Maui Weather Forecast for September 18, 2023
West Side
Today: Partly sunny. Breezy. Scattered showers early in the morning, then isolated showers in the late morning and afternoon. Highs 82 to 89. Northeast winds 10 to 20 mph. Chance of rain 30 percent.
Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then isolated showers after midnight. Lows 68 to 75. East winds 10 to 20 mph decreasing to up to 15 mph after midnight. Chance of rain 50 percent.
Tuesday: Partly sunny with isolated showers. Highs 82 to 89. East winds up to 15 mph. Chance of rain 20 percent.
South Side
Today: Mostly sunny. Highs 86 to 91. North winds up to 15 mph.
Tonight: Mostly cloudy. Isolated showers after midnight. Lows around 69. North winds up to 15 mph. Chance of rain 20 percent.
Tuesday: Mostly sunny in the morning then becoming partly sunny. Breezy. Highs 86 to 91. North winds up to 10 mph increasing to up to 20 mph in the afternoon.
North Shore
Today: Mostly cloudy. Breezy. Numerous showers early in the morning, then scattered showers in the late morning and afternoon. Highs 81 to 87 near the shore to 65 to 70 near 5000 feet. East winds 10 to 20 mph decreasing to up to 20 mph in the afternoon. Chance of rain 70 percent.
Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then numerous showers after midnight. Lows 65 to 72 near the shore to around 55 near 5000 feet. Southeast winds up to 20 mph becoming 10 to 15 mph after midnight. Chance of rain 70 percent.
Tuesday: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 81 to 87 near the shore to around 67 near 5000 feet. East winds up to 20 mph. Chance of rain 70 percent.
Central Maui
Today: Breezy. Partly sunny with isolated showers early in the morning, then mostly sunny in the late morning and afternoon. Highs around 89. East winds up to 25 mph increasing to 10 to 25 mph in the afternoon. Chance of rain 20 percent.
Tonight: Breezy. Mostly cloudy with isolated showers. Lows 67 to 73. East winds 10 to 20 mph decreasing to up to 15 mph after midnight. Chance of rain 20 percent.
Tuesday: Breezy. Partly sunny with isolated showers. Highs around 89. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 20 percent.
Upcountry
Today: Mostly sunny early in the morning then becoming partly sunny. Scattered showers. Highs around 63 at the visitor center to around 60 at the summit. East winds up to 15 mph. Chance of rain 50 percent.
Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 51 at the visitor center to around 48 at the summit. East winds up to 20 mph. Chance of rain 50 percent.
Tuesday: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 63 at the visitor center to around 60 at the summit. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.
East Maui
Today: Mostly cloudy. Breezy. Numerous showers early in the morning, then scattered showers in the late morning and afternoon. Highs 81 to 87 near the shore to 65 to 70 near 5000 feet. East winds 10 to 20 mph decreasing to up to 20 mph in the afternoon. Chance of rain 70 percent.
Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then numerous showers after midnight. Lows 65 to 72 near the shore to around 55 near 5000 feet. Southeast winds up to 20 mph becoming 10 to 15 mph after midnight. Chance of rain 70 percent.
Tuesday: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 81 to 87 near the shore to around 67 near 5000 feet. East winds up to 20 mph. Chance of rain 70 percent.
Lanai City
Today: Sunny early in the morning, then partly sunny with isolated showers in the late morning and afternoon. Highs 74 to 83. Northeast winds up to 15 mph. Chance of rain 20 percent.
Tonight: Mostly cloudy. Isolated showers after midnight. Lows around 68. Northeast winds up to 15 mph in the evening becoming light. Chance of rain 20 percent.
Tuesday: Partly sunny. Isolated showers in the afternoon. Highs 74 to 83. Northeast winds up to 15 mph. Chance of rain 20 percent.
Kaunakakai
Today: Partly sunny. Breezy. Isolated showers early in the morning. Highs 80 to 90. East winds 10 to 20 mph. Chance of rain 20 percent.
Tonight: Mostly cloudy with isolated showers. Lows 63 to 74. East winds 10 to 15 mph. Chance of rain 20 percent.
Tuesday: Partly sunny with isolated showers. Highs 80 to 90. East winds 10 to 15 mph. Chance of rain 20 percent.
Detailed Forecast
Synopsis
Moderate to breezy easterly trade winds will continue through the week, with clouds and showers favoring windward and mauka locations overnight through the morning periods as pockets of moisture move through. The trades may ease slightly next weekend as the ridge to the north weakens.
Discussion
Guidance remains in agreement and shows a typical easterly trade wind pattern persisting through the week as deep troughing remains off to the west and the surface ridge positioned to the north. Clouds and showers will favor windward and mauka locations, with the best chances being overnight through the early morning hours as pockets of moisture move through. Although a few showers will make it into leeward areas (inversions around 8-10 kft), rainfall accumulations should remain light. Simulated satellite imagery does depict a band of high clouds spreading over the state later today from west to east, then lingering through the first half of the week due to the upper trough/low off to the west. Any high clouds that move in should clear out through the second half of the week as upper heights rise and the upper flow shifts. For the extended forecast, guidance shows a weakness forming in the ridge to the north, which could lead to our trades easing slightly next weekend if it materializes.
Aviation
Surface high pressure north of the state will continue to bring moderate to locally breezy trades the islands through the forecast period. An inversion height of 8 to 10 kft will allow for scattered moderate to occasionally heavier showers along windward locations. In addition, isolated activity may push over the elevated terrain and affect leeward areas. Brief periods of MVFR ceilings and visibility may accompany some of the more robust showers this morning.
AIRMET SIERRA remains in effect above 2500 feet for north through east sections of Oahu and the Big Island for tempo mountain obscuration from clouds and showers.
Marine
A high far northeast of the main Hawaiian Islands will continue to drive moderate to strong trade winds across local waters. A Small Craft Advisory (SCA) remains in effect through Wednesday afternoon for the typical windier waters around Maui and the Big Island. This SCA will likely be extended through the end of the week.
A small, medium to long period south (170-180 degree) swell will slowly decrease today and Tuesday. Another long period background south swell will arrive late Tuesday through Wednesday, boosting surf heights slightly along south facing shores. Persistent moderate trade winds will keep small east chop into next week. No significant swells are expected to reach north and west facing shores for the next seven days.
HFO Watches/Warnings/Advisories
Small Craft Advisory until 6 PM HST Wednesday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.
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Data Courtesy of NOAA.gov