Photo Credit: Jason Weingardt

West Kaua’i

Today: Mostly sunny. Scattered showers in the afternoon. Highs around 86 near the shore to around 74 above 3000 feet. Light winds. Chance of rain 40 percent.

Tonight: Mostly clear. Isolated showers in the evening. Lows 65 to 70 near the shore to around 56 above 3000 feet. Light winds becoming northeast up to 10 mph after midnight. Chance of rain 20 percent.

Wednesday: Mostly sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs around 87 near the shore to around 75 above 3000 feet. East winds up to 10 mph shifting to the southwest in the afternoon. Chance of rain 30 percent.

South Kaua’i

Today: Mostly sunny with isolated showers. Highs around 83. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 63 to 69. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny with isolated showers. Highs around 84. East winds 10 to 15 mph. Chance of rain 20 percent.

Kaua’i Mountains

Today: Mostly sunny with scattered showers. Highs 73 to 80 in the valleys to around 64 above 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with scattered showers. Lows 56 to 61 in the valleys to around 51 above 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Wednesday: Partly sunny with scattered showers. Highs 74 to 81 in the valleys to around 65 above 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

North Kaua’i

Today: Mostly sunny with isolated showers. Highs 76 to 85. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with scattered showers. Lows 59 to 69. East winds up to 10 mph in the evening becoming light. Chance of rain 40 percent.

Wednesday: Mostly sunny with scattered showers in the morning, then partly sunny with isolated showers in the afternoon. Highs 77 to 86. East winds up to 10 mph. Chance of rain 40 percent.

East Kaua’i

Today: Mostly sunny with isolated showers. Highs 76 to 84. Northeast winds around 10 mph. Chance of rain 20 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows 57 to 69. Northeast winds up to 10 mph in the evening becoming light. Chance of rain 50 percent.

Wednesday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 77 to 85. East winds up to 10 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

A weak surface ridge to the north will maintain light to moderate trade winds with localized land and sea breezes across sheltered areas into Thursday. Showers will favor windward slopes during the night and morning hours and will shift to interior and leeward areas each afternoon. Trades will likely strengthen Friday and hold into early next week, bringing the return of more typical trade wind weather to the island chain.

Discussion

Currently at the surface, a weak front is located around 400 miles north of Kauai, while a weak surface ridge is positioned around 275 miles north of Honolulu. The resulting gradient is producing light to moderate trade winds across the island chain early this morning, with land breezes present across most of Kauai and sheltered sections of the other islands. Infrared satellite imagery shows some high clouds streaming over the eastern end of the state and some low clouds moving into windward areas with the trades. Overall, partly cloudy conditions prevail in most areas, with a bit more extensive cloud cover over windward portions of the Big Island. Radar imagery shows scattered showers moving into windward areas, and a few light decaying showers spilling into leeward locales at times. Main short term focus revolves around rain chances and trade wind trends.
A weak ridge of high pressure north of the islands will remain nearly stationary through mid week, keeping the gradient loose and trade winds in the light to moderate range. The trades will be light enough to allow for overnight land breezes and daytime sea breezes in many leeward areas and even some windward sections over the western end of the state. The ridge will strengthen and lift northward Thursday, with breezy trades possible Friday through early next week.
As for the remaining details, a fairly stagnant weather pattern can be expected through Thursday, with showers favoring windward areas during nights and mornings, then transitioning over to interior and leeward areas each afternoon and early evening. A return to more typical trade wind weather featuring windward showers and the occasional leeward spillover is expected late Thursday through early next week.

Aviation

A frontal system moving north of the state will keep surface high pressure weak, allowing light to locally moderate trades to persist across the islands through the next couple of days. A few showers will mainly affect windward areas overnight through the early mornings, with cloud build-ups and scattered showers over leeward and island interiors during the afternoons. VFR conditions will prevail, though brief mountains obscurations may occur at times within showers.
No AIRMETs are currently in effect nor expected through this afternoon.

Marine

A cold front passing far north of the region will weaken the high pressure ridge far north of the state. Trade winds will remain light to fresh through Wednesday and then strengthen from Thursday onward as high pressure builds back into the region.
Small surf will continue along south facing shores as a mix of background long period south-southwest (200-220 degree) swells continue into next weekend.
Surf along exposed north and west facing shores will remain near the seasonal average each day through Tuesday. An out of season west-northwest (300-310 degree) swell is expected to fill in by Wednesday, peak Thursday, then decrease through the weekend.
Surf along east facing shores will remain small through the week due to the light trade winds expected through Wednesday. A slight increasing trend will start late Thursday as trade winds strengthen.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov