Photo Credit: Tyler Rooke

West Side

Today: Isolated showers before 1pm. Mostly sunny, with a high near 85. Breezy, with an east northeast wind around 15 mph, with gusts as high as 21 mph. Chance of precipitation is 20%.

Tonight: Mostly clear, with a low around 67. Breezy, with an east northeast wind 15 to 17 mph, with gusts as high as 24 mph.

Tuesday: Sunny, with a high near 83. Breezy, with an east northeast wind around 17 mph, with gusts as high as 24 mph.

South Side

Today: Isolated showers after noon. Mostly sunny, with a high near 80. West northwest wind around 14 mph, with gusts as high as 18 mph. Chance of precipitation is 20%.

Tonight: Mostly clear, with a low around 62. Breezy, with a northeast wind around 15 mph, with gusts as high as 21 mph.

Tuesday: Mostly sunny, with a high near 78. Breezy, with a west northwest wind around 15 mph, with gusts as high as 21 mph.

North Shore

Today: Scattered showers, mainly before noon. Partly sunny, with a high near 78. Breezy, with an east northeast wind around 21 mph, with gusts as high as 29 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers, mainly after midnight. Partly cloudy, with a low around 65. Breezy, with an east northeast wind around 20 mph, with gusts as high as 28 mph. Chance of precipitation is 30%.

Tuesday: Scattered showers before noon. Mostly sunny, with a high near 77. Breezy, with an east northeast wind around 21 mph, with gusts as high as 29 mph. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Central Maui

Today: Scattered showers, mainly before noon. Partly sunny, with a high near 79. Windy, with a northeast wind around 23 mph, with gusts as high as 32 mph. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers after midnight. Partly cloudy, with a low around 65. Breezy, with a northeast wind around 18 mph, with gusts as high as 25 mph. Chance of precipitation is 30%.

Tuesday: Isolated showers before noon. Mostly sunny, with a high near 78. Breezy, with a northeast wind around 22 mph, with gusts as high as 31 mph. Chance of precipitation is 20%.

Upcountry

Today: Isolated showers. Mostly sunny, with a high near 68. South wind around 10 mph. Chance of precipitation is 20%.

Tonight: Mostly clear, with a low around 51. East wind around 11 mph.

Tuesday: Sunny, with a high near 66. South wind around 11 mph.

East Maui

Today: Showers likely, mainly before noon. Mostly cloudy, with a high near 74. Breezy, with an east northeast wind around 18 mph, with gusts as high as 25 mph. Chance of precipitation is 70%. New precipitation amounts between a tenth and quarter of an inch possible.

Tonight: Showers likely, mainly after midnight. Mostly cloudy, with a low around 66. Breezy, with an east northeast wind around 17 mph, with gusts as high as 24 mph. Chance of precipitation is 70%. New precipitation amounts of less than a tenth of an inch possible.

Tuesday: Occasional showers, mainly before noon. High near 73. Breezy, with an east northeast wind around 18 mph, with gusts as high as 25 mph. Chance of precipitation is 80%. New precipitation amounts of less than a tenth of an inch possible.

Lanai City

Today: Isolated showers. Mostly sunny, with a high near 73. Breezy, with a northeast wind around 17 mph, with gusts as high as 24 mph. Chance of precipitation is 20%.

Tonight: Mostly clear, with a low around 61. Breezy, with a northeast wind around 16 mph, with gusts as high as 22 mph.

Tuesday: Increasing clouds, with a high near 71. Breezy, with a northeast wind around 18 mph, with gusts as high as 25 mph.

Kaunakakai

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

Tonight: Mostly clear, with a low around 67. Breezy, with an east northeast wind around 18 mph, with gusts as high as 25 mph.

Tuesday: Sunny, with a high near 81. Breezy, with an east northeast wind around 18 mph, with gusts as high as 25 mph.

Detailed Forecast

Synopsis

Breezy trade winds will persist through Tuesday as strong high pressure holds far north of the state. A band of moisture will produce active showers along mainly windward portions of Maui County and the Big Island this morning, and then drift south of the state late today, as a drier air mass moves in from the north. Trade winds will decrease on Wednesday and remain at moderate strength through Friday, leading to typical trade wind weather.

Discussion

The forecast remains on track, so little change with this morning’s package. High pressure remains far north of the islands, and a nearly stationary low remains to the northeast. Breezy trade winds are expected today with a bit of a downward trend expected tomorrow.
The remains of an old front continue to bring showers to the islands in the trade wind flow. The band had been focused over Oahu and Maui County earlier in the evening, but is drifting southward, impacting Maui County and the Big Island early this morning. Any of this moisture making it to the summits on the Big Island could fall in the form of winter weather with temperatures below freezing. An upper level trough axis is just east of the Big Island this morning and is expected to continue moving away from the islands today.
A drier airmass is sinking in over Kauai, with the overnight sounding showing precipitable water (PW) values of 0.91 inches. Satellite derived PW shows that drier air is spreading over Oahu early this morning. Anticipate the drier airmass to spread over Maui County and the Big Island tonight, and then stick around state wide through the end of the week.
Dew points are already in the low 60s in many locations, and are expected to fall into the mid to upper 50s by tonight, and then stay low through much of the week. Combined with the drier airmass, it will feel a little on the cool side, particularly at night with the breezy trades. As this pattern sets up, expect showers to be focused on the windward sides of the islands.
Trade winds will likely drop a notch on Wednesday and remain at moderate strength through Friday. Global models show a mid- to upper-level trough just east of the state and an upper ridge to the west. At this time, it looks like the islands will remain in a stable trade wind flow, with some shallow bands of moisture riding in on the trades from time to time.
Heading into next weekend, the GFS and ECMWF show the cutoff low to the northeast falling apart and drifting toward the islands. As a result, we could experience a decrease in trades with additional moisture moving in.

Aviation

Breezy northeast trade winds will continue, with clouds and showers focusing over windward and mountain locations. The greatest shower coverage will continue to be from Oahu to Big Island where a band of clouds/moisture lingers. MVFR CIGS/VSBYS can be expected in and around these passing showers.
AIRMET SIERRA for mountain obscuration remains in effect for Windward Big Island through Oahu.
AIRMET TANGO remains in effect for lee turbulence for the entire area.

Marine

High pressure far to the north will maintain fresh to strong northeast trade winds into Wednesday before gradually dropping to moderate levels Thursday as the high weakens. A small craft advisory is in effect for all coastal waters for winds and seas.
A gale low centered near 35N140W is expected to retrograde toward Hawaii over the next few days, sending NNE swell toward the islands. Current buoy observations show some small forerunners heightening surf along exposed shores but a more robust increase is expected this afternoon/evening with a peak Tuesday night, and then a gradual decline into the weekend. A high surf advisory will likely be necessary Tuesday/Wednesday for east facing shores exposed to this NNE swell. An increase in surf is also possible for the northern beaches on Lanai and along the shoreline north of Keahole Point on the Big Island. More normal trade wind swell will also increase with gusty trade winds. Background, long period southerly swells will bring small surf to south facing shores through the week. A slight increase in southerly surf is possible by the weekend.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Tuesday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.
Small Craft Advisory from 6 AM this morning to 6 PM HST Tuesday for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Kauai Channel, Oahu Windward Waters, Oahu Leeward Waters, Kaiwi Channel, Maui County Windward Waters, Maui County Leeward Waters, Big Island Windward Waters.

Data Courtesy of NOAA.gov