Weather Forecast

Maui Weather Forecast for April 21, 2021

April 21, 2021, 7:15 AM HST
A
A
A

no slideshow

Photo Credit: Jeni Ji Cousins

West Side

Today: Mostly sunny, with a high near 85. Northeast wind 6 to 8 mph becoming west southwest in the morning.

Tonight: Partly cloudy, with a low around 65. Northeast wind 5 to 8 mph.

Thursday: Mostly sunny, with a high near 85. East northeast wind around 9 mph.

South Side

Today: Isolated showers after noon. Mostly sunny, with a high near 85. East wind 6 to 8 mph becoming west southwest in the morning. Chance of precipitation is 20%.

Tonight: Partly cloudy, with a low around 64. East northeast wind 6 to 8 mph.

ARTICLE CONTINUES BELOW AD

Thursday: Mostly sunny, with a high near 85. East northeast wind 8 to 10 mph.

North Shore

ARTICLE CONTINUES BELOW AD

Today: Isolated showers before noon. Mostly sunny, with a high near 84. Southeast wind 6 to 9 mph becoming north in the morning. Chance of precipitation is 20%.

Tonight: Isolated showers. Partly cloudy, with a low around 64. Breezy, with an east wind 9 to 17 mph, with gusts as high as 23 mph. Chance of precipitation is 20%.

Thursday: Mostly sunny, with a high near 84. Breezy, with an east wind around 17 mph, with gusts as high as 24 mph.

Central Maui

ARTICLE CONTINUES BELOW AD

Today: Mostly sunny, with a high near 84. West wind 6 to 11 mph becoming east northeast in the morning.

Tonight: Partly cloudy, with a low around 63. East wind 7 to 14 mph, with gusts as high as 18 mph.

Thursday: Mostly sunny, with a high near 84. East wind around 14 mph, with gusts as high as 18 mph.

Upcountry

Today: Partly sunny, with a high near 71. East wind around 7 mph becoming southwest in the morning.

Tonight: Partly cloudy, with a low around 54. East wind 5 to 9 mph.

Thursday: Mostly sunny, with a high near 71. East northeast wind 9 to 11 mph.

East Maui

Today: Scattered showers, mainly before 1pm. Partly sunny, with a high near 82. Southwest wind 6 to 11 mph becoming east in the morning. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Showers likely, mainly after 1am. Mostly cloudy, with a low around 61. East wind 8 to 11 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

Thursday: Showers likely, mainly before 7am. Partly sunny, with a high near 82. East wind around 11 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

Lanai City

Today: Scattered showers after noon. Partly sunny, with a high near 75. East wind 7 to 9 mph becoming southwest in the morning. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Isolated showers. Partly cloudy, with a low around 62. Northeast wind 5 to 8 mph. Chance of precipitation is 20%.

Thursday: Partly sunny, with a high near 75. East northeast wind 8 to 10 mph.

Kaunakakai

Today: Mostly sunny, with a high near 84. East wind 7 to 9 mph becoming west in the morning.

Tonight: Partly cloudy, with a low around 70. Breezy, with an east wind 9 to 15 mph, with gusts as high as 20 mph.

Thursday: Mostly sunny, with a high near 83. Breezy, with an east wind 15 to 18 mph, with gusts as high as 25 mph.

Detailed Forecast

Synopsis

High clouds will gradually decrease today. Leeward sea breezes will support inland clouds and a few showers this afternoon. Breezy trades and more typical trade wind weather will return by the end of the week.

Discussion

Overcast mid and high clouds are thinning and slowly pushing southward as an upper wave shifts east of the area. Showers remain confined to the adjacent waters of Kauai and southeast sections of Big Island. Light winds and land breezes will maintain dry conditions over the smaller islands through early this morning. Mid-level subsidence associated with a building ridge from the west will bring an increase in stability today. However, the existing ribbon of deep moisture over the area will still hold in place through at least the lowest 10kft. As a result, afternoon leeward sea breezes should have an easy time causing afternoon cloud build-ups and a even few showers over inland areas. The same could be said for Thursday, although the gradual increase in trades reduces confidence in sea breeze development. So, showers may instead manifest in more typical trade wind fashion by Thursday afternoon, especially for Oahu through Big Island.
Locally breezy trades will return by week’s end as high pressure establishes over the north-central pacific. There is strong model consensus that weak shortwave energy currently near 170E/35N will shear toward the islands along the eastern periphery of the building ridge, eventually cutting off near or directly over the area this weekend. The resulting reduction in stability will support a wetter trade wind pattern for the weekend. Low confidence with respect to the to the evolution of this closed low results in higher than normal forecast uncertainty by early next week.

Aviation

A trough northwest of the islands continues to spread layered clouds across the whole of the state. As of 2am HST, radar indicated only isolated light showers within the layered clouds. These conditions are expected to persist throughout the day today. Mostly clear skies developing across the smaller islands late this evening.
On the Big Island, weak southeasterly flow will steer bands of low topped clouds and isolated showers towards east facing slopes and coasts this morning. In the afternoon and early evening hours, light sea breezes will focus shower activity over the island’s interior.
SIGMET Xray is in effect for severe turbulence above FL320 associated with a digging upper level trough. The band of moderate to severe upper level turbulence currently affects all the smaller islands and will spread across the Big Island within the next few hours. Conditions should improve from the northwest later this morning.

Marine

A trough northwest of Kauai will gradually dissipate through Friday. In doing so, light trade winds are expected to spread westward from Maui and the Big Island today. A surface high is forecast to pass north of the islands Thursday through Friday, resulting in a boost in the trade winds with speeds reaching locally strong for especially the sensitive nearshore areas of Maui County and waters south of the Big Island. This breezy trades will persist through Sunday followed by a drop off Sunday night into Monday. A Small Craft Advisory for those nearshore waters will be hoisted as early as tonight.
A small to moderate northwest swell arriving today will lead to a bump up to the north and west facing shores. This swell will max out Thursday followed by a gradual decline through Friday. A small to moderate long period west-northwest swell is slated to arrive next week Monday night and peak Tuesday, followed by a slow decline. A continuous stream of small but long period swell from the south and southwest will maintain small surf to the south facing shores throughout the forecast period. The return of the trade wind means the surf along the east facing shores will be on the rise between Friday and Saturday when the trades turn breezy. Expect surf to build to small to moderate heights. Surf along the east facing shores will be on the downtrend Monday as the trade winds weaken.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov

E-Mail Newsletters Receive daily or weekly updates via e-mail. Subscribe Now
News Alerts Breaking news alerts on your mobile device. Get the App

Comments

This comments section is a public community forum for the purpose of free expression. Although Maui Now encourages respectful communication only, some content may be considered offensive. Please view at your own discretion. View Comments