Photo Credit: Braden Jarvis

West Kaua’i

Today: Mostly sunny with isolated showers. Highs 78 to 86 near the shore to around 71 above 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Mostly clear with isolated showers. Lows 65 to 70 near the shore to around 58 above 3000 feet. Northeast winds up to 15 mph. Chance of rain 20 percent.

Monday: Mostly sunny with isolated showers. Highs 78 to 86 near the shore to around 72 above 3000 feet. Northeast winds up to 15 mph. Chance of rain 20 percent.

South Kaua’i

Today: Partly sunny with numerous showers in the morning, then mostly sunny with scattered showers in the afternoon. Highs 77 to 85. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 69. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Monday: Partly sunny with numerous showers in the morning, then mostly sunny with scattered showers in the afternoon. Highs 77 to 85. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Kaua’i Mountains

Today: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 70 to 78 in the valleys to around 62 above 4000 feet. East winds up to 15 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 60 to 68 in the valleys to around 57 above 4000 feet. East winds up to 15 mph. Chance of rain 70 percent.

Monday: Partly sunny with numerous showers in the morning, then mostly sunny with scattered showers in the afternoon. Highs 72 to 79 in the valleys to around 63 above 4000 feet. East winds up to 15 mph. Chance of rain 70 percent.

North Kaua’i

Today: Partly sunny with scattered showers. Highs 73 to 82. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows 62 to 69. East winds 10 to 15 mph shifting to the southeast after midnight. Chance of rain 50 percent.

Monday: Mostly sunny with scattered showers. Highs 73 to 82. East winds up to 15 mph. Chance of rain 50 percent.

East Kaua’i

Today: Partly sunny with scattered showers. Highs 69 to 82. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 62 to 73. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Monday: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 71 to 83. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Moderate to locally breezy trade winds will prevail today, then ease through the first half of next week. Showers will favor windward and mauka areas with a few showers spilling leeward during this time. The trades will cut off late Wednesday through Thursday as a front approaches from the north, with showers favoring the island interiors each afternoon. A cold front could bring some more widespread rainfall to the island chain Thursday night and Friday, with the potential for some heavier showers and even a few thunderstorms not out of the question. A transition back to a more typical trade wind pattern is expected next weekend.

Discussion

Currently at the surface, a ridge of high pressure is positioned around 400 miles north of Kauai, while a cold front is located around 1150 miles west-northwest of the Garden Isle. Moderate to locally breezy trade winds prevail across the island chain early this morning. Infrared satellite imagery shows mostly cloudy conditions in windward areas and clear to partly cloudy skies in most leeward locales. Radar imagery shows scattered to numerous trade wind showers moving into windward slopes and coasts with some of these showers reaching leeward areas at times. Main short term focus revolves around trade wind trends and rain chances.
The ridge of high pressure north of the islands will keep moderate to locally breezy trade winds in place today. The trades will ease slightly tonight and Monday as an approaching front weakens the ridge north of the state. The trades will briefly rebound back to moderate levels Tuesday as a new high builds north-northwest of the islands and a trough of low pressure sets up to the northeast. The trades will begin easing again Wednesday as a new front begins to approach from the northwest. Light and variable winds will develop Wednesday night and continue into Thursday ahead of the front, with moderate to locally breezy northeasterly trades filling in from northwest to southeast down the island chain Thursday night and Friday behind the front. A new high building northwest of the state will then keep moderate to locally breezy northeasterly trades in place next weekend.
As for the remaining weather details, a fairly typical winter time trade wind pattern will prevail through Wednesday, with showers favoring windward slopes and coasts. Showers will be most prevalent during the overnight and early morning hours, with a few showers reaching leeward areas from time to time. As the trades cut off Wednesday afternoon through Thursday, showers will decrease in coverage and favor the island interiors each afternoon and the coastal waters at night. Depending on the strength and progression of a cold front into/through the islands Thursday night and Friday, we could see more widespread rain affect the islands, with some heavier showers and even some thunderstorms not out of the question. In the wake of the front, we will transition back into a trade wind regime next weekend.

Aviation

Moderate to locally breezy trades will bring scattered showers to mainly windward locations through the remainder of this morning. Expect brief periods of MVFR ceilings and visibility to accompany this activity. Isolated showers elsewhere.
An upper level low is forecast to bring moderate turbulence, with isolated pockets of severe turbulence, over the eastern portions of the state late this morning through the afternoon, mainly in the mid to upper levels. An AIRMET or SIGMET may be needed if these conditions materialize.
AIRMET Tango remains in effect for low-level mechanical turbulence associated with the breezy trade winds.

Marine

Surface high pressure far northeast of the state will drive moderate to locally strong trades today before easing slightly through the first half of the week as the ridge to the north weakens and a front passes by to the north. The trades are expected to become disrupted entirely by Thursday with light winds over the marine area as a potential cold front moves through the area. A Small Craft Advisory (SCA) is currently in effect for the windier waters and channels around Maui and the Big island through 6 pm HST today.
A new moderate long-period northwest swell has begun to fill in across north and west facing shores. Surf is expected to peak this afternoon, then lower on Monday but remain below High Surf Advisory (HSA) levels. A slightly larger northwest swell will arrive early Monday, peak Monday through Tuesday, then gradually decline through Thursday. This swell will bring surf heights up to HSA criteria for most north and west facing shores Monday through Tuesday night. Then, an even larger, long-period northwest swell is expected fill in for the end of the week that could bring High Surf Warning (HSW) level surf to most north and west facing shores Friday.
Surf along east facing shores will hold relatively steady today, then lower a bit Monday and Tuesday as the trades ease. East shore surf looks to become very small Wednesday and Thursday as the trades become disrupted, with a north swell potentially giving surf a boost to exposed shorelines on Friday.
South shore surf will remain very small through the middle of the week. An out of season long-period south swell may move through the islands at the end of the week, bringing a sizable boost to south shore surf.

Fire weather

No critical fire conditions anticipated during the forecast period.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST this evening for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

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