Photo Credit: Jason Weingardt

West Kaua’i

Today: Mostly sunny. Highs around 91 near the shore to around 79 above 3000 feet. East winds up to 15 mph.

Tonight: Partly cloudy. Lows around 73 near the shore to around 62 above 3000 feet. Northeast winds up to 10 mph.

Friday: Mostly sunny. Highs around 90 near the shore to around 78 above 3000 feet. Northeast winds up to 15 mph.

South Kaua’i

Today: Mostly sunny. Isolated showers in the morning. Highs 82 to 91. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows around 74. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Friday: Mostly sunny. Isolated showers in the morning. Highs 82 to 91. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Kaua’i Mountains

Today: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 77 to 88 in the valleys to around 68 above 4000 feet. East winds up to 15 mph. Chance of rain 40 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows 64 to 72 in the valleys to around 60 above 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Friday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 76 to 87 in the valleys to around 68 above 4000 feet. East winds up to 15 mph. Chance of rain 40 percent.

North Kaua’i

Today: Mostly sunny with isolated showers. Highs 78 to 90. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 66 to 74. East winds up to 15 mph shifting to the southeast after midnight. Chance of rain 20 percent.

Friday: Mostly sunny with isolated showers. Highs 78 to 90. East winds up to 15 mph. Chance of rain 20 percent.

East Kaua’i

Today: Mostly sunny with isolated showers. Highs 75 to 87. East winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 66 to 77. Northeast winds around 10 mph. Chance of rain 20 percent.

Friday: Mostly sunny with isolated showers. Highs 75 to 88. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

A fairly dry moderate to locally breezy trade wind pattern will continue through Friday afternoon. An weak disturbance moving through the Hawaii region by this weekend will increase shower trends for all islands, especially over windward and mountain areas. Isolated thunderstorms are possible for Kauai and Oahu from Saturday night through Sunday. Drier trends return from next week Monday onward.

Discussion

Local radar imagery shows little shower activity across the state this morning with only brief showers reaching windward and mountain areas. Stable looking stratocumulus clouds are drifting into the islands on the easterly trade winds this morning with bands of high level cirrus clouds passing over the island chain. These cirrus clouds, made of ice crystals, will likely enhance sunrise and sunset colors into the weekend.
In the larger scale, a high pressure ridge remains far north of the Hawaiian Islands and this ridge will continue to produce moderate to locally breezy trade winds through Friday. Wind speeds will decrease slightly this weekend, as the ridge weakens in response to a cold front passing through the Central Pacific basin. Fairly strong subsidence (downward vertical motions) across the region will limit rainfall coverage through Friday afternoon.
A weak low level trough riding in on the easterly trade winds will link up with an upper level low drifting into the islands from the north. These two systems will produce more unstable conditions statewide and increase shower trends statewide from Friday night through Sunday. Isolated thunderstorms are possible over Kauai and Oahu from Saturday night through Sunday. The development of any thunderstorms will highly depend on the strength of this developing upper low near the western islands this weekend.
Drier conditions will return from next week from Monday onward as these low pressure systems diminish and move westward away from the state. Moderate to locally breezy trade winds continue with brief overnight to early morning showers possible over windward and mountain areas.

Aviation

Breezy easterly trade winds will continue through the 24 h TAF period, with clouds and showers favoring windward and mauka locations. Brief periods with MVFR CIGS/VSBYS are possible as showers pass through. Otherwise, VFR conditions will prevail.
AIRMET Tango for low-level turbulence over and downwind of island terrain is possible later today.

Marine

Moderate to locally strong trades should remain in place through the weekend due to high pressure northeast of the islands. A slight weakening of the high could decrease wind speeds early next week. A Small Craft Advisory is in effect for the typical windy waters around Maui and the Big Island through 6 AM Saturday.
North shore surf will remain very small through the weekend until mid-week when a 3 to 5 foot medium to long-period northwest swell could arrive. East shore surf will hold near seasonal levels today then slowly lower through early next week. A mix of southeast, south and southwest swells will keep small surf rolling into south facing shores through Monday. A slight bump in south shore surf is possible around middle of next week as a slightly larger long- period southwest swell moves through.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 AM HST Saturday for windier waters surrounding Maui and the Big Island.

Data Courtesy of NOAA.gov