Photo Credit: Braden Jarvis

West Kaua’i

Rest Of Today: Windy. Cloudy with showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs around 78 near the shore to around 63 above 3000 feet. North winds up to 30 mph shifting to the northeast 15 to 30 mph in the afternoon. Chance of rain 90 percent.

Tonight: Partly cloudy. Windy. Lows around 61 near the shore to around 50 above 3000 feet. Northeast winds 10 to 30 mph.

Saturday: Mostly sunny. Windy. Highs around 77 near the shore to around 63 above 3000 feet. Northeast winds up to 30 mph.

South Kaua’i

Rest Of Today: Windy. Cloudy with showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 74 to 79. North winds 10 to 30 mph shifting to the northeast 20 to 30 mph in the afternoon. Chance of rain 80 percent.

Tonight: Partly cloudy. Windy. Lows around 60. Northeast winds 25 to 30 mph.

Saturday: Mostly sunny. Windy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 72 to 78. Northeast winds 25 to 30 mph. Chance of rain 30 percent.

Kaua’i Mountains

Rest Of Today: Windy. Showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 66 to 72 in the valleys to around 57 above 4000 feet. North winds 10 to 30 mph. Chance of rain near 100 percent.

Tonight: Partly cloudy. Windy. Isolated showers after midnight. Lows 52 to 58 in the valleys to around 49 above 4000 feet. Northeast winds 10 to 30 mph. Chance of rain 20 percent.

Saturday: Mostly sunny. Windy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 66 to 72 in the valleys to around 56 above 4000 feet. Northeast winds 10 to 30 mph. Chance of rain 30 percent.

North Kaua’i

Rest Of Today: Windy. Showers in the morning, then mostly sunny with scattered showers in the afternoon. Highs 67 to 77. North winds 10 to 30 mph. Chance of rain near 100 percent.

Tonight: Partly cloudy. Windy. Lows 54 to 62. Northeast winds 10 to 30 mph.

Saturday: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 66 to 76. Northeast winds 10 to 25 mph with gusts to 45 mph. Chance of rain 30 percent.

East Kaua’i

Rest Of Today: Windy. Showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 66 to 77. North winds 10 to 30 mph. Chance of rain near 100 percent.

Tonight: Partly cloudy. Windy. Isolated showers after midnight. Lows 54 to 65. Northeast winds 15 to 30 mph. Chance of rain 20 percent.

Saturday: Mostly sunny. Windy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 65 to 75. Northeast winds 15 to 30 mph. Chance of rain 30 percent.

Detailed Forecast

Update

Central valley and windward Maui added to the wind advisory.

Synopsis

The weather impacts through this weekend and into early next week are wind driven. Expect strengthening northerly winds starting today behind a rapidly moving cold front. These strong northerly winds turn into windy northeast to east trade winds from early Saturday morning into the first half of next week affecting all Hawaiian Islands. Strong trades gradually drop down to moderate to locally breezy levels by next week Thursday. Wet weather will continue today statewide with decreasing rainfall trends developing after the cold front passes through each island. Trade wind showers return starting late Saturday to Sunday mainly over windward and mountain areas with drier conditions forecast over leeward areas.

Discussion

The morning big picture satellite imagery shows the cold front is moving into Kauai with cloud and showers from the front merging with the nearly stationary surface trough near Maui. Local radar imagery continues to show light to moderate showers developing statewide. Wet weather will continue today statewide today with decreasing rainfall trends developing after the cold front passes through each island. Trade wind showers return starting late Saturday to Sunday mainly over windward and mountain areas with drier conditions forecast over leeward areas.
This cold front will sweep across the state today with strong northerly winds filling in behind the front as it passes through each island. Wind speeds will accelerate to advisory levels over all islands through the day with the strongest wind speeds and highest wind gusts forecast over and down wind of mountains, and along west and east slopes of island terrain. A Wind Advisory was issued for all islands to cover these stronger wind impacts lasting through Sunday. Even stronger wind speeds are forecast over the highest elevation summits of Mauna Kea and Mauna Loa on the Big Island, where a High Wind Warning was issued this morning.
An extended period of strong trade winds will continue into the first half of next week. A strong high pressure system will build into the region through early next week producing strong to windy trade winds. Wind directions will veer from northerly windy today and tonight, to a more northeasterly direction on Saturday, to a more easterly direction from Sunday through Monday.
Strong winds will gradually decrease each day from Tuesday onward, where the easterly trade winds will blow at more moderate to locally breezy levels by Thursday. Another low pressure system will move into the Central Pacific basin by the end of next week, with decreasing southeasterly winds in the forecast as the trailing cold front breaks down the high pressure ridge north of the islands.

Aviation

Bands of clouds and showers ahead of an approaching cold front continue to stream out of the west-northwest. As of 2 AM HST this morning, late night radar imagery indicated most of the shower activity to be focused over Maui County and spreading quickly eastward. Occasional MVFR ceilings and visibilities are associated with this shower activity. AIRMET Sierra for mountain obscuration now includes Oahu, Molokai, Lanai, and Maui, and will likely be further expanded to include northwest exposures of the Big Island later this morning.
Winds will shift from west to north today as the front passes over the western islands. Drier conditions and gusty winds are expected behind the front. AIRMET Tango for low level turbulence to the south and west of island terrain will likely be needed for Kauai and Oahu later this morning and the rest of the state by late evening.

Marine

High pressure to the distant northwest will build eastward in the vicinity of 30N, pushing a cold front southeastward through the island chain today and tonight. North winds gradually increase today, with SCA level winds expected across all waters by late this afternoon. The high will strengthen and shift northeastward Saturday and Saturday night, before settling southward and closer to the islands Sunday through the middle of next week. Strong to near Gale force winds are expected during this time, with the strongest winds in the windier waters around Maui and the Big Island, where Gale force winds are possible. A Gale Watch remains in effect for these areas Saturday through Sunday. A Small Craft Advisory is now in effect for all marine zones today and tonight, and for areas outside of the Gale Watch through Tuesday.
A pair of overlapping north to north-northeast swells continue to run higher than predicted at nearshore buoys early this morning. As a result, a High Surf Advisory is in effect for north and east facing shores of most islands through Sunday as well as west facing shores of Maui. Given the strong north to northeast winds along with the north-northeast swell direction, impacts are also likely from harbor surges at exposed northern harbors, including Hilo and Kahului harbors. See the Marine Weather Statement for additional details.
Advisory level surf may linger through Monday along north and east facing shores, as a new large northwest swell builds and easterly trade wind swell trends higher, even as the north-northeast swell declines. North shore surf should lower below advisory thresholds by Tuesday, with east shore surf likely holding at advisory levels through Wednesday. Surf should lower below advisory levels along east facing shores by Thursday as the trades begin to ease.
South shore surf will remain small through late next week.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST Sunday for north and east facing shores of Niihau, Kauai, Oahu, Molokai, Maui and Big Island.
Wind Advisory until 6 PM HST Sunday for all low elevation areas.
High Wind Warning until 6 AM HST Saturday for Big Island Summits.
Gale Watch from Saturday morning through Sunday afternoon for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Southeast Waters.
Small Craft Advisory until 6 AM HST Saturday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Southeast Waters.
Small Craft Advisory until 6 PM HST Tuesday 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, Big Island Windward Waters, Big Island Leeward Waters.

Data Courtesy of NOAA.gov