Photo Credit: Brendan Stephen

West Kaua’i

Today: Mostly sunny with scattered showers. Highs around 87 near the shore to around 75 above 3000 feet. Light winds. Chance of rain 50 percent.

Tonight: Partly cloudy with isolated showers. Lows 66 to 71 near the shore to around 57 above 3000 feet. Light winds. Chance of rain 20 percent.

Friday: Mostly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Highs around 87 near the shore to around 75 above 3000 feet. Northeast winds around 10 mph. Chance of rain 50 percent.

South Kaua’i

Today: Mostly sunny with scattered showers. Highs around 84. Northeast winds up to 10 mph. Chance of rain 50 percent.

Tonight: Partly cloudy. Scattered showers early in the evening, then isolated showers in the late evening and overnight. Lows 64 to 70. Northeast winds around 10 mph. Chance of rain 50 percent.

Friday: Mostly sunny with scattered showers. Highs around 84. Northeast winds around 10 mph. Chance of rain 50 percent.

Kaua’i Mountains

Today: Partly sunny. Scattered showers in the morning, then showers likely in the afternoon. Highs 74 to 81 in the valleys to around 65 above 4000 feet. Light winds becoming north up to 10 mph in the afternoon. Chance of rain 70 percent.

Tonight: Partly cloudy with scattered showers. Lows 57 to 62 in the valleys to around 52 above 4000 feet. Northeast winds around 10 mph. Chance of rain 50 percent.

Friday: Partly sunny with showers likely in the morning, then mostly sunny with scattered showers in the afternoon. Highs 74 to 81 in the valleys to around 65 above 4000 feet. Northeast winds around 10 mph. Chance of rain 60 percent.

North Kaua’i

Today: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 77 to 86. North winds up to 10 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with scattered showers. Lows 60 to 70. Northeast winds around 10 mph. Chance of rain 50 percent.

Friday: Mostly sunny with scattered showers. Highs 77 to 86. Northeast winds around 10 mph. Chance of rain 50 percent.

East Kaua’i

Today: Partly sunny with scattered showers. Highs 77 to 85. North winds up to 10 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with scattered showers. Lows 58 to 72. Northeast winds around 10 mph. Chance of rain 50 percent.

Friday: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 77 to 85. Northeast winds around 10 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Expect humid conditions with pockets of heavy rainfall through today. Thunderstorms are possible across the Big Island interior this afternoon. A ridge will build north of the state Friday and drive the return of moderate trades by Friday afternoon. Windward areas could be showery at times this weekend, especially over the eastern half of the state, where increased moisture will likely linger. Trade winds will weaken again early next week.

Discussion

An upper trough moving across the western end of the state reinforced showers and triggered a few thunderstorms over coastal waters overnight, with some of this activity moving over land. The threat of heavy rainfall has diminished a bit, but brief bouts may still occur through today. Most of the heavier showers should remain offshore this morning as land breezes persist. Activity should increase over land as the day wears on and sea breezes develop. Expect pockets of heavy showers from Oahu to the Big Island during the afternoon. Thunderstorms are possible across the Big Island interior this afternoon. Showers that develop over interior areas may drift toward leeward areas this afternoon and evening.
As a ridge builds north of the state Friday, expect a return of moderate northeast trades by that afternoon. Lingering moisture will keep scattered showers across windward areas and will linger over the eastern half of the state this weekend. Depending on where the moisture stalls, we could see frequent showers over windward areas this weekend. Drier air will move in by Saturday, which should make temperatures feel much cooler than the past few days. The return of the trade winds will be short-lived as models show another front approaching the state from the northwest early next week.

Aviation

A front approaching Kauai from the northwest will maintain light and variable winds across the state today. This will continue to allow the development of local afternoon sea breeze and nighttime land breeze circulations on each of the individual islands. In addition, deep tropical moisture will remain over the area today, which will produce clouds and scattered showers across portions of the state through this morning. The clouds and showers may produce periods of MVFR ceilings and visibilities over some of the islands. Note that light rime icing is possible in some of the layered clouds above 15 thousand feet near the Big Island. These conditions are expected to gradually improve later today as the high clouds start shifting east of the area.
By this afternoon, the sea breezes will cause clouds and showers to develop over most leeward and interior sections of the state. Some locally heavy downpours are possible on some of the islands. In addition, isolated thunderstorms are in the forecast for most of the Big Island this afternoon.
No AIRMETs are in effect, and none are expected through mid- morning. AIRMET SIERRA for mountain obscuration may be needed later today for one or more islands if widespread cloud cover and showers develop over some of the higher terrain.

Marine

Light winds will prevail over the islands through today as a low north of the state keep the trades suppressed. The low will move off to the east tonight and Friday as high pressure builds northwest of the state, allowing moderate trades to return late Friday through the weekend. The trades will likely ease off again early next week as a cold front approaches from the northwest.
The current north swell will continue to slowly lower through today. A new north swell will build in late tonight and peak near advisory levels along north facing shores Friday before gradually lowering through the weekend. A north-northwest swell is forecast to arrive Saturday night, potentially producing advisory level surf for north facing shores late Sunday through early Monday. An even larger north swell is anticipated around middle of next week.
A small long-period south swell will continue to slowly fill in today, and will boost south shore surf up to around the summertime average through Saturday, before returning to mainly background levels Sunday through early next week.
East shore surf will remain well below normal for the next couple of days due to the lack of trades over and upstream of the islands, but could see a small bump over the weekend into early next week as trades briefly return.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov