West Side

Today: Partly sunny. Breezy. Isolated showers in the morning. Highs 80 to 85. Northeast winds 10 to 20 mph shifting to the east up to 20 mph in the afternoon. Chance of rain 20 percent.

Tonight: Breezy. Partly cloudy with isolated showers. Lows 67 to 74. Northeast winds 10 to 20 mph shifting to the east up to 20 mph after midnight. Chance of rain 20 percent.

Sunday: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs 80 to 85. East winds up to 15 mph shifting to the south in the afternoon. Chance of rain 20 percent.

South Side

Today: Partly sunny. Breezy. Highs around 88. North winds up to 20 mph increasing to 10 to 20 mph in the afternoon.

Tonight: Partly cloudy. Lows 67 to 75. Northwest winds up to 10 mph.

Sunday: Mostly sunny in the morning then becoming partly sunny. Highs around 89. Northwest winds up to 10 mph shifting to the west in the afternoon.

North Shore

Today: Mostly cloudy. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 79 to 85 near the shore to around 67 near 5000 feet. East winds up to 20 mph. Chance of rain 70 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 71 near the shore to 48 to 53 near 5000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Sunday: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 79 to 85 near the shore to around 68 near 5000 feet. East winds up to 20 mph. Chance of rain 70 percent.

Central Maui

Today: Partly sunny. Breezy. Isolated showers in the morning. Highs 81 to 89. Northeast winds 10 to 25 mph shifting to the east up to 25 mph in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy. Lows 66 to 71. East winds up to 15 mph. Gusts up to 35 mph.

Sunday: Mostly sunny with isolated showers in the morning, then partly sunny in the afternoon. Highs 82 to 89. East winds up to 15 mph. Chance of rain 20 percent.

Upcountry

Today: Mostly cloudy with scattered showers. Highs around 64 at the visitor center to around 70 at the summit. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows 42 to 54. East winds up to 15 mph. Chance of rain 50 percent.

Sunday: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Highs around 64 at the visitor center to around 67 at the summit. Southeast winds up to 10 mph. Chance of rain 50 percent.

East Maui

Today: Mostly cloudy. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 79 to 85 near the shore to around 67 near 5000 feet. East winds up to 20 mph. Chance of rain 70 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 71 near the shore to 48 to 53 near 5000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Sunday: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 79 to 85 near the shore to around 68 near 5000 feet. East winds up to 20 mph. Chance of rain 70 percent.

Lanai City

Today: Breezy. Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs 73 to 80. Northeast winds 10 to 20 mph decreasing to up to 20 mph in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy. Lows around 65. Northeast winds up to 15 mph in the evening becoming light.

Sunday: Mostly sunny in the morning, then mostly cloudy with isolated showers in the afternoon. Highs 73 to 80. Light winds becoming north up to 10 mph in the afternoon. Chance of rain 20 percent.

Kaunakakai

Today: Mostly sunny. Breezy. Isolated showers in the morning. Highs 72 to 89. East winds 15 to 20 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Breezy. Lows 60 to 73. East winds up to 20 mph.

Sunday: Mostly sunny with isolated showers in the morning, then partly sunny in the afternoon. Highs 73 to 89. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Moderate to locally breezy trade winds will persist today 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

High pressure systems far northwest and northeast of Hawaii will maintain breezy trade winds today. Incoming low clouds and showers will focus across windward Kauai and Big Island this morning, likely decreasing over these areas around midday. Mostly dry conditions will persist across the rest of the state, but any clouds and showers that do move in will impact windward areas. Cirrus clouds filled in last night, but expecting these to move off to the east this morning. Leeward clouds from the daytime sea breezes will impact the Kona slopes on the Big Island this afternoon.
Sunday into Monday, a board low level trough will develop over the islands as the high pressure systems become separated by front in the North Central Pacific. Winds will weaken and veer east southeasterly and guidance depicts an uptick in clouds and showers tracking in from the 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. A typical summertime upper trough near the state and above the low/midlevel trade wind inversion may contribute to some shower enhancement before the surface trough and associated moisture clears the islands to the west Monday night.
Winds will remain lighter into Tuesday. The trades will build in Wednesday with a band of moisture from an old front that will track in from the east Wednesday night and Thursday. 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 today. Brief MVFR ceilings and visibility possible with incoming windward showers. AIRMET Sierra is in effect for tempo mountain obscurationsfor windward sides of Kauai and the Big Island above 2500 feet likely continuing through the morning. Mostly dry and VFR conditions are expected elsewhere today. AIRMET Tango remains in effect for low-level lee turbulence caused by the breezy and stable trade winds.

Marine

Moderate to locally breezy trades are expected through at least Saturday as high pressure remains in place far northeast of the islands. A Small Craft Advisory has been extended for the typical windier waters and channels around Maui and the Big Island through Sunday 6AM. 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.
A tiny long-period reinforcement south swell should arrive this 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 AM HST Sunday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov