West Side

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Windy. Isolated showers. Lows 67 to 73. East winds 10 to 20 mph shifting to the northeast 15 to 30 mph after midnight. Chance of rain 20 percent.

Tuesday: Windy. Mostly sunny with isolated showers. Highs 78 to 83. East winds 15 to 30 mph. Chance of rain 20 percent.

Tuesday Night: Partly cloudy. Breezy. Scattered showers in the evening, then isolated showers after midnight. Lows 66 to 72. Northeast winds 15 to 20 mph. Chance of rain 40 percent.

South Side

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Breezy. Lows 65 to 75. Northeast winds up to 15 mph increasing to 10 to 20 mph after midnight.

Tuesday: Sunny and breezy. Highs around 88. Northeast winds up to 25 mph.

Tuesday Night: Mostly clear. Lows 65 to 74. Northeast winds 10 to 15 mph.

North Shore

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows around 70 near the shore to around 51 near 5000 feet. East winds up to 15 mph. Chance of rain 70 percent.

Tuesday: Partly sunny in the morning then becoming mostly sunny. Breezy. Scattered showers. Highs 77 to 82 near the shore to around 65 near 5000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Tuesday Night: Mostly cloudy. Breezy. Numerous showers in the evening, then scattered showers after midnight. Lows around 69 near the shore to around 50 near 5000 feet. East winds up to 20 mph increasing to 10 to 20 mph after midnight. Chance of rain 70 percent.

Central Maui

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Breezy. Lows 65 to 70. Northeast winds 10 to 25 mph decreasing to 10 to 15 mph after midnight.

Tuesday: Sunny and breezy. Highs 81 to 88. Northeast winds up to 20 mph increasing to 15 to 25 mph in the afternoon.

Tuesday Night: Partly cloudy. Breezy. Isolated showers in the evening. Lows around 67. East winds 10 to 20 mph. Chance of rain 20 percent.

Upcountry

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 42 to 53. East winds up to 20 mph. Chance of rain 50 percent.

Tuesday: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 61 at the visitor center to around 64 at the summit. East winds up to 25 mph. Chance of rain 50 percent.

Tuesday Night: Mostly cloudy in the evening then becoming partly cloudy. Breezy. Scattered showers. Lows around 44 at the visitor center to around 42 at the summit. East winds 10 to 25 mph. Chance of rain 50 percent.

East Maui

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows around 70 near the shore to around 51 near 5000 feet. East winds up to 15 mph. Chance of rain 70 percent.

Tuesday: Partly sunny in the morning then becoming mostly sunny. Breezy. Scattered showers. Highs 77 to 82 near the shore to around 65 near 5000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Tuesday Night: Mostly cloudy. Breezy. Numerous showers in the evening, then scattered showers after midnight. Lows around 69 near the shore to around 50 near 5000 feet. East winds up to 20 mph increasing to 10 to 20 mph after midnight. Chance of rain 70 percent.

Lanai City

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Lows 62 to 67. Northeast winds up to 15 mph increasing to 10 to 15 mph after midnight.

Tuesday: Mostly sunny. Breezy. Highs 73 to 80. Northeast winds up to 25 mph.

Tuesday Night: Partly cloudy. Breezy. Lows around 64. Northeast winds 10 to 20 mph.

Kaunakakai

Tonight: Breezy. Mostly cloudy in the evening, then partly cloudy with isolated showers after midnight. Lows 57 to 73. Northeast winds 10 to 20 mph decreasing to up to 20 mph after midnight. Chance of rain 20 percent.

Tuesday: Breezy. Mostly sunny with isolated showers. Highs 69 to 86. Northeast winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 20 percent.

Tuesday Night: Breezy. Partly cloudy with isolated showers. Lows 56 to 72. East winds 15 to 20 mph. Chance of rain 20 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.

Data Courtesy of NOAA.gov