Photo Credit: Tyler Rooke

West Side

Today: Mostly sunny with isolated showers. Highs 74 to 82. East winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 56 to 64. East winds 10 to 15 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny with isolated showers. Highs 73 to 81. East winds around 10 mph shifting to the west in the afternoon. Chance of rain 20 percent.

South Side

Today: Sunny. Highs around 84. Northeast winds 10 to 15 mph.

Tonight: Mostly clear. Lows around 61. Northeast winds around 10 mph.

Wednesday: Mostly sunny with isolated showers. Highs around 84. Northeast winds around 10 mph shifting to the west in the afternoon. Chance of rain 20 percent.

North Shore

Today: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs around 82 near the shore to around 69 near 5000 feet. East winds 10 to 15 mph. Chance of rain 40 percent.

Tonight: Partly cloudy with isolated showers. Lows around 64 near the shore to around 46 near 5000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs around 81 near the shore to around 69 near 5000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Central Maui

Today: Mostly sunny with isolated showers. Highs around 83. East winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Isolated showers after midnight. Lows around 61. East winds around 10 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs 80 to 85. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Upcountry

Today: Mostly sunny with isolated showers. Highs around 58 at the visitor center to around 64 at the summit. East winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Mostly clear with isolated showers. Lows around 43. East winds 10 to 15 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny with isolated showers. Highs around 59 at the visitor center to around 67 at the summit. East winds 10 to 15 mph. Chance of rain 20 percent.

East Maui

Today: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs around 82 near the shore to around 69 near 5000 feet. East winds 10 to 15 mph. Chance of rain 40 percent.

Tonight: Partly cloudy with isolated showers. Lows around 64 near the shore to around 46 near 5000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs around 81 near the shore to around 69 near 5000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Lanai City

Today: Mostly sunny with isolated showers. Highs 71 to 77. East winds around 10 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Isolated showers after midnight. Lows 54 to 61. East winds around 10 mph in the evening becoming light. Chance of rain 20 percent.

Wednesday: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs 73 to 79. Light winds. Chance of rain 20 percent.

Kaunakakai

Today: Breezy. Sunny with isolated showers. Highs 69 to 82. East winds 15 to 20 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers after midnight. Lows 49 to 65. East winds 10 to 15 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs 71 to 83. East winds 10 to 15 mph shifting to the west in the afternoon. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Moderate trade winds continue today and then transition to more light and variable winds from Wednesday through Friday as a high pressure ridge drifts over the region. An approaching cold front will weaken this ridge and diminish north of the island chain on Friday as high pressure builds in north of the state. Trade winds will return this weekend with increasing shower trends.

Discussion

Satellite imagery this morning shows a high pressure ridge axis just northwest of Kauai with an approaching cold front near 170W. An upper level low lingering roughly 900 miles northeast of the Big Island is producing some unstable low level cloud bands that will drift towards the islands on the easterly trade winds. Radar imagery shows scattered showers across the region mainly affecting windward and mountain sections of each island.
Expect continued moderate trade winds today with brief passing showers over windward and mountain areas. Shower activity will decrease a bit as the high pressure ridge axis begins to drift closer to the islands and the subsidence temperature inversion height lowers to around 6,000 to 7,000 feet. Trade winds will diminish on Wednesday as the ridge axis weakens and moves over the islands chain and a more variable land and sea breeze pattern develops over each island. Clouds will then build over island mountain and interior sections due to converging sea breeze winds and island surface heating. Cooling of the land at night will cause down slope land breezes to form, clearing out cloud cover each evening. Expect limited rainfall in this pattern due to strong subsidence aloft from the high pressure ridge. A cold front approaching the islands will stall out and diminish north of the state on Friday. Remnant clouds with this dissipated frontal band will drift through the region on returning trade winds this weekend.
A high pressure system will drift eastward through the region on Saturday and Sunday, passing just north of the Hawaiian Islands. This system will increase large scale pressure gradients and allow a return to moderate trade wind weather. Expect increasing shower trends from the dissipated frontal band and possibly from a nearby upper level low that long range models suggest will develop near the Hawaii region. Still some uncertainty on the location and intensity of this upper low and that limits our confidence in island by island precipitation coverage and amounts for this weekend. Stay tuned.

Aviation

Moderate to locally breezy trade winds will continue through twenty-four hours and beyond. Weak land breezes will promote overnight clearing along south and west facing slopes. Leeward sea breezes will encourage cumulus development over island interiors in the afternoon and early evening. Expect showers to favor north and east facing slopes and coasts in the late night and morning hours then island interiors in the afternoon and evening hours.
The air mass over the state is becoming increasingly stable due to a strengthening trade wind inversion between 05 kft and 08 kft. This will inhibit vertical cloud development and limit shower intensity. Brief MVFR CIG or VIS possible in showers, otherwise VFR conditions will prevail all areas.
The next cold front is expected to approach the state on Wednesday. This will weaken the background trade wind flow and allow land and sea breezes to drive local weather.

Marine

Trade winds have begun easing, so the Small Craft Advisory that had been in effect for the windier zones around Maui County and the Big Island has been dropped. Winds will further ease today and will remain light to moderate through Friday as an approaching front from the northwest nudges a ridge south over the islands. A high passing north of the area will bring strengthening trade winds by Saturday.
A moderate west-northwest swell will arrive late today into Wednesday, potentially boosting surf to near High Surf Advisory levels. This swell will slowly lower through Thursday, then persist at small to moderate heights into the weekend. Another, larger, northwest swell may arrive in just about a week. Slightly elevated, short-period east swell and a small south swell will continue for the next day or two.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov