Photo Credit: Sebastien Gabriel

West Kaua’i

Today: Mostly sunny. Breezy. Highs 82 to 87 near the shore to around 72 above 3000 feet. Northeast winds up to 20 mph.

Tonight: Partly cloudy. Lows around 68 near the shore to around 57 above 3000 feet. Northeast winds up to 15 mph.

Saturday: Mostly sunny. Breezy. Highs around 84 near the shore to around 71 above 3000 feet. Northeast winds up to 20 mph.

South Kaua’i

Today: Partly sunny. Breezy. Isolated showers in the morning. Highs 77 to 85. Northeast winds 15 to 25 mph. Chance of rain 20 percent.

Tonight: Breezy. Mostly cloudy with isolated showers. Lows around 69. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Saturday: Partly sunny. Breezy. Isolated showers in the morning. Highs 76 to 84. Northeast winds 10 to 25 mph. Chance of rain 20 percent.

Kaua’i Mountains

Today: Mostly cloudy. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 71 to 82 in the valleys to around 63 above 4000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 62 to 67 in the valleys to around 56 above 4000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Saturday: Mostly cloudy. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 70 to 82 in the valleys to around 62 above 4000 feet. East winds up to 20 mph. Chance of rain 50 percent.

North Kaua’i

Today: Partly sunny with isolated showers. Highs 75 to 85. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with isolated showers. Lows 62 to 70. East winds up to 15 mph. Chance of rain 20 percent.

Saturday: Partly sunny with isolated showers. Highs 74 to 84. East winds 10 to 15 mph decreasing to up to 15 mph in the afternoon. Chance of rain 20 percent.

East Kaua’i

Today: Mostly cloudy with isolated showers. Highs 72 to 83. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with isolated showers. Lows 63 to 74. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Saturday: Breezy. Mostly cloudy with isolated showers. Highs 71 to 83. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Moderate to breezy trade winds will continue into the weekend as the high pressure ridge lingers north of the Hawaiian Islands. Drier trade wind weather remains in the forecast through Friday night. Increasing shower trends return from Saturday afternoon through Sunday as a weak disturbance aloft passes through the region. A cold front approaching from the northwest on Monday will break down down the ridge north of the state weakening trades from Monday through Wednesday. A weak cold front may drift into the islands by the end of next week potentially increasing shower trends.

Discussion

This morning's soundings from Hilo and Lihue indicated inversions at approximately 8000 feet and 5000 feet, respectively, at 2 AM HST (12Z). Latest satellite imagery showcases an extensive band of fairly stable clouds along the eastern slopes of the islands from the Big Island northwest to Oahu as of 3 AM HST. These cloud tops within the aforementioned band are capable of producing periods of scattered showers along these windward slopes through the morning hours.
High pressure ridging remains dominant north of the islands with an upper-level low south of the islands slowly moving westward, maintaining moderate to breezy trade winds through the next couple days, and then weakening through early next week. A slight boost in trade wind showers remains in the forecast from Saturday through Sunday mainly over the windward and mountain areas of all islands due to a passing short wave trough. Brief passing showers will remain in the forecast through Sunday mainly over the windward and mountain areas, favoring the overnight to early morning hours.
Large scale winds will transition to a more light and variable pattern from Monday through Wednesday. These lighter large scale winds will allow local scale land and sea breezes to expand in coverage over all islands in a fairly stable weather pattern with limited shower activity.
There are some early signs of a weakening cold front drifting into the Hawaii region by the end of next week, possibly bringing our next best chance for widespread rainfall coverage. The forecast rainfall impacts and the track of the frontal cloud band this far out remains challenging, and at this point we can say the western islands have higher chances to pick up enhanced showers. Stay tuned.

Aviation

Breezy trade winds will continue during the next 24 hours, with light showers bringing some MVFR cigs/vsbys to windward areas, particularly at night and during the early morning hours. VFR conditions will prevail in leeward areas.
AIRMET Sierra remains in effect for mountain obscuration across windward sections of Kauai, Oahu, Molokai, Maui, and the Big Island. Conditions should improve around mid morning.
AIRMET Tango remains in effect for moderate low-level turbulence over and downwind of the terrain of all islands. This AIRMET will likely continue through the day.

Marine

Fresh to strong easterly trade winds will prevail through Sunday, easing Sunday night into early next week as the ridge weakens and shifts south due to a series of cold fronts passing to the north. Seas are currently at or near Small Craft Advisory levels for most windward waters, which will persist through Saturday before subsiding Sunday. Starting Sunday night, light and variable winds will develop near the coasts, accompanied by overnight and early morning land breezes and daytime sea breezes. This pattern will persist through the first half of next week as the background flow shifts southeast Sunday night, then south to southwest Tuesday through midweek.
Surf along exposed north and west-facing shores will remain steady today as a fresh northwest swell fills in, with heights staying well below advisory levels. A decrease in surf is expected from Saturday through Monday as the swell eases. By Tuesday, surf will begin to rise again, with a significant upward trend anticipated through the second half of next week. This increase will be driven by a decent-sized fetch developing over the far northwest Pacific, near the Aleutians from the Date Line to the Kuril Islands. Heights could exceed warning-levels (XL: 25-39 ft faces) late next week if conditions evolve as projected.
Surf along east-facing shores will remain rough through the weekend but will gradually decrease late Sunday and into much of next week as the trade winds diminish.
Surf along south-facing shores will remain near seasonal averages, influenced by a mix of short-period southeast swells and occasional longer-period background south-southwest swells.

Fire weather

While rather dry weather is expected through much of the forecast period, wind speeds and relative humidity levels will remain below critical fire weather thresholds through the seven day forecast period.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Saturday for Oahu Windward Waters, Oahu Leeward Waters, Kaiwi Channel, Maui County Windward Waters, Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Windward Waters, Big Island Leeward Waters, Big Island Southeast Waters.

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