45 mph. Chance of rain 70 percent.

Thursday: Breezy. Mostly cloudy with scattered showers. Highs 64 to 84. East winds 10 to 25 mph with gusts to 45 mph. Chance of rain 50 percent.

South Big Island

Today: Breezy. Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 85 near the shore to around 68 near 5000 feet. East winds up to 25 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Breezy. Isolated showers in the evening. Lows around 73 near the shore to around 54 near 5000 feet. Northeast winds up to 20 mph. Chance of rain 20 percent.

Thursday: Breezy. Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 84 near the shore to around 66 near 5000 feet. East winds up to 25 mph. Chance of rain 20 percent.

Puna

Today: Mostly cloudy with showers likely. Highs 78 to 83 near the shore to 64 to 70 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Tonight: Cloudy. Showers likely in the evening, then showers after midnight. Lows 63 to 71 near the shore to 55 to 60 at 4000 feet. North winds up to 15 mph. Chance of rain 90 percent.

Thursday: Cloudy. Showers likely in the morning, then scattered showers in the afternoon. Highs 77 to 83 near the shore to 62 to 68 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Waikoloa

Today: Windy. Sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs 83 to 90 near the shore to 68 to 74 above 4000 feet. Northeast winds up to 30 mph. Chance of rain 40 percent.

Tonight: Breezy. Partly cloudy with isolated showers. Lows around 75 near the shore to 52 to 58 above 4000 feet. East winds up to 25 mph with gusts to 45 mph. Chance of rain 20 percent.

Thursday: Windy. Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs 82 to 89 near the shore to 67 to 73 above 4000 feet. Northeast winds up to 30 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Breezy trades will weaken to moderate by this weekend and will focus clouds and showers over windward and mauka areas through the forecast period.

Discussion

Breezy trades remain established across the islands this morning and will continue through mid-week. And the high coverage of stratocu extending well upstream of the islands is as strong of an indication as any that trades will remain on the wetter side for the next few days. Although upper ridging building across the area during the next 24 hours will bring a return to stable conditions, forecast soundings indicate only moderate stability characterized by pronounced dry layer and rather weak temperature inversion. Thus, although clouds and showers will tend to focus over windward and mauka areas, breezy trades will also usher light showers leeward with greater efficiency, especially overnight and during the early morning.
Deepening low pressure over the northeast Pacific during the latter half of the week will cause gradient to relax across the islands as surface pressure falls pervade the eastern and central Pacific. Global model consensus remains strong that trades will relax to moderate intensity by this weekend. Wetter trades will likely favored during this time as broad upper troughing encompassing the region favors below normal stability.

Aviation

Breezy trade winds will continue over the next several days. AIRMET Tango is posted for tempo moderate low-level turbulence below 080 south through west of mountains for all islands due to the breezy winds.
The trades will carry in clouds and fast-moving showers this morning that will bring brief mountain obscurations/MVFR ceilings and visibility over the windward slopes. More extensive mountain obscurations will occur over the windward sides of Kauai and Oahu, where AIRMET Sierra is in effect. Overall showers should taper off by late morning.

Marine

The strong high pressure system to the northeast continues to drive fresh to locally strong trades across the region. An overnight ASCAT pass showed winds just below gales in the Alenuihaha Channel. The Small Craft Advisory (SCA) remains in effect today for all waters mostly for winds, but some areas are also seeing some seas in excess of 10 feet. The SCA has been extended through Thursday for coastal waters near Oahu eastward. Winds over the typical windier area near Maui and the Big Island will likely remain at SCA levels through Friday. The high pressure system to the northeast is expected to move to the east and be replaced by a new high to the north over the upcoming weekend. A front passing north of the area will help to disrupt the ridge to the north of the islands, helping to weaken winds a bit for the latter part of the weekend.
The persistent trade winds will continue to bring elevated surf to east facing shores over the next couple of days, with surf gradually lowering later in the week and into early next week. A small northwest swell is expected to begin filling in Thursday, peak on Friday, then lower slowly over the weekend and into early next week. The current south swell will continue to lower over the next couple of days. Otherwise, there will be a few small, mainly background south and southeast swells throughout the forecast period.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Thursday for Oahu Leeward Waters, Kaiwi Channel, Maui County Windward Waters, Maui County Leeward Waters, Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Windward Waters, Big Island Leeward Waters, Big Island Southeast Waters.
Small Craft Advisory until 6 PM HST this evening for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Kauai Channel, Oahu Windward Waters.

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Data Courtesy of NOAA.gov