West Side

Today: Sunny. Highs 81 to 87. Northeast winds up to 15 mph.

Tonight: Mostly clear. Lows 69 to 76. East winds up to 15 mph.

Tuesday: Sunny. Isolated showers in the afternoon. Highs 81 to 87. East winds up to 10 mph. Chance of rain 20 percent.

South Side

Today: Sunny. Highs around 90. North winds up to 15 mph.

Tonight: Mostly clear. Lows 69 to 77. North winds up to 15 mph.

Tuesday: Sunny. Highs around 90. North winds up to 15 mph.

North Shore

Today: Mostly sunny with isolated showers. Highs 80 to 85 near the shore to around 68 near 5000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows around 73 near the shore to around 53 near 5000 feet. East winds up to 15 mph. Chance of rain 40 percent.

Tuesday: Mostly sunny with scattered showers. Highs 80 to 85 near the shore to around 68 near 5000 feet. East winds up to 15 mph. Chance of rain 40 percent.

Central Maui

Today: Sunny. Highs 83 to 91. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon.

Tonight: Mostly clear. Isolated showers in the evening. Lows 69 to 74. Northeast winds up to 15 mph. Chance of rain 20 percent.

Tuesday: Sunny. Highs 84 to 91. Northeast winds up to 15 mph.

Upcountry

Today: Mostly sunny. Breezy. Highs around 65 at the visitor center to around 73 at the summit. East winds up to 20 mph.

Tonight: Mostly clear. Breezy. Lows 46 to 55. East winds up to 20 mph.

Tuesday: Mostly sunny. Breezy. Isolated showers in the afternoon. Highs around 65 at the visitor center to around 70 at the summit. East winds up to 20 mph. Chance of rain 20 percent.

East Maui

Today: Mostly sunny with isolated showers. Highs 80 to 85 near the shore to around 68 near 5000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows around 73 near the shore to around 53 near 5000 feet. East winds up to 15 mph. Chance of rain 40 percent.

Tuesday: Mostly sunny with scattered showers. Highs 80 to 85 near the shore to around 68 near 5000 feet. East winds up to 15 mph. Chance of rain 40 percent.

Lanai City

Today: Mostly sunny. Isolated showers in the afternoon. Highs 75 to 83. Northeast winds up to 15 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Lows 64 to 69. Northeast winds up to 15 mph.

Tuesday: Sunny. Isolated showers in the afternoon. Highs 75 to 83. Northeast winds up to 15 mph. Chance of rain 20 percent.

Kaunakakai

Today: Sunny. Highs 74 to 91. East winds 10 to 15 mph.

Tonight: Mostly clear. Lows 60 to 75. Northeast winds 10 to 15 mph decreasing to up to 10 mph after midnight.

Tuesday: Sunny. Highs 74 to 91. Northeast winds up to 10 mph increasing to 10 to 15 mph in the afternoon.

Detailed Forecast

Synopsis

Typical weather setup with moderate to locally breezy trade winds. This will keep the most showers windward and mauka into Tuesday. Afternoon showers will develop over leeward slopes of the Big Island, but most other leeward areas will be dry. Showers may increase slightly Wednesday in most areas. Trades will decrease slightly midweek and may further decline Friday.

Discussion

Fairly stable, moderate to locally breezy trade winds are forecast to continue through at least Tuesday. The trades are being driven by robust surface high pressure centered roughly 1,000 miles north of Kauai. Stable conditions cover the islands as an upper- level ridge building in from the east has pushed the inversion down to between 6,000 to 7,000 ft. The locally breezy trade wind flow produced modest rainfall over windward slopes Sunday, with just a few hundredths of an inch recorded at most gages. Early this morning, isolated showers were seen on radar mainly moving into windward Oahu and Kauai.
Little change is expected through late Thursday in the basic trade wind pattern. Increased moisture is expected to provide an uptick in shower activity, mainly windward, Tuesday night and Wednesday. The surface high to the north will be split in two by a trough beginning late Wednesday, with a low centered north of Kauai by Thursday afternoon. The influence of this low and the displacement of the high to the east will shift the trades to southeast Friday into Saturday. Trades return Sunday with vigor.

Aviation

Moderate to locally breezy trades will continue to favor limited clouds and showers, mainly over windward and mauka areas. Localized MVFR possible within passing showers, but most sites will remain VFR.
AIRMET Sierra in effect for mountain obscuration due to low clouds and showers over Kauai, Oahu, Molokai, Lanai, Maui, and the Big Island. Conditions expected to improve later this morning.

Marine

Moderate to locally fresh easterly trade winds will continue to build into the area through Monday. A Small Craft Advisory (SCA) for windier waters and channels around Maui and the Big Island remains in effect through this afternoon.
A small medium period north swell will build into the Hawaii Region today. A series of small medium period swells from the north and northwest will trickle in through the middle of the week. A moderate long period northwest (330 deg) swell will overlap with a smaller medium period north swell starting Friday night building surf heights along north and west facing shores this weekend.
Surf along south facing shores will slowly fade today from a small medium period south swell. A series of small medium period south swells will keep surf along south facing shores from going flat through the week.
Surf along east facing shores will remain on the small side in moderate trade wind flow.

Fire weather

Locally breezy trade winds and rather dry conditions will persist into Tuesday, but conditions should remain just below critical fire weather thresholds. A brief period of wetter trade wind weather is expected on Wednesday. A strengthening inversion will build down to 5,000 to 6,000 feet on Monday.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST this evening for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov