Photo Credit: Pamela Goguen Lynch

West Side

Today: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 80 to 88. East winds 10 to 15 mph. Chance of rain 40 percent.

Tonight: Partly cloudy with scattered showers. Lows 69 to 76. Northeast winds 10 to 15 mph. Chance of rain 40 percent.

Sunday: Sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 80 to 88. East winds 10 to 15 mph. Chance of rain 40 percent.

South Side

Today: Sunny and breezy. Highs around 88. North winds 10 to 20 mph.

Tonight: Mostly clear. Breezy. Lows 69 to 76. North winds 10 to 20 mph.

Sunday: Sunny and breezy. Highs around 89. North winds 10 to 20 mph.

North Shore

Today: Partly sunny. Showers likely in the morning, then scattered showers in the afternoon. Highs 79 to 84 near the shore to around 67 near 5000 feet. East winds 10 to 15 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy with showers likely. Lows around 72 near the shore to 51 to 56 near 5000 feet. East winds 10 to 15 mph. Chance of rain 70 percent.

Sunday: Occasional showers in the morning, then mostly sunny with scattered showers in the afternoon. Highs 80 to 85 near the shore to around 69 near 5000 feet. East winds 10 to 15 mph. Chance of rain near 100 percent.

Central Maui

Today: Mostly sunny. Isolated showers in the morning. Highs 80 to 88. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows around 71. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Sunday: Sunny. Isolated showers in the morning. Highs 82 to 89. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Upcountry

Today: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 65 at the visitor center to around 61 at the summit. East winds 15 to 20 mph. Chance of rain 50 percent.

Tonight: Breezy. Partly cloudy with scattered showers. Lows around 50 at the visitor center to around 47 at the summit. East winds 15 to 20 mph. Chance of rain 50 percent.

Sunday: Sunny and breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 66 at the visitor center to around 61 at the summit. East winds 10 to 20 mph. Chance of rain 50 percent.

East Maui

Today: Partly sunny. Showers likely in the morning, then scattered showers in the afternoon. Highs 79 to 84 near the shore to around 67 near 5000 feet. East winds 10 to 15 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy with showers likely. Lows around 72 near the shore to 51 to 56 near 5000 feet. East winds 10 to 15 mph. Chance of rain 70 percent.

Sunday: Occasional showers in the morning, then mostly sunny with scattered showers in the afternoon. Highs 80 to 85 near the shore to around 69 near 5000 feet. East winds 10 to 15 mph. Chance of rain near 100 percent.

Lanai City

Today: Sunny. Highs 75 to 83. East winds 10 to 15 mph.

Tonight: Mostly clear. Lows around 67. Northeast winds 10 to 15 mph.

Sunday: Sunny. Isolated showers in the afternoon. Highs 74 to 83. East winds 10 to 15 mph. Chance of rain 20 percent.

Kaunakakai

Today: Mostly sunny. Isolated showers in the morning. Highs 71 to 90. East winds around 15 mph. Chance of rain 20 percent.

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

Sunday: Sunny. Isolated showers in the morning. Highs 71 to 91. East winds around 15 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Locally breezy trade winds will continue into next week, delivering passing showers that will favor windward areas. Deeper moisture will move over the islands Sunday night and Monday, likely bringing increased shower coverage, especially over the Big Island, where some heavy showers may develop.

Discussion

A lingering low-level trough about 700 miles NNW of the islands will move W and finally dissipate this weekend, allowing consolidating surface high pressure along 40N to drive breezy and locally gusty trade winds into next week. The returning trade wind flow has been gradually moistening the last couple of days, and radar this morning shows scattered showers moving ashore over windward areas, with a few small heavy rain cores noted. This gradual moistening is likely to continue through the weekend, leading to passing showers over windward areas occasionally bringing a few sprinkles to leeward areas through Sunday, especially night and morning.
Model guidance indicates that a sharp 700 mb trough currently about 700 miles SE of the Big Island (from 11N to 18N along ~146W) will move W and bring increased low- and mid-level moisture over the islands from Sunday night through Monday. Although low-level winds may only veer slightly to the ESE, the 700 mb flow will become southerly as the trough passes, leading to moisture extending as high as 12-15 kft, mainly over the Big Island. With PWAT expected to exceed 2″, the forecast includes mention of heavy showers over the Big Island Sunday night into Monday. While the moisture increase over the smaller islands is not expected to be as deep, an increase in windward showers is likely, with low-level dew points in the low- to mid-70s making it feel muggy statewide.
After the trough moves W of the islands Tuesday and Wednesday, a fairly typical trade wind weather pattern is expected. As we approach the end of the dry season however, we anticipate increased interruptions to the trade wind flow as the N Pacific storm track begins to get started. Though confidence is low, guidance has been trending toward a solution that would lead to decreasing and veering winds for a short period around the the end of next week, with trade winds increasing again in about 7-8 days.

Aviation

Moderate to locally breezy trades expected through the weekend. SHRA and low cigs with periods of MVFR conds should be focused over windward and mauka areas. VFR conds should prevail elsewhere.
AIRMET Sierra is in effect for mtn obsc for windward Big Island.

Marine

Moderate to locally strong trades continue into next week as broad high pressure develops over the NE Pacific. A Small Craft Advisory (SCA) remains posted for the typical windier waters of Maui County and the Big Island through Sunday night. The SCA may eventually require an extension through the first half of next week as the high remains nearly stationary.
Choppy surf along east facing shores will hold through the first half of next week due to persistent trades locally and upstream. A small, long period south- southwest swell will peak today generating small surf then hold into Sunday before declining Monday. Background southeast and south swells will then keep tiny surf along south facing shores through much of next week. North facing shore surf will remain nearly flat through much of next week. Models show a gale low developing and tracking along the Aleutian Islands early next week that may send a small northwest swell locally toward the end of next week.
Water levels at local tide gauges are running over half a foot above predicted and are expected to reach above the 1 foot Mean Higher High Water threshold this afternoon due to above normal water levels coinciding with the spring tides. This may result in nuisance coastal flooding around the peak high tide each afternoon through Monday. A Coastal Flood Statement has been issued to highlight this threat.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 AM HST Monday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

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Data Courtesy of NOAA.gov