Hilo

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows around 72 near the shore to around 60 at 4000 feet. Northwest winds up to 10 mph. Chance of rain 50 percent.

Wednesday: Mostly cloudy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 85 near the shore to 70 to 75 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Wednesday Night: Mostly cloudy with scattered showers. Lows around 72 near the shore to around 60 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Kona

Tonight: Partly cloudy with isolated showers. Lows around 76 near the shore to around 56 near 5000 feet. Light winds. Chance of rain 20 percent.

Wednesday: Mostly sunny in the morning then becoming mostly cloudy. Isolated showers. Highs 83 to 88 near the shore to around 70 near 5000 feet. West winds up to 10 mph. Chance of rain 20 percent.

Wednesday Night: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Lows around 76 near the shore to around 56 near 5000 feet. Light winds. Chance of rain 20 percent.

Waimea

Tonight: Partly cloudy with isolated showers. Lows around 72 near the shore to 60 to 67 near 3000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Wednesday: Partly sunny with isolated showers. Highs around 83 near the shore to 70 to 80 near 3000 feet. East winds 10 to 15 mph decreasing to up to 15 mph in the afternoon. Chance of rain 20 percent.

Wednesday Night: Mostly cloudy with isolated showers. Lows around 72 near the shore to 60 to 67 near 3000 feet. East winds up to 10 mph. Chance of rain 20 percent.

Kohala

Tonight: Partly cloudy with isolated showers. Lows around 72 near the shore to 60 to 67 near 3000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Wednesday: Partly sunny with isolated showers. Highs around 83 near the shore to 70 to 80 near 3000 feet. East winds 10 to 15 mph decreasing to up to 15 mph in the afternoon. Chance of rain 20 percent.

Wednesday Night: Mostly cloudy with isolated showers. Lows around 72 near the shore to 60 to 67 near 3000 feet. East winds up to 10 mph. Chance of rain 20 percent.

South Big Island

Tonight: Mostly clear. Isolated showers in the evening. Lows around 77 near the shore to around 57 near 5000 feet. Northeast winds up to 15 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny. Breezy. Highs around 87 near the shore to around 74 near 5000 feet. East winds up to 20 mph.

Wednesday Night: Partly cloudy. Lows around 77 near the shore to around 57 near 5000 feet. East winds 10 to 15 mph.

Puna

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows around 72 near the shore to around 60 at 4000 feet. Northwest winds up to 10 mph. Chance of rain 50 percent.

Wednesday: Mostly cloudy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 85 near the shore to 70 to 75 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Wednesday Night: Mostly cloudy with scattered showers. Lows around 72 near the shore to around 60 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Waikoloa

Tonight: Mostly clear. Lows around 77 near the shore to around 58 above 4000 feet. East winds up to 15 mph.

Wednesday: Sunny in the morning then becoming partly sunny. Highs around 87 near the shore to 71 to 77 above 4000 feet. Northeast winds up to 15 mph.

Wednesday Night: Mostly clear. Lows around 77 near the shore to around 58 above 4000 feet. Light winds.

Synopsis

Trade winds will ease into the light to moderate range for the second half of the week as a surface ridge weakens north of the state. Light showers will mainly favor windward and mauka areas locations, with a few afternoon interior and leeward showers possible under the lighter winds. Breezy trades return over the weekend as high pressure builds to the north.

Discussion

Satellite and radar imagery continue to show partly cloudy skies across the state this afternoon, with a few light showers moving into windward areas on the trades. The 00Z upper air soundings from Hilo and Lihue show generally stable conditions with an inversion between 5-6 kft and extensive dry air aloft. This will keep overall shower activity somewhat suppressed, with rainfall amounts on the lighter side for the next several days.
A deep-layer ridge will remain over the region, then begin to break down as an upper trough digs southeastward toward the area tonight through Wednesday. The accompanying surface front is forecast to stall several hundred miles north of the state Wednesday through the second half of the week. This pattern transition will relax the pressure gradient over the state, allowing the trades to ease into the light to moderate range and veer slightly more southeasterly. The deep-layer moisture axis and any accompanying instability will remain north of the islands for the most part, keeping the dry and stable pattern in place across the the majority of the state. Light showers will continue to favor windward and mauka areas, particularly through the overnight and morning periods. However, with the proximity of the front to the western/northern end of the island chain, stability may be weakened a bit there, allowing some showers to be on the more moderate side toward the end of the week. As the winds ease, localized sea breezes are expected, especially over the western half of the island chain. Despite the mostly stable conditions in place, some cloud build- ups and brief showers can’t be ruled out over interior and leeward sections where these sea breezes form. Breezy trades will return later this weekend and into early next week as high pressure builds back north of the region and the aforementioned moisture axis to the north diminishes.

Aviation

AIRMET Tango remains in effect for tempo moderate low-level turbulence over and downwind of the terrain of all islands. This AIRMET will remain in effect through 04Z, and then cancelled for tonight as the trade winds are expected to weaken. No other AIRMETs are in effect or expected through the night.

Marine

A front pushing into the subtropical ridge has begun to weaken our trade winds this afternoon. As a result, the Small Craft Advisory (SCA) for the windier waters and channels around Maui County and the Big Island has been canceled. Breezy trade wind conditions should return by the weekend as high pressure rebuilds to our north.
Surf along east facing shores will decrease slightly as trades ease through the rest of the week. Small background swells from the south and southwest will keep the surf from going entirely flat for south facing shores through the week. A small, medium- period northerly swell is expected to arrive Thursday night, peak Friday then slowly decline through the weekend.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov