West Side

Today: Mostly sunny with isolated showers. Haze in the afternoon. Highs 76 to 81. East winds up to 10 mph in the morning becoming light. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Haze. Lows 65 to 71. Light winds. Chance of rain 20 percent.

Sunday: Sunny and haze. Highs around 79. Light winds.

South Side

Today: Mostly sunny. Isolated showers in the afternoon. Haze in the afternoon. Highs around 83. North winds up to 10 mph in the morning becoming light. Chance of rain 20 percent.

Tonight: Mostly clear. Haze. Lows 63 to 73. Light winds.

Sunday: Sunny and haze. Highs around 84. Light winds.

North Shore

Today: Partly sunny. Scattered showers in the morning, then scattered showers and isolated thunderstorms in the afternoon. Haze in the afternoon. Highs around 79 near the shore to around 63 near 5000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Haze through the night. Lows around 68 near the shore to around 49 near 5000 feet. Southeast winds up to 10 mph in the evening becoming light. Chance of rain 50 percent.

Sunday: Mostly sunny. Haze through the day. Isolated showers in the afternoon. Highs around 80 near the shore to around 64 near 5000 feet. Light winds. Chance of rain 20 percent.

Central Maui

Today: Mostly sunny with isolated showers. Haze in the afternoon. Highs 79 to 84. Northeast winds up to 10 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Haze. Lows around 66. South winds up to 10 mph in the evening becoming light.

Sunday: Sunny and haze. Highs 80 to 85. Light winds.

Upcountry

Today: Partly sunny. Numerous showers in the morning, then scattered showers and isolated thunderstorms in the afternoon. Haze in the afternoon. Highs around 58 at the visitor center to around 60 at the summit. Light winds. Chance of rain 70 percent.

Tonight: Mostly cloudy with scattered showers in the evening, then partly cloudy after midnight. Haze through the night. Lows around 44 at the visitor center to around 40 at the summit. Light winds. Chance of rain 50 percent.

Sunday: Mostly sunny in the morning, then partly sunny with scattered showers in the afternoon. Haze through the day. Highs around 60 at the visitor center to around 64 at the summit. Light winds. Chance of rain 40 percent.

East Maui

Today: Partly sunny. Scattered showers in the morning, then scattered showers and isolated thunderstorms in the afternoon. Haze in the afternoon. Highs around 79 near the shore to around 63 near 5000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Haze through the night. Lows around 68 near the shore to around 49 near 5000 feet. Southeast winds up to 10 mph in the evening becoming light. Chance of rain 50 percent.

Sunday: Mostly sunny. Haze through the day. Isolated showers in the afternoon. Highs around 80 near the shore to around 64 near 5000 feet. Light winds. Chance of rain 20 percent.

Lanai City

Today: Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Haze in the afternoon. Highs 70 to 77. Light winds. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Haze. Lows around 63. Light winds. Chance of rain 20 percent.

Sunday: Mostly sunny. Isolated showers in the afternoon. Haze in the afternoon. Highs 71 to 78. Northwest winds around 10 mph. Chance of rain 20 percent.

Kaunakakai

Today: Partly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Haze in the afternoon. Highs 67 to 83. East winds up to 10 mph in the morning becoming light. Chance of rain 50 percent.

Tonight: Partly cloudy with isolated showers. Haze. Lows 55 to 70. Light winds. Chance of rain 20 percent.

Sunday: Sunny. Haze in the afternoon. Highs 69 to 84. Light winds.

Detailed Forecast

Synopsis

Moisture and instability will linger over the islands today, though will gradually decrease by the end of the weekend. Winds will weaken and veer east-southeasterly today, then become light and southerly on Sunday, allowing land and sea breezes to dominate and drive afternoon showers over interior and leeward areas. Forecast confidence decreases early next week as one or more weak fronts approach the state, though limited upper-level support should keep rainfall impacts modest.

