West Side

Tonight: Partly cloudy. Isolated showers in the evening. Lows 67 to 73. East winds up to 15 mph. Chance of rain 20 percent.

Thursday: Sunny and breezy. Highs 78 to 83. East winds up to 20 mph shifting to the northeast 10 to 20 mph in the afternoon.

Thursday Night: Mostly clear. Breezy. Lows 67 to 73. East winds 10 to 20 mph.

South Side

Tonight: Partly cloudy. Isolated showers in the evening. Lows 65 to 75. Light winds becoming northwest up to 10 mph after midnight. Chance of rain 20 percent.

Thursday: Sunny. Highs around 86. North winds up to 15 mph shifting to the northeast in the afternoon.

Thursday Night: Mostly clear. Lows 64 to 74. Northeast winds up to 15 mph.

North Shore

Tonight: Partly cloudy with scattered showers. Lows around 69 near the shore to around 50 near 5000 feet. Southeast winds up to 15 mph. Chance of rain 50 percent.

Thursday: Breezy. Mostly sunny with scattered showers. Highs 78 to 83 near the shore to around 66 near 5000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Thursday Night: Breezy. Mostly cloudy with scattered showers. Lows around 69 near the shore to around 50 near 5000 feet. Southeast winds up to 20 mph. Chance of rain 50 percent.

Central Maui

Tonight: Partly cloudy. Isolated showers in the evening. Lows around 67. East winds up to 10 mph. Chance of rain 20 percent.

Thursday: Sunny and breezy. Highs 81 to 87. Northeast winds up to 20 mph increasing to 15 to 25 mph in the afternoon.

Thursday Night: Partly cloudy. Breezy. Lows around 67. East winds 10 to 20 mph.

Upcountry

Tonight: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Lows around 45 at the visitor center to around 42 at the summit. East winds up to 15 mph. Chance of rain 50 percent.

Thursday: Mostly sunny. Breezy. Isolated showers in the morning. Highs around 61 at the visitor center to around 65 at the summit. East winds up to 20 mph. Chance of rain 20 percent.

Thursday Night: Partly cloudy in the evening then becoming mostly cloudy. Breezy. Scattered showers. Lows around 44 at the visitor center to around 46 at the summit. East winds up to 20 mph. Chance of rain 50 percent.

East Maui

Tonight: Partly cloudy with scattered showers. Lows around 69 near the shore to around 50 near 5000 feet. Southeast winds up to 15 mph. Chance of rain 50 percent.

Thursday: Breezy. Mostly sunny with scattered showers. Highs 78 to 83 near the shore to around 66 near 5000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Thursday Night: Breezy. Mostly cloudy with scattered showers. Lows around 69 near the shore to around 50 near 5000 feet. Southeast winds up to 20 mph. Chance of rain 50 percent.

Lanai City

Tonight: Mostly cloudy with scattered showers in the evening, then mostly clear after midnight. Lows around 65. Light winds. Chance of rain 50 percent.

Thursday: Sunny and breezy. Highs 73 to 81. Northeast winds up to 15 mph increasing to 10 to 20 mph in the afternoon.

Thursday Night: Mostly clear. Breezy. Lows 62 to 67. Northeast winds 10 to 20 mph.

Kaunakakai

Tonight: Partly cloudy. Isolated showers in the evening. Lows 57 to 73. East winds up to 10 mph. Chance of rain 20 percent.

Thursday: Sunny and breezy. Highs 70 to 86. East winds 10 to 20 mph.

Thursday Night: Mostly clear. Breezy. Lows 57 to 73. East winds 10 to 20 mph.

Detailed Forecast

Synopsis

Strengthening trade winds will be locally breezy into next week. Brief showers will favor windward and mauka areas, and leeward areas will be mostly dry.

Discussion

A persistent trough NW of Kauai will weaken and move W while strengthening high pressure will pass well N of the islands. Trade wind speeds will continue to increase, with locally breezy E winds expected into the weekend. Some subtle weakening and veering in wind direction (to the ESE) may occur late this weekend as the high moves far NE of the islands, and a front passes to the NW. Early next week, a new, strong high is expected to build well N of the islands as the front stalls, leading to increased trade wind speeds.
Troughing aloft will continue to move E and away from the islands, with a building mid-level ridge leading to increased stability. As a result, just a few brief windward showers are expected through the weekend. Weak troughing aloft may return next week, potentially leading to an increase in windward showers. Leeward areas will start the dry season with limited rainfall, except for a few afternoon showers over the Kona slopes.
In the short term, limited windward showers are expected overnight, except over windward Big Island, where a clump of showery low clouds arriving on the trades will make for a wet evening in many areas.

Aviation

Trade winds have started to develop across the state this evening and look to prevail through the forecast period. VFR conditions will prevail with spotty MVFR conditions focusing clouds and showers over windward and mauka areas.
AIRMET Sierra has been issued for mountain obscuration for windward Big Island. Conditions are expected to improve through late tonight as winds shift from onshore to offshore.
No other AIRMETs are in effect.

Marine

High pressure approximately 1,200 nautical miles northwest of the islands will travel east and be north of the state by late Thursday…northeast of the area this weekend. The pressure gradient between the high and lower equatorial pressure will be tight enough to produce high end moderate/fresh to locally strong trade winds from as early as Thursday afternoon through most of next week. Several days of Small Craft Advisory (SCA) level winds will occur over the notoriously windier channels and bays surrounding Maui County and south of Big Island that will commence Thursday.
A relatively small size, moderate to long period north northwest swell has arrived at the far northwest buoys this afternoon and will be passing around the islands through the early Thursday morning hours. This swell will peak late Thursday then slowly decline this weekend. A series of northwest to north swells are expected next week that should produce near or above seasonal average (6 foot) surf.
A small, long period south southwest swell will continue to fill in tonight and peak Thursday into Friday. This latest swell will result in above summer average surf heights before slowly fading this weekend. A mix of both a reinforcing south southwest swell and new long period south southeast swell energy this weekend should this near to above average (5 foot) surf. South-facing shore surf will generally decline next week, but smaller south southwest swells will hold surf near summer averages through the middle of next week.
Recent upstream trade winds will keep east-facing shore surf on the small side. An increase in east wind wave chop is expected on Friday as the trade winds pick up a notch over and upstream of the state.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov