Photo Credit: Brendan Stephen

West Kaua’i

Rest Of Today: Sunny. Highs 74 to 82 near the shore to around 67 above 3000 feet. Northwest winds 10 to 15 mph shifting to the west in the afternoon.

Tonight: Partly cloudy. Lows around 61 near the shore to around 51 above 3000 feet. North winds up to 10 mph.

Friday: Mostly sunny. Highs 74 to 82 near the shore to around 68 above 3000 feet. Light winds.

South Kaua’i

Rest Of Today: Sunny. Highs 74 to 81. Northwest winds up to 15 mph shifting to the west in the afternoon.

Tonight: Partly cloudy. Lows around 61. West winds around 10 mph shifting to the north after midnight.

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

Kaua’i Mountains

Rest Of Today: Mostly sunny. Highs 68 to 75 in the valleys to around 60 above 4000 feet. Northwest winds up to 10 mph.

Tonight: Partly cloudy. Lows 52 to 61 in the valleys to around 49 above 4000 feet. Light winds.

Friday: 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.

North Kaua’i

Rest Of Today: Mostly sunny. Highs 69 to 77. West winds up to 15 mph.

Tonight: Partly cloudy. Lows 55 to 63. Southwest winds up to 10 mph in the evening becoming light.

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

East Kaua’i

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

Tonight: Partly cloudy. Lows 54 to 64. West winds up to 10 mph in the evening becoming light.

Friday: Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs 68 to 80. Light winds becoming northeast up to 10 mph in the afternoon. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Gentle northwest winds will weaken today allowing for seabreeze/land breeze to develop as a weak front dissipates over the Big Island. A relatively wet pattern will gradually develop from east to west Friday into early next week as moderate northeast trades return, advecting and area of enhanced moisture over the state. Another front may move through portions of the state Sunday into Monday keeping a rather wet pattern over the state and varying winds.

Discussion

Satellite and radar imagery shows a weak, thinned out frontal boundary near the Big Island with a band of isolated to moderate showers streaming from south to north just west of the Big Island in the Alenuihaha channel. Radar shows little to no rainfall elsewhere. Dewpoints have now dropped in the low 50's around Kauai and Oahu and into the mid to upper 50's around Molokai. Drier air is still inching eastward over Maui County and expect dewpoints dip just below 60's today and hold through tonight. Big Island will remain in the low to mid 60's. Light northwesterlies give way to sea breezes this afternoon, though interior clouds may be hard to come by given the extremely dry state of the boundary layer. The exception will be the Big Island where lingering moisture will mix upslope during daytime heating yielding typical extensive cloud cover and a few interior showers.
Friday through the weekend, dewpoints will gradually rebound from east to west as gentle to breezy trades return, ushering in an area of enhanced moisture from a trough east of the Big Island. Expect an increase in clouds and showers that will mainly along windward and mauka showers. Another weak front may move over portions of the state Sunday into Monday shifting winds again and reviving available moisture, keeping a rather wet pattern in the forecast. The next round of upper- level energy potentially pushes the remnant frontal zone westward back through the forecast area. The final position of this boundary may ultimately be important as it potentially serves as a focus for rainfall late next week.

Aviation

A weakening cold front near Maui and the Big Island will continue to dissipate today. A cool, dry and stable air mass will linger over Kauai through parts of Maui County today behind the front. Stable low clouds will favor N and W facing slopes and gradually weakening winds favor a W to NW direction. Associated clouds and showers will likely still produce layered clouds with embedded SHRA, leading to localized MVFR VIS/CIG mainly over the eastern portion of the state.
AIRMET Sierra for mountain obscuration is posted for parts of Maui County, with gradually improving conditions through the day. Moderate to severe upper-level turbulence is expected to persist through the day over and N of the islands due to a sharp trough aloft.

Marine

Moderate west to northwest winds will gradually weaken today as a ridge builds over the state, with a period of light and variable winds expected tonight through early Friday. The ridge will lift northward late Friday into the weekend, which should allow light to moderate trade winds to return. The winds become more uncertain early next week as a trough moves in from the east and a cold front approaches from the northwest.
A Small Craft Advisory (SCA) is now in effect for most marine zones through 6 pm Friday due to 10+ foot seas.
A pair of short and medium period northwest swells are producing large disorganized surf along north facing shores early this morning. A new large north to north-northwest swell will arrive this afternoon, peak tonight, then gradually decline Friday through the weekend. A High Surf Advisory remains in effect for north facing exposures through 6 pm Friday. A series of moderate northwest and north swells are possible early next week.
Aside from areas exposed to wrap from north swells, east shore surf will remain well below normal through the middle of next week.
South shore surf will remain at background very small levels through the middle of next week.

Fire weather

Low dewpoints will cause afternoon RH values to fall well into the 40s today and Friday but winds are forecast to remain light and firmly below the critical fire behavior threshold. RH values are then expected to climb back up over the weekend and into next week limiting critical fire behavior.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST Friday for north facing shores of Niihau Kauai Oahu Molokai and Maui.
Small Craft Advisory until 6 PM HST Friday 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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