Hilo

Today: Mostly cloudy. Showers likely in the morning, then showers likely and isolated thunderstorms in the afternoon. Highs 75 to 81 near the shore to 62 to 67 at 4000 feet. Northeast winds up to 10 mph shifting to the east in the afternoon. Chance of rain 70 percent.

Tonight: Mostly cloudy with showers likely. Lows 61 to 70 near the shore to 53 to 58 at 4000 feet. East winds 10 to 15 mph. Chance of rain 70 percent.

Sunday: Partly sunny. Showers likely in the morning, then scattered showers and isolated thunderstorms in the afternoon. Highs 76 to 82 near the shore to 63 to 68 at 4000 feet. East winds 10 to 15 mph. Chance of rain 70 percent.

Kona

Today: Mostly sunny. Scattered showers and isolated thunderstorms in the afternoon. Highs around 83 near the shore to around 65 near 5000 feet. Light winds becoming west up to 10 mph in the afternoon. Chance of rain 40 percent.

Tonight: Mostly cloudy with scattered showers in the evening, then mostly clear after midnight. Lows 68 to 73 near the shore to 47 to 54 near 5000 feet. West winds around 10 mph in the evening becoming light. Chance of rain 40 percent.

Sunday: Sunny in the morning, then partly sunny with scattered showers and isolated thunderstorms in the afternoon. Highs 81 to 86 near the shore to around 68 near 5000 feet. Northeast winds around 10 mph shifting to the west in the afternoon. Chance of rain 40 percent.

Waimea

Today: Partly sunny. Breezy. Scattered showers in the morning, then scattered showers and isolated thunderstorms in the afternoon. Highs 63 to 83. East winds up to 20 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 63 near the shore to 53 to 61 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Sunday: Partly sunny. Breezy. Scattered showers in the morning, then scattered showers and isolated thunderstorms in the afternoon. Highs 64 to 84. East winds 10 to 20 mph. Chance of rain 50 percent.

Kohala

Today: Partly sunny. Breezy. Scattered showers in the morning, then scattered showers and isolated thunderstorms in the afternoon. Highs 63 to 83. East winds up to 20 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 63 near the shore to 53 to 61 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Sunday: Partly sunny. Breezy. Scattered showers in the morning, then scattered showers and isolated thunderstorms in the afternoon. Highs 64 to 84. East winds 10 to 20 mph. Chance of rain 50 percent.

South Big Island

Today: Breezy. Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers and isolated thunderstorms in the afternoon. Highs around 81 near the shore to around 66 near 5000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Tonight: Partly cloudy. Breezy. Isolated showers in the evening. Lows around 70 near the shore to around 50 near 5000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Sunday: Mostly sunny. Scattered showers and isolated thunderstorms in the afternoon. Highs around 81 near the shore to around 66 near 5000 feet. East winds 10 to 15 mph. Chance of rain 30 percent.

Puna

Today: Mostly cloudy. Showers likely in the morning, then showers likely and isolated thunderstorms in the afternoon. Highs 75 to 81 near the shore to 62 to 67 at 4000 feet. Northeast winds up to 10 mph shifting to the east in the afternoon. Chance of rain 70 percent.

Tonight: Mostly cloudy with showers likely. Lows 61 to 70 near the shore to 53 to 58 at 4000 feet. East winds 10 to 15 mph. Chance of rain 70 percent.

Sunday: Partly sunny. Showers likely in the morning, then scattered showers and isolated thunderstorms in the afternoon. Highs 76 to 82 near the shore to 63 to 68 at 4000 feet. East winds 10 to 15 mph. Chance of rain 70 percent.

Waikoloa

Today: Mostly sunny. Scattered showers and isolated thunderstorms in the afternoon. Highs 79 to 85 near the shore to 63 to 69 above 4000 feet. East winds up to 10 mph shifting to the north in the afternoon. Chance of rain 40 percent.

Tonight: Partly cloudy. Isolated showers in the evening. Lows 66 to 73 near the shore to 48 to 54 above 4000 feet. Northeast winds 10 to 15 mph shifting to the east after midnight. Chance of rain 20 percent.

Sunday: Mostly sunny. Scattered showers and isolated thunderstorms in the afternoon. Highs 79 to 87 near the shore to 65 to 72 above 4000 feet. East winds 10 to 15 mph shifting to the north in the afternoon. Chance of rain 30 percent.

Detailed Forecast

Synopsis

East-southeasterly winds will dominate through this weekend as showers continue to favor windward slopes. An upper trough will enhance showers at times and bring isolated thunderstorms to the Big Island each afternoon through Sunday. Drier and more stable trade wind weather is expected next week.

Discussion

An upper trough persists over the western portion of the state. A high far northeast of Hawaii has an associated ridge extending southwestward, resulting in breezy east to east-southeast flow across the islands. Satellite and radar show low clouds and scattered showers focusing over windward slopes. Trade showers may be enhanced through the weekend as the upper trough slowly tracks eastward across the area. Heavy showers are possible, but breezy trades will ensure any showers will move along quickly, at least over the smaller islands. Strong trades will allow some of these showers to reach leeward areas. East-southeasterly flow produces a shadowing effect west of Maui, a trend that is likely to continue through the weekend. Plume showers may set up and interact with island terrain to trigger longer lived showers along windward slopes.
As the upper trough deepens overhead today and Sunday, temperatures aloft will decrease and lapse rates will steepen, mainly over the eastern end of the state. With the addition of daytime heating, interior portions of the Big Island may see afternoon thunderstorms today and Sunday. For the smaller islands, expect the next three days to be characterized by unstable east- southeast trades with briefly heavy showers, mainly over windward and mauka zones. Expect a return to drier and more stable trade wind weather next week.

Aviation

Breezy easterly trades continue across the state through tonight as an area of high pressure remains anchored north of the region. The trade wind pattern will focus a majority of clouds and showers over windward locations again today, occasionally generating periods of MVFR cigs and vsby. A weak upper level feature moving over the region today will increase moisture and instability, which will enhance thunderstorm chances over the Big Island during this afternoon.
AIRMET Tango for low-level turbulence continues across the islands due to locally gusty easterly trade winds. AIRMET Sierra for tempo mtn obsc continues across portions of the islands again today.

Marine

Moderate to strong trades will continue through the middle of next week, with some slight easing possible Sunday through Monday as a front stalls out several hundred miles northwest of the island chain. The Small Craft Advisory (SCA) has been scaled back to include only the typically windy waters around Maui and the Big Island this morning, and is now in effect until 6 PM this evening. This SCA may need to be extended through Sunday for some of the windy waters around Maui and the Big Island.
The current northwest swell will continue to lower today, with north shore surf dropping to very small heights this afternoon through Sunday. A small west-northwest swell will provide a small boost Monday and Tuesday, with surf then dropping to very small levels again Wednesday and Thursday. A new small northwest swell will bring another boost to north shore surf Friday through next weekend.
The recent period of fresh to strong trades upstream of the islands will keep elevated surf in place along east facing shores through Tuesday. East shore surf will then gradually trend downward from mid to late next week.
Several overlapping south swells will keep south shore surf elevated in the 3 to 5 foot, possibly 4 to 6 foot range tonight through Tuesday. South shore surf will lower to small levels Wednesday through Friday, before trending back up next weekend.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST this evening for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

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Data Courtesy of NOAA.gov