Discussion

The 12z upper air soundings from Lihue and Hilo show that a moist and somewhat unstable air mass remains in place across the island chain early this morning as the inversion has eroded a bit compared to 24 hours ago. A late evening ASCAT pass revealed that light to moderate easterly trade winds have briefly returned to the state overnight as surface high pressure continues to slide eastward away from the state. Showers and low clouds during the past twelve hours or so have primarily favored windward and mauka areas, particularly for the island of Maui yesterday evening, and now predominantly Oahu early this morning. Meanwhile, ample moisture aloft is resulting in scattered high clouds moving across the region.
As high pressure continues to shift east ahead of the next front approaching from the northwest, winds are expected to gradually veer east-southeasterly today, then weaken further and turn southwesterly across the western half of the state by Sunday. As the winds decrease, this will set up a daytime sea breeze and overnight land breeze regime across the islands. Meanwhile, the upper-level trough that has been supplying instability will slowly move off to the east, allowing atmospheric stability to increase from west to east as mid-level ridging builds into the region. With that said, moisture and instability will linger today as the upper trough moves over and eventually past the region. This will keep showers in the forecast, and isolated thunderstorms have also been introduced across eastern portions of the island chain for the afternoon. Additionally, with cold temperatures and deep moisture over the summits, snow showers and freezing fog may emerge again this afternoon as daytime heating sparks convection over the Big Island.
By Sunday, instability and moisture will be decreasing, and confidence in thunderstorm chances remains too low to include in the forecast at this time. Isolated to scattered showers will still be possible over interior and leeward areas during the afternoon where sea breeze induced surface convergence commences.
An unusual amount of uncertainty exists in the forecast early next week, as global models still offer wildly different solutions regarding a potential front moving into or through the area. The ECMWF, for example, brings a front into the western part of the island chain by late Sunday night, then shows it quickly moving down the island chain on Monday. This scenario offers a wetter solution and breezy northeasterly winds following the frontal passage. Meanwhile, the GFS keeps the front north of the state, with the island chain remaining in a drier pattern with lighter winds persisting. In any case, even if the front does move into the islands, with mid-level ridging forecast to persist over the state, there would be limited upper-level support.
The rest of the week next week looks to remain fairly dry with light southeasterly winds returning for much of the week. This would once again favor a land and sea breeze regime ahead of another potential front towards the end of next week.

Aviation

Isolated showers continue over the eastern islands with most locations remaining in VFR conditions. Easterly winds will remain light and gentle through the day and may veer to the southeast over the western end of the state by the afternoon. With the light winds, the chance for seabreeze and land breeze patterns may set up over interior sections of the islands. Drier conditions are expected as some MVFR cigs/vsbys may affect interior portions of the islands in the afternoon but predominantly VFR conditions are expected statewide.
Currently, no AIRMETs are effect.

Marine

A high pressure system currently north of the state will drift eastward over the weekend as another front approaches the state from the northwest. Moderate trades will veer from a more southeasterly direction today, then become light southerlies from tonight into Sunday. Winds should become light enough for near shore land and sea breezes to develop during this time. The tail end of the cold front will likely move into the northwest waters late Sunday into Monday with fresh north to northeast winds blowing in north of the front. There are still some uncertainty on how far southeast the front will move into the islands, which will alter the reach and extent of both northerly winds and rain showers over island waters. Highest chances are that the forward motion of this weak cold front stalls out near Kauai waters by Monday morning.
The current medium period north-northwest (330-340 degree) swell will continue to decline today. Surf heights will remain elevated as a series of small overlapping northwest swells will pass through the Hawaii region through the weekend into early next week. The first pulse should arrive late Saturday and peak on Sunday, followed by another pulse late Monday. A slightly larger north-northwest (330 degree) swell is expected Tuesday into Wednesday. In the long range, there is potential for a large long period northwest swell building to warning levels impacting north and west facing shores towards the end of next week.
Surf along east facing shores will remain small into next week due to the lack of persistent trade winds locally and upstream. South facing shores will remain nearly flat through the weekend. A tiny long-period south-southwest swell may produce a slight boost to south shore surf heights from late Sunday into Tuesday.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov