Photo Credit: Braden Jarvis

West Kaua’i

Today: Partly sunny in the morning then becoming mostly sunny. Breezy. Isolated showers. Highs around 85 near the shore to around 70 above 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows around 69 near the shore to around 58 above 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Saturday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 85 near the shore to around 71 above 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

South Kaua’i

Today: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 76 to 83. East winds 15 to 20 mph. Chance of rain 60 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 68. East winds 10 to 15 mph. Chance of rain 50 percent.

Saturday: Partly sunny with scattered showers. Highs 77 to 84. East winds 10 to 15 mph. Chance of rain 50 percent.

Kaua’i Mountains

Today: Mostly cloudy. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 70 to 81 in the valleys to around 61 above 4000 feet. East winds 10 to 20 mph. Chance of rain 60 percent.

Tonight: Mostly cloudy with numerous showers. Lows around 66 in the valleys to around 56 above 4000 feet. East winds up to 15 mph. Chance of rain 70 percent.

Saturday: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 72 to 82 in the valleys to around 62 above 4000 feet. East winds up to 10 mph. Chance of rain 70 percent.

North Kaua’i

Today: Breezy. Partly sunny with scattered showers. Highs 74 to 85. East winds up to 20 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 62 to 71. Southeast winds up to 15 mph. Chance of rain 70 percent.

Saturday: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 75 to 84. East winds up to 15 mph. Chance of rain 60 percent.

East Kaua’i

Today: Mostly cloudy. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 70 to 81. East winds 10 to 20 mph. Chance of rain 60 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 63 to 72. East winds 10 to 15 mph decreasing to up to 10 mph after midnight. Chance of rain 70 percent.

Saturday: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 72 to 82. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 60 percent.

Detailed Forecast

Synopsis

Strong trade winds will gradually ease and veer toward the east- southeast through early next week. Plumes of moisture will produce passing showers across windward and mountain areas through Saturday. A drier weather pattern is expected Sunday into early next week with light to moderate east to east-southeast winds. Winds should be light enough for sea breezes to develop during the day and land breezes at night, especially early next week.

Discussion

A 1032 mb high far northeast of the state is currently producing gentle to locally windy trade winds across the state this morning. Latest satellite and radar imagery shows low scattered clouds and showers riding in with the trade winds along windward areas with some of these showers spilling over to leeward locations of the smaller islands. There is also a veil of thin high clouds filling in from the west. Low clouds and showers may clear a little this afternoon but will soon be followed by another plume of moisture later this afternoon into Saturday. Shower will primarily be focused over windward areas with some spillage to leeward locales of the smaller islands. Rainfall amounts should remain light to moderate, due to stable conditions aloft.
An area of low pressure will develop along a front today roughly 1000 miles northwest of the state and is expected to continue to develop through Saturday before shifting northeast. This set up will shift winds slightly to the east- southeast on Saturday for the western half of the state allowing for a hybrid wind pattern over the weekend with land/sea breezes developing over leeward areas of the smaller islands. There will still be an easterly component of the winds producing a moderate to locally breezy showers over windward areas, especially for the eastern half of the state.
A trough extending from the low will inch roughly 500 miles northwest of the state early next week as the low tracks far north of the state early next week. This will further ease winds locally allowing for a more dominate land/sea breezes pattern. The surface trough and associated upper level trough will provide a conveyor belt, drawing a tongue of near to slightly above normal moisture levels over the state. These features could allow for taller clouds to develop each afternoon with the seas breezes, especially near Kauai. However rainfall totals are not expected to be significant. Expect clouds and chances of showers to diminish each night with the land breeze.

Aviation

Nearly stationary surface high pressure to the distant NE of the islands will generally support locally strong ENE trade winds, but some subtle veering and weakening of the low-level flow is anticipated through tonight. AIRMET Tango for moderate low-level turbulence downwind of the terrain remains posted for now, with a chance it could be dropped later today.
VFR conditions will prevail, especially leeward, with the stable island atmosphere strongly capped at heights between 6 and 8 kft. However, passing low cloud clusters will bring brief periods of MVFR CIG/VIS in SHRA, mainly to windward coasts and slopes.

Marine

A 1031 mb surface high, centered about 900 nm northeast of the state, will slowly drift eastward over the next several days. Meanwhile, a new low is forecast to develop about 900 nm northwest of Hawaii today. Strong east-northeast trade winds are expected through channeled areas this morning, but should gradually weaken and shift to the east-southeast by Saturday in response to the approaching low.
A Small Craft Advisory (SCA) remains in effect for all Big Island Waters as well as the more typically windy areas surrounding Maui and Molokai. Conditions are expected to end from the west late this evening or early Saturday.
Surf heights will remain below advisory thresholds for all shores through the forecast period. Multiple small northwest swells are expected now through Saturday night. Expect these swells to produce small surf along north and northwest facing shores. A small southerly swell will lead to a slight bump in surf heights along south facing beaches through this afternoon. Strong trade winds will continue to produce choppy, rough surf along east facing beaches through this afternoon. Smaller, smoother surf is expected along east facing shores starting Saturday and continuing through the coming week.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST this evening for Kaiwi Channel, Maui County Windward Waters, Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Windward Waters, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov