West Kaua’i

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 86 to 92 near the shore to around 78 above 3000 feet. South winds up to 10 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with isolated showers. Lows around 74 near the shore to around 63 above 3000 feet. Light winds becoming east up to 10 mph after midnight. Chance of rain 20 percent.

Thursday: Mostly sunny with isolated showers. Highs 87 to 93 near the shore to around 79 above 3000 feet. East winds up to 10 mph. Chance of rain 20 percent.

South Kaua’i

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 83 to 91. Light winds. Chance of rain 50 percent.

Tonight: Partly cloudy with isolated showers in the evening, then mostly cloudy with scattered showers after midnight. Lows around 75. Light winds becoming east around 10 mph after midnight. Chance of rain 30 percent.

Thursday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 84 to 92. East winds 10 to 15 mph. Chance of rain 30 percent.

Kaua’i Mountains

Today: Mostly cloudy. Scattered showers in the morning, then numerous showers in the afternoon. Highs 77 to 85 in the valleys to around 68 above 4000 feet. Light winds. Chance of rain 70 percent.

Tonight: Mostly cloudy with scattered showers. Lows 66 to 72 in the valleys to around 60 above 4000 feet. Light winds becoming southeast up to 10 mph after midnight. Chance of rain 40 percent.

Thursday: Partly sunny with scattered showers. Highs 78 to 86 in the valleys to around 69 above 4000 feet. East winds up to 10 mph. Chance of rain 40 percent.

North Kaua’i

Today: Mostly cloudy with numerous showers. Highs 79 to 89. Light winds. Chance of rain 70 percent.

Tonight: Mostly cloudy with scattered showers. Lows 67 to 76. Southeast winds up to 10 mph. Chance of rain 40 percent.

Thursday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 81 to 89. East winds up to 15 mph. Chance of rain 30 percent.

East Kaua’i

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 78 to 90. South winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 67 to 79. Light winds becoming east up to 10 mph after midnight. Chance of rain 40 percent.

Thursday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 77 to 89. East winds around 10 mph. Chance of rain 40 percent.

Detailed Forecast

Update

Kiko has been downgraded to a post-tropical cyclone. Have updated the previous AFD below.

Synopsis

As weakening Post-Tropical Cyclone Kiko skims the northern windward coastal waters of Oahu and Kauai early this morning, higher moisture and light southeasterlies associated with this system could potentially lead to areas of topographically- enhanced precipitation. Once Kiko exits stage left, moderate trades will return by early Thursday morning. Higher rain chances Thursday night and Friday with relatively drier weekend conditions.

Prev discussion

/ISSUED 420 AM HST Wed Sep 10 2025/ Today's challenge focuses on where rain will fall and where more organized showers will root themselves within higher terrain later this afternoon into evening. Post-Tropical Cyclone Kiko has introduced a more moist air mass to the islands, especially the western half of the chain, where this morning's Lihue sounding precipitable water 1.71 inches places it in the upper 10% range (mean of 1.4 inches). Swaths of higher moisture moving up within the banding features associated with Kiko, whose low level circulation is located approximately 80 miles north of Turtle Bay, Oahu at 3 AM HST, will pass over the islands the next 12 to 18 hours. The Lihue sounding also indicated a unstable enough profile (near 1.5k j/kg MU CAPE) to suggest that, with lift or within any downstream plume, robust convection could easily occur and sustain itself within this moistened near 7k ft boundary layer. The positioning of these near north-to-south orientated bands of higher moisture will ultimately determine the have and the have nots of any significant rainfall. A weak wind field left in Kiko's wake will slowly veer more southeast today and this weak wind direction could cause problems across Oahu from the Molokai plume as well as over Kauai's higher terrain. An outer band that is currently coming across the eastern end of the state is increasing shower coverage across windward Big island and Maui during the pre-dawn hours. So, while Kiko will have no direct impacts to the islands, the indirect impacts will come from stationary cells within this favorable veered east-southeast flow that could easily produce a quick inch or two of rain within a hour. Higher resolution modeling solutions are not focusing the highest precipitation on any particular area, but they are suggesting that convection could anchor along Oahu's Koolaus and Big Island's windward Hilo, Puna and Ka'u regions. Thus, while we are currently holding off on a statewide Flood Watch, the radar will need to be closely monitored today in the event that isolated areas do receive a quick 2 to 4 inches, initiating downstream flooding issues.
Locally breezy trades return overnight tonight as upper ridging builds in from the northwest. A ribbon of higher mid-layer moisture passing by from the east Thursday afternoon and Friday will increase statewide rain chances with the highest QPF likely focused along more eastern island windward upslope mauka. An uneventful weekend where many locales will remain dry with only brief showers occurring along east-facing exposures and within higher terrain. Rain chances will again be on the rise next Tuesday and Wednesday as a lobe of higher moisture expands up from the ITCZ and clips the state.

Aviation

Post-Tropical Cyclone Kiko will continue on a westward track, disrupting trade winds as the low center passes just north of the western Hawaiian Islands today. Deep tropical moisture surrounding Kiko will produce some enhanced shower activity along wind convergence bands across the region, including island mountain and interior sections in daytime sea breezes. Periods of MVFR conditions with +SHRA and low clouds are possible.
Trade winds build back into the region as Kiko weakens and departs the region towards the west from later tonight through Thursday. Stronger large scale winds will limit daytime island sea breezes to sheltered western mountain slopes on Thursday.
No AIRMETs in effect, an AIRMET for mountain obscuration is possible later today as shower bands develop in the wake of Kiko's passage through the region.

Marine

Post-Tropical Cyclone Kiko is about 70 NM NE of Oahu this morning and continues to track west-northwest just north of the coastal waters. As Kiko continues to track westward, moderate to locally fresh east to southeast trades will build from east to west across the island chain today. Thursday, the high pressure ridge will build north of the waters bringing a return to moderate to locally fresh trade winds through the forecast period.
Nearshore buoys across the state exposed to the easterly swell from Kiko, has peaked and is dropping quickly this morning. Therefore, the Small Craft Advisory (SCA) for seas above 10 feet for western waters, the High Surf Warning and Advisory for all east facing shores have been cancelled.
Surf along south facing shores will remain near the summertime average today as the reinforcing swell out of the south-southwest peaks today before slowly declining through Thursday. Another small bump from the south is possible on Friday. Additionally, multiple small pules of northwest to north- northwest swell energy will generate small surf along north facing beaches throughout the week and into the weekend. A short-lived northeast swell is possible for select exposures as Post-Tropical Kiko passes to our north.

Fire weather

High humidity and light to moderate winds continue for the next couple of days with scattered showers focused over island interiors during the afternoon. Locally breezy trades then return Wednesday night as humidity falls to typical values.

HFO Watches/Warnings/Advisories

None.

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