Photo Credit: Brendan Stephen

West Kaua’i

Today: Breezy. Partly sunny with isolated showers. Highs around 86 near the shore to around 74 above 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Tonight: Breezy. Partly cloudy with isolated showers. Lows 68 to 73 near the shore to around 59 above 3000 feet. Northeast winds up to 20 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny with isolated showers. Highs around 86 near the shore to around 74 above 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

South Kaua’i

Today: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 83. Northeast winds 10 to 20 mph. Chance of rain 70 percent.

Tonight: Breezy. Partly cloudy with scattered showers. Lows 66 to 72. Northeast winds 10 to 20 mph. Chance of rain 50 percent.

Wednesday: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs around 83. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Kaua’i Mountains

Today: Mostly cloudy. Breezy. Occasional showers in the morning, then scattered showers in the afternoon. Highs 73 to 80 in the valleys to around 64 above 4000 feet. East winds 10 to 20 mph. Chance of rain 90 percent.

Tonight: Partly cloudy with scattered showers in the evening, then mostly cloudy with numerous showers after midnight. Lows 59 to 64 in the valleys to around 54 above 4000 feet. East winds 10 to 15 mph decreasing to up to 10 mph after midnight. Chance of rain 70 percent.

Wednesday: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 73 to 80 in the valleys to around 64 above 4000 feet. East winds up to 15 mph. Chance of rain 70 percent.

North Kaua’i

Today: Partly sunny with scattered showers. Highs 76 to 85. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with scattered showers. Lows 62 to 72. East winds up to 15 mph. Chance of rain 50 percent.

Wednesday: Partly sunny with scattered showers. Highs 76 to 85. East winds up to 15 mph. Chance of rain 50 percent.

East Kaua’i

Today: Mostly cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 76 to 84. East winds 10 to 15 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy with scattered showers. Lows 60 to 73. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Wednesday: Partly sunny with scattered showers. Highs 76 to 84. East winds 10 to 15 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

High pressure northeast of the islands will keep moderate to locally breezy trade winds blowing during the next 7 days, with only minor fluctuations in strength. A disturbance aloft will bring a few more trade wind showers than normal, with showers favoring windward areas during nights and mornings.

Discussion

Currently at the surface, a 1034 mb high is centered around 1500 miles northeast of Honolulu, and is driving moderate to breezy trade winds 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 areas, with some of these spilling over into leeward communities at times. Main short term focus revolves around rain chances and trade wind trends.
High pressure will remain anchored northeast of the islands during the next 7 days, with just some minor fluctuations in position and strength. This should keep the trades blowing at moderate to locally breezy levels through the period.
As for the remaining weather details, a weakness aloft over the islands this morning will gradually strengthen and close off into a upper level low over the state by the end of the work week. The upper level low is then forecast to remain over or near the islands through early next week. Bands of moisture caught up in the trades in combination with elevated inversion heights due to the weakness aloft, will bring a more showery than normal trade wind pattern to the islands. Clouds and showers will favor windward and mauka areas, particularly during nights and mornings, with a few showers reaching leeward areas at times as well.

Aviation

A surface high to the northeast of the Hawaiian islands will keep moderate to locally breezy trade winds in place through the next several days. Low clouds and showers will be widespread over windward areas and scattered over leeward areas as a band of moisture associated with an old front gets pushed over the islands. MVFR conditions can be expected within the showers. Clouds and showers could then decrease in coverage and intensity by late morning.
AIRMET Tango remains in effect below 9000 feet over and immediately southwest through northwest of the mountains due to moderate turbulence. This AIRMET will likely be needed throughout the next several days.
AIRMET Sierra is in effect for mountain obscuration due to low clouds and showers for the windward portions of Kauai and the Big Island. This may be expanded to include other islands.

Marine

High pressure far northeast of the state will produce moderate to locally strong easterly trades throughout the week. A band of showers moving into the area early this morning will bring a slight uptick in wind speeds especially over windward waters. The Small Craft Advisory remains in effect for the windier waters and channels around Maui County and the Big Island through Wednesday, and will likely be extended further.
Background energy from the northwest will continue to linger along north facing exposures over the next few days. In the extended forecast, former Typhoon Guchol should send another out- of-season northwest (300-320 deg) swell to Hawaii this weekend.
Surf along south facing shores will remain small throughout the week with a mix of small, long-period south and southwest (170-220 deg) swells. A slight increase in south swell energy is possible Tuesday into Wednesday.
Surf along east facing shores will remain mostly steady this week, with only minor fluctuations in response to small changes in trade wind speeds.

HFO Watches/Warnings/Advisories

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

Data Courtesy of NOAA.gov