West Side

Today: Sunny with isolated showers. Highs 81 to 88. Northeast winds up to 15 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Isolated showers in the evening. Lows 73 to 79. Northeast winds 10 to 15 mph decreasing to up to 15 mph after midnight. Chance of rain 20 percent.

Wednesday: Breezy. Mostly sunny with isolated showers. Highs 81 to 88. Northeast winds up to 25 mph increasing to 10 to 25 mph in the afternoon. Chance of rain 20 percent.

South Side

Today: Sunny and breezy. Highs around 90. North winds up to 15 mph increasing to 10 to 20 mph in the afternoon.

Tonight: Mostly clear. Lows 73 to 82. North winds up to 15 mph.

Wednesday: Mostly sunny. Breezy. Isolated showers in the afternoon. Highs around 91. North winds 10 to 25 mph. Chance of rain 20 percent.

North Shore

Today: Partly sunny with scattered showers. Highs around 83 near the shore to around 70 near 5000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows around 75 near the shore to around 60 near 5000 feet. Southeast winds up to 15 mph. Chance of rain 70 percent.

Wednesday: Mostly cloudy. Numerous showers in the morning, then frequent showers in the afternoon. Highs around 83 near the shore to around 71 near 5000 feet. East winds up to 15 mph. Chance of rain 80 percent.

Central Maui

Today: Sunny and breezy. Isolated showers in the morning. Highs 83 to 90. Northeast winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening. Lows around 75. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Wednesday: Breezy. Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 83 to 91. Northeast winds 10 to 20 mph. Chance of rain 50 percent.

Upcountry

Today: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 64 to 83. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with scattered showers. Lows around 57 at the visitor center to around 49 at the summit. East winds up to 15 mph. Chance of rain 50 percent.

Wednesday: Mostly sunny in the morning then becoming partly sunny. Breezy. Scattered showers. Highs 66 to 84. East winds up to 15 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

East Maui

Today: Partly sunny with scattered showers. Highs around 83 near the shore to around 70 near 5000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows around 75 near the shore to around 60 near 5000 feet. Southeast winds up to 15 mph. Chance of rain 70 percent.

Wednesday: Mostly cloudy. Numerous showers in the morning, then frequent showers in the afternoon. Highs around 83 near the shore to around 71 near 5000 feet. East winds up to 15 mph. Chance of rain 80 percent.

Lanai City

Today: Mostly sunny. Breezy. Isolated showers in the afternoon. Highs 75 to 84. Northeast winds up to 15 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 20 percent.

Tonight: Mostly clear. Breezy. Lows 70 to 75. Northeast winds 10 to 20 mph.

Wednesday: Mostly sunny. Breezy. Isolated showers in the afternoon. Highs 79 to 85. Northeast winds 10 to 25 mph. Chance of rain 20 percent.

Kaunakakai

Today: Mostly sunny. Isolated showers in the afternoon. Highs 72 to 91. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 20 percent.

Tonight: Mostly clear. Lows 65 to 79. Northeast winds 10 to 15 mph.

Wednesday: Mostly sunny. Breezy. Isolated showers in the afternoon. Highs 78 to 90. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Light to moderate trades will strengthen through Wednesday. Moisture from the remains of Norbert should move through the islands Wednesday night through Friday morning as trades strengthen to moderate to fresh levels. Drier air will move back in this weekend as trades continue. Moisture from the remnants of tropical depression 15-E may bring another round of enhanced showers early next week.

Discussion

Radar and satellite show showers mainly offshore to the north of Maui County and Oahu this morning. Only isolated showers were noted over land, mainly Molokai. Winds averaged 5 to 15 mph.
A large surface high pressure system centered almost 2000 miles northeast of the state dominated the Pacific between Hawaii and Alaska this morning. This high will weaken and slide slowly southeast through the week, as a trough moves east across the northern Pacific. Trades will continue to bring ENE to E winds to the region. Embedded in this flow is an area of moisture from the remnants of Norbert, and this moisture will bring a sharp increase in showers from late Wednesday night through early Friday. Instability will be sufficient for an isolated thunderstorm as well. Heavy rain is possible, and a flood watch may be needed as we get closer in time.
Moisture will decrease late Friday through the weekend, but the latest guidance shows that another area of increasing moisture (from the remnants of tropical depression 15-E) will likely move into the area Monday or Tuesday next week. The GFS is especially bullish with this moisture, showing PW values over 2 inches. The ECMWF is not as wet. A better estimate of how much moisture this system will bring should be available by Friday, just as the initial moisture from the remnants of Norbert depart. Trade winds are forecast to be moderate to breezy starting Wednesday and lasting into early next week.

Aviation

Moderate trade winds will continue through the morning, then gradually strengthen to become locally breezy this afternoon into the evening. Moisture along a dissipating surface trough moving over the eastern half of the state this morning will move up the island chain through the day and increase windward cloud and shower coverage as it passes through. MVFR conditions will be possible in passing showers. Otherwise, VFR conditions will prevail.
AIRMET Sierra is in effect for tempo mountain obscuration for windward areas of the Big Island through Oahu and may be needed through the morning hours as showers linger.

Marine

Moderate to locally fresh trade winds will persist today as a weak trough lingers to the northeast. By Wednesday, high pressure building north of the islands will increase the trade winds into the fresh to locally strong range through the weekend. Also by Wednesday afternoon, the remnants of Norbert will begin to move into the offshore waters as a trough and increase shower coverage as it traverses east to west across the islands, potentially through the weekend.
A series of long-period south to southwest swells will fill in through the week, leading to a gradual increase in surf for south-facing shores through the week. The first pulse fills in today into Wednesday out of the southwest, followed by larger south-southwest swells Friday into the weekend. Small surf is expected through Wednesday, after which an upward trend is expected, and surf could approach advisory thresholds by this weekend.
Surf along east-facing shores should see a gradual increase this week as trade winds strengthen and a small, medium-period east swell from Tropical Storm Norbert arrives. Flat to tiny surf along north facing shores is expected through the forecast period.

Fire weather

Fire weather risk should remain low through the remainder of the week due to light to moderate winds and the effects of recent (and upcoming) rainfall. Inversion heights from Maui to the Big Island should be 7000 to 8000 ft through Wednesday. Showers will dramatically increase from late Wednesday into early Friday, keeping vegetation moist.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov