Photo Credit: Jason Weingardt

West Kaua’i

Today: Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 85 near the shore to around 75 above 3000 feet. East winds 10 to 15 mph shifting to the northeast in the afternoon. Chance of rain 20 percent.

Tonight: Mostly cloudy with isolated showers. Lows 66 to 71 near the shore to around 57 above 3000 feet. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Saturday: Partly sunny with isolated showers in the morning, then mostly sunny with scattered showers in the afternoon. Highs around 84 near the shore to around 74 above 3000 feet. East winds 10 to 15 mph shifting to the northeast in the afternoon. Chance of rain 50 percent.

South Kaua’i

Today: Mostly sunny with isolated showers in the morning, then mostly cloudy with scattered showers in the afternoon. Highs around 83. East winds around 15 mph. Chance of rain 50 percent.

Tonight: Cloudy with scattered showers. Lows 64 to 70. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Saturday: Mostly cloudy in the morning then becoming mostly sunny. Scattered showers. Highs around 82. Northeast winds around 15 mph. Chance of rain 50 percent.

Kaua’i Mountains

Today: Breezy. Partly sunny with scattered showers in the morning, then cloudy with numerous showers in the afternoon. Highs around 78 in the valleys to around 67 above 4000 feet. East winds 15 to 20 mph. Chance of rain 70 percent.

Tonight: Cloudy with numerous showers. Lows around 60 in the valleys to around 52 above 4000 feet. East winds 10 to 15 mph. Chance of rain 70 percent.

Saturday: Mostly cloudy with numerous showers. Highs around 77 in the valleys to around 66 above 4000 feet. East winds around 15 mph. Chance of rain 70 percent.

North Kaua’i

Today: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Highs 78 to 84. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 60 to 69. East winds 10 to 15 mph. Chance of rain 50 percent.

Saturday: Partly sunny with scattered showers. Highs 77 to 83. East winds 10 to 15 mph. Chance of rain 50 percent.

East Kaua’i

Today: Mostly sunny with isolated showers in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 76 to 82. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 58 to 72. East winds 10 to 15 mph. Chance of rain 70 percent.

Saturday: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 75 to 81. East winds 10 to 15 mph. Chance of rain 70 percent.

Detailed Forecast

Synopsis

Trade winds will decrease slightly into the weekend. Rainfall will favor windward slopes, with an increase in shower activity expected Friday into Sunday. This trade wind weather pattern will prevail into next week.

Discussion

Trade winds will decrease slightly today through the weekend as surface ridging to our north weakens. A ragged area of increased moisture embedded within trade flow will fuel an increase in showers over windward portions of the Big Island and Maui this morning before spreading westward during the afternoon. Total rainfall will be light. High clouds will thicken as an upper trough to the west drifts eastward.
Ridging to our north will weaken over the next few days as a front passes by, also causing a decrease in airmass stability. This may trigger an increase in shower activity and cloud cover, mainly tonight and Saturday. Trade winds will become breezy again early next week as high pressure rebuilds north of the state. A strengthening upper ridge across the islands will stabilize our airmass and support a typical pattern of mainly windward rainfall. Models show that the remnants of the above mentioned front may get caught up in trade wind flow and provide a boost to windward rainfall around Wednesday.

Aviation

Stable and breezy trade wind conditions will prevail, with clouds and brief showers favoring the typical windward locations through the morning hours.
AIRMET Tango remains in effect for moderate upper level turbulence over the entire state and will likely continue through the day.
AIRMET Tango is also in place for moderate low level turbulence over and downwind of island terrain due to breezy trade winds.

Marine

Moderate to locally strong easterly trade winds will persist through this evening. High pressure just north of the state is forecast to shift south and weaken this weekend as a cold front approaches from the north. This will translate to a slight drop off in winds Saturday into early Sunday. High pressure building in behind the front early next week will re-tighten the upstream pressure gradient and result in fresh to locally strong trades. The Small Craft Advisory (SCA) for the windier zones around Maui and Big Island will be in effect through this afternoon. There will be a brief moment over the weekend where winds will fall below SCA criteria. SCA conditions are forecast to return across the more notorious windier zones surrounding Maui County and Big Island late Sunday and then, with strengthening trades, expand westward across the majority of the remaining marines zones by Tuesday.
Surf along east-facing shores will generally remain rough and choppy, but will subtly subside this weekend in response to the aforementioned weakening ridge and subsequent lighter winds. Surf along eastern exposures will again become more rough and choppy through most of next week as fresh to locally strong trades make a comeback. The lack of any north swell equates to very small weekend surf along north and west-facing shores. The only exception will be along more east-facing exposures that receive some trade swell wrap. The next mentionable north swell will be from the arrival of a small, medium period (360 degree) swell mid next week. South surf will remain small for the foreseeable future as very small, short period southeast to southwest swells roll in.

HFO Watches/Warnings/Advisories

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

Data Courtesy of NOAA.gov