West Side

Today: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 77 to 84. Northeast winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly clear. Lows 68 to 75. Northeast winds up to 15 mph.

Sunday: Sunny. Highs 78 to 84. Northeast winds up to 15 mph.

South Side

Today: Mostly sunny with isolated showers. Highs 76 to 85. North winds up to 15 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Lows 67 to 75. North winds up to 15 mph.

Sunday: Sunny and breezy. Highs 77 to 86. North winds up to 20 mph.

North Shore

Today: Partly sunny with scattered showers. Highs 80 to 85 near the shore to around 67 near 5000 feet. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers in the evening, then mostly clear with isolated showers after midnight. Lows 70 to 75 near the shore to around 52 near 5000 feet. East winds 10 to 15 mph shifting to the southeast after midnight. Chance of rain 40 percent.

Sunday: Breezy. Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 80 to 85 near the shore to around 67 near 5000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

Central Maui

Today: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 79 to 86. Northeast winds up to 15 mph. Chance of rain 40 percent.

Tonight: Partly cloudy with isolated showers in the evening, then clear after midnight. Lows 66 to 72. Northeast winds up to 15 mph. Chance of rain 20 percent.

Sunday: Sunny and breezy. Highs 79 to 86. Northeast winds up to 20 mph increasing to 10 to 20 mph in the afternoon.

Upcountry

:

East Maui

Today: Partly sunny with scattered showers. Highs 80 to 85 near the shore to around 67 near 5000 feet. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers in the evening, then mostly clear with isolated showers after midnight. Lows 70 to 75 near the shore to around 52 near 5000 feet. East winds 10 to 15 mph shifting to the southeast after midnight. Chance of rain 40 percent.

Sunday: Breezy. Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 80 to 85 near the shore to around 67 near 5000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

Lanai City

Today: Mostly sunny with isolated showers. Highs 72 to 79. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Breezy. Lows around 67. Northeast winds 10 to 20 mph.

Sunday: Sunny and breezy. Highs 73 to 79. Northeast winds 10 to 20 mph.

Kaunakakai

Today: Mostly sunny with isolated showers. Highs 71 to 85. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 20 percent.

Tonight: Mostly clear. Lows 59 to 74. Northeast winds 10 to 15 mph.

Sunday: Sunny and breezy. Highs 71 to 84. Northeast winds 10 to 20 mph.

Detailed Forecast

Synopsis

A weak surface trough will gradually move east to west across the islands through tonight, resulting in light winds and land/sea breeze showers. As this trough dissipates, trades will build in stronger through Monday. Trades will be on the increase Tuesday onward.

Discussion

Windward and mauka showers with some limited spillover to leeward areas are ongoing across the island chain. Satellite indicates low clouds over or near the higher terrain on each island, along with high clouds streaming in from the southwest.
A weak surface trough near Maui will slowly drift westward, reaching Kauai on Sunday. Trade winds will build in behind this trough from east to west through the weekend. Wind speeds will initially be light to moderate, but will become moderate to locally breezy into early next week. This trough will keep winds weak enough to allow for land/sea-breeze showers to occasionally develop over leeward areas, even as trade winds build in and bring their typical windward and mauka focused showers.
While that is occurring at the surface, the flow aloft will change significantly. We will transition from weak troughing to our north this weekend to the rapid development of a closed ridge to our northwest by Monday. This ridge will become elongated along an east-west axis and remain with us all next week. Its presence will keep a surface ridge in place, allowing the trades to blow at least through the end of next week, and likely longer. This means mainly windward and mauka showers will hang around. There will be occasional fluctuations in available moisture throughout this period, and these will result in periods of enhanced shower activity from time to time.

Aviation

Light to moderate trades gradually return tonight, becoming locally breezy today and persisting through the next several days. Expect cloud and shower activity to develop along the typical windward and mauka areas, resulting in periods of MVFR conditions. Otherwise, VFR conditions will prevail.
AIRMET Sierra remains in effect for mountain obscuration over much of the state due to lingering showers.
There may be the need for AIRMET Tango for low-level turbulence as trades gradually return.

Marine

A high pressure ridge will remain in place north of the islands with gentle to fresh trade winds for most coastal waters with periods of strong trade winds developing over the windier waters and channels near Maui and the Big Island from Sunday onward. A Small Craft Advisory may be needed for these windier waters by tonight or possibly by Sunday.
A declining medium period northwest swell and associated surf heights along north and west facing shores will slowly fade through the weekend. Small north-northwest medium period swell energy will keep surf heights on the small side through the first half of next week.
The current small south swell energy will fade through the weekend. Small pulses of background long period swell energy will keep surf heights along south facing shores above flat levels.
Surf along east facing shores will remain below normal this weekend, but will gradually increase next week as trade winds strengthen.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov