Photo Credit: James Grenz

Hilo

Today: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 79 to 86 near the shore to 65 to 72 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 30 percent.

Tonight: Partly cloudy with isolated showers in the evening, then mostly cloudy with scattered showers after midnight. Lows 62 to 72 near the shore to around 58 at 4000 feet. North winds up to 10 mph shifting to the west after midnight. Chance of rain 50 percent.

Sunday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 80 to 87 near the shore to 65 to 72 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Kona

Today: Mostly sunny with isolated showers. Highs 83 to 88 near the shore to around 71 near 5000 feet. West winds up to 10 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows around 73 near the shore to 54 to 59 near 5000 feet. Northeast winds up to 10 mph in the evening becoming light. Gusts up to 35 mph. Chance of rain 20 percent.

Sunday: Sunny in the morning then becoming partly sunny. Isolated showers. Highs 83 to 88 near the shore to 69 to 74 near 5000 feet. Light winds. Gusts up to 35 mph in the morning. Chance of rain 20 percent.

Waimea

Today: Breezy. Mostly sunny with isolated showers. Highs 65 to 86. East winds 10 to 25 mph. Chance of rain 20 percent.

Tonight: Breezy. Partly cloudy with isolated showers. Lows 63 to 72 near the shore to 56 to 62 near 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Sunday: Breezy. Mostly sunny with isolated showers. Highs around 81 near the shore to 70 to 80 near 3000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 20 percent.

Kohala

Today: Breezy. Mostly sunny with isolated showers. Highs 65 to 86. East winds 10 to 25 mph. Chance of rain 20 percent.

Tonight: Breezy. Partly cloudy with isolated showers. Lows 63 to 72 near the shore to 56 to 62 near 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Sunday: Breezy. Mostly sunny with isolated showers. Highs around 81 near the shore to 70 to 80 near 3000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 20 percent.

South Big Island

Today: Sunny and windy. Isolated showers in the afternoon. Highs around 85 near the shore to around 69 near 5000 feet. East winds up to 30 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Windy. Lows around 74 near the shore to around 56 near 5000 feet. Northeast winds 10 to 30 mph.

Sunday: Sunny and breezy. Isolated showers in the afternoon. Highs around 86 near the shore to around 70 near 5000 feet. East winds up to 25 mph becoming 10 to 20 mph in the afternoon. Chance of rain 20 percent.

Puna

Today: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 79 to 86 near the shore to 65 to 72 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 30 percent.

Tonight: Partly cloudy with isolated showers in the evening, then mostly cloudy with scattered showers after midnight. Lows 62 to 72 near the shore to around 58 at 4000 feet. North winds up to 10 mph shifting to the west after midnight. Chance of rain 50 percent.

Sunday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 80 to 87 near the shore to 65 to 72 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Waikoloa

Today: Sunny and breezy. Highs 84 to 91 near the shore to 67 to 74 above 4000 feet. Northeast winds up to 20 mph.

Tonight: Mostly clear. Breezy. Lows around 74 near the shore to 54 to 59 above 4000 feet. Southeast winds up to 20 mph.

Sunday: Sunny. Isolated showers in the afternoon. Highs 85 to 90 near the shore to 67 to 74 above 4000 feet. Northeast winds up to 15 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Fresh trade winds with limited windward showers and rather dry leeward conditions will continue through next week.

Discussion

A 1034 mb high far north of the state is driving fresh trade winds. Infrared satellite imagery and radar show showery low clouds moving in from upstream of the smaller islands. These showers are mostly impacting windward and mountain areas and will likely linger into around midday. Soundings from Lihue and Hilo show a dry, stable air mass has moved over the state with precipitable water values just over an inch.
The overall pattern changes very little through the next week with only minor fluctuations in trade wind speeds and a continued stable atmosphere. Mostly sunny/clear conditions expected leeward, while partly cloudy skies and few passing showers windward and mauka. Any passing showers are most likely to occur during the nighttime and early morning hours. However, daytime heating will lead to sea breeze development along the Kona slopes of the Big Island will cause clouds and a few showers each afternoon.

Aviation

A high pressure ridge far north of the Hawaiian Islands will keep moderate to locally breezy trade winds in the forecast through Sunday. Brief periods of showers are possibly especially during the overnight to early morning hours. VFR conditions will prevail outside of showers.
AIRMET Tango remains in effect for moderate low level turbulence over and downwind of island mountains. Conditions are expected to continue through Sunday.

Marine

Fresh to strong easterly trade winds will continue through the upcoming week as high pressure remains positioned far north of the area.
Surf along east facing shores will remain rough and choppy each day due to the persistent fresh onshore breezes. Wave guidance shows the peak period holding around 6-7 seconds through much of the upcoming week.
Surf along south facing shores will remain at background levels through the weekend, then trend up Sunday night through early next week as a long-period southwest swell from the Tasman Sea arrives and moves through. Observations at the American Samoa PacIOOS buoy reflect this new southwest source this morning with the peak energy centered around the 16-18s band (3 ft). This will result in a building trend through the day Monday given the expected travel time, before peaking sometime between Tuesday and midweek. A return of smaller surf with mainly background southerly sources is expected late next week.
As we head into August, water levels are running higher than predicted (0.3 to 0.5 ft), which will lead to minor coastal flooding concerns through the afternoon periods around the peak daily high tides Sunday afternoon through early next week. This combined with a small long-period southwest swell peaking will lead to minor flooding of beaches that normally remain dry, low- lying roads, docks, boat ramps, marina parking lots, and other coastal infrastructure.

HFO Watches/Warnings/Advisories

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

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Data Courtesy of NOAA.gov