Hilo

Tonight: Mostly cloudy with numerous showers. Lows 63 to 70 near the shore to 50 to 58 at 4000 feet. North winds up to 10 mph. Chance of rain 70 percent.

Saturday: Cloudy with numerous showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 78 to 84 near the shore to around 66 at 4000 feet. East winds up to 10 mph. Chance of rain 70 percent.

Saturday Night: Mostly cloudy. Numerous showers in the evening, then scattered showers after midnight. Lows 63 to 69 near the shore to 50 to 57 at 4000 feet. East winds up to 10 mph. Chance of rain 70 percent.

Kona

Tonight: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Lows around 73 near the shore to 49 to 54 near 5000 feet. Light winds. Chance of rain 50 percent.

Saturday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 85 near the shore to around 67 near 5000 feet. Light winds. Chance of rain 50 percent.

Saturday Night: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Lows around 73 near the shore to around 51 near 5000 feet. Light winds. Chance of rain 50 percent.

Waimea

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Breezy. Scattered showers. Lows 62 to 71 near the shore to 55 to 62 near 3000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Saturday: Breezy. Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs around 80 near the shore to 68 to 78 near 3000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Saturday Night: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows 63 to 70 near the shore to 55 to 62 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Kohala

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Breezy. Scattered showers. Lows 62 to 71 near the shore to 55 to 62 near 3000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Saturday: Breezy. Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs around 80 near the shore to 68 to 78 near 3000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Saturday Night: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows 63 to 70 near the shore to 55 to 62 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

South Big Island

Tonight: Mostly clear. Breezy. Isolated showers in the evening. Lows around 73 near the shore to around 53 near 5000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Saturday: Mostly sunny. Breezy. Isolated showers in the afternoon. Highs around 86 near the shore to around 65 near 5000 feet. East winds up to 25 mph. Chance of rain 20 percent.

Saturday Night: Partly cloudy. Isolated showers in the evening. Lows around 72 near the shore to around 52 near 5000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Puna

Tonight: Mostly cloudy with numerous showers. Lows 63 to 70 near the shore to 50 to 58 at 4000 feet. North winds up to 10 mph. Chance of rain 70 percent.

Saturday: Cloudy with numerous showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 78 to 84 near the shore to around 66 at 4000 feet. East winds up to 10 mph. Chance of rain 70 percent.

Saturday Night: Mostly cloudy. Numerous showers in the evening, then scattered showers after midnight. Lows 63 to 69 near the shore to 50 to 57 at 4000 feet. East winds up to 10 mph. Chance of rain 70 percent.

Waikoloa

Tonight: Mostly clear. Breezy. Scattered showers in the evening. Lows around 73 near the shore to around 53 above 4000 feet. East winds up to 20 mph. Chance of rain 30 percent.

Saturday: Mostly sunny. Isolated showers in the afternoon. Highs 84 to 90 near the shore to 64 to 72 above 4000 feet. Northeast winds up to 15 mph. Chance of rain 20 percent.

Saturday Night: Partly cloudy with isolated showers. Lows around 73 near the shore to 50 to 55 above 4000 feet. Light winds. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Moderate to locally breezy trade winds will persist through Saturday then weaken and veer out of the east-southeast Sunday into early next week as a broad, weak trough develops and moves across the area. The lighter flow may allow for some isolated sea breeze showers across leeward areas, in addition to the typical windward and mauka showers. Midweek and beyond, the high to our northeast will gradually build and bring breezy trades to the area by next weekend.

Discussion

Radar and satellite imagery show a few clouds and showers continuing to filter in on the moderate to locally breezy trades this afternoon, with most of the showers focusing over the eastern end of the state. In addition, diurnal heating caused clouds and showers to build over the Kona slopes of the Big Island throughout the day, as is typical for this time of year. Some wispy high cirrus clouds can also be seen streaming across the island chain from the west-southwest, which may help create another beautiful Hawaiian sunset this evening.
Over the weekend and into early next week a surface ridge will remain centered to the far northeast of the state, maintaining moderate to locally breezy trades. Stability will increase as mid level ridging tries to settle over the state from the east. However, a series of upper level lows and troughs will keep an area of upper level troughing to the northwest of the state. This will translate to weak broad troughing developing at the surface over or just north of the state later this weekend into early next week, which will cause the low level flow to weaken and veer out of the east-southeast. The instability provided by this weak troughing over/near the state combined with pockets of moisture moving in on the trades may be enough to enhance windward and mauka showers during the overnight hours with some spillage over into interior and leeward areas, and to help some clouds and showers build over island interiors and leeward areas in the afternoons where any sea breezes manage to develop in the lighter flow. However, mid level ridging will still be present over the majority of the state, despite the upper lows'/troughs' efforts to penetrate in from the northwest…so not expecting a major uptick in shower activity as the weak surface trough moves across from the east.
By midweek, the surface trough will move west of the state and dampen out. With high pressure remaining to the northeast, the low level flow will back out of the east and strengthen to moderate to locally breezy levels. Then heading into next weekend, the surface high to our northeast will build, strengthening the local pressure gradient and bringing breezy easterly trades across the island chain. Overall, typical trade wind weather can be expected through the second half of the week with periods of windward and mauka showers.

Aviation

Breezy and stable trade wind weather will continue to persist through Saturday. A pocket of moisture continues to linger over the eastern half of the state this afternoon, which are producing brief MVFR conditions with the heavier showers. Conditions should gradually improve this evening, but some brief periods of MVFR conditions will remain possible with any showers. Mostly dry conditions are expected on Saturday, with the exception of some scattered showers over windward Kauai and windward Big Island.
AIRMET Tango remains in effect for low-level lee turb. AIRMET Sierra remains in effect for windward Maui due to clouds and showers. This AIRMET should be cancelled sometime tonight as showers decrease over windward Maui.

Marine

Moderate to locally breezy trade winds are expected through at least Saturday as high pressure remains in place far northeast of the main Hawaiian Islands. A Small Craft Advisory has been extended for the typical windier waters and channels around Maui and the Big Island through the day on Saturday. However, early next week, a disturbance passing to the north of the islands may weaken the trades a bit as they veer to become slightly east- southeast.
South shore surf will remain near current levels through the first half of the weekend as the current south swell declines but a tiny long-period reinforcement arrives early Saturday morning. Guidance remains in good agreement that a small, long-period south swell will arrive late Sunday into Monday. This swell is expected to boost south shore surf up to near the summertime average, peaking on Monday and then declining through much of next week.
Surf along east shores will remain rough and choppy for the next couple of days due to the locally breezy trades. Surf along north facing shores will remain tiny throughout the next week.

HFO Watches/Warnings/Advisories

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

Data Courtesy of NOAA.gov