Photo Credit: Jason Weingardt

West Kaua’i

Today: Mostly sunny with isolated showers. Highs 82 to 87 near the shore to around 74 above 3000 feet. Light winds. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows around 64 near the shore to around 54 above 3000 feet. Light winds. Chance of rain 20 percent.

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

South Kaua’i

Today: Mostly sunny. Highs 80 to 87. Northeast winds up to 15 mph.

Tonight: Partly cloudy. Lows around 66. Northeast winds around 10 mph.

Wednesday: Mostly sunny. Highs 79 to 87. Northeast winds 10 to 15 mph.

Kaua’i Mountains

Today: Partly sunny with isolated showers. Highs 72 to 81 in the valleys to around 65 above 4000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with isolated showers. Lows 56 to 63 in the valleys to around 52 above 4000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs 72 to 81 in the valleys to around 65 above 4000 feet. Northeast winds up to 15 mph. Chance of rain 20 percent.

North Kaua’i

Today: Mostly sunny. Isolated showers in the morning. Highs 73 to 85. East winds up to 10 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 58 to 66. East winds up to 10 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny. Highs 74 to 85. East winds up to 10 mph.

East Kaua’i

Today: Mostly sunny with isolated showers. Highs 73 to 84. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 58 to 69. North winds up to 10 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny. Highs 72 to 84. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon.

Detailed Forecast

Synopsis

Cool northeasterly winds and a high pressure ridge over the island chain will keep stable conditions, cool nights, and relatively dry humidity levels across the state through much of this week. Trade winds will strengthen a bit and shift from a more easterly direction from Thursday into Saturday. Expect a few more clouds and brief passing overnight to early morning showers, mainly over windward and mountain areas as these trade winds return. Trade wind speeds will decline once again early next week in a fairly stable regime.

Discussion

The satellite imagery this morning continues to show a stable weather pattern with a subtropical jet stream in the upper levels just south of the Big Island. Local radar imagery completes the stable picture with just a few isolated showers across the state. A small band of low clouds upstream of the islands in Maui County might keep some extra clouds along the windward areas of Molokai and Maui today. Elsewhere mostly clear and mostly sunny skies will continue through much of this week. Upper air weather balloon soundings from 2 AM HST (12Z) this morning show 4,000 to 5,000 foot subsidence inversion heights at Lihue and Hilo respectively.
A stable and dry light wind weather pattern will continue through Wednesday with strong subsidence (downward vertical motions) under the influence of a high pressure ridge aloft. Afternoon onshore sea breeze winds will develop over all islands in this light wind pattern. Relatively dry moisture levels across the state will allow for increased radiational cooling (releasing heat into space),resulting in below normal overnight to early morning temperatures statewide through at least Thursday morning. The strong subsidence aloft will keep temperature inversion heights in the roughly 4,000 to 5,000 foot range through Wednesday. Resulting in limited low clouds in this stable pattern with mostly isolated to scattered rainfall coverage over the windward mountain peaks of each island, near zero chances for rainfall elsewhere.
Trade winds will increase slightly and veer from a more easterly direction from Thursday into the weekend allowing for a small increase to humidity levels. Overall atmospheric conditions will remain fairly stable and dry weather trends will continue into the upcoming weekend. Trade winds will trend lower once again early next week with limited clouds and showers.

Aviation

Weak northerly flow over the state will bring scattered low clouds with a few light showers this morning, mainly windward areas. This will also lead to localized sea breezes before northeast trade winds gradually return this afternoon. Some brief MVFR ceilings will be possible with any clouds or showers. Otherwise, VFR conditions should prevail.
No AIRMETs are in effect.

Marine

Light to moderate north to northeast winds will gradually shift out of the northeast and increase into the moderate to fresh category tonight through the second half of the week as high pressure builds north of the area. Winds may ease next weekend and into early next week with a potential front passing to the north. Seas will potentially reach the 10 ft Small Craft Advisory level Friday through Saturday for waters exposed to large west-northwest swells.
Surf along exposed north and west facing shores will remain up into Thursday, due to a mix of a fresh, long-period west- northwest swell and a couple of fading, shorter period north- northwest and north-northeast swells. This west-northwest swell will peak today, then lower Wednesday through Thursday. Toward the end of the week, a large long-period west-northwest swell is expected due to a storm-force low developing around 1500-2000 NM west-northwest of the islands today. Surf heights could reach warning levels late Friday into early Saturday before easing during the remainder of the weekend.
Surf along east facing shores will remain up through the weekend due to a lingering short-period north-northeast swell and a short-period northeast swell expected late Thursday through the weekend. Heights will peak Friday into the weekend below the advisory level as this northeast swell arrives and peaks.
Surf along S facing shores will remain near seasonal averages this week, driven by a mix of short period SE and background long period SSW swells. Early next week, an out-of-season SSW is possible. This swell is expected to originate from a recent broad gale passing southeast of New Zealand. 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

We do not foresee any critical fire weather conditions developing through the first half of next week as wind speeds will remain below critical thresholds. Dry relative humidity levels may briefly touch fire weather criteria over drier leeward zones this week.

HFO Watches/Warnings/Advisories

None.

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