Maui Weather Forecast for July 21, 2023
West Side
Today: Breezy. Partly sunny with isolated light showers in the morning, then mostly sunny in the afternoon. Highs 80 to 92. East winds 10 to 25 mph. Chance of rain 20 percent.
Tonight: Partly cloudy. Breezy. Isolated light showers in the evening, then scattered light showers after midnight. Lows 70 to 78. Northeast winds 10 to 20 mph decreasing to up to 15 mph after midnight. Chance of rain 30 percent.
Saturday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 81 to 91. East winds up to 15 mph shifting to the northeast in the afternoon. Chance of rain 40 percent.
South Side
Today: Mostly sunny. Breezy. Highs around 90. Northeast winds 15 to 25 mph.
Tonight: Mostly clear. Breezy. Lows 70 to 78. Northeast winds 10 to 20 mph.
Saturday: Mostly sunny. Breezy. Highs around 90. Northeast winds 10 to 20 mph.
North Shore
Today: Mostly cloudy. Breezy. Light showers likely in the morning, then scattered light showers in the afternoon. Highs 79 to 86 near the shore to around 69 near 5000 feet. East winds 10 to 20 mph. Chance of rain 70 percent.
Tonight: Mostly cloudy. Scattered light showers in the evening, then light showers likely after midnight. Lows around 73 near the shore to 50 to 56 near 5000 feet. East winds 10 to 15 mph. Chance of rain 70 percent.
Saturday: Partly sunny with scattered showers. Highs 80 to 87 near the shore to around 68 near 5000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.
Central Maui
Today: Breezy. Partly sunny with isolated light showers in the morning, then mostly sunny in the afternoon. Highs 83 to 91. Northeast winds 15 to 25 mph. Chance of rain 20 percent.
Tonight: Partly cloudy. Breezy. Isolated light showers after midnight. Lows around 72. Northeast winds 10 to 20 mph. Chance of rain 20 percent.
Saturday: Breezy. Partly sunny with isolated showers in the morning, then mostly sunny in the afternoon. Highs 84 to 91. Northeast winds 10 to 20 mph. Chance of rain 20 percent.
Upcountry
Today: Breezy. Mostly sunny with scattered light showers in the morning, then partly sunny with isolated light showers in the afternoon. Highs around 65 at the visitor center to around 62 at the summit. East winds 10 to 20 mph. Chance of rain 40 percent.
Tonight: Partly cloudy. Isolated light showers in the evening, then scattered light showers after midnight. Lows around 51 at the visitor center to around 47 at the summit. East winds 10 to 15 mph. Chance of rain 50 percent.
Saturday: Mostly sunny with scattered showers in the morning, then partly sunny with isolated showers in the afternoon. Highs around 65 at the visitor center to around 61 at the summit. East winds 10 to 15 mph. Chance of rain 40 percent.
East Maui
Today: Mostly cloudy. Breezy. Light showers likely in the morning, then scattered light showers in the afternoon. Highs 79 to 86 near the shore to around 69 near 5000 feet. East winds 10 to 20 mph. Chance of rain 70 percent.
Tonight: Mostly cloudy. Scattered light showers in the evening, then light showers likely after midnight. Lows around 73 near the shore to 50 to 56 near 5000 feet. East winds 10 to 15 mph. Chance of rain 70 percent.
Saturday: Partly sunny with scattered showers. Highs 80 to 87 near the shore to around 68 near 5000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.
Lanai City
Today: Mostly sunny in the morning then becoming partly sunny. Breezy. Highs 73 to 81. Northeast winds 15 to 20 mph.
Tonight: Partly cloudy. Breezy. Isolated light showers in the evening. Lows around 67. Northeast winds 10 to 20 mph. Chance of rain 20 percent.
Saturday: Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs 74 to 82. Northeast winds 10 to 15 mph. Chance of rain 20 percent.
Kaunakakai
Today: Breezy. Partly sunny with isolated light showers in the morning, then mostly sunny in the afternoon. Highs 70 to 92. East winds 15 to 25 mph. Chance of rain 20 percent.
Tonight: Partly cloudy. Breezy. Isolated light showers after midnight. Lows 60 to 76. East winds 10 to 20 mph. Chance of rain 20 percent.
Saturday: Breezy. Mostly sunny with isolated showers in the morning, then partly sunny in the afternoon. Highs 70 to 93. East winds 10 to 20 mph. Chance of rain 20 percent.
Detailed Forecast
Synopsis
Breezy trade winds will continue into next week, with low clouds and brief showers favoring windward and mauka areas, especially night and morning.
Discussion
Slow-moving surface high pressure to the distant N of the islands will support breezy trade winds through the next week, with subtle day-to-day fluctuations. A nearby mid-level ridge will support a strong and relatively low subsidence inversion (currently based near 5000 feet) that will limit rainfall coverage and amounts, with brief showers over windward areas favoring nights and mornings. A persistent and seasonable trough aloft to the N of the islands will bring periods of thin high clouds through the next week.
The Big Island's leeward slopes will see afternoon and evening clouds that will drop a few showers before gradually dissipating overnight. Even with the strong stability in place, a few spots (Kealakekua and Waiaha) received close to an inch of rain in the 12 hour period ending at 2 am this morning.
Current satellite images show broken to overcast low clouds streaming over the islands from the E, with radar detecting randomly distributed light showers. Some diurnal decrease in cloud cover is expected by this afternoon, only to increase again overnight. An area of increased PWAT currently near 140W may arrive late Saturday into Sunday, bringing the potential for an increase in windward shower coverage.
Aviation
Breezy trade winds will continue through the 24-hr forecast and beyond, with clouds and light showers favoring windward and mountain areas. The broken stratus/stratocumulus deck will lead to periods of MVFR CIGS through the morning hours across windward areas, especially in and around any light showers that move through.
AIRMET Tango remains in effect for tempo moderate turbulence below 9000 feet over and immediately south through west of mountains on all islands.
AIRMET Sierra is now in effect for mountain obscuration over windward areas/slopes, which will likely persist through the morning hours.
Marine
Surface high pressure far northwest of the state will slowly move east southeast the next few days. The pressure gradient south of the weakening high will remain tight enough to maintain generally fresh to locally strong trade winds across our nearshore waters through next week. This morning's ASCAT pass across the eastern third of the island chain observed a wide swath of Small Craft Advisory (SCA) level winds through the notoriously windier Alenuihaha Channel and around Big Island's South Point. Areawide trades are forecast to slightly back off the next couple of days as the center of the high moves closer to the state but still stay up around Maui County and Big Island's coastal waters into next week.
No significant arriving swell from any direction the next several days will equate to small surf across all shores into early next week. Choppy surf primarily driven by trade wind energy along east- facing shores will remain relatively small. Very small, long period south southwest (200 degree) swell will move around the islands from Sunday through Tuesday. This background energy will provide a small bump to the south-facing shore surf heights.
HFO Watches/Warnings/Advisories
Small Craft Advisory until 6 AM HST Saturday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.
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Data Courtesy of NOAA.gov