Photo Credit: Jason Weingardt

West Kaua’i

Today: Mostly sunny. Breezy. Highs around 77 near the shore to around 65 above 3000 feet. Northeast winds up to 25 mph.

Tonight: Partly cloudy. Breezy. Lows around 65 near the shore to around 54 above 3000 feet. Northeast winds up to 20 mph.

Saturday: Mostly sunny. Breezy. Highs around 79 near the shore to around 67 above 3000 feet. Northeast winds up to 20 mph.

South Kaua’i

Today: Partly sunny. Windy. Isolated light showers in the morning. Highs around 76. Northeast winds 20 to 30 mph. Chance of rain 20 percent.

Tonight: Breezy. Mostly cloudy with isolated light showers. Lows 61 to 66. Northeast winds 15 to 25 mph. Chance of rain 20 percent.

Saturday: Partly sunny. Breezy. Isolated light showers in the morning. Highs 75 to 80. Northeast winds 15 to 25 mph. Chance of rain 20 percent.

Kaua’i Mountains

Today: Mostly cloudy. Windy. Scattered light showers in the morning, then isolated light showers in the afternoon. Highs 65 to 73 in the valleys to around 59 above 4000 feet. Northeast winds 10 to 30 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered light showers. Lows 54 to 59 in the valleys to around 48 above 4000 feet. Northeast winds 10 to 25 mph decreasing to up to 20 mph after midnight. Chance of rain 50 percent.

Saturday: Breezy. Cloudy with scattered light showers in the morning, then partly sunny with isolated light showers in the afternoon. Highs 66 to 74 in the valleys to around 61 above 4000 feet. Northeast winds up to 20 mph. Chance of rain 50 percent.

North Kaua’i

Today: Breezy. Partly sunny with isolated light showers. Highs 70 to 77. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 20 percent.

Tonight: Breezy. Mostly cloudy with isolated light showers. Lows 57 to 66. East winds 10 to 20 mph. Chance of rain 20 percent.

Saturday: Partly sunny with isolated light showers. Highs 71 to 78. East winds 10 to 15 mph. Chance of rain 20 percent.

East Kaua’i

Today: Breezy. Partly sunny with isolated light showers. Highs 69 to 77. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Tonight: Breezy. Mostly cloudy with isolated light showers. Lows 55 to 67. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Saturday: Breezy. Mostly cloudy with isolated light showers. Highs 71 to 77. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

The cool and windy conditions will continue into the weekend as strong high pressure remains north of the area. The northeast trades will ease into the moderate to breezy range by Sunday, then shift out of the east and become gusty through the first half of next week. Increasing moisture combined with the breezy easterly trades and an upper disturbance moving through will lead to increasing cloud and shower coverage Monday through midweek.

Discussion

Deep north-northeast flow following a cold front that moved through continues to channel cooler and drier air into the islands. Observations around the state reflect this with dewpoints hovering in the low to mid 50s and PWs down to around three quarters of an inch shown in the morning upper air soundings. Despite the drier conditions, light showers are managing to form and move through periodically. Several rain gages around the state are showing a few hundredths to a tenth of an inch accumulations over the past 6-Hrs. Wind observations are ranging from 20 to 30 mph with peak gusts as high as 35 to 45 mph, which has come down slightly (enough to lower the warning). The latest hi-res guidance shows this trend persisting today, which supports extending the High Wind Advisory.
The northeast winds will ease into the moderate to breezy category over the weekend as high pressure to the north weakens briefly. The dry conditions, however, will linger with the dewpoints hovering into the 50s through Saturday (PWs remaining around an inch or less). Any showers that form will be brief with little accumulations.
The extended guidance shows a moistening trend early next week with the low-level flow becoming easterly and strengthening. Model precipitable water values climb into the 1.5-2 inch range Tuesday through midweek. This moisture combined with lowering upper heights due to an upper trough moving into the area will translate to cloudier conditions with better rainfall chances.

Aviation

A strong cell of high pressure will reside north of the state today and help maintain breezy trades across the island chain. However, a relatively dry airmass in place will keep shower coverage limited. Scattered showers may affect windward sections of the Big Island with only isolated activity elsewhere along windward sections of the smaller islands. VFR conditions and partly cloudy skies expected for leeward area.
AIRMET TANGO remains in effect below 8000 feet over and immediately south through west of all mountainous terrain on all islands.

Marine

High pressure north of the state will continue to drive strong to Gale force northeast trade winds across the marine area today. The trades should gradually ease tonight, with moderate to locally strong trades then expected over the weekend as the high to the north weakens. High pressure will then restrengthen north of the islands early next week, ramping the trades back up to strong to near Gale force.
The Gale Warning for the windier zones around Maui County and the Big Island is now in effect through 6 pm this evening. A Small Craft Advisory remains in effect elsewhere through 6 pm Saturday. The SCA will likely need to be extended for portions of the marine area through early next week.
A medium period north swell is expected to peak today, with a gradual decline then expected tonight and Saturday. A High Surf Advisory remains in effect for north facing shores through 6 PM this afternoon. The HSA has also been expanded to include east facing shores. A small long period northwest swell will move through Monday through the middle of next week, with a moderate sized reinforcing northwest swell then arriving late next week giving north and west shore surf a nice boost.
A building northeast swell is expected to fill in Sunday and Sunday night, with surf likely building to advisory levels along east facing shores Monday and Tuesday, with a gradual decline expected Wednesday through late next week. Some wrap into north facing shores will likely occur with this swell as well. South shore surf will remain tiny through the weekend, with a small boost possible Monday through late next week as a small long period south-southwest swell moves through.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST this evening for Niihau, Oahu North Shore, Olomana, Maui Windward West, Kauai North, Kauai East, Koolau Windward, Molokai Windward, Molokai North, Lanai Windward, Maui Central Valley North, Windward Haleakala, Big Island East, Big Island North.
Wind Advisory until 6 PM HST this evening for Kauai Mountains, Waianae Coast, Waianae Mountains, Lanai Mauka, Maui Windward West, Maui Leeward West, Kona, Kohala, Kauai North, Kauai South, East Honolulu, Koolau Leeward, Molokai Leeward South, Lanai Windward, Lanai Leeward, Lanai South, Maui Central Valley North, Maui Central Valley South, South Maui/Upcountry, Big Island Southeast, Big Island East, Big Island North.
Small Craft Advisory until 6 PM HST Saturday for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Kauai Channel, Oahu Windward Waters, Oahu Leeward Waters, Kaiwi Channel, Maui County Windward Waters, Maui County Leeward Waters.
Gale Warning until 6 PM HST this evening for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Windward Waters, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov