West Side

Today: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 81 to 86. Northeast winds up to 20 mph. Chance of rain 40 percent.

Tonight: Mostly clear. Breezy. Scattered showers in the evening, then isolated showers after midnight. Lows 70 to 78. Northeast winds 10 to 25 mph. Chance of rain 40 percent.

Tuesday: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 81 to 87. Northeast winds up to 20 mph. Chance of rain 40 percent.

South Side

Today: Mostly sunny. Breezy. Highs around 88. North winds up to 20 mph.

Tonight: Mostly clear. Breezy. Lows 70 to 78. North winds 10 to 25 mph.

Tuesday: Mostly sunny. Breezy. Highs around 89. North winds up to 20 mph.

North Shore

Today: Mostly cloudy. Breezy. Occasional showers in the morning, then scattered showers in the afternoon. Highs 81 to 86 near the shore to around 65 near 5000 feet. East winds 10 to 25 mph. Chance of rain 80 percent.

Tonight: Breezy. Mostly cloudy with numerous showers. Lows around 75 near the shore to around 57 near 5000 feet. East winds up to 20 mph. Chance of rain 70 percent.

Tuesday: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 84 near the shore to around 68 near 5000 feet. East winds up to 20 mph. Chance of rain 70 percent.

Central Maui

Today: Breezy. Mostly sunny with isolated showers. Highs 81 to 89. East winds up to 20 mph increasing to 10 to 25 mph in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy. Breezy. Isolated showers in the evening, then scattered showers after midnight. Lows 70 to 77. Northeast winds 10 to 20 mph. Chance of rain 40 percent.

Tuesday: Breezy. Mostly sunny with isolated showers. Highs 82 to 89. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Upcountry

Today: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 61 at the visitor center to around 59 at the summit. East winds up to 20 mph. Chance of rain 50 percent.

Tonight: Mostly clear with scattered showers. Lows around 49 at the visitor center to around 46 at the summit. East winds up to 15 mph. Chance of rain 50 percent.

Tuesday: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 64 at the visitor center to around 60 at the summit. East winds up to 15 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

East Maui

Today: Mostly cloudy. Breezy. Occasional showers in the morning, then scattered showers in the afternoon. Highs 81 to 86 near the shore to around 65 near 5000 feet. East winds 10 to 25 mph. Chance of rain 80 percent.

Tonight: Breezy. Mostly cloudy with numerous showers. Lows around 75 near the shore to around 57 near 5000 feet. East winds up to 20 mph. Chance of rain 70 percent.

Tuesday: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 84 near the shore to around 68 near 5000 feet. East winds up to 20 mph. Chance of rain 70 percent.

Lanai City

Today: Mostly sunny. Breezy. Isolated showers in the afternoon. Highs 73 to 82. East winds up to 10 mph increasing to northeast 10 to 25 mph in the afternoon. Chance of rain 20 percent.

Tonight: Mostly clear. Breezy. Lows 67 to 72. Northeast winds 10 to 25 mph.

Tuesday: Breezy. Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs 73 to 82. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Kaunakakai

Today: Breezy. Mostly sunny with isolated showers. Highs 72 to 89. East winds 10 to 20 mph. Chance of rain 20 percent.

Tonight: Breezy. Mostly clear with isolated showers. Lows 62 to 76. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Tuesday: Breezy. Mostly sunny with isolated showers. Highs 71 to 89. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Moderate to locally breezy trade winds will persist through the week and into the upcoming weekend. Bands of low clouds and showers will periodically push across the islands, focusing primarily over windward and mauka areas during the overnight and early morning hours. A couple bands of enhanced moisture will move through the islands today through Thursday morning, bringing an increase in shower coverage and intensity, with some locally heavy rainfall possible. In addition, humidity levels will rise, bringing muggier conditions across the island chain through the middle of this week.

Discussion

Currently at the surface, a 1037 mb high is centered around 1650 miles north-northeast of Honolulu, driving moderate trade winds across the island chain this evening. Infrared satellite imagery shows mostly cloudy to overcast conditions across much of the state, with a few leeward areas experiencing less cloud coverage. Radar imagery shows numerous showers moving into windward slopes and coasts, with some showers spilling over into leeward communities at times. Main short term focus revolves around rain chances.
High pressure will meander well to the north of state during the next 7 days, keeping moderate, to at times locally breezy, trade winds solidly in place. Somewhat wetter than normal, summertime trade wind weather is expected through the period, with showers favoring windward and mauka areas, particularly during the night and early morning hours. A couple bands of enhanced moisture will affect the state this week, bringing an increase in shower coverage and intensity as they move through. The first batch of enhanced moisture is already affecting the island chain, and will continue to do so through the day today, before exiting to the west of the state tonight. The next area of enhanced moisture is located around 550 miles east-northeast of the state in the vicinity of 147W. Portions of this area of enhanced moisture will begin to affect the islands beginning Tuesday night, and lingering into early Thursday, increasing shower coverage and intensity once again.
Both these bands will raise precipitable water values into the 1.5 to 2.0 inch range and elevate inversion heights to between 10 and 12 kft. Some locally heavy rainfall can't be ruled out as these bands of moisture move through, particularly the second batch of moisture affecting the islands during the middle of the week. That said, with the trades in place, a widespread flash flood threat is not expected, but some minor flooding could very well necessitate flood advisories over windward and mauka areas during this time. Additionally, dewpoints are forecast to increase to around 70 or the lower 70s today through the middle of the week, making it feel more muggy across the island chain.

Aviation

An easterly wave moving through the islands will produce MVFR conditions and showers across the state through the morning hours. MVFR conditions could decrease in coverage and frequency through the afternoon. Another low level disturbance will move through the islands bringing another round of MVFR conditions and showers from Tuesday night into Thursday.
AIRMET Sierra remains in effect for mountain obscuration above 020 along northern and eastern mountain slopes of most islands. These conditions will persist through the morning hours, then decrease in coverage later this afternoon.

Marine

An area of surface high pressure will remain centered well north of the Hawaiian Islands this week and help drive moderate to fresh trades trades across the region. The Small Craft Advisory (SCA) will continue through this afternoon for much of the waters around Maui County and Big Island, as well as the Kaiwi Channel. The SCA will then be trimmed back to the typical windy waters around Maui County and the Big Island by this evening as trades ease slightly into Tuesday.
The current long period south swell will maintain today, then gradually decline through midweek. Another larger south swell energy pulse will arrive by late Saturday.
Surf along east facing shores will remain rough and choppy through the week with moderate to fresh trades in place. Surf heights along north facing shores will remain nearly flat.

HFO Watches/Warnings/Advisories

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

Data Courtesy of NOAA.gov