Photo Credit: Sebastien Gabriel

West Kaua’i

Today: Sunny. Highs 76 to 84 near the shore to around 70 above 3000 feet. Northeast winds up to 10 mph in the morning becoming light.

Tonight: Mostly clear. Lows 62 to 68 near the shore to around 56 above 3000 feet. Northeast winds up to 10 mph increasing to 10 to 15 mph after midnight.

Sunday: Sunny. Highs 77 to 85 near the shore to around 71 above 3000 feet. Northeast winds up to 15 mph.

South Kaua’i

Today: Mostly sunny. Breezy. Highs 75 to 83. Northeast winds 15 to 20 mph.

Tonight: Partly cloudy. Breezy. Lows around 67. Northeast winds 10 to 20 mph.

Sunday: Mostly sunny. Breezy. Highs 76 to 84. Northeast winds 10 to 20 mph.

Kaua’i Mountains

Today: Mostly sunny. Highs 68 to 75 in the valleys to around 60 above 4000 feet. Northeast winds up to 15 mph.

Tonight: Partly cloudy in the evening, then mostly cloudy with isolated showers after midnight. Lows 56 to 65 in the valleys to around 53 above 4000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Sunday: Partly sunny. Breezy. Isolated showers early in the morning. Highs 70 to 77 in the valleys to around 62 above 4000 feet. Northeast winds up to 15 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 20 percent.

North Kaua’i

Today: Mostly sunny. Highs 70 to 80. East winds up to 15 mph shifting to the northeast in the afternoon.

Tonight: Partly cloudy. Isolated showers after midnight. Lows 59 to 68. East winds around 10 mph. Chance of rain 20 percent.

Sunday: Mostly sunny. Isolated showers early in the morning. Highs 72 to 80. East winds 10 to 15 mph. Chance of rain 20 percent.

East Kaua’i

Today: Mostly sunny. Highs 68 to 80. Northeast winds 10 to 15 mph.

Tonight: Partly cloudy in the evening, then mostly cloudy with isolated showers after midnight. Lows 60 to 71. North winds 10 to 15 mph. Chance of rain 20 percent.

Sunday: Partly sunny early in the morning then becoming mostly sunny. Breezy. Isolated showers early in the morning. Highs 70 to 81. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

A cold front has diminished into a trough, leaving behind a remnant moisture axis with some showers lingering this morning over the Big Island. Elsewhere across the state, much drier and more stable conditions have filled in, which will persist through the weekend. A gradual return to a more typical trade wind pattern is anticipated Sunday night through Tuesday, with showers favoring windward and mauka areas. Rainfall chances could increase again around midweek as another cold front approaches, though uncertainty remains regarding its potential impact on winds and rainfall distribution.

Discussion

Latest satellite imagery shows a remnant moisture axis associated with a diminished cold front near the Big Island, bringing a brief period of showers to windward areas of the Big Island as it continues southeastward. This moisture axis is expected to clear the Big Island by this afternoon. Dewpoints are expected to hover in the mid- to upper-50s across the region as a much drier and stable airmass fills in through the weekend. Northerly winds combined with the dry air, brings a low probability of fire weather concerns during the afternoons today and Sunday, with the primary factor in the lowered probabilities being that winds fall short of the threshold.
As the remnant boundary exits the region, the latest analysis continues to show a broad, mid-level ridge anchored just to the west, building eastward toward the islands. Trade winds will reestablish themselves by the end of the weekend, leading to a return of windward and mauka showers Sunday night through Tuesday. Stronger model consensus indicates a strong mid-latitude disturbance, which could bring another cold front to the forecast area by midweek. However, uncertainty remains high regarding the development and timing of the mid-level wave and its attendant cold front, ranging from a benign, progressive frontal passage, as portrayed by the GFS, to a more well-developed front, as shown by the Euro.

Aviation

The remnants of a dissipated cold front will continue to push clouds and a few showers into the north and east slopes of the Big Island this morning. These low clouds will linger through the morning hours with brief MVFR conditions possible in showers. Northeasterly winds will bring stable and dry conditions for most areas lasting through Sunday.
AIRMET Sierra for mountain obscuration remains in effect over the North through East slopes of the Big Island this morning. Drier conditions will cause these low cloud CIGS to diminish from the late morning to afternoon hours.

Marine

A trough is hanging up near Big Island this morning. Scattered storms in association with this boundary are impacting the far eastern offshore waters. This activity will move east of the area later today. High pressure building in behind the front will strengthen trade winds tonight. Moderate to locally strong trades will occur from tonight through early Tuesday.
The large, long period northwest (300-320 degree) swell that peaked last night will steadily decline through the day. This will translate to slowly declining surf today, a more significant drop tomorrow. North and west facing surf will fall to borderline warning levels by mid-day and be at advisory levels tonight. Thus, a High Surf Warning (HSW) remains in effect for the north and west- facing shores of Niihau, Kauai, Oahu, Molokai, along with north facing shores of Maui, through the afternoon. Surf is peaking early this morning on the west-facing shores of Big Island. A HSW also remains in effect for these shores through the day. A Small Craft Advisory (SCA) is in effect today for elevated seas brought on by this passing large northwest swell. The SCA will be pared back to the windier waters surrounding Maui County and Big Island Sunday. The next northwest swell is scheduled to arrive next Tuesday into Wednesday. This swell could generate advisory level surf along many north and west-facing shores.
The recent 2 to 3 foot south swell that peaked last night will gradually decline this weekend. South surf should return to background levels, or be nearly flat, by the middle of next week.
East-facing shore surf will become more choppy the next couple of days as a result of post-frontal moderate trade flow. East shore surf becomes more rough Sunday and Monday in response to strengthening trades. Select northeastern to eastern exposures may experience some wrap today from the passing large northwest swell.

Fire weather

The likelihood for critical fire weather conditions remains low through the period, with the best chances been this afternoon and again Sunday due to the dry air that has filled in behind a cold front that moved through Friday.

HFO Watches/Warnings/Advisories

High Surf Warning until 6 PM HST this evening for Niihau, Kauai Leeward, Waianae Coast, Oahu North Shore, Maui Windward West, Kona, Kohala, Kauai North, Molokai Windward, Molokai North, Molokai West, Maui Central Valley North, Windward Haleakala, Big Island South.
Small Craft Advisory until 6 PM HST this evening for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Kauai Channel, Oahu Windward Waters, Oahu Leeward Waters, Kaiwi Channel, Maui County Windward Waters, Maui County Leeward Waters, Big Island Windward Waters, Big Island Leeward Waters.
Small Craft Advisory until 6 AM HST Monday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Southeast Waters.

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