Photo Credit: Braden Jarvis

West Kaua’i

Today: Mostly sunny with isolated showers. Highs around 84 near the shore to around 74 above 3000 feet. Light winds. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers after midnight. Lows 64 to 69 near the shore to around 55 above 3000 feet. Light winds. Chance of rain 20 percent.

Friday: Mostly sunny with isolated showers. Highs around 84 near the shore to around 74 above 3000 feet. East winds up to 15 mph shifting to the southeast in the afternoon. Chance of rain 20 percent.

South Kaua’i

Today: Mostly sunny. Isolated showers in the late morning and afternoon. Highs around 82. Light winds becoming southeast around 10 mph in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 62 to 68. Northeast winds around 10 mph. Chance of rain 20 percent.

Friday: Partly sunny with scattered showers. Highs around 82. East winds 10 to 15 mph. Chance of rain 40 percent.

Kaua’i Mountains

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 77 in the valleys to around 66 above 4000 feet. Light winds. Chance of rain 40 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows around 58 in the valleys to around 50 above 4000 feet. Light winds. Chance of rain 50 percent.

Friday: Partly sunny with scattered showers. Highs around 77 in the valleys to around 66 above 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

North Kaua’i

Today: Mostly sunny. Isolated showers in the late morning and afternoon. Highs 77 to 83. Light winds. Chance of rain 20 percent.

Tonight: Mostly cloudy with scattered showers. Lows 58 to 67. Light winds. Chance of rain 50 percent.

Friday: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Highs 77 to 83. East winds up to 15 mph. Chance of rain 40 percent.

East Kaua’i

Today: Mostly sunny with isolated showers. Highs 75 to 81. Light winds. Chance of rain 20 percent.

Tonight: Mostly cloudy with scattered showers. Lows 56 to 69. Light winds. Chance of rain 50 percent.

Friday: Partly sunny with scattered showers. Highs 75 to 81. East winds up to 10 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

A stationary front in the vicinity of the Big Island, will weaken into a trough and drift back westward across the central smaller islands tonight. This pattern will maintain some showers across the islands through Friday. Trade winds will return Friday across most of the state, before weakening and veering southeast this weekend. Conditions will be mainly stable for the weekend, with mostly fair weather expected with some scattered showers.

Discussion

Current radar shows showers continue to drift across the islands this morning. Radar estimates show mainly light rainfall occurring this morning, however some isolated enhanced rainfall remained embedded within the showers.
Today through tonight…showers will continue across the islands as the weakened boundary, and band of enhanced moisture (PW 1.60″ to 1.70″), begin to drift back westward across the state. The boundary is forecast to finally weaken north of the region Friday. Light background winds today will also promote afternoon sea breeze showers for island interiors and mountain areas. With the lighter winds, showers will likely be slow moving and capable of producing brief downpours. Models also indicate weak instability (SW 0C to -1C) across the Big Island today, suggesting some chance for isolated thunderstorms remaining possible along the Big Island slopes. Later tonight, a ridge of high pressure will begin to restrengthen north of the state. This pattern should begin to establish trade wind flow over the state.
Friday into the weekend…an area of high pressure well northeast of the state, will maintain moderate southeast trades over the region into the first half of the weekend. However a cold front associated with low pressure well northwest of the state, will approach Kauai and weaken the trade wind flow during the second half of the weekend. With the southeast background wind flow, lighter winds are expected over Oahu and Kauai due to shadowing from the Big Island, allowing for afternoon sea breezes and potential showers for leeward areas. For Maui County and the Big Island, light to moderate east to southeast winds will generate some trade wind showers, mainly at night through early morning. Late in the weekend, shower chances may increase across Kauai as the front approaches from the northwest.
Monday through next week…models are in fairly similar agreement with the approaching front from the northwest, moving eastward and potentially increasing rainfall chances to begin the work week. Then the boundary weakens and drifts quickly east away from the state, helping to establish mainly stable and drier conditions (PW under 1.30″) and limiting the areal coverage of showers by mid week.

Aviation

Expect mostly VFR conditions for all airfields today as drier air continues to move in from the west. Light winds today will produce stable sea breezes over each island during the day with land breezes overnight. A few showers are possible mainly over island interior sections during the day.
No AIRMETs in effect and none are expected.

Marine

Winds will remain light and variable across the vast majority of the marine area today, as a weak stationary front in the vicinity of the Big Island weakens into a trough. The trough will shift west tonight and Friday as a ridge of high pressure builds north of the islands, allowing light to moderate trades to return. An approaching front will ease the winds over the western islands Friday night through the weekend. Moderate trades will hold over the eastern end of the state through Saturday before becoming light and variable on Sunday. A weakening front will push southward into the islands early next week, bringing a return of light to moderate trade winds.
The current moderate sized (short to medium period) west- northwest swell will peak today, then gradually decline through Saturday. A new long-period northwest swell is forecast to arrive Friday night, build through the day Saturday, then peak Saturday night into Sunday. A reinforcing long period northwest swell will move in Sunday night, peak on Monday, then slowly lower through the middle of next week.
Surf along south facing shores will remain tiny through Friday. A new long-period south swell will arrive Friday night, peak over the weekend, and then slowly decline through the middle of next week. This swell will give south shore surf a noticeable boost to near the summertime average Saturday through Monday.
Surf along east facing shores will remain small through the middle of next week.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov