West Kaua’i

Tonight: Mostly cloudy. Breezy. Lows around 76 near the shore to around 67 above 3000 feet. East winds 10 to 25 mph.

Tuesday: Mostly cloudy. Windy. Numerous showers in the morning, then frequent showers in the afternoon. Highs around 87 near the shore to around 77 above 3000 feet. East winds 10 to 30 mph shifting to the southeast 20 to 30 mph in the afternoon. Chance of rain 90 percent.

Tuesday Night: Windy. Frequent showers. Lows around 75 near the shore to around 66 above 3000 feet. Southeast winds 15 to 30 mph with gusts to 50 mph. Chance of rain near 100 percent.

South Kaua’i

Tonight: Breezy. Mostly cloudy with isolated showers. Lows 73 to 78. East winds 10 to 20 mph. Chance of rain 20 percent.

Tuesday: Mostly cloudy. Breezy. Scattered showers in the morning, then frequent showers in the afternoon. Highs 80 to 88. Southeast winds 10 to 25 mph. Chance of rain 80 percent.

Tuesday Night: Breezy. Frequent showers. Lows 72 to 77. Southeast winds 15 to 25 mph. Chance of rain near 100 percent.

Kaua’i Mountains

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 71 in the valleys to around 63 above 4000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Tuesday: Cloudy and windy. Numerous showers in the morning, then frequent showers in the afternoon. Highs 74 to 82 in the valleys to around 68 above 4000 feet. Southeast winds 10 to 20 mph increasing to 15 to 30 mph in the afternoon. Chance of rain 90 percent.

Tuesday Night: Windy. Frequent showers. Lows around 71 in the valleys to around 63 above 4000 feet. South winds 10 to 30 mph with gusts to 50 mph. Chance of rain near 100 percent.

North Kaua’i

Tonight: Breezy. Mostly cloudy with isolated showers. Lows 67 to 77. Southeast winds 10 to 20 mph. Chance of rain 20 percent.

Tuesday: Mostly cloudy. Breezy. Scattered showers in the morning, then numerous showers in the afternoon. Highs 71 to 87. Southeast winds 10 to 20 mph. Gusts up to 40 mph in the afternoon. Chance of rain 70 percent.

Tuesday Night: Mostly cloudy. Breezy. Numerous showers in the evening, then frequent showers after midnight. Lows 67 to 76. Southeast winds 10 to 25 mph with gusts to 45 mph. Chance of rain 80 percent.

East Kaua’i

Tonight: Breezy. Mostly cloudy with isolated showers. Lows 69 to 78. East winds 10 to 20 mph. Chance of rain 20 percent.

Tuesday: Cloudy and breezy. Scattered showers in the morning, then frequent showers in the afternoon. Highs 77 to 86. Southeast winds 10 to 15 mph increasing to 15 to 25 mph in the afternoon. Chance of rain 90 percent.

Tuesday Night: Breezy. Frequent showers. Lows 68 to 77. Southeast winds 15 to 25 mph. Chance of rain near 100 percent.

Detailed Forecast

Synopsis

Breezy east southeast winds with a drier airmass will limit clouds and showers through tonight. Clouds and showers will increase Tuesday through Thursday as Nolo passes to the west with rain bands along the east side of the storm encroaching Kauai and Oahu. Nolo moves away to the northwest by this weekend with trades filling in.

Discussion

Breezy east southeast winds with a drier airmass will limit clouds and showers tonight. Major Hurricane Nolo (cat. 4) is around 415 miles west southwest of Honolulu this afternoon and has made it's turn to the northwest. Main impacts in the short-term will be the breezy, but weakening winds across the state due to the pressure difference between Nolo and the subtropical high far to the northeast, and the southwest swell directed towards Kauai. Nolo will weaken down to a cat. 1 hurricane and stall around 250 to 300 miles west of Kauai on Tuesday night and Wednesday, then continue on a more west northwesterly track away from the state through the second half of the week.
Winds will remain brisk and gradually veer southeasterly as Nolo gains latitude. Rain bands along Nolo's eastern flank will bring an increase in rainfall across Kauai beginning Tuesday and Oahu by Tuesday night, as the southeasterly flow directs showers over populated areas of both islands. Guidance shows varying amounts and lengths of time that the bands will impact the western end of the state, and will ultimately depend on Nolo's eventual path over the next few days. QPF has been adjusted for the Tuesday to Thursday period with 3 to 6 inches of additional rain on Kauai and Niihau, and up to 4 inches on Oahu. Not considering a Flood Watch at this time with the anticipation these rainfall amounts will be spread out over several days and showers should be moving along quickly.
East southeasterly winds will continue, but gradually weaken, through the second half of the week as Nolo tracks away. By this weekend, trade winds are forecast to build in bringing drier and more stable conditions again.

