Hilo

Today: Cloudy. Showers in the morning, then numerous showers and isolated thunderstorms in the afternoon. Highs 75 to 84 near the shore to around 68 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 90 percent.

Tonight: Showers. Lows 61 to 70 near the shore to around 55 at 4000 feet. North winds up to 10 mph in the evening becoming light. Chance of rain near 100 percent.

Saturday: Mostly cloudy. Numerous showers in the morning, then scattered showers and isolated thunderstorms in the afternoon. Highs 75 to 84 near the shore to 64 to 69 at 4000 feet. East winds up to 10 mph. Chance of rain 70 percent.

Kona

Today: Mostly sunny with isolated showers in the morning, then mostly cloudy with scattered showers and isolated thunderstorms in the afternoon. Highs 81 to 87 near the shore to around 67 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 around 72 near the shore to 48 to 53 near 5000 feet. Light winds. Chance of rain 40 percent.

Saturday: Mostly sunny in the morning, then mostly cloudy with scattered showers and isolated thunderstorms in the afternoon. Highs 81 to 87 near the shore to around 65 near 5000 feet. Southwest winds up to 10 mph. Chance of rain 50 percent.

Waimea

Today: Mostly cloudy. Numerous showers in the morning, then scattered showers and isolated thunderstorms in the afternoon. Highs 72 to 79 near the shore to 68 to 77 near 3000 feet. East winds up to 15 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy with numerous showers. Lows 61 to 70 near the shore to 54 to 61 near 3000 feet. East winds up to 15 mph. Chance of rain 70 percent.

Saturday: Mostly cloudy. Numerous showers in the morning, then scattered showers and isolated thunderstorms in the afternoon. Highs 72 to 79 near the shore to 67 to 77 near 3000 feet. East winds up to 15 mph. Chance of rain 70 percent.

Kohala

Today: Mostly cloudy. Numerous showers in the morning, then scattered showers and isolated thunderstorms in the afternoon. Highs 72 to 79 near the shore to 68 to 77 near 3000 feet. East winds up to 15 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy with numerous showers. Lows 61 to 70 near the shore to 54 to 61 near 3000 feet. East winds up to 15 mph. Chance of rain 70 percent.

Saturday: Mostly cloudy. Numerous showers in the morning, then scattered showers and isolated thunderstorms in the afternoon. Highs 72 to 79 near the shore to 67 to 77 near 3000 feet. East winds up to 15 mph. Chance of rain 70 percent.

South Big Island

Today: Mostly sunny with isolated showers in the morning, then mostly cloudy with scattered showers and isolated thunderstorms in the afternoon. Highs around 84 near the shore to around 65 near 5000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers in the evening, then mostly clear after midnight. Lows around 73 near the shore to around 52 near 5000 feet. Northeast winds up to 15 mph. Chance of rain 40 percent.

Saturday: Breezy. Sunny in the morning, then partly sunny with isolated showers and thunderstorms in the afternoon. Highs around 83 near the shore to around 63 near 5000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Puna

Today: Cloudy. Showers in the morning, then numerous showers and isolated thunderstorms in the afternoon. Highs 75 to 84 near the shore to around 68 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 90 percent.

Tonight: Showers. Lows 61 to 70 near the shore to around 55 at 4000 feet. North winds up to 10 mph in the evening becoming light. Chance of rain near 100 percent.

Saturday: Mostly cloudy. Numerous showers in the morning, then scattered showers and isolated thunderstorms in the afternoon. Highs 75 to 84 near the shore to 64 to 69 at 4000 feet. East winds up to 10 mph. Chance of rain 70 percent.

Waikoloa

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers and isolated thunderstorms in the afternoon. Highs 82 to 87 near the shore to 64 to 72 above 4000 feet. North winds up to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with isolated showers. Lows around 73 near the shore to 49 to 54 above 4000 feet. East winds up to 10 mph. Chance of rain 20 percent.

Saturday: Sunny in the morning, then partly sunny with isolated showers and thunderstorms in the afternoon. Highs 82 to 87 near the shore to 64 to 71 above 4000 feet. North winds up to 10 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

A high pressure ridge will remain in place north of Hawaii into next week, producing moderate trade winds through the weekend, and then strengthening into the moderate to breezy range from Monday onward. Passing showers are expected to mainly affect windward and mountain areas, favoring the overnight to early morning hours. An upper level low will drift from east to west over the islands this weekend, likely increasing shower activity as it passes through the state. Isolated thunderstorms are possible over the interior Big Island on Friday and Saturday afternoons, and near Kauai this weekend.

Discussion

A band of unstable low clouds will continue to enhance clouds and showers over the islands through the morning and afternoon hours. The water vapor channel satellite imagery continues to show an upper level low roughly 550 miles northeast of Hilo, Hawaii. This low will slowly drift westward across the island chain through the weekend, enhancing trade wind showers as it passes through the state.
Global weather models continue to show a slight weakening of the ridge induced trade winds through the weekend, as the upper low passes over the region. Isolated thunderstorms are possible over the Big Island interior on Friday and Saturday afternoons, and then near Kauai from Saturday night to Sunday.
The ridge north of the island chain will then strengthen after the upper low weakens and drifts away from the islands on Monday, increasing trade winds into the moderate to breezy range from Monday onward. The strengthening ridge will also keep the trade wind thermal inversion at more stable and at lower heights from 5,000 to 6,500 fee next week, limiting shower activity for most of the days.

Aviation

Moderate trades are expected to continue across the island chain through the weekend. Showers and low clouds embedded in the trades will bring brief periods of MVFR conditions over windward and mauka locations. Otherwise, VFR conditions should prevail.
AIRMET Sierra is in effect for tempo mountain obscuration across the windward portions of the island chain early this morning as a band of low clouds and showers moves in from the east. In addition, an upper-level low is forecasted to approach the islands this weekend and is expected to increase shower coverage. As such, AIRMET Sierra may be needed periodically throughout the weekend.

Marine

High pressure north of the state will maintain moderate to fresh trade winds through the weekend. The trades are expected to strengthen back to fresh and strong levels early next week, and a Small Craft Advisory will likely be required for the typically windy waters around Maui and the Big Island.
A series of south swells will keep south shore surf near the summertime average through Saturday. Surf will lower below normal levels much of next week.
Typical mostly flat summertime conditions will continue along prevail north facing shores through late next week.
East shore surf will remain well below normal through the weekend, then trend up and closer to seasonal levels next week as the trades strengthen over and upstream of the islands.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov