Photo Credit: Joan M. Flake

West Side

Today: Sunny. Isolated showers in the afternoon. Highs 81 to 90. East winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 69 to 77. East winds 10 to 15 mph. Chance of rain 30 percent.

Friday: Sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 80 to 89. Light winds becoming east around 10 mph in the afternoon. Chance of rain 30 percent.

South Side

Today: Sunny. Highs around 89. North winds 10 to 15 mph.

Tonight: Mostly clear. Lows 68 to 77. North winds around 10 mph.

Friday: Sunny. Highs around 89. Light winds becoming north around 10 mph in the afternoon.

North Shore

Today: Partly sunny with scattered showers. Highs 78 to 88 near the shore to around 68 near 5000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then showers likely after midnight. Lows around 72 near the shore to 50 to 56 near 5000 feet. Southeast winds 10 to 15 mph. Chance of rain 70 percent.

Friday: Mostly cloudy with showers likely in the morning, then mostly sunny with scattered showers in the afternoon. Highs 78 to 88 near the shore to around 68 near 5000 feet. East winds 10 to 15 mph. Chance of rain 70 percent.

Central Maui

Today: Sunny and breezy. Highs 84 to 90. Northeast winds 10 to 20 mph.

Tonight: Partly cloudy with isolated showers. Lows 69 to 74. East winds 10 to 15 mph in the evening becoming light. Chance of rain 20 percent.

Friday: Sunny. Isolated showers in the morning. Highs 84 to 91. Light winds becoming northeast around 10 mph in the afternoon. Chance of rain 20 percent.

Upcountry

Today: Mostly sunny. Breezy. Isolated showers in the morning, then scattered showers in the afternoon. Highs around 63 at the visitor center to around 57 at the summit. East winds 10 to 20 mph. Chance of rain 40 percent.

Tonight: Breezy. Partly cloudy with scattered showers. Lows around 50 at the visitor center to around 46 at the summit. East winds 10 to 20 mph. Chance of rain 50 percent.

Friday: Mostly sunny with scattered showers. Highs around 61 at the visitor center to around 55 at the summit. East winds 10 to 15 mph. Chance of rain 50 percent.

East Maui

Today: Partly sunny with scattered showers. Highs 78 to 88 near the shore to around 68 near 5000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then showers likely after midnight. Lows around 72 near the shore to 50 to 56 near 5000 feet. Southeast winds 10 to 15 mph. Chance of rain 70 percent.

Friday: Mostly cloudy with showers likely in the morning, then mostly sunny with scattered showers in the afternoon. Highs 78 to 88 near the shore to around 68 near 5000 feet. East winds 10 to 15 mph. Chance of rain 70 percent.

Lanai City

Today: Sunny. Highs 75 to 82. Northeast winds 10 to 15 mph.

Tonight: Mostly clear. Lows 64 to 69. Northeast winds 10 to 15 mph in the evening becoming light.

Friday: Sunny. Isolated showers in the afternoon. Highs 74 to 81. Light winds becoming southeast around 10 mph in the afternoon. Chance of rain 20 percent.

Kaunakakai

Today: Sunny and breezy. Highs 72 to 91. Northeast winds 10 to 20 mph.

Tonight: Mostly clear with isolated showers. Lows 60 to 76. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Friday: Sunny. Isolated showers in the morning. Highs 71 to 91. Light winds becoming east around 10 mph in the afternoon. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Light to moderate trade winds will deliver low clouds and a few showers to windward areas through Friday, while leeward areas remain mostly dry. Lighter winds on Saturday may allow a few afternoon showers to develop over leeward and interior areas. Moisture associated with a dissipating front could bring more widespread windward showers on Sunday and Monday, especially to Kauai and Oahu, with trade winds increasing slightly.

Discussion

Mostly dry trade wind weather remained in place most of the night, but a slight increase in low-level moisture associated with a weak low-level trough has brought a few showers to windward portions of Maui and the Big Island. A mid-level ridge centered NW of the islands will continue to support a relatively low and strong subsidence inversion, so this increased moisture will likely only lead to a modest increase in primarily windward showers over the next 24 hours or so. Light to moderate trade winds will prevail through Friday, supported by a surface high pressure cell centered far NE of the islands.
A cut-off deep-layer low will develop far to the NE on Friday, then move S along 150W this weekend, sending an associated front toward the islands from the N. This will substantially weaken the local pressure gradient Friday night into Saturday, with some uncertainty with the forecast thereafter. The light winds will briefly allow land and sea breezes to influence weather over land, with clouds and showers over interior areas during the afternoon, becoming mostly clear night and morning.
Reduced forecast confidence thereafter is due to somewhat inconsistent model guidance regarding the southward progression of the front on Sunday and Monday, but a consensus appears to be developing. A weakening E-W oriented band of showery low clouds is now anticipated to move S over Kauai and Oahu Sunday and Monday, with a slight increase in NE winds over Kauai, before the boundary stalls and dissipates over the islands through Tuesday. This is somewhat early in the season for a frontal boundary to make it to the latitude of the islands, so a significant air mass change is not expected. It does appear increasingly likely that a band of clouds and showers will move over Kauai and Oahu, bringing mainly windward showers, Sunday into Monday.

Aviation

High pressure far northeast of the state will maintain light to moderate trade winds through the forecast period. The relatively dry air mass will continue to limit cloud and shower activity for most areas today. Expect mainly VFR conditions, but the old front near Kauai may bring a few isolated showers this morning. Will see an increase in clouds and showers across windward areas tonight as moisture arrives from the east. Conditions will remain mainly VFR, but could see occasional MVFR conditions under passing showers.
No AIRMETs are currently in effect. However, AIRMET Sierra for mountain obscuration over windward areas may be needed tonight.

Marine

A weak high pressure ridge north of the state will continue to produce moderate to fresh trade winds into Friday morning. Wind speeds will weaken by Friday afternoon as a cold front dropping in out of the north will weaken the ridge. Expect light to moderate trade winds from Friday onward as this weakening frontal boundary slows down and then stalls out near Kauai and Oahu on Sunday. Moderate to locally fresh trade winds move into the region just north of the front, these stronger trades will spread across the region by Tuesday as the frontal boundary fades away.
A series of small north and northwest swells are expected along north facing exposures through Friday. Forerunners from a slightly larger north-northwest swell will fill in Friday and peak over the weekend. A cut off low will develop far north of the state on today through Friday, sending a north swell towards the islands arriving by Sunday. A decent fetch area will point towards Hawaii with 20 to 35 knots of wind developing around the west side of the low center. Depending on how the storm develops over the next 48 hours, we could see surf heights approaching High Surf Advisory thresholds along north facing shores on Monday.
Surf will remain small along south facing shores over the next few days with mainly background energy from the south and southeast. Another small, a more noticeable long-period south swell is expected to fill in Sunday into Monday then decline through the middle of next week.
East facing shores will remain small during the next several days due to the lack of strong trade winds upstream of the state. Areas exposed to the north should see an increase Sunday into Monday as a moderate north-northeast swell wraps into select eastern exposures.

HFO Watches/Warnings/Advisories

None.

Maui Now Weather is brought to you by Blue Hawaiian Helicopters.

Check out their Maui Helicopter Tours today!

Data Courtesy of NOAA.gov