Photo Credit: Jason Weingardt

West Kaua’i

Today: Partly sunny. Highs 81 to 86 near the shore to around 72 above 3000 feet. Southwest winds 10 to 15 mph.

Tonight: Mostly cloudy with a 20 percent chance of showers in the evening, then partly cloudy after midnight. Lows 65 to 71 near the shore to around 58 above 3000 feet. Southwest winds around 10 mph in the evening becoming light.

Christmas Day: Mostly sunny. Highs 81 to 86 near the shore to around 73 above 3000 feet. Light winds.

South Kaua’i

Today: Partly sunny. Highs 81 to 86. West winds 10 to 15 mph.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Lows around 67. West winds around 10 mph in the evening becoming light.

Christmas Day: Mostly sunny. Highs 81 to 87. Light winds.

Kaua’i Mountains

Today: Partly sunny. Highs 73 to 80 in the valleys to around 65 above 4000 feet. Southwest winds 10 to 15 mph.

Tonight: Mostly cloudy with a 20 percent chance of showers in the evening, then partly cloudy after midnight. Lows 59 to 65 in the valleys to around 56 above 4000 feet. West winds 10 to 15 mph.

Christmas Day: Mostly sunny. Highs 73 to 79 in the valleys to around 65 above 4000 feet. Light winds.

North Kaua’i

Today: Partly sunny. Highs 75 to 83. South winds 10 to 15 mph.

Tonight: Mostly cloudy with a 20 percent chance of showers in the evening, then partly cloudy after midnight. Lows 61 to 69. Southwest winds around 10 mph in the evening becoming light.

Christmas Day: Mostly sunny. Highs 75 to 83. Light winds.

East Kaua’i

Today: Partly sunny. Highs 73 to 83. Southwest winds 10 to 15 mph.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Lows 60 to 71. Southwest winds around 10 mph in the evening becoming light.

Christmas Day: Mostly sunny. Highs 73 to 84. Light winds.

Detailed Forecast

Synopsis

A dry weather pattern will continue for at least the next couple of days. Light to moderate south to southwest winds are expected over Kauai and Oahu today, with winds becoming light and variable over all islands from Christmas Day into Tuesday. Light to moderate trade winds may make a short-lived appearance around the middle of next week, before diminishing again by the end of the week.

Discussion

A strong zonal jet across the N Pacific will ensure that an E-W oriented surface ridge remains near the islands well into next week, generally keeping winds light. A mid-level ridge will build directly overhead and remain in place through the remainder of the year, severely limiting any chance of rainfall.
In the short term, a rapidly-developing hurricane-force low will pass well to the N today, but will tighten the low-level gradient over the islands. With the surface ridge along 20N, moderate to locally breezy SW winds are expected over Kauai and Oahu, with lighter S to SW winds over Maui and Hawaii counties allowing island- scale land and sea breezes to prevail. No significant increase in moisture is expected, and conditions will be dry nearly everywhere. Some thin high clouds will move over the islands within the strong jet, but will diminish Sunday and Monday.
As the low departs, the ridge will gradually move N, with the light wind land/sea breeze pattern spreading to all islands Sunday into Tuesday. A period of light to moderate E-SE trade winds may occur by the middle of the week (a little sooner for the Big Island) as the ridge moves N of all islands, with light winds thereafter as the ridge moves S again.

Aviation

Rather benign weather is expected today with dry conditions and partly cloudy skies for the majority of the island chain. Expect light to moderate southwesterly flow to prevail. An upper trough will continue to move over the state from west to east and will likely generate turbulence in the mid to upper levels. See SIGMET TANGO below for more details.
AIRMET TANGO remains in effect for moderate turbulence between FL180 and FL250. See SIGMET XRAY series for severe turbulence, which covers the mid to upper levels above the whole island chain.

Marine

Moderate to locally fresh southwest winds will continue over the Kauai and Oahu waters today as low pressure passes by to the north, while variable winds over the rest of the state shift out of the south to southeast direction and increase to light to moderate. Overall, wind speeds will begin to relax through the second half of the weekend and early next week as a ridge builds in over the islands. A brief return of moderate to fresh trades is possible Tuesday through midweek as the ridge shifts north of the area.
Surf along north and west facing shores of the smaller islands will hold at high-end advisory levels through the weekend due to overlapping northwest swells. These swells will keep seas at or around the Small Craft Advisory level (10 ft) through Sunday as well. A downward trend is anticipated early next week as these swells move out. To finish off the year, the active pattern for surf along exposed north and west facing shores will persist, with a rising trend potentially beginning as early as Wednesday. Surf along east and south facing shores will remain small due to the lack trade winds and any significant south swells.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST Sunday for North and West facing shores of Niihau Kauai Oahu Molokai and for North facing shores of Maui.
Small Craft Advisory until 6 PM HST Sunday for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Kauai Channel, Oahu Windward Waters, Oahu Leeward Waters, Kaiwi Channel, Maui County Windward Waters.

Data Courtesy of NOAA.gov