Hilo

Today: Mostly cloudy with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs around 82 near the shore to 65 to 72 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 64 to 71 near the shore to around 57 at 4000 feet. Northeast winds up to 10 mph shifting to the west after midnight. Chance of rain 50 percent.

Sunday: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 80 to 85 near the shore to 65 to 74 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 40 percent.

Kona

Today: Sunny with isolated showers early in the morning, then mostly sunny with scattered showers in the late morning and afternoon. Highs around 88 near the shore to around 71 near 5000 feet. West winds up to 10 mph. Chance of rain 40 percent.

Tonight: Mostly cloudy with isolated showers in the evening, then mostly clear after midnight. Lows 71 to 76 near the shore to 53 to 58 near 5000 feet. Light winds. Chance of rain 20 percent.

Sunday: Sunny in the morning, then cloudy with isolated 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 20 percent.

Waimea

Today: Partly sunny with scattered showers early in the morning, then mostly sunny with isolated showers in the late morning and afternoon. Highs 67 to 88. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with scattered showers. Lows around 67 near the shore to 57 to 64 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Sunday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 68 to 88. East winds up to 15 mph. Chance of rain 40 percent.

Kohala

Today: Partly sunny with scattered showers early in the morning, then mostly sunny with isolated showers in the late morning and afternoon. Highs 67 to 88. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with scattered showers. Lows around 67 near the shore to 57 to 64 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Sunday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 68 to 88. East winds up to 15 mph. Chance of rain 40 percent.

South Big Island

Today: Mostly sunny. Breezy. Scattered showers in the late morning and afternoon. Highs around 85 near the shore to around 69 near 5000 feet. East winds up to 25 mph. Chance of rain 30 percent.

Tonight: Mostly cloudy in the evening then becoming mostly clear. Breezy. Lows around 73 near the shore to around 53 near 5000 feet. Northeast winds up to 20 mph.

Sunday: Mostly sunny. Breezy. Highs around 85 near the shore to around 70 near 5000 feet. East winds up to 20 mph.

Puna

Today: Mostly cloudy with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs around 82 near the shore to 65 to 72 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 64 to 71 near the shore to around 57 at 4000 feet. Northeast winds up to 10 mph shifting to the west after midnight. Chance of rain 50 percent.

Sunday: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 80 to 85 near the shore to 65 to 74 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 40 percent.

Waikoloa

Today: Mostly sunny. Isolated showers in the late morning and afternoon. Highs 83 to 90 near the shore to 67 to 75 above 4000 feet. Northwest winds up to 10 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Lows 71 to 76 near the shore to 51 to 59 above 4000 feet. Southeast winds up to 10 mph.

Sunday: Sunny. Highs 82 to 90 near the shore to 67 to 76 above 4000 feet. North winds up to 15 mph.

Detailed Forecast

Synopsis

Southeast wind will focus clouds and showers over southeast- facing slopes of Maui County and the Big Island while afternoon sea breezes bring interior clouds and showers to the western end of the state. Trades return to the entire state tonight into early Sunday.

Discussion

Trades will make a gradual return during the next 18 to 24 hours as the surface trough near Kauai exits stage west concurrent with the southern periphery of the northeast Pacific high pressure building toward the islands. For Kauai and Oahu, continued light winds during the day will once again give way to localized sea breezes, interior cloud development, and a few showers. Reductions to mid-level stability will occur as the resident batch of moisture centered south of the islands works through the area today. This, combined with an uptick in boundary layer moisture will offer potential for a slightly greater convective response compared to yesterday. Over the eastern end of the state, building ESE winds will deliver occasional clouds and showers to favored east and southeast-facing slopes.
As trades become established early next week, the diffuse nature of the pressure gradient suggested by recent modeling puts the islands in a somewhat precarious position in terms of forecast confidence for the strength of said trade winds. While breezy trades are indicated through much of next week, the tightening of the local gradient appears to be more closely tied to pressure falls in the tropics south and southeast of the islands which inherently carries comparatively greater uncertainty. In either case, some semblance of easterly trades will develop on Sunday and persist through most or all of next week bringing a return to a more typical trade wind pattern. As noted in the previous discussion, any additional pressure falls south of the area such as those related to tropical development would have the potential to give local winds another upward nudge during mid-week.

Aviation

Land breezes have pushed much of the clouds and showers offshore overnight over the smaller islands. Trade wind flow will become reestablished over windward Big Island this morning and spread across the remainder of the state through tonight. Leeward areas over the western end of the state may still experience localized sea breezes and inland clouds/showers this afternoon as the trades slowly return. A few bands of showery low clouds will continue to move into east and southeastern portions of the Big Island and Maui this morning, before dissipating by the afternoon. Shower activity will return to a more typical windward and mauka focus tonight.

Marine

A surface trough N of the area will gradually drift northward and weaken over the next few days, allowing surface high pressure to the distant N to re-exert its influence on our winds. As a result, E to SE winds will increase from E to W across the island chain. Winds will remain on the lighter side over Kauai and Oahu today, but are expected to increase over Maui and Big Island waters, and a Small Craft Advisory (SCA) has been issued in anticipation that winds will increase. Winds will likely continue to gradually increase into the middle of next week as the high moves closer, and a potential tropical disturbance passes far S of the islands.
Little significant swell is anticipated through next week. A small short-period NE swell will continue today and diminish tomorrow. The increasing trade winds bringing a gradual increase in short- period waves to E shores early next week. A small, long-period S swell may arrive around the middle of next week, with a small, shorter-period SSE swell expected over the next couple of days.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 AM HST Monday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.
Small Craft Advisory until 6 AM HST Sunday for Maui County Windward Waters, Big Island Windward Waters.

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Data Courtesy of NOAA.gov