Photo Credit: Brittney Cruz

West Side

Today: Sunny and breezy. Isolated showers in the afternoon. Highs around 78. Northeast winds 10 to 25 mph. Chance of rain 20 percent.

Tonight: Breezy. Partly cloudy with isolated showers. Lows 64 to 70. Northeast winds 15 to 25 mph with gusts to 45 mph. Chance of rain 20 percent.

Tuesday: Mostly sunny. Windy. Isolated showers in the morning, then scattered showers in the afternoon. Highs around 78. Northeast winds 20 to 30 mph decreasing to 10 to 30 mph in the afternoon. Chance of rain 50 percent.

South Side

Today: Sunny and breezy. Highs 79 to 85. Northeast winds 10 to 25 mph.

Tonight: Mostly clear. Breezy. Isolated showers after midnight. Lows around 66. Northeast winds 15 to 25 mph. Chance of rain 20 percent.

Tuesday: Sunny and breezy. Isolated showers in the afternoon. Highs 80 to 85. Northeast winds 10 to 25 mph with gusts to 45 mph. Chance of rain 20 percent.

North Shore

Today: Mostly sunny. Breezy. Isolated showers in the morning, then scattered showers in the afternoon. Highs around 80 near the shore to around 68 near 5000 feet. East winds 10 to 20 mph. Chance of rain 40 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Breezy. Scattered showers. Lows around 67 near the shore to around 52 near 5000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Tuesday: Breezy. Mostly cloudy with scattered showers. Highs around 80 near the shore to around 68 near 5000 feet. East winds 15 to 25 mph. Chance of rain 50 percent.

Central Maui

Today: Sunny and breezy. Highs around 83. Northeast winds 10 to 20 mph.

Tonight: Partly cloudy. Breezy. Isolated showers after midnight. Lows around 66. Northeast winds 15 to 20 mph. Chance of rain 20 percent.

Tuesday: Breezy. Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 83. Northeast winds 15 to 25 mph. Chance of rain 30 percent.

Upcountry

Today: Sunny and breezy. Isolated showers in the afternoon. Highs 63 to 72. East winds 10 to 20 mph. Chance of rain 20 percent.

Tonight: Breezy. Partly cloudy with scattered showers. Lows 46 to 52. East winds 10 to 25 mph. Chance of rain 50 percent.

Tuesday: Windy. Mostly sunny with isolated showers. Highs 62 to 72. East winds 15 to 30 mph. Chance of rain 20 percent.

East Maui

Today: Mostly sunny. Breezy. Isolated showers in the morning, then scattered showers in the afternoon. Highs around 80 near the shore to around 68 near 5000 feet. East winds 10 to 20 mph. Chance of rain 40 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Breezy. Scattered showers. Lows around 67 near the shore to around 52 near 5000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Tuesday: Breezy. Mostly cloudy with scattered showers. Highs around 80 near the shore to around 68 near 5000 feet. East winds 15 to 25 mph. Chance of rain 50 percent.

Lanai City

Today: Sunny and breezy. Isolated showers in the afternoon. Highs 73 to 78. Northeast winds 10 to 25 mph. Chance of rain 20 percent.

Tonight: Breezy. Partly cloudy with isolated showers. Lows around 63. Northeast winds 15 to 25 mph. Chance of rain 20 percent.

Tuesday: Windy. Sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs around 76. Northeast winds 15 to 30 mph. Chance of rain 40 percent.

Kaunakakai

Today: Sunny and breezy. Isolated showers in the afternoon. Highs 70 to 82. Northeast winds 10 to 25 mph. Chance of rain 20 percent.

Tonight: Breezy. Partly cloudy with isolated showers. Lows 57 to 70. Northeast winds 15 to 25 mph. Chance of rain 20 percent.

Tuesday: Windy. Sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 71 to 81. Northeast winds 15 to 30 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Trade winds will strengthen, becoming breezy today, as strong surface high pressure sets up far north of the area. Relatively dry afternoon conditions with limited rainfall primarily over windward exposures and the Big Island Kona region. More frequent showers will occur from Tuesday through the remainder of the week. Residual moisture associated with the remnants of a cold front will be drifting south across islands later this week. Higher moisture within a less stable atmosphere will increase areawide precipitation probabilities through mid to late week.

