West Kaua’i

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 68 to 73 near the shore to around 61 above 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tuesday: Mostly sunny. Isolated showers in the morning. Highs 83 to 89 near the shore to around 75 above 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tuesday Night: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows around 70 near the shore to around 60 above 3000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

South Kaua’i

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows around 70. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Tuesday: Breezy. Mostly cloudy with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 80 to 87. Northeast winds 10 to 20 mph. Chance of rain 50 percent.

Tuesday Night: Breezy. Mostly cloudy with numerous showers. Lows around 71. Northeast winds 15 to 20 mph. Chance of rain 70 percent.

Kaua’i Mountains

Tonight: Mostly cloudy. Numerous showers in the evening, then occasional showers after midnight. Lows 62 to 69 in the valleys to around 58 above 4000 feet. East winds up to 15 mph. Chance of rain 90 percent.

Tuesday: Mostly cloudy. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 74 to 81 in the valleys to around 65 above 4000 feet. East winds up to 15 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 70 percent.

Tuesday Night: Mostly cloudy. Breezy. Numerous showers in the evening, then occasional showers after midnight. Lows 62 to 69 in the valleys to around 58 above 4000 feet. East winds 10 to 20 mph. Chance of rain 90 percent.

North Kaua’i

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 64 to 72. East winds up to 15 mph. Chance of rain 70 percent.

Tuesday: Partly sunny with scattered showers. Highs 75 to 85. East winds up to 15 mph. Chance of rain 50 percent.

Tuesday Night: Mostly cloudy with numerous showers. Lows 63 to 71. East winds up to 15 mph. Chance of rain 70 percent.

East Kaua’i

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 64 to 74. Northeast winds up to 15 mph. Chance of rain 70 percent.

Tuesday: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 73 to 85. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Tuesday Night: Mostly cloudy with numerous showers. Lows 64 to 74. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Detailed Forecast

Synopsis

Breezy trade winds will carry periodic bands of showers across the Hawaiian Islands throughout the week. Rainfall will focus on windward and mountain areas, with stray showers reaching leeward areas.

Discussion

The fairly typical rainfall distribution has continued in the past 24 hours, although windward Big Island has remained on the dry side. Rainfall from the past 24 hours is generally from .10 to .50 of an inch other windward areas, and .10 inch or less leeward. Winds are breezy to gusty this afternoon with a few areas reaching 35 mph or greater in Maui's Central Valley and north shores, and the Kohala District on the Big Island.
A 1036 mb high located far to the north northwest of the state moving slowly eastward will weaken and take up a closer position north of the state by the weekend. Thus we expect a continuation of breezy trade winds to be felt this week. Afternoon gustiness is expected over and around island terrain in the normally windier areas each day.
A weak upper level ridge is roughly positioned over Hawaii this afternoon, which weakens further this week as the effects of an amplifying upper trough in the westerlies brushes by Thursday and Friday. The upper trough should have little impact to our weather, but will give us the benefit of more ample trade wind showers in our forecast for the week. The forecast model guidance is in agreement in keeping atmospheric instability limited, with inversion heights ranging from 7 to 10 k ft through the week, so rainfall totals should add up to near to even a bit above normal amounts for the 7 day period.

Aviation

Moderate to locally breezy easterly trade winds will continue through the week. Low clouds and showers will favor windward and mauka areas, with pockets of moisture producing MVFR conditions. Otherwise, VFR conditions will prevail. High clouds associated with an upper level disturbance will continue to stream across the state through tonight.
AIRMET Sierra for tempo mountain obscuration remains in effect for Oahu, with conditions continuing into tonight.
AIRMET Tango for moderate low level turbulence will remain marginal for areas east of Molokai due to breezy trade winds.

Marine

Moderate to locally strong trades will prevail today across the coastal waters, then strengthen to fresh to strong levels Tuesday night through the end of the work week. A Small Craft Advisory (SCA) remains in effect for the typically windy waters around Maui County and the Big Island through 6 PM HST Tuesday. This SCA will likely be extended in time through the end of the week and potentially expanded to additional waters around mid-week.
A long-period south swell will decline through Thursday. A larger south swell will arrive by the end of the week, and peak near advisory levels along south facing shores next weekend.
Surf along east-facing shores will hold steady near seasonal averages through the week. A series of small northwest and north swells will move through the islands bumping up north and west shore surf heights by Tuesday.

HFO Watches/Warnings/Advisories

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

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