Photo Credit: Sebastien Gabriel

West Kaua’i

Today: Partly sunny with isolated showers. Highs around 80 near the shore to around 68 above 3000 feet. Southwest winds up to 10 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Lows around 63 near the shore to around 52 above 3000 feet. Southwest winds up to 10 mph. Chance of rain 20 percent.

Monday: Mostly sunny with isolated showers. Highs around 81 near the shore to around 69 above 3000 feet. Southwest winds around 10 mph. Chance of rain 20 percent.

South Kaua’i

Today: Partly sunny. Isolated showers in the morning. Highs around 79. West winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Lows 59 to 64. West winds 10 to 15 mph in the evening becoming light. Chance of rain 20 percent.

Monday: Mostly sunny with isolated showers. Highs around 80. Southwest winds around 10 mph. Chance of rain 20 percent.

Kaua’i Mountains

Today: Partly sunny with isolated showers. Highs 67 to 75 in the valleys to around 62 above 4000 feet. Southwest winds up to 15 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with isolated showers in the evening, then partly cloudy with scattered showers after midnight. Lows 52 to 57 in the valleys to around 46 above 4000 feet. Southwest winds up to 10 mph. Chance of rain 30 percent.

Monday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 68 to 76 in the valleys to around 63 above 4000 feet. Southwest winds up to 15 mph. Chance of rain 30 percent.

North Kaua’i

Today: Partly sunny. Isolated showers in the morning. Highs 72 to 79. South winds up to 15 mph shifting to the north in the afternoon. Chance of rain 20 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Lows 55 to 64. Southwest winds up to 10 mph in the evening becoming light. Chance of rain 20 percent.

Monday: Mostly sunny with isolated showers. Highs 73 to 80. Southwest winds up to 10 mph. Chance of rain 20 percent.

East Kaua’i

Today: Partly sunny with isolated showers in the morning, then mostly sunny in the afternoon. Highs 72 to 79. Southwest winds up to 15 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Lows 53 to 65. West winds up to 15 mph in the evening becoming light. Chance of rain 20 percent.

Monday: Mostly sunny with isolated showers. Highs 73 to 80. Southwest winds up to 10 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

A high pressure ridge just south of the islands and a cold frontal system passing just to the north of the state will keep Hawaii in a stable light to moderate southwesterly wind pattern through Tuesday. A prefrontal convergence band may increase showers near Kauai and Oahu by Tuesday night with a cold front stalling just northwest of Kauai enhancing showers over the Garden Isle from Wednesday to Thursday morning. A weak high pressure ridge builds back in over the eastern islands in Maui and Hawaii Counties from Thursday through Saturday. Expect stable and dry conditions and lighter winds to spread across the western islands by Thursday afternoon as the cold frontal system lifts northward.

Discussion

Satellite imagery this morning continues to show a convergent cloud band south and east of the Big Island, and a cold frontal system northwest of Kauai. Fairly stable light to moderate southwesterly winds are expected over the next few days. Strong winds over the Big Island Summits continue today due to stronger winds aloft, and a High Wind Warning remains in effect through the afternoon hours. Upper level wind speeds will decrease from later tonight into Monday as a subtropical jet stream moves farther away from the islands, and the high wind warnings for the summit zones will likely be cancelled by tonight. Another upper level jet stream associated with the cold front northwest of Kauai will produce some feathering high cirrus clouds over the western islands through the week, enhancing sunrise and sunset colors.
Southwesterly surface wind speeds are increasing as a cold front approaches the islands from the northwest. This cold front will stall out just northwest of Kauai from Wednesday to Thursday. Prefrontal convergence bands may increase cloud and shower coverage over Kauai and Oahu by Tuesday night with additional shower activity ramping up near Kauai from Wednesday into Thursday. Moderate rainfall accumulations are possible over Kauai during this time period.
A drier weather story will develop over the eastern Hawaiian Islands this week. A surface ridge will lift northward over the islands in Maui and Hawaii Counties this week. Drier conditions will remain in place with lighter winds forecast from Monday through Friday. Expect warm days and cool nights for these central and eastern islands.
The extended range forecast outlook shows the possibility of another cold front moving into the region with trade winds returning to the islands around March 20th.

Aviation

Light to locally moderate southwest flow will continue today and tonight, allowing for development of local land and sea breezes. In general, expect limited shower coverage across the islands as dry and stable conditions continue. Mainly VFR conditions will continue through Monday. However, localized MVFR ceilings are possible in showers across the Big Island fueled by a persistent band of low clouds.
A strong jetstream extends across the state, so we will continue the turbulence AIRMET Tango through this afternoon. No other AIRMETS are in effect or expected.

Marine

Southwest winds will increase into the moderate to fresh category today (highest Kauai and Oahu waters) as low pressure passes north of the area. Guidance shows the southwest winds dipping back into the light category tonight through Monday as this feature quickly advances eastward allowing the surface ridge to retreat northward back over the islands. A replay of this pattern with a return of moderate southwest winds is expected Tuesday through midweek as another low develops and tracks eastward, passing the islands to the north Wednesday. The front associated with this second feature may reach/near the western end of the state by Wednesday before it stalls and diminishes.
Surf along north and west facing shores will continue to ease today as a north-northwest swell moves out. Observations at the offshore buoys to the northwest reflect this trend with the spectral peak now centered around the 10 second band and swell height within this band down to around 3 ft. Guidance lines up well with the current pattern and depicts well below normal conditions continuing this week with mainly small background northwest and northeast energy moving through.
Surf along east facing shores will remain small through the week due to the lack of trades locally and upstream across the eastern Pacific. Only the wrap from the current north-northwest swell moving through today and from a small north-northeast swell expected to linger into the start of the week will generate surf for eastern shores.
Surf along south facing shores will remain small with a mix of background southerly pulses moving through and some added short period chop due to the periods of moderate southwest winds anticipated today and again Tuesday into Wednesday.

HFO Watches/Warnings/Advisories

High Wind Warning until 6 PM HST this evening for Big Island Summits.

Data Courtesy of NOAA.gov