Kauai Weather

West Kaua’i

Today: Sunny with isolated showers. Highs 79 to 86 near the shore to around 73 above 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Lows 63 to 69 near the shore to around 57 above 3000 feet. East winds up to 15 mph.

Friday: Sunny. Isolated showers in the afternoon. Highs 78 to 85 near the shore to around 72 above 3000 feet. Southeast winds up to 10 mph. Chance of rain 20 percent.

South Kaua’i

Today: Partly sunny in the morning then becoming mostly sunny. Breezy. Scattered showers. Highs 77 to 85. Northeast winds 10 to 20 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with isolated showers. Lows around 67. East winds 10 to 15 mph shifting to the northeast after midnight. Chance of rain 20 percent.

Friday: Mostly sunny with isolated showers. Highs 78 to 85. East winds up to 10 mph in the morning becoming light. Chance of rain 20 percent.

Kaua’i Mountains

Today: Partly sunny with scattered showers. Highs 72 to 79 in the valleys to around 63 above 4000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows 58 to 66 in the valleys to around 55 above 4000 feet. East winds up to 10 mph in the evening becoming light. Chance of rain 30 percent.

Friday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 73 to 80 in the valleys to around 64 above 4000 feet. Light winds. Chance of rain 30 percent.

North Kaua’i

Today: Mostly sunny with scattered showers. Highs 74 to 83. Southeast winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly clear with isolated showers. Lows 61 to 68. Southeast winds up to 10 mph. Chance of rain 20 percent.

Friday: Mostly sunny with isolated showers. Highs 74 to 82. Southeast winds up to 10 mph shifting to the southwest in the afternoon. Chance of rain 20 percent.

East Kaua’i

Today: Partly sunny with scattered showers. Highs 70 to 82. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with isolated showers. Lows 61 to 71. East winds up to 10 mph shifting to the southeast after midnight. Chance of rain 20 percent.

Friday: Mostly sunny with isolated showers. Highs 71 to 83. Southwest winds up to 10 mph shifting to the southeast in the afternoon. Chance of rain 20 percent.

Synopsis

Moderate to locally breezy trades will continue through today with clouds and showers favoring windward and mauka areas. Overnight land breezes and afternoon sea breeze pattern will take over Friday through early next week as winds weaken to light to gentle southerly background flow. A cold front may move over portions of the state middle of next week.

Discussion

Satellite and radar imagery show isolated to scattered showers moving into mainly windward and mauka areas early this morning as a plume of moisture rides in on the trades. Surface ridging to the north and northeast of the state will help to maintain moderate to locally breezy trades across the island chain through today. Continue to expect clouds and showers to focus mainly along windward and mauka areas through today with a transition to southeasterly flow later tonight into Friday as a front approaches the state to the northwest.
A weak cold front will stall northwest of the state Friday, pushing the surface ridge over the state and allowing winds to weaken and veer out of the southeast then out of the south southwest Saturday into early next week. In this weaker flow, land and sea breezes will become more prevalent, bringing clouds and a few showers over leeward and interior areas during the daylight hours and then clearing out overnight. Sunday into early next week, southwesterly wind speeds over the western half of the state could increase chances of clouds and showers for leeward locations of Kauai and Oahu as another front approaches the state.
Model guidance shows that an upper level trough will dive down and sweep across the central Pacific middle through the second half of next week that could help drive the next cold front through at least a portion of the island chain. This pattern could make for more active showers across the state as the moisture associated with the front lingers over the state and moderate to locally breezy trades fill in behind the front. However, there are still differences between the global models which decreases forecast confidence Tuesday and beyond.
Finally, a hot spot over Halemaumau Crater on the Big Island continues to be seen on infrared satellite imagery. The University of Hawaii Vog Model shows that SO2 emissions should remain confined to portions of the Big Island and adjacent waters to the west and southwest through tomorrow. However, assuming constant SO2 emissions, vog will likely begin to increase across the rest of the state late this Friday into early next week as winds weaken and become more southerly.

Aviation

Moderate to locally breezy trade winds will continue today, with clouds and showers favoring windward and mauka locations. Expect periods of MVFR CIGS/VSBYS in showers through the morning hours. The trades will trend down and shift out of the east-southeast tonight into Friday, translating to a land and sea breeze regime developing over the western end of the state.
AIRMET Sierra is in effect for TEMPO mountain obscuration above 025 impacting north through east sections Maui and Molokai. This may need to be expanded to the windward sections of Oahu later this morning.
AIRMET Tango is in effect for TEMPO moderate turbulence above FL280. This should shift east of the state later today in the wake of an upper trough moving through.

Marine

A high pressure system passing north of the islands will keep fresh to locally strong trade winds blowing for one more day today. A Small Craft Advisory remains in effect for the typical windier waters around Maui and the Big Island. Trade winds will weaken and shift from a more southeasterly direction from Friday into Sunday as the high drifts into the East Pacific and an approaching cold front stalls out northwest of the state. Lighter southeasterly winds will place most islands, from Maui to Kauai, in the leeward wind and rain shadow of the Big Island. These weaker large scale winds will cause near shore land and sea breezes to expand in coverage during this time period. Southerly winds develop across the region from late Sunday into Monday ahead of another cold front.
An active period with several northwest swells will move through the islands through the next seven days. The first of several northwest swells was delayed a bit and will still build to advisory levels later today, then gradually decline on Friday. A low pressure system currently moving through the West Pacific is producing hurricane force winds along a fetch that lines up a significant northwest swell pointed directly towards the Hawaiian Islands. This significant long period northwest swell will swiftly build into the island chain through the day on Saturday, the swell energy will peak by Saturday night and Sunday, and then slowly lower from Sunday night into Monday. This swell will produce warning level surf heights along exposed north and west facing shores through much of the weekend. Yet another significant long period northwest swell will arrive from late Monday into Tuesday, possibly pushing surf heights back up to warning levels, with another reinforcing northwest swell pushing surf heights well above warning levels by next week Wednesday.
Surf along east and south facing shores will remain small through the first half of next week.

Fire weather

No critical fire weather conditions are expected for the next seven days. Moderate to locally breezy trade winds will gradually ease late tonight into Friday. Land/seabreeze pattern will develop Friday into early next week as a weak southerly background flow takes over. Relative humidities will stay above critical levels through the forecast period. A front may move through the state by mid week next week that could provide much needed rainfall to leeward locations.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 AM HST Friday for north and west facing shores of Niihau Kauai Oahu Molokai and north facing shores of Maui.
Small Craft Advisory until 6 PM HST this evening for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

Kauai Now Weather is brought to you by Blue Hawaiian Helicopters.

Data Courtesy of NOAA.gov