Photo Credit: Randy Alona Gallegos

West Side

Today: Sunny. Highs 78 to 89. East winds 10 to 15 mph.

Tonight: Mostly clear. Lows 69 to 76. East winds 10 to 15 mph decreasing to up to 10 mph after midnight.

Friday: Sunny. Highs 79 to 91. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon.

South Side

Today: Sunny. Highs around 88. North winds up to 15 mph increasing to 10 to 15 mph in the afternoon.

Tonight: Clear. Lows 69 to 75. North winds 10 to 15 mph shifting to the northwest after midnight.

Friday: Sunny. Isolated showers in the afternoon. Highs around 90. Northwest winds 10 to 15 mph. Chance of rain 20 percent.

North Shore

Today: Mostly sunny with isolated showers. Highs 76 to 85 near the shore to around 68 near 5000 feet. East winds 10 to 15 mph decreasing to up to 15 mph in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows around 71 near the shore to 50 to 56 near 5000 feet. Southeast winds up to 15 mph becoming around 10 mph after midnight. Chance of rain 40 percent.

Friday: Mostly sunny in the morning then becoming partly sunny. Breezy. Scattered showers. Highs 77 to 87 near the shore to around 68 near 5000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Central Maui

Today: Sunny. Highs 82 to 90. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon.

Tonight: Mostly clear. Lows around 71. Northeast winds 10 to 15 mph shifting to the south after midnight.

Friday: Sunny and breezy. Highs 84 to 92. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon.

Upcountry

Today: Sunny. Isolated showers in the afternoon. Highs around 63 at the visitor center to around 57 at the summit. East winds up to 10 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Lows around 48 at the visitor center to around 43 at the summit. Southeast winds up to 10 mph.

Friday: Sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs around 64 at the visitor center to around 59 at the summit. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 40 percent.

East Maui

Today: Mostly sunny with isolated showers. Highs 76 to 85 near the shore to around 68 near 5000 feet. East winds 10 to 15 mph decreasing to up to 15 mph in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows around 71 near the shore to 50 to 56 near 5000 feet. Southeast winds up to 15 mph becoming around 10 mph after midnight. Chance of rain 40 percent.

Friday: Mostly sunny in the morning then becoming partly sunny. Breezy. Scattered showers. Highs 77 to 87 near the shore to around 68 near 5000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Lanai City

Today: Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs 73 to 81. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening. Lows 63 to 68. Northeast winds up to 15 mph. Chance of rain 20 percent.

Friday: Sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs 74 to 83. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 40 percent.

Kaunakakai

Today: Mostly sunny. Isolated showers in the afternoon. Highs 70 to 91. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Isolated showers in the evening. Lows 60 to 75. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Friday: Mostly sunny. Isolated showers in the afternoon. Highs 72 to 92. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Locally breezy trade winds will ease today as the ridge north of the state weakens. Limited shower activity will favor windward areas this morning, with increasing moisture and instability enhancing showers later today and Friday. A return to breezy trade winds, and somewhat dry and stable weather, is due this weekend, with lighter trades during the middle of next week.

Discussion

No major changes to the forecast with the morning package. In the short term, things seem to be on track, and no surprises in the models for the long term.
A ridge to the north of the islands will be disrupted today and tomorrow by a surface trough to the east of the islands. As the trough dissipates and moves west of the islands, the ridge will build back in, allowing trade winds to strengthen this weekend.
Satellite derived precipitable water (PW) shows a dry atmosphere over the region. An upper level trough digging southward towards the west end of the state will help to maintain a few showers over Kauai, but otherwise expect continued minimal rainfall over windward slopes of the smaller islands tonight, with leeward areas expected to be dry. The upper level trough could trigger an isolated heavier shower around the Garden Isle, mainly over interior and leeward areas this afternoon. The overnight sounding from Lihue showed no trade wind inversion, lending confidence in the possibility of a heavier shower this afternoon.
Heading into Friday, the weaker trades will continue, and the upper level trough will linger nearby. Some additional low level moisture, associated with the surface trough to the east, could help to produce an isolated heavy shower over windward areas and across leeward terrain in the afternoon. Confidence in this scenario remains low, but humidity levels will rise, as dew points are expected to increase into the lower 70s.
A stable and breezy trade wind regime will return during the weekend. The upper level trough and the surface trough will move off to the west, allowing ridging at the surface and aloft to dominate. Expect drier weather with modest showers confined to windward slopes. Aside from a few afternoon showers over North and South Kona slopes of the Big Island, leeward areas will be dry, and the breezy condition could bring fire weather concerns into Monday. Long term guidance suggests a drop in trade winds Tuesday and next Wednesday.

Aviation

Trade winds will continue to diminish across the islands today, as high pressure far north of the region weakens. Showers and clouds will remain limited through tonight, as generally dry and stable conditions continues. However, an upper trough settling west of the islands, will continue to slightly enhance rainfall chances and areal coverage across Kauai through tonight. Diurnally driven sea breeze circulations are expected to develop again today, allowing for a few afternoon showers across leeward locations. VFR conditions are expected through the TAF period, with isolated heavier showers and brief MVFR cigs drifting across Kauai at times through tonight.
Currently there are no AIRMETs in effect. However, there is a potential period of tempo moderate turbulence above FL340 developing near Kauai into this afternoon as upper dynamics slowly increase in the region. Currently these turbulent conditions are expected to remain below AIRMET criteria.

Marine

A weak surface trough remains roughly 250 NM east of Hilo, Hawaii moving westward. This trough is moving through the northeast offshore waters today, drifting slowly through the region reducing trade wind speeds through Friday. High pressure will build in from the east on Saturday with moderate to strong trade winds returning to the region. Expect Small Craft Advisory conditions over the windier eastern waters and channels on Saturday and Sunday.
The forerunners from a new long-period south swell (190 degrees) are expected to arrive later this afternoon. This swell will likely continue to build through tonight, and it is expected to peak on Friday, and then hold into Saturday. The surf heights may briefly approach the High Surf Advisory thresholds along south facing shores during the peak of this event. This south swell will slowly lower on Sunday and will be reinforced by a smaller south swell by Monday.
Modest, choppy surf along east facing shores will ease as the trades weaken through Friday. Surf heights will gradually increase along east facing shores from Saturday into early next week as the trades strengthen. Finally, nearly flat summertime conditions will persist along most north facing shores through early next week.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov