Photo Credit: Braden Jarvis

West Kaua’i

Today: Mostly sunny. Chance of showers in the morning, then slight chance of showers in the afternoon. Highs 81 to 86 near the shore to around 73 above 3000 feet. Light winds. Chance of rain 40 percent.

Tonight: Mostly clear with a 20 percent chance of showers. Lows around 68 near the shore to around 58 above 3000 feet. Light winds.

Tuesday: Sunny. Highs 82 to 87 near the shore to around 74 above 3000 feet. Light winds becoming southwest up to 10 mph in the afternoon.

South Kaua’i

Today: Sunny. Highs 79 to 86. Light winds becoming north up to 10 mph in the afternoon.

Tonight: Mostly clear. A 20 percent chance of showers after midnight. Lows around 67. North winds up to 10 mph.

Tuesday: Sunny. A 20 percent chance of showers in the morning. Highs 80 to 87. Northeast winds up to 15 mph.

Kaua’i Mountains

Today: Partly sunny with chance of showers in the morning, then mostly sunny with slight chance of showers in the afternoon. Highs 71 to 80 in the valleys to around 64 above 4000 feet. Light winds becoming north up to 10 mph in the afternoon. Chance of rain 50 percent.

Tonight: Partly cloudy with a 20 percent chance of showers. Lows around 67 in the valleys to around 54 above 4000 feet. Light winds.

Tuesday: Mostly sunny with a 30 percent chance of showers. Highs 72 to 81 in the valleys to around 65 above 4000 feet. Light winds becoming northeast up to 15 mph in the afternoon.

North Kaua’i

Today: Mostly sunny with a 20 percent chance of showers. Highs 73 to 84. West winds up to 10 mph shifting to the north in the afternoon.

Tonight: Partly cloudy with a 20 percent chance of showers. Lows 61 to 69. Light winds.

Tuesday: Mostly sunny with a 20 percent chance of showers. Highs 74 to 85. Southeast winds up to 10 mph shifting to the northeast in the afternoon.

East Kaua’i

Today: Mostly sunny with a 20 percent chance of showers. Highs 72 to 84. North winds up to 10 mph.

Tonight: Partly cloudy with a 20 percent chance of showers. Lows 62 to 70. North winds up to 10 mph in the evening becoming light.

Tuesday: Mostly sunny with a 20 percent chance of showers. Highs 72 to 84. North winds up to 15 mph shifting to the northeast in the afternoon.

Detailed Forecast

Synopsis

A weak front will dissipate near Maui today. Gentle northeasterly trades will gradually strengthen to breezy levels by mid week. Trades will then veer out of a more easterly tradewind direction during the second half of the week and strengthen slightly. Light showers will be possible over windward and mountain areas primarily during the overnight and early morning hours.

Discussion

Latest satellite imagery shows a weak frontal boundary dissipating over Maui. The past 24 hour rainfall totals from this front range from 0.40 inches to 0.01 inches. High clouds continue to stream from west to east across the eastern half of the state but is expected to thin out later today. Gentle northerly winds have filled in behind the front with a narrow dry slot moving over Kauai and Oahu early this morning clearing out any remaining low clouds and light showers. Elsewhere, limited low clouds and light showers are mainly focused along windward areas. As the day progresses today, sheltered leeward areas could see a few clouds develop along the upslope and interior areas in afternoon as seabreezes develop in this light wind pattern.
After the front dissipates, a weak high will gradually build in from the west to just north of the state on Tuesday. Winds will veer out of a more northeast trade wind direction and slightly strengthen to gentle to breezy levels by Tuesday afternoon. Trades may strengthen a bit more Wednesday into Thursday while shifting to a more easterly trade wind direction as the high continues on a easterly track. Clouds and limited showers will focus mainly along windward and mauka areas as precipitable water vapor remains near to below normal. A very dry and stable airmass is expected during the second half of the week further limiting chances of showers.
Long range models are in fairly good agreement with trades gradually weakening as a ridge of high pressure moves closer to the state this weekend. Dry and stable conditions should continue through the weekend maintaining fair weather.

Aviation

Light winds will remain in place over the islands today with a ridge nearby. This will result in some land and sea breezes across the state. The tail end of a front moving down the island chain from the north will bring MVFR conditions with it. AIRMET SIERRA is in effect for Maui County early this morning, but conditions are expected to improve later this morning as the front dissipates. Additional low clouds near the Big Island, partially obscured by the high clouds over Maui County and the Big Island, have at times produced MVFR conditions over the windward side of the island. AIRMET SIERRA remains in place, with improving conditions expected later this morning.
AIRMET Tango remains in effect for moderate upper level turbulence between FL250 and FL410 from Oahu eastward.

Marine

Light to moderate northerly winds will persist through Tuesday, then transition to moderate to fresh northeast to east trades by midweek as high pressure builds north of the area in the wake of a diminishing front. Expect localized wind accelerations into the moderate to fresh category near and along some east and west facing coasts through the late morning and afternoon periods, while the background northerly flow persists. Winds may ease next weekend with a potential front passing to the north.
Surf along exposed north and west-facing shores will hold around the advisory levels today, then begin to gradually lower later tonight through midweek as a medium-period northwest (310 degrees) swell fades. A fresh, long-period northwest swell will arrive later today, peak late Tuesday into Tuesday night, and then gradually subside through Thursday. Toward the end of the week, a larger long-period northwest (300-320 degrees) swell is expected due to a storm-force low developing around 1500 NM northwest of the islands this week. If conditions develop as forecast, surf heights could reach warning levels late Friday into early Saturday before easing gradually over the weekend.
Surf along east-facing shores will remain up through the first half of the week as a small, short- to medium-period north- northeast (020 degrees) swell lingers. By late week, a northeast swell generated by strong winds north of a broad area of low- pressure developing about 1000 NM northeast of the islands may arrive Friday and peak over the weekend.
Surf along south-facing shores will remain near seasonal averages this week, driven by a mix of short-period southeast and background long-period south-southwest swells. Early next week, an out-of-season south-southwest swell is possible, originating from a broad gale passing southeast of New Zealand today. This active trend may persist through the first week of December, as a similar system passing near New Zealand is forecast to follow later this week.

Fire weather

KBDI values remain elevated across leeward areas. Relative humidity values have increase slightly due to a passing front and will remain above the critical thresholds over the next few days. We are starting to get to the time of year, where it is harder to reach critical fire weather thresholds due to the cooler day time temperatures helping to keep the humidities from dropping below 45%. Critical fire weather is not anticipated this upcoming week.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST this evening for NORTH AND WEST FACING SHORES OF NIIHAU AND KAUAI

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