Discussion

Relatively dry trade wind flow is strengthening across the island chain. Trades have returned and will be strengthening in response to a surface high moving in from the west in the wake of a diffuse ridge axis slowly lifting north of the islands early this morning. This high, centered about 900 miles north of the island chain, will produce a tight enough downstream pressure gradient to support several days of gusty trades. Ridging aloft will likely maintain a near 5 to 6k ft inversion. Localized afternoon to evening winds under this weakening inversion could gust to 40 mph over and just downwind of higher elevation ridge tops. These stable conditions and a near inch precipitable water air mass will (and has) limit(ed) rainfall with the majority of the shower activity remaining focused over more windward-facing exposures. Recent dew points in the seasonal lower to middle 60s has made it feel less sticky than compared to previously humid days. Greater eastern moisture will advect in through mid week and increase humidity. Haze will be less of an issue as moderate to fresh trades more efficiently mix out the downstream transport of vog; higher SO2 concentrations will be confined to areas just downwind of the Halemaumau Crater.
A front moving through the northwest offshore waters is expected to become more parallel to the upper level westerly flow as it encounters mid to upper ridding…dissipating just north of the island chain. The surface high roughly a thousand miles north northeast of the islands will strengthen going into the middle of the week. This will maintain breezy trades and, although the ridge aloft and its resulting inversion will begin to erode, the threat for localized high wind gusts may still exist the next day or so. Residual moisture tied to the diffuse frontal boundary north of the state will sag south southeastward toward the state and likely provide enough fuel to increase smaller island precipitation chances Tuesday. In addition to this remnant frontal moisture over the northern nearshore waters, ribbons of higher mid layer moisture from the east will periodically advect in on established trades through mid to late week. The greatest rain will likely fall across windward Big Island and Maui with the higher accumulations occurring from Wednesday into the weekend. There will be a touch more instability in response to a minor lowering of heights subtly cooling temperatures aloft in association with a trough passing far north of Hawaii in tandem with the weaker southern branch of the polar jet passing over the state. This less stable and more moist scenario should increase the probabilities of a more wet trade wind pattern during the second half of the week.

Aviation

Moderate to breezy easterly trades will strengthen through the afternoon hours, as a high pressure system builds in and passes by just north of the Hawaiian Islands. Periods of clouds and brief showers will favor windward and mountain slopes during the overnight to early morning hours.
AIRMET TANGO for low-level turbulence over and downstream of island terrain will likely be issued later today due to the strengthening trade winds.

Marine

High pressure building to near 1037 mb N of the islands will lead to strengthening trade winds today and tonight, with fresh to near gale-force winds likely remaining into next weekend. A Small Craft Advisory (SCA) is currently slated to start at noon today for all waters.
A new NW swell will lead to advisory-level surf along exposed N ad W facing shores as it peaks later today/early Tuesday. Increasing swell energy has been reported in the 15-17 second bands at NDBC buoys NW of Kauai overnight, and while current wave heights will not result in high surf, the swell is expected to continue to build through the day, and a High Surf Advisory will go into effect at noon today. This swell will diminish later Tuesday into Wednesday, with another NW swell around Friday potentially leading to advisory-level surf again. Another pulse of NW swell is possible next weekend. A small S swell is possible today. Choppy surf along E facing shores will increase in response to the building trade winds.

HFO Watches/Warnings/Advisories

High Surf Advisory from noon today to 6 PM HST Tuesday for Niihau, Kauai Leeward, Waianae Coast, Oahu North Shore, Maui Windward West, Kauai North, Molokai Windward, Molokai North, Molokai West, Maui Central Valley North, Windward Haleakala.
Small Craft Advisory from noon today to 6 PM HST Wednesday for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Kauai Channel, Oahu Windward Waters, Oahu Leeward Waters, Maui County Windward Waters, Maui County Leeward Waters, Big Island Windward Waters.
Small Craft Advisory until 6 PM HST Wednesday for Kaiwi Channel, Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

Maui Now Weather is brought to you by Blue Hawaiian Helicopters.

Check out their Maui Helicopter Tours today!

Data Courtesy of NOAA.gov