Photo Credit: Jason Weingardt

West Kaua’i

Today: Breezy. Mostly cloudy with numerous showers in the morning, then mostly sunny with scattered showers in the afternoon. Highs 78 to 83 near the shore to around 68 above 3000 feet. Northwest winds 10 to 25 mph. Gusts up to 45 mph in the morning. Chance of rain 70 percent.

Tonight: Partly cloudy with isolated showers. Lows 65 to 70 near the shore to around 57 above 3000 feet. Northwest winds 10 to 15 mph decreasing to up to 10 mph after midnight. Chance of rain 20 percent.

Wednesday: Mostly sunny with isolated showers. Highs 79 to 84 near the shore to around 70 above 3000 feet. Light winds. Chance of rain 20 percent.

South Kaua’i

Today: Breezy. Partly sunny with scattered showers in the morning, then mostly sunny in the afternoon. Highs 77 to 83. Northwest winds 10 to 20 mph. Chance of rain 30 percent.

Tonight: Partly cloudy. Lows around 67. Northwest winds around 10 mph in the evening becoming light.

Wednesday: Mostly sunny with isolated showers. Highs 78 to 84. Light winds. Chance of rain 20 percent.

Kaua’i Mountains

Today: Mostly cloudy in the morning then becoming mostly sunny. Windy. Scattered showers. Highs 67 to 75 in the valleys to around 60 above 4000 feet. West winds 10 to 30 mph shifting to the northwest 10 to 20 mph in the afternoon. Chance of rain 40 percent.

Tonight: Partly cloudy with isolated showers. Lows 59 to 64 in the valleys to around 54 above 4000 feet. Northwest winds up to 10 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny with isolated showers. Highs 70 to 76 in the valleys to around 61 above 4000 feet. Light winds. Chance of rain 20 percent.

North Kaua’i

Today: Breezy. Mostly cloudy with numerous showers in the morning, then mostly sunny with scattered showers in the afternoon. Highs 70 to 80. West winds 10 to 25 mph. Chance of rain 70 percent.

Tonight: Partly cloudy with isolated showers. Lows 60 to 69. West winds around 10 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny with isolated showers. Highs 72 to 81. Light winds becoming west up to 10 mph in the afternoon. Chance of rain 20 percent.

East Kaua’i

Today: Breezy. Partly sunny with scattered showers in the morning, then mostly sunny in the afternoon. Highs 68 to 80. Northwest winds 10 to 20 mph. Chance of rain 40 percent.

Tonight: Partly cloudy. Lows 59 to 70. Northwest winds around 10 mph in the evening becoming light.

Wednesday: Mostly sunny with isolated showers. Highs 69 to 80. Light winds. Chance of rain 20 percent.

Detailed Forecast

Synopsis

More stable conditions with breezy westerly winds are filling in across the Hawaii region today. Strong westerly winds with higher gusts are still expected across the state today with decreasing trends by this evening. Strong wind gusts may develop in showers or along eastern slopes of mountains through the afternoon. Weather conditions will continue to improve with decreasing shower trends today. Light winds with isolated to scattered showers remain in the forecast from Wednesday into the weekend.

Discussion

Westerly winds will continue to flip the script on typical shower activity for the Hawaiian Islands today. Typically drier western slopes will see scattered showers with more limited showers over typically wetter eastern slopes of all islands. Local radar imagery this morning shows scattered to numerous shower activity drifting through the breezy westerly winds. These showers will become more scattered a few hours after sunrise. Any showers that develop today may pull down stronger winds aloft and produce higher wind gusts. Wind Advisories are posted for all islands with High Wind Warnings in effect for portions of the Big Island including the Big Island Summits. The Winter Storm Warning for Big Island Summits was also cancelled this morning.
Wednesday through Friday…Westerly winds will trend lower tonight becoming light and variable for the second half of the week. A weak high pressure ridge aloft will limit vertical cloud development and reduce shower activity into the isolated to scattered range during this time period.
Saturday through Monday…Light winds will continue into the weekend as two weak fronts pass by north of the islands chain. Weather impacts will be minimal. However, these passing frontal troughs will weaken the surface high pressure ridge near the islands and keep lighter wind speeds in the forecast. Lighter winds will keep more humid conditions than normal over the islands. The ridge axis shifts slightly north of the state on Monday with a potential return to light trade winds.

Aviation

Locally strong westerly winds will continue today, with a trend downward in wind speeds expected this afternoon, with the winds easing further tonight. Scattered showers will continue to affect the islands this morning, possibly bringing some brief MVFR vsbys with them as they move through. Showers coverage should decrease this afternoon with fairly dry conditions continuing tonight. VFR conditions should generally prevail at all TAF sites during the next 24 hours.
AIRMET Tango remains in effect for strong surface winds. Conditions should improve this afternoon. AIRMET Tango is also in effect for moderate low level turbulence over and downwind of the terrain of all islands. This AIRMET will likely remain in effect through the day.

Marine

In the wake of the cold front, strong to locally gale force west to northwest winds are expected through today as low pressure passes eastward a couple hundred miles north of the islands. A Gale warning continues for waters around the Big Island through this evening. All other marine zones remain in Small Craft Advisory conditions for strong west to northwest winds and high seas. Winds will sharply decline tonight through the end of the week as the low departs to the northeast and a ridge builds over the area. A weak cold front approaching the islands may pass just north of the region this weekend.
A High Surf Warning (HSW) for exposed north and west facing shores is in effect for a long lived northwest swell through Wednesday afternoon. There is high potential for wave run- up onto vulnerable roadways and coastal areas in the HSW areas. This swell is expected to drop below warning thresholds Wednesday afternoon. Expect another large northwest swell towards the end of the week reaching High Surf Advisory (HSA) levels. Surf along east facing shores remains flat except for areas that are exposed to the northwest swell wrap through Wednesday. South and west facing shores will also see an increase in short- period wind waves today due to the strong onshore winds. A tiny south swell looks to arrive Thursday.

HFO Watches/Warnings/Advisories

High Wind Warning until 6 PM HST this evening for Big Island Interior, Big Island South, Big Island Southeast, Big Island North.
High Wind Warning until 6 AM HST Wednesday for Big Island Summits.
Wind Advisory until 6 PM HST this evening for Niihau, Kauai, Oahu Molokai, Lanai and Maui.
Gale Warning until 6 PM HST this evening for Big Island Waters and the Alenuihaha Channel.
Small Craft Advisory until 6 PM HST this evening for all other Hawaiian waters and channels.
High Surf Warning until 6 PM HST Wednesday for north and west facing shores of Niihau, Kauai, Oahu, Molokai, and north facing shores of Maui.
High Surf Advisory until 6 PM HST Wednesday for west facing shores of the Big Island.

Data Courtesy of NOAA.gov