Photo Credit: Brendan Stephen

West Kaua’i

Today: Sunny. Highs 80 to 87 near the shore to around 75 above 3000 feet. East winds up to 10 mph shifting to the southwest in the afternoon.

Tonight: Mostly clear. Lows 65 to 70 near the shore to around 59 above 3000 feet. Light winds.

Thursday: Mostly sunny. Scattered showers in the afternoon. Highs 80 to 87 near the shore to around 74 above 3000 feet. Northwest winds up to 10 mph shifting to the northeast in the afternoon. Chance of rain 50 percent.

South Kaua’i

Today: Sunny. Highs 79 to 87. West winds 10 to 15 mph.

Tonight: Mostly clear. Lows around 69. West winds up to 10 mph in the evening becoming light.

Thursday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 79 to 86. Light winds. Chance of rain 50 percent.

Kaua’i Mountains

Today: Sunny. Highs 74 to 81 in the valleys to around 67 above 4000 feet. Light winds.

Tonight: Mostly clear. Isolated showers in the evening. Lows 60 to 67 in the valleys to around 57 above 4000 feet. Light winds. Chance of rain 20 percent.

Thursday: 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 65 above 4000 feet. Light winds becoming north up to 10 mph in the afternoon. Chance of rain 50 percent.

North Kaua’i

Today: Sunny. Highs 75 to 84. West winds up to 10 mph shifting to the north in the afternoon.

Tonight: Mostly clear. Lows 62 to 69. Light winds.

Thursday: Sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs 74 to 83. Northwest winds up to 10 mph. Chance of rain 40 percent.

East Kaua’i

Today: Sunny. Highs 76 to 86. Southwest winds up to 15 mph.

Tonight: Mostly clear. Lows 62 to 72. Light winds.

Thursday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 73 to 84. North winds up to 15 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Stable and relatively dry conditions will persist statewide today, with a deep- layer ridge remaining in place over much of the region. This will result in a land and sea breeze regime, with afternoon clouds and a potentially a few brief showers over interior and leeward areas. An approaching cold front could result in slightly better shower coverage over Kauai and Oahu Thursday, with dry weather continuing elsewhere. Another cold front will approach and potentially reach the islands by early next week.

Discussion

Current satellite imagery shows little to no clouds around Maui County and a couple of bands of clouds streaming from the southwest to northeast over the western half of the state. A ridge of high pressure over the state has set up southeast flow around Big Island focusing some clouds around the southeast coast and slopes. Radar indicates isolated light to moderate showers embedded in these clouds. As the day progress today expect clouds to develop over interior and leeward locations during the afternoon hours as sea breezes kick in. While a few brief afternoon showers can't be ruled out, accumulations will be minimal due to stable conditions.
Guidance indicates that an approaching front could graze the northern islands as it dissipates on Thursday. This could result in a few more showers for Kauai and Oahu, though latest guidance shows only light accumulations at best. Gentle to breezy northerly winds will develop behind the front as a weak high builds north of the state and tracks east.
Over the weekend winds will become light and veer out the south as another front approaches the state from the northwest. Land/seabreeze patterns will take over again but expect dry and stable conditions as another deep layer ridge builds over the state. Most ensemble members show the front passing north or just grazing Kauai late Sunday into Monday with minimal rainfall totals. Breezy easterly trades look to return early next week as a stronger high develops north of the state.

Aviation

Light winds will prevail through today allowing for the development of afternoon sea breezes. Radar and satellite imagery show a band of clouds and showers streaming across the western islands this morning. Guidance shows this band weakening later this morning. Otherwise, dry conditions will tend to limit cloud and shower activity to the interior this afternoon. An weak front will approach the state from the northwest tonight bringing an increasing chance of low clouds and showers to the region. Expect mainly VFR today, with brief MVFR under passing showers.
No AIRMETs are currently in effect.

Marine

A surface ridge over the islands will maintain an overall light wind pattern today. Winds will be lightest over the central waters. A dissipating front to the northwest will move towards the northern end of the islands Thursday. This will spread lighter winds across most of the coastal waters. A weak high behind the front will bring northerly winds to the area, followed by a brief period of trades on Friday. Much of the weekend will see a return of light winds as the ridge once again sets up over the islands. Fresh trades may redevelop late Sunday or Monday.
A series of large to extra large northwest to north-northwest swells will persist through the week. Long-period northwest (315 degrees) swell at the NOAA buoys northwest of Kauai has continued to rise overnight, with the latest observations being around 12 ft at 16 to 17 seconds, with additional energy at longer periods. With observations running about 2 feet above guidance, the forecast continues to reflect this trend. Surf along north and west facing shores of the smaller islands is expected to be at advisory levels this morning, and rising to warning levels this afternoon and evening. A series of storm lows passing northwest of Hawaii will continue to send larger pulses of north-northwest swell that will should keep surf above warning levels through the weekend. For now, the High Surf Warning (HSW) runs through Thursday afternoon but it will be extended. While winds will remain rather light this week, seas will be above the 10 foot Small Craft Advisory threshold for waters exposed due to the large swells, thus like the HSW, conditions will persist into the weekend.
Aside from areas exposed to wrapping northwest swell, surf along east and south facing shores will remain small through much of the week. The best chance for a small rise in southwest swell will be on Thursday and Friday.

Fire weather

Critical fire weather conditions are not anticipated through the rest of the week due to light winds. Additionally, an increase in moisture across the western end of the state as a front approaches on Thursday will also mitigate any fire weather concerns.

HFO Watches/Warnings/Advisories

High Surf Warning until 6 PM HST Thursday for north and west facing shores of Niihau Kauai Oahu and Molokai and for north facing shores of Maui.
Small Craft Advisory until 6 PM HST Friday for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Kauai Channel, Oahu Windward Waters, Kaiwi Channel, Maui County Windward Waters, Big Island Windward Waters.

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