Photo Credit: Braden Jarvis

West Kaua’i

Today: Mostly sunny. Breezy. Isolated showers in the morning, then scattered showers in the afternoon. Highs around 81 near the shore to around 71 above 3000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Gusts up to 40 mph. Chance of rain 50 percent.

Tonight: Partly cloudy. Breezy. Scattered showers in the evening, then isolated showers after midnight. Lows 71 to 76 near the shore to around 62 above 3000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Monday: Breezy. Mostly sunny with isolated showers. Highs around 82 near the shore to around 72 above 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

South Kaua’i

Today: Breezy. Mostly cloudy with numerous showers. Highs around 80. East winds 15 to 25 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy. Breezy. Numerous showers in the evening, then scattered showers after midnight. Lows 71 to 77. East winds 15 to 20 mph. Chance of rain 70 percent.

Monday: Breezy. Partly sunny with scattered showers. Highs around 81. East winds 10 to 20 mph. Chance of rain 50 percent.

Kaua’i Mountains

Today: Breezy. Mostly cloudy with occasional showers. Highs 69 to 75 in the valleys to around 64 above 4000 feet. East winds 10 to 25 mph. Chance of rain 80 percent.

Tonight: Breezy. Mostly cloudy with occasional showers. Lows around 66 in the valleys to around 58 above 4000 feet. East winds 10 to 25 mph. Chance of rain 90 percent.

Monday: Mostly cloudy. Breezy. Occasional showers in the morning, then scattered showers in the afternoon. Highs 70 to 76 in the valleys to around 65 above 4000 feet. East winds 10 to 20 mph. Chance of rain 90 percent.

North Kaua’i

Today: Breezy. Partly sunny with scattered showers. Highs 71 to 80. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 66 to 74. East winds up to 20 mph. Chance of rain 50 percent.

Monday: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 72 to 81. East winds up to 15 mph. Chance of rain 50 percent.

East Kaua’i

Today: Breezy. Mostly cloudy with numerous showers. Highs 71 to 81. East winds 10 to 20 mph. Chance of rain 70 percent.

Tonight: Breezy. Mostly cloudy with numerous showers. Lows 64 to 77. East winds 10 to 20 mph. Chance of rain 70 percent.

Monday: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 72 to 82. East winds 10 to 15 mph. Chance of rain 70 percent.

Detailed Forecast

Synopsis

Windy trades today will ease to breezy levels on Monday, then slowly diminish through the middle of next week. The trades will continue to deliver showers to windward slopes and coasts, with a few showers spilling into leeward communities at times. The showers could be a bit heavier over the eastern end of the state through Tuesday as a disturbance aloft meanders near the Big Island. Drier and more stable weather will build in on Wednesday, with mostly dry conditions and light winds expected Thursday into next weekend.

Discussion

Currently at the surface, a 1040 mb high is centered around 1450 miles north of Honolulu and is driving breezy to locally windy trades across the island chain early this morning. Infrared satellite imagery shows mostly cloudy conditions in windward areas and partly cloudy skies in most leeward locales. Radar imagery shows scattered to numerous showers moving into windward slopes and coasts, with a few showers reaching leeward areas at times. Main short term focus revolves around the strong trade winds and rain chances during the next couple days.
A strong area of high pressure north of the state will shift southeastward and gradually weaken today through Monday, with windy trades today easing off to breezy levels on Monday. A Wind Advisory remains in effect for Maui County and the Big Island through 6 pm this evening. The trades will steadily ease Tuesday and Wednesday as the ridge north of the islands weakens. Winds will become light Thursday into next weekend as a ridge is displaced near or over the state by an approaching cold front to the north, with land and sea breezes becoming common.
As for the remaining weather details, the trades will continue to deliver showers to windward slopes and coasts during the next few days, with a few showers reaching leeward areas at times. An upper low will meander over or near the Big Island through Tuesday, which could bring some locally heavier showers to the eastern end of the state. The airmass aloft although cool, will remain very dry, so the potential for any thunder and wintry weather for the Big Island summits appears low. A drier more stable airmass will build in on Wednesday, with rather dry conditions expected statewide Thursday into next weekend.

Aviation

Strong trades will continue through TODAY before tapering down into tonight into the new work week. A band of moisture moving through the islands has increased clouds and SHRA along windward and mauka areas. MVFR conds are possible in any SHRA, but VFR conds should generally prevail.
AIRMET Sierra remains in effect for mtn obsc for windward locations across the island chain.
AIRMET Tango remains in effect for mod low-level turb over and downwind of island terrain.

Marine

Strong high pressure centered approximately 1250 nm north of the Hawaiian Islands will maintain a tight pressure gradient back toward the state. This will continue to support strong to locally gale force trade winds across the local waters. The high will weaken and drift southeast tonight into Monday in response to a low passing far north of the area. A Gale Warning remains in effect through tonight for the windier waters surrounding Maui County and Big Island. A Small Craft Advisory (SCA) also remains in effect through tonight for strong east trades and seas greater than 10 feet over the remaining coastal waters. Winds could drop below SCA thresholds Tuesday as the next high pressure cell northeast of the islands drifts closer to the state.
East-facing shore surf will continue to remain very rough and choppy through tonight in response to strong east trades. The High Surf Advisory (HSA) for all east-facing shores remains in effect through tonight. East surf will likely hover near HSA thresholds through Monday morning before steadily declining the rest of next week as a result of weakening trades. North and south-facing shorelines exposed to these easterly wind waves may experience elevated surf and rough waves through the day.
A small, medium period northwest (320 degree) swell is expected to fill in later today and then fade Monday afternoon. A similar pulse from the northwest is possible late Wednesday night into Thursday. A small to moderate size north swell may arrive toward the end of the week. This swell will originate from a North Pacific low that comes within proximity of the north offshore waters.
Peak monthly tides will occur during the early morning hours through Monday morning. These high tides, combined with elevated seas from strong trade winds, may increase coastal inundation impacts for historically vulnerable locations during high tides. A Coastal Flood Statement is in effect through early Monday morning to address nuisance coastal flooding.

Fire weather

Strong gusty winds, dry fuels and near critical relative humidity levels will keep fire danger elevated today. Winds are expected ease below critical levels on Monday, with the trades continuing to decrease as the weak progresses.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 AM HST Monday for Olomana, Maui Windward West, Kauai East, Koolau Windward, Molokai Southeast, Windward Haleakala, Kipahulu, South Haleakala, Big Island Southeast, Big Island East, Big Island North.
Wind Advisory until 6 PM HST this evening for Lanai Mauka, Kahoolawe, Maui Windward West, Maui Leeward West, Kohala, Big Island Interior, Molokai North, Molokai West, Molokai Leeward South, Lanai Windward, Lanai Leeward, Maui Central Valley North, Maui Central Valley South, South Haleakala, Big Island South, Big Island Southeast, Big Island North.
Small Craft Advisory until 6 AM HST Monday 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.
Gale Warning until 6 AM HST Monday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov