Photo Credit: Brendan Stephen

West Kaua’i

Today: Mostly sunny with slight chance of showers in the morning, then partly sunny with chance of showers in the afternoon. Highs 81 to 87 near the shore to around 73 above 3000 feet. Northwest winds up to 10 mph shifting to the southwest in the afternoon. Chance of rain 50 percent.

Tonight: Partly cloudy with scattered showers. Lows around 66 near the shore to around 56 above 3000 feet. Light winds. Chance of rain 50 percent.

Monday: Mostly sunny with a 20 percent chance of showers. Highs 81 to 86 near the shore to around 73 above 3000 feet. Light winds becoming south up to 10 mph in the afternoon.

South Kaua’i

Today: Mostly sunny. A 20 percent chance of showers in the afternoon. Highs 79 to 86. Light winds.

Tonight: Mostly clear with a 20 percent chance of showers. Lows around 68. Light winds.

Monday: Sunny. A 20 percent chance of showers in the morning. Highs 79 to 86. Light winds becoming southwest up to 10 mph in the afternoon.

Kaua’i Mountains

Today: Mostly sunny with slight chance of showers in the morning, then mostly cloudy with showers likely in the afternoon. Highs 72 to 81 in the valleys to around 65 above 4000 feet. Light winds. Chance of rain 70 percent.

Tonight: Mostly cloudy with numerous showers. Lows 59 to 65 in the valleys to around 54 above 4000 feet. Light winds. Chance of rain 70 percent.

Monday: Partly sunny with scattered showers. Highs 71 to 80 in the valleys to around 64 above 4000 feet. Light winds becoming north up to 10 mph in the afternoon. Chance of rain 50 percent.

North Kaua’i

Today: Mostly sunny in the morning, then mostly cloudy with showers likely in the afternoon. Highs 74 to 84. Northwest winds up to 10 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy with numerous showers. Lows 61 to 69. Southwest winds up to 10 mph in the evening becoming light. Chance of rain 60 percent.

Monday: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 73 to 84. West winds up to 10 mph shifting to the north around 10 mph in the afternoon. Chance of rain 40 percent.

East Kaua’i

Today: Sunny in the morning, then partly sunny with showers likely in the afternoon. Highs 72 to 84. North winds up to 10 mph shifting to the east in the afternoon. Chance of rain 70 percent.

Tonight: Mostly cloudy with scattered showers. Lows 60 to 71. Northwest winds up to 10 mph in the evening becoming light. Chance of rain 50 percent.

Monday: Mostly sunny. Scattered showers in the morning, then slight chance of showers in the afternoon. Highs 72 to 84. North winds up to 10 mph. Chance of rain 40 percent.

Detailed Forecast

Synopsis

A weak front will moving over the area will increase the chance of showers for the western half of the state starting this afternoon through Monday. Showers will focus mainly along windward portions of Kauai and Oahu. Otherwise expect mostly dry conditions. A brief period of moderate trade winds is possible around the middle of the week, with winds potentially diminishing by the end of the week.

Discussion

Latest satellite imagery shows thinning high clouds mainly over the eastern half of the state and a weak front approaching the area from the north as a diffused band of low clouds. This band of clouds and embedded showers is expected to reach Kauai later this afternoon and evening, focusing showers mainly on northern exposures. The cloud band and associated showers are then expected to move over Oahu later tonight into Monday before dissipating near Maui. No significant rainfall totals are expected.
Generally light winds and mostly dry weather will prevail this coming week. Limited (windward) to no (leeward) rainfall is expected after the front dissipates. A relatively weak high will build behind the front, that will bring a gentle to moderate north to northeast trade wind flow. The weak background flow could still allow for a hybrid land and sea breezes pattern to develop in sheltered areas on land.
Models continue to show strengthening ENE trade winds around mid- week that may reach moderate level when the high moves to a position NE of the islands. Although confidence is low, trade winds may diminish again by the end of the week as a low passes N of the islands.

Aviation

Light winds will allow for the development of land breezes overnight and sea breezes during the day across most of the island chain through Monday. Mostly dry and stable conditions will support prevailing VFR conditions ahead of a weak front expected to move into Kauai from the northwest late this afternoon and evening and then gradually progress towards Oahu as it dissipates. Light to moderate NNE winds will accompany this front, along with the potential for a few showers, which may lead to brief MVFR conditions.
A plume of moisture that pushed into windward Big Island yesterday is continuing to lead to periods of MVFR and even IFR conditions for south and east facing slopes and coasts of the Big Island early this morning due to persistent clouds and showers. As such, AIRMET Sierra for tempo mountain obscuration remains in effect through 16Z this morning for windward Big Island.
AIRMET Tango is in effect for moderate upper level turbulence between FL280 and FL350 over the smaller islands due to a weak jet streak moving overhead. This AIRMET may need to be expanded across the Big Island later today as the jet streak gradually shifts south.

Marine

A weak front moving in from the northwest will move over Kauai waters today. The front will then track slowly southeastward down the island chain before dissipating over Maui Waters tomorrow night. Winds will remain light and variable during this time with land and sea breezes developing near the island coastlines. A weak area of high pressure will build in behind the front, bringing a return of light to moderate trade winds around midweek.
A medium-period NW (310) swell will peak today then gradually trend downwards over the next 48 hours. A High Surf Advisory remains in effect for north and west facing shores of Niihau, Kauai, Oahu, Molokai, and north facing shores of Maui. Meanwhile, a series of small NNE (020-040) swells will keep surf along north facing shores elevated through at least Thursday.
Later in the week, a new large long- period NW swell will build in across the western Islands. This swell will likely generate surf heights approaching High Surf Warning levels on Friday or Saturday.
No significant south swells are expected.

Fire weather

KBDI values remain elevated across leeward areas, and no significant leeward rainfall is anticipated for at least the next several days. Relative humidity values may approach the critical 45% threshold during the late morning and afternoon hours as a relatively dry air mass remains in place. However, light winds will prevent critical fire weather conditions from developing.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 AM HST Monday for North and West facing shores of Niihau Kauai Oahu Molokai and for North facing shores of Maui.

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