Maui Weather Forecast for August 18, 2021
West Side
Today: Mostly sunny with isolated showers. Highs 80 to 86. Light winds becoming north up to 10 mph in the afternoon. Chance of rain 20 percent.
Tonight: Partly cloudy with scattered showers. Lows 67 to 75. North winds up to 10 mph shifting to the east after midnight. Chance of rain 50 percent.
Thursday: Breezy. Partly sunny with scattered showers in the morning, then sunny in the afternoon. Highs 80 to 86. East winds 10 to 20 mph. Chance of rain 40 percent.
South Side
Today: Mostly sunny with isolated showers. Highs 84 to 89. Light winds. Chance of rain 20 percent.
Tonight: Mostly clear. Lows around 67. Light winds becoming northwest up to 10 mph after midnight.
Thursday: Sunny. Isolated showers in the morning. Highs 84 to 89. East winds up to 15 mph shifting to the north in the afternoon. Chance of rain 20 percent.
North Shore
Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 80 near the shore to around 67 near 5000 feet. East winds up to 15 mph. Chance of rain 50 percent.
Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then numerous showers after midnight. Lows 66 to 72 near the shore to around 53 near 5000 feet. Southeast winds up to 15 mph increasing to 10 to 20 mph after midnight. Chance of rain 70 percent.
Thursday: Breezy. Mostly cloudy with numerous showers in the morning, then mostly sunny with scattered showers in the afternoon. Highs around 80 near the shore to around 68 near 5000 feet. East winds up to 25 mph. Chance of rain 70 percent.
Central Maui
Today: Mostly sunny with isolated showers. Highs 83 to 89. Light winds becoming northeast up to 10 mph in the afternoon. Chance of rain 20 percent.
Tonight: Partly cloudy with isolated showers. Lows 65 to 71. East winds up to 10 mph shifting to the southeast after midnight. Chance of rain 20 percent.
Thursday: Mostly sunny. Breezy. Isolated showers in the morning. Highs 83 to 89. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 20 percent.
Upcountry
Today: Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 64 at the visitor center to around 62 at the summit. Light winds becoming east up to 10 mph in the afternoon. Chance of rain 20 percent.
Tonight: Partly cloudy with scattered showers. Lows around 49 at the visitor center to around 46 at the summit. East winds up to 10 mph. Chance of rain 50 percent.
Thursday: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 62 to 72. Northeast winds 10 to 20 mph. Chance of rain 50 percent.
East Maui
Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 80 near the shore to around 67 near 5000 feet. East winds up to 15 mph. Chance of rain 50 percent.
Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then numerous showers after midnight. Lows 66 to 72 near the shore to around 53 near 5000 feet. Southeast winds up to 15 mph increasing to 10 to 20 mph after midnight. Chance of rain 70 percent.
Thursday: Breezy. Mostly cloudy with numerous showers in the morning, then mostly sunny with scattered showers in the afternoon. Highs around 80 near the shore to around 68 near 5000 feet. East winds up to 25 mph. Chance of rain 70 percent.
Lanai City
Today: Mostly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Highs 76 to 83. Light winds. Chance of rain 30 percent.
Tonight: Partly cloudy. Isolated showers after midnight. Lows around 67. South winds up to 10 mph in the evening becoming light. Chance of rain 20 percent.
Thursday: Breezy. Mostly sunny with isolated showers. Highs 76 to 83. Northeast winds up to 20 mph. Chance of rain 20 percent.
Kaunakakai
Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 75 to 89. Light winds becoming east up to 10 mph in the afternoon. Chance of rain 40 percent.
Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 62 to 74. East winds up to 15 mph. Chance of rain 40 percent.
Thursday: Mostly sunny. Breezy. Scattered showers in the morning. Highs 75 to 89. Northeast winds up to 20 mph shifting to the east 10 to 20 mph in the afternoon. Chance of rain 40 percent.
Detailed Forecast
Synopsis
Sea breezes will continue today with scattered showers in the afternoon to early evening forecast. Expect a return back to passing windward and mountain showers in moderate to locally breezy trade winds starting tonight into Saturday. A tropical low will pass just north of the islands from late Saturday into Monday disrupting the trade wind flow once again. Expect humid sea breeze conditions during the day and the potential for locally heavy showers during this time period.
Discussion
An upper level low passing north of the state will drift northwestward away from the islands through Thursday. More stable weather trends are expected as this unstable low drifts away from the state. Expect converging sea breeze winds again today with building trades by tonight. Periods of afternoon showers will develop mainly along these convergence zones favoring western and interior sections of each island.
Thursday through Saturday…The high pressure ridge will build in far north of the state, increasing trade winds into the moderate range through Saturday. Increasing atmospheric stability will also decrease shower activity with brief passing showers favoring more typical windward and mountain areas.
Sunday and Monday…A tropical low, the remnants of Tropical Cyclone Linda, will pass just north of the Hawaiian Islands shutting down the trade winds once again. Deeper tropical moisture will move up into the islands producing very humid conditions. In the absence of trade winds, local scale land and sea breezes will develop, and converging sea breeze winds will produce periods of showers over island interior sections. Some of these showers may become locally heavy at times. Due to the uncertainties of this long range pattern it remains too early for island by island weather impacts. Stay tuned for more detailed information, as the time period grows shorter, and this extended range forecast evolves.
Aviation
Trade flow will gradually return over the next few days, shifting our cloud and shower pattern to one favoring windward areas. Expect VFR conditions across the TAF sites even as low clouds stubbornly cling to portions of Oahu this morning. An area of low clouds may reach windward and southeast portions of the Big Island within the next few hours, possibly spreading MVFR ceilings there.
No AIRMETs are currently in effect.
Marine
A surface trough extending south to just east of Kauai will continue to move west of the island later today. Trade winds will be returning to the area later today through tonight with trades reaching locally strong on Thursday. This will not last long as trades are expected to turn light and variable over the weekend. This comes about as the remnants of tropical cyclone Linda passes north of the islands Sunday through Monday night.
A above normal south swell may have peaked as per deep ocean buoys 51002 and 51003 south of the islands. So the surf will be trending down gradually through the day today. A high surf advisory (HSA) is in effect for the south facing shores through this afternoon, with the likelihood that it will be extended later today. No significant swells from the south are through early next week, although small moderate period swells will prevent the surf from going flat.
A small northwest pulse will continue to trend down today as well, with no significant northerly swells expected through the period. The swell from Hurricane Linda is expected to arrive this afternoon and spread west through Thursday and maintain moderate surf along east facing shores into the weekend.
HFO Watches/Warnings/Advisories
High Surf Advisory until 6 PM HST this evening for south facing shores of all islands.
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Data Courtesy of NOAA.gov