Photo Credit: Braden Jarvis

West Kaua’i

Today: Mostly sunny with scattered showers. Highs around 88 near the shore to around 76 above 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with isolated showers. Lows 70 to 75 near the shore to around 61 above 3000 feet. Northeast winds up to 15 mph. Chance of rain 20 percent.

Sunday: Breezy. Mostly sunny with isolated showers. Highs around 88 near the shore to around 76 above 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

South Kaua’i

Today: Partly sunny in the morning then becoming mostly sunny. Breezy. Scattered showers. Highs around 85. Northeast winds 15 to 20 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 68 to 74. Northeast winds 10 to 20 mph. Chance of rain 50 percent.

Sunday: Breezy. Partly sunny with numerous showers in the morning, then mostly sunny with scattered showers in the afternoon. Highs around 85. Northeast winds 15 to 20 mph. Chance of rain 70 percent.

Kaua’i Mountains

Today: Partly sunny. Breezy. Frequent showers in the morning, then scattered showers in the afternoon. Highs 75 to 82 in the valleys to around 66 above 4000 feet. East winds 10 to 20 mph. Chance of rain 80 percent.

Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then numerous showers after midnight. Lows 61 to 66 in the valleys to around 56 above 4000 feet. East winds up to 20 mph. Chance of rain 70 percent.

Sunday: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 75 to 82 in the valleys to around 66 above 4000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 70 percent.

North Kaua’i

Today: Partly sunny with scattered showers. Highs 78 to 87. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 64 to 74. East winds up to 15 mph. Chance of rain 50 percent.

Sunday: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 78 to 87. East winds up to 15 mph. Chance of rain 50 percent.

East Kaua’i

Today: Partly sunny with scattered showers. Highs 78 to 86. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 62 to 75. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Sunday: Partly sunny with scattered showers. Highs 78 to 86. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

High pressure to the north and northwest of the islands will keep moderate to breezy trade winds in place through late next week, with only minor fluctuations in strength. Fairly typical trade wind weather will prevail, with showers favoring windward and mauka areas and a stray shower reaching leeward communities at times.

Discussion

Currently at the surface, a 1027 mb high centered around 1500 miles northwest of Honolulu continues to drive moderate to locally breezy trade winds across the island chain early this morning. Infrared satellite imagery shows partly to mostly cloudy skies across the state, with cloud coverage the greatest in windward and mauka locales. Radar imagery shows scattered to numerous showers moving into windward slopes and coasts, with some of these showers making it into leeward communities as well. Main short term focus revolves around trade wind trends and rain chances.
High pressure will remain anchored to the northwest of the islands during the next couple days, while a cold front drops steadily southward well to the north of the state. Little change in trade wind strength is expected through the weekend, with moderate to locally breezy trade winds prevailing. The high northwest of the state will weaken and shift eastward Sunday night and Monday, while the front edges southward and closer to the island chain, eventually stalling out well north of the islands Monday night. This should ease the trades into the moderate range early next week. The high will then re-strengthen north of the islands Tuesday through late next week, bringing a return of moderate to breezy trade winds.
As for the remaining weather details, fairly typical trade wind weather will prevail during the next 7 days, although there could be a slight decrease in shower coverage Sunday afternoon through Tuesday. Overall, showers will favor windward and mauka areas through the period, particularly at night and during the early morning hours, with a few showers reaching leeward areas at times.

Aviation

A high pressure system far northwest of the islands will keep moderate to locally breezy trade winds in the forecast through tonight. Passing showers are expected, mainly over the windward and mountain areas in the overnight to early morning hours through Sunday. Isolated showers may reach leeward airfields during the overnight hours. MVFR conditions are possible with these showers, especially over windward airfields.
AIRMET Sierra for tempo mountain obscuration remains in effect for north through east sections of Maui and the Big Island. This AIRMET may expand westward to other islands later this morning. This AIRMET will likely diminish by 20Z.
AIRMET Tango for moderate low level turbulence remains in effect over and south through west of island mountains. These conditions may continue through this afternoon.

Marine

A broad area of surface high pressure located far north of the state will continue to produce locally strong trade winds this weekend. As a result, the Small Craft Advisory (SCA) has been extended through Sunday afternoon for the typically windier waters adjacent to the islands of Maui County and the Big Island. The latest forecast indicates the trade winds may remain locally strong from Sunday night through early next week. Therefore, the SCA may eventually need to be extended for the same typically windier waters in the vicinity of the eastern islands during Monday / Tuesday. Note that SCA conditions may develop over additional waters by the middle of next week if the gusty trade winds become more widespread.
The current small, medium-period southwest (210 degrees) swell will continue to gradually lower today. A new small, long-period southwest (210 degree) swell is expected to arrive by Sunday. This southwest swell energy combined with a lingering southeast trade wind swell will likely maintain small surf along south facing shores through early next week.
A small, medium-period north-northwest (330 degrees) swell will continue to spread down across the area during the next couple of days. This will likely cause a slight bump in surf along exposed north and west facing shores this weekend. In addition, a small north (350-360 degrees) swell may arrive around Tuesday, followed by a modest north-northeast (020 degrees) swell from Thursday into Friday.
Moderate, rough surf will likely persist along east facing shores into early Sunday. The surf may lower slightly along east facing shores from late Sunday into Tuesday due to a slight weakening of the trade winds. Moderate, rough surf may return along east facing shores by the middle of next week due to strengthening of the trade winds.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Sunday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov