Photo Credit: Leosan Miguel

West Side

Today: Isolated showers before noon. Sunny, with a high near 84. Southwest wind 3 to 6 mph. Chance of precipitation is 20%.

Tonight: Mostly clear, with a low around 65. Light and variable wind.

Tuesday: Sunny, with a high near 83. Calm wind becoming south 5 to 7 mph in the afternoon.

South Side

Today: Isolated showers after noon. Mostly sunny, with a high near 84. West wind 3 to 6 mph. Chance of precipitation is 20%.

Tonight: Mostly clear, with a low around 63. Light and variable wind becoming northeast around 5 mph after midnight.

Tuesday: Isolated showers after noon. Mostly sunny, with a high near 83. Calm wind becoming west southwest 5 to 7 mph in the afternoon. Chance of precipitation is 20%.

North Shore

Today: Isolated showers. Mostly sunny, with a high near 82. Breezy, with an east wind 14 to 17 mph, with gusts as high as 24 mph. Chance of precipitation is 20%.

Tonight: Isolated showers. Partly cloudy, with a low around 64. East wind 5 to 14 mph, with gusts as high as 18 mph. Chance of precipitation is 20%.

Tuesday: Isolated showers. Mostly sunny, with a high near 81. South southeast wind 5 to 9 mph becoming north in the afternoon. Chance of precipitation is 20%.

Central Maui

Today: Mostly sunny, with a high near 82. Breezy, with a northeast wind 8 to 15 mph, with gusts as high as 21 mph.

Tonight: Partly cloudy, with a low around 62. Northeast wind 5 to 8 mph becoming calm in the evening.

Tuesday: Mostly sunny, with a high near 81. Light and variable wind becoming north northeast 6 to 11 mph in the afternoon.

Upcountry

Today: Mostly sunny, with a high near 70. West northwest wind around 6 mph becoming calm in the afternoon.

Tonight: Partly cloudy, with a low around 53. Light and variable wind.

Tuesday: Mostly sunny, with a high near 69. Calm wind becoming west 5 to 7 mph in the afternoon.

East Maui

Today: Scattered showers. Partly sunny, with a high near 80. Southeast wind 10 to 13 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers. Mostly cloudy, with a low around 60. Southeast wind 6 to 10 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Tuesday: Scattered showers. Partly sunny, with a high near 79. Southeast wind 7 to 14 mph, with gusts as high as 20 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Lanai City

Today: Scattered showers after noon. Partly sunny, with a high near 76. Calm wind becoming north northeast 5 to 7 mph in the afternoon. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Isolated showers. Partly cloudy, with a low around 62. North wind 3 to 7 mph. Chance of precipitation is 20%.

Tuesday: Scattered showers, mainly after noon. Mostly sunny, with a high near 75. Light and variable wind becoming south southwest 5 to 10 mph in the afternoon. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Kaunakakai

Today: Sunny, with a high near 82. East wind 5 to 9 mph.

Tonight: Mostly clear, with a low around 66. East wind around 5 mph becoming calm in the evening.

Tuesday: Sunny, with a high near 81. Light and variable wind becoming south southwest 5 to 9 mph in the afternoon.

Detailed Forecast

Synopsis

Moderate trade winds will remain today with passing showers favoring windward and mauka areas. Winds will weaken Tuesday with afternoon seabreezes and nighttime land breezes expected. Increasing showers are in the forecast Wednesday and Thursday as a front dissipates across the islands and trade winds resume. Winds will diminish again late in the week as another front approaches, bringing the possibility of inclement weather late in the weekend.

Discussion

A high pressure ridge stretching across 26N latitude is providing moderate trade winds throughout the islands with some isolated showers across windward and mountain areas. Expect a gradual decline in winds tonight as a front pushes the ridge south toward the state. By Tuesday, winds will turn from the southeast as the front approaches, placing the smaller islands in the wind shadow of the Big Island. Expect afternoon seabreezes across leeward locations with limited interior showers and cloud buildups. Trade wind weather will remain for the Big Island and windward areas of Maui. Winds will turn from the southwest Tuesday night and then west Wednesday as the weakening front reaches Kauai sometime Wednesday. The front is forecast to dissipate Wednesday night into Thursday but remaining frontal moisture will bring increasing showers and cloud cover as winds flip back to northeasterly trades Thursday.
Trade winds will not last long, as another approaching front turns island winds southeast Thursday night with widespread seabreezes expected again Friday and Saturday afternoons. Right now, forecast models stall the front northwest of Kauai through Saturday before another reinforcing front pushes toward Kauai on Sunday. This has the potential to bring widespread rain late Sunday and into next week.

Aviation

Surface high pressure will build northeast of the state today and help to generate light to moderate trades. Thus, expect isolated showers to mainly affect areas along the windward coasts and slopes, with brief MVFR ceilings and visibility. Elsewhere, expect partly cloud skies and VFR conditions.
AIRMET TANGO remains in effect for the entire island chain between 25000 and 40000 feet due to tempo moderate turbulence. This should ease later this morning and the airmet can likely be dropped.

Marine

Easterly trade winds will remain on the lighter side through Monday night as high pressure lies far northeast of the area. Winds will become southeasterly on Tuesday then west southwesterly Tuesday night and Wednesday as a front approaches from the northwest. The front is expected to move across the area Wednesday night with northerly winds filling in behind the front. Winds will rapidly swing around to the east southeast on Thursday as another front approaches the area. Light southerly flow is expected on Friday as the front gets closer to the state. Winds will remain below Small Craft Advisory levels through the period however a series of large northwest swells will cause seas to exceed the 10 foot advisory threshold at times.
A High Surf Advisory (HSA) is currently posted for north facing shores of Maui County and the Big Island as a north swell continues to move through the eastern waters. This swell will lower throughout the day.
Long period forerunners from a new large northwest swell will gradually fill in today, peak tonight and Tuesday, then lower gradually Tuesday night and Wednesday. A HSA will likely be issued later today for most north and west facing shorelines. A larger northwest swell is expected to arrive Wednesday night, peak on Thursday, then lower gradually Thursday night and Friday. Model guidance indicates warning level surf during the peak of this swell. An even larger northwest swell is on tap for the weekend with warning level surf expected once again.
A combination of large surf this week coinciding with peak monthly high tides will worsen beach erosion issues for shores exposed to north and northwest swells. Additionally, vulnerable low- lying locations not exposed to the large swells may experience nuisance flooding at and around the peak daily tide cycles this week (between midnight and daybreak).
Short period surf along east facing shores will remain small through the week and through the weekend due to the lack of trade winds upstream of the state. Surf along south facing shores will trend up slightly by midweek from recent activity down south in the Tasman Sea.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST this evening for Molokai, Maui Windward West, Maui Central Valley, Windward Haleakala, Big Island North and East.
Small Craft Advisory until 6 PM HST Tuesday for Maui County Windward Waters, Alenuihaha Channel, Big Island Windward Waters.