Aviation

Breezy trade winds continue through this evening before winds decrease overnight. Trade winds are generally expected to be lighter tomorrow as Hurricane Nolo continues to move away from the state. Trade showers continue to the east of the islands and across windward and mountain locations. Tuesday afternoon into Wednesday, there will be an increase in moisture being transported towards Kauai and Oahu which will bring an increased likelihood of shower chances there. Showers are most likely across Kauai starting late Tuesday morning with shower chances gradually increasing for Oahu late Tuesday into Wednesday.
AIRMET Tango remains in effect for moderate turbulence below 9,000 feet over and immediately downwind of island terrain. This AIRMET will likely be needed through mid- week.

Marine

Strong E trades become moderate to breezy out of the SE tonight in response to Hurricane Nolo advancing northwestward. The exception will be around Kauai where proximity to Nolo will allow for the gradient to remain strong. Near gales will be possible immediately west of Kauai tonight through Wednesday, particularly in the channel between Kauai and Niihau. Here, the Small Craft Advisory (SCA) has been extended through Wednesday for both winds and seas. Elsewhere, the SCA remains in place and is still scheduled to expire Tuesday morning. Moderate easterlies
Tiny long period energy out of the S is noted on the Barber's Point PacIOOS Buoy this afternoon. This energy represents the initial forerunners of a rather small (about 1 foot), long period swell that will maintain elevated surf for S shores through mid- week. This is separate from the more substantial short to medium period fresh swell emanating from Nolo which has prompted today's High Surf Advisories (HSA) for S shores and W facing shores of the Big Island. Uncertainty related to the size of Nolo's swell coupled with its slow forward motion Tuesday night through Wednesday will be a theme in the forecast for the next couple of days. The latest observations support expiring the HSA for all but Kauai and Niihau where the bulk of the SW energy is directed. For Kauai/Niihau in particular, high surf may linger into midweek conditional on the exact size of Nolo's swell. Likewise, as Nolo lifts north, it's westerly swell influence will increase potentially supporting an HSA for Big Island-West during the middle of this week.
Surf along E shores slowly declines as trades veer to SE and diminish then return as light to moderate easterlies this weekend. A small, long period S swell originating east of New Zealand is poised to arrive early next week in maintenance of elevated surf along S facing shores.
For N facing shores, the existing small medium period swell fades through Wednesday. Multiple rounds of tiny swell originating out of the NW quadrant will reach N and select W facing exposures next week as the storm track in the vicinity of the Aleutian Islands becomes increasingly active.

Fire weather

Dry and stable with breezy east southeast winds expected through through tonight, with a gradual increase in humidity through midweek. Moisture drawn northward along the eastern sides of Nolo will increase rain chances across the western part of the state. Fire conditions will improve statewide over the next couple days as winds weaken and humidity levels rise.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 AM HST Tuesday for Niihau, Kauai Leeward, Kauai South.
Small Craft Advisory until 6 PM HST Wednesday for Kauai Northwest Waters, Kauai Leeward Waters.
Small Craft Advisory until 6 AM HST Tuesday for Kauai Windward Waters, Kauai Channel, Oahu Windward Waters, Oahu Leeward Waters, Kaiwi Channel, Maui County Windward Waters, Maui County Leeward Waters, Pailolo Channel, Alenuihaha Channel, Big Island Windward Waters, Big Island Leeward Waters, Big Island Southeast Waters.

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Data Courtesy of NOAA.gov