Photo Credit: Braden Jarvis

West Kaua’i

Today: Mostly sunny. Highs 73 to 81 near the shore to around 68 above 3000 feet. Light winds.

Tonight: Mostly clear. Lows around 60 near the shore to around 52 above 3000 feet. Light winds becoming northeast up to 10 mph after midnight.

Saturday: Sunny. Highs 77 to 84 near the shore to around 71 above 3000 feet. Northeast winds around 10 mph.

South Kaua’i

Today: Mostly sunny. Highs 75 to 81. Light winds.

Tonight: Mostly clear. Lows around 61. Northeast winds up to 10 mph.

Saturday: Sunny. Highs 77 to 84. Northeast winds around 10 mph.

Kaua’i Mountains

Today: Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs 68 to 75 in the valleys to around 60 above 4000 feet. Light winds. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 51 to 59 in the valleys to around 50 above 4000 feet. Light winds becoming east up to 15 mph after midnight. Chance of rain 20 percent.

Saturday: Mostly sunny. Isolated showers in the afternoon. Highs 71 to 77 in the valleys to around 63 above 4000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

North Kaua’i

Today: Mostly sunny in the morning then becoming partly sunny. Highs 69 to 77. Light winds becoming north up to 10 mph in the afternoon.

Tonight: Partly cloudy with scattered showers. Lows 54 to 62. Light winds becoming southeast up to 10 mph after midnight. Chance of rain 30 percent.

Saturday: Mostly sunny. Highs 73 to 81. East winds around 10 mph.

East Kaua’i

Today: Mostly sunny. Highs 68 to 80. Light winds becoming northeast up to 10 mph in the afternoon.

Tonight: Partly cloudy with isolated showers. Lows 54 to 66. North winds up to 10 mph. Chance of rain 20 percent.

Saturday: Mostly sunny. Isolated showers in the afternoon. Highs 71 to 82. Northeast winds around 10 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Light northwest winds will shift to northeast tonight and Saturday while gradually strengthening. Dewpoints will rebound toward normal and enhanced trade showers will focus mainly along windward and mauka areas, spilling over to leeward areas at times through the weekend and into early next week.

Discussion

Cool and crisp conditions are apparent this morning. Dewpoints are in the low 50s to 60 across the state. Overnight land breeze cleared out remaining low level clouds and thin upper level clouds has allowed for temperatures to cool in the mid to low 60s. Expect another rather dry and cool day today for Kauai and Oahu. Maui County the Big Island will see dewpoints climb today and tonight due to a transient surface high to our west shifting over the state today and tonight allow for winds to shift from the northwest to northeast before gradually to moderate levels by tonight. In addition, CIMSS precipitable water vapor imagery shows a conveyor belt of enhanced moisture being drawn from the tropics northward associated with a gale low far north of the state and a trough 260 miles west of the Big Island. The low will weaken and get absorbed by a stronger low to the far northwest and with the return of easterlies locally, that area of enhanced moisture will shift westward, reaching the Big Island this afternoon and early evening then Maui County tonight. High resolution model guidance shows the added moisture will generate enhanced trade wind showers around Maui County and the Big Island late this afternoon and evening as an upper level short wave trough dives down, adding some vertical support along with diurnal tradewind shower pattern.
A ridge will quickly fill in aloft Saturday into Sunday and support more typical tradewinds showers over the state as the area of moisture shifts over the entire state. A weak front approaching from the north will move or pass just north of the state reviving the moisture band over the sate and will keep wet trades in the forecast for Sunday into Monday.
The extended forecast remains on track where guidance continues to show renewed troughing within NW flow aloft that will favor low pressure development over the lower latitudes of the Central Pacific. The remnant frontal boundary will strengthen in response to developing forcing and will serve as the baroclinic pathway for the surface low to track near or north of the forecast area during the middle to latter portion of next week. There is still considerable differences in the model guidance where the low will develop in relation to the state and the exact impacts, but the second half of next week seemingly looks like it could produce some meaningful rainfall across some or all of the island chain.

Aviation

Dry and stable northwest flow will persist through the morning hours. Trade winds and trade wind showers will build in this afternoon. VFR conditions will prevail all areas through this evening. Mountain obscuration could become an issue for portions of windward Big Island or East Maui late tonight or early Saturday.
No AIRMETs are in effect or anticipated today.

Marine

A ridge over the islands will begin to lift north today into the weekend. Light winds this morning will transition to light to moderate trades this afternoon then ramp up to moderate to fresh levels over the weekend. As we head into early next week, while a trade wind regime should remain in place there is some uncertainty as a trough moves in from the east and a cold front approaches from the northwest.
A Small Craft Advisory remains in effect for most marine zones until 6 pm this evening due to seas in the 10ft range.
Disorganized surf due to a combination of northwest and north swells should continue along north facing shores during the next couple days. These swells should gradually decline today and through the weekend. A High Surf Advisory remains in effect for north facing shores until 6 pm this evening. A series of overlapping, moderate sized, north and northwest swells, should move through during the first half of next week, giving a boost to north shore surf.
Some wrap around surf can be expected from the northerly swells. East shore surf should remain below normal through the middle of next week. South shore surf will remain at very small levels through at least Wednesday.

Fire weather

Afternoon RH values will be in the 40s again today, but winds will fall short of the critical fire behavior threshold. Minimum RH values will then rebound above 45 percent Saturday into early next week. Thus, no critical fire behavior is expected during the forecast period.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST this evening for Niihau, Oahu North Shore, Maui Windward West, Kauai North, Molokai Windward, Molokai North, Maui Central Valley North, Windward Haleakala.
Small Craft Advisory until 6 PM HST this evening for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Kauai Channel, Oahu Windward Waters, Oahu Leeward Waters, Kaiwi Channel, Maui County Windward Waters, Alenuihaha Channel, Big Island Windward Waters.

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