West Side

Today: Mostly sunny. Breezy. Highs 78 to 91. East winds up to 20 mph shifting to the northeast 10 to 20 mph in the afternoon.

Tonight: Partly cloudy. Breezy. Lows 69 to 77. East winds 10 to 20 mph.

Wednesday: Mostly sunny with isolated showers. Highs 77 to 89. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

South Side

Today: Sunny and breezy. Highs 79 to 92. North winds up to 20 mph shifting to the northeast 10 to 20 mph in the afternoon.

Tonight: Partly cloudy. Breezy. Lows 71 to 77. North winds 10 to 20 mph.

Wednesday: Mostly sunny. Breezy. Highs 78 to 91. North winds 10 to 20 mph.

North Shore

Today: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 83 to 89 near the shore to around 71 near 5000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with isolated showers. Lows around 73 near the shore to around 54 near 5000 feet. Southeast winds up to 15 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 82 to 89 near the shore to around 70 near 5000 feet. East winds up to 15 mph shifting to the northeast in the afternoon. Chance of rain 40 percent.

Central Maui

Today: Mostly sunny. Breezy. Highs 83 to 91. Northeast winds up to 20 mph increasing to 15 to 20 mph in the afternoon.

Tonight: Partly cloudy. Breezy. Lows around 72. Northeast winds 10 to 20 mph.

Wednesday: Mostly sunny. Breezy. Highs 82 to 89. Northeast winds 10 to 20 mph.

Upcountry

Today: Breezy. Mostly sunny with isolated showers. Highs 56 to 76. East winds up to 20 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Breezy. Lows around 52 at the visitor center to around 49 at the summit. East winds up to 20 mph.

Wednesday: Mostly sunny. Highs 56 to 75. Northeast winds up to 15 mph.

East Maui

Today: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 83 to 89 near the shore to around 71 near 5000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with isolated showers. Lows around 73 near the shore to around 54 near 5000 feet. Southeast winds up to 15 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 82 to 89 near the shore to around 70 near 5000 feet. East winds up to 15 mph shifting to the northeast in the afternoon. Chance of rain 40 percent.

Lanai City

Today: Mostly sunny. Breezy. Isolated showers in the morning. Highs 74 to 84. Northeast winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy. Breezy. Lows 65 to 70. Northeast winds 10 to 20 mph.

Wednesday: Mostly sunny. Breezy. Isolated showers in the morning. Highs 73 to 83. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Kaunakakai

Today: Mostly sunny. Breezy. Highs 75 to 92. Northeast winds 10 to 20 mph.

Tonight: Partly cloudy. Lows 62 to 76. Northeast winds 10 to 15 mph.

Wednesday: Mostly sunny. Highs 74 to 91. Northeast winds 10 to 15 mph.

Detailed Forecast

Synopsis

A high pressure ridge building back in across the Hawaiian Islands will bring increasing trade winds to the region. Trade winds will blow into the moderate to locally breezy range through Wednesday. A low level trough will weaken the trade winds and increase shower activity from Thursday Gentle to moderate trades will build back tonight, but warm and muggy conditions continue. A low level trough drifting westward across the state will decrease trade wind speeds and bring increasing clouds and showers from Thursday through Friday. High pressure will build back in across the region will bring a return to moderate to locally breezy trade winds through early next week.

Discussion

Satellite imagery this morning shows easterly trade winds returning with bands of stable stratocumulus clouds riding into the windward slopes of each island. The strong ridge aloft will cap these clouds and limit shower activity in the isolated to scattered range through Wednesday, as clouds and showers will tend to favor the windward and mountain areas during the overnight to early morning hours. Trade winds will strengthen into the moderate to locally breezy range through Wednesday.
By Thursday and Friday the weather pattern changes as an easterly wave drifting in on the easterly trade winds moves into the eastern islands. Trade winds will decrease and local scale island heating will drive afternoon upsloping sea breezes across the state. Clouds and showers will increase from east to west across the island chain as dynamics associated with the passing trough lift subsidence temperature inversion heights to around 8,000 feet through Friday night.
This trough in the easterlies will drift away from the islands late Friday with the ridge building back into the region, bringing more stable weather conditions and increasing trade winds back into the moderate to locally breezy range from Saturday onward into early next week.

Aviation

Moderate to locally breezy trade winds will return today and Wednesday with mainly VFR conditions expected. Brief passing showers are possible mainly over windward and mountain areas.
No AIRMETs are currently in effect.

Marine

A weak ridge axis extending south from parent high pressure over the north Pacific is becoming established over the islands as Hurricane Henriette continues to move far north of the islands. Moderate to locally strong trade winds will build across the island chain through mid-week. A Small Craft Advisory (SCA) has been issued for the windier waters and channels around Maui County and the Big Island through Wednesday afternoon. A weak surface trough then advances westward across the state resulting in a brief period of light easterlies which may be variable at times on Thursday. Locally fresh trades then builds across area waters Friday into the weekend.
The current south swell will continue to gradually decline through the middle of the week. A small long period south swell is expected to fill in by Saturday to bring surf heights back up for the weekend.
Surf along east facing shores will see a slight uptick through Wednesday, before declining slightly Thursday and Friday. Short period chop increases this weekend again as stronger trades develop. Surf along north facing shores will remain tiny through the forecast period.

Fire weather

Weather conditions will likely remain below critical fire weather conditions this week as wind speeds and humidity levels will remain just below critical thresholds. Drier and more stable trade winds will return from Saturday onward into early next week. Temperature inversion heights today near Maui and the Big Island will range from 5,000 to 6,000 feet.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Wednesday for windier waters and channels near Maui and the Big Island.

Data Courtesy of NOAA.gov