West Side

Today: Sunny. Highs 79 to 84. Northeast winds up to 15 mph.

Tonight: Mostly clear. Lows 69 to 75. East winds up to 10 mph.

Wednesday: Sunny. Highs 79 to 85. Light winds becoming southwest up to 10 mph in the afternoon.

South Side

Today: Sunny. Highs around 85. North winds up to 15 mph increasing to 10 to 15 mph in the afternoon.

Tonight: Clear. Lows 69 to 78. North winds up to 15 mph.

Wednesday: Sunny. Highs around 87. North winds up to 10 mph shifting to the northwest in the afternoon.

North Shore

Today: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 80 to 86 near the shore to around 65 near 5000 feet. East winds up to 15 mph. Chance of rain 40 percent.

Tonight: Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows 70 to 75 near the shore to around 55 near 5000 feet. Southeast winds up to 15 mph. Chance of rain 50 percent.

Wednesday: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Highs 81 to 87 near the shore to around 66 near 5000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Central Maui

Today: Sunny. Highs 79 to 86. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon.

Tonight: Mostly clear. Lows around 71. Northeast winds up to 15 mph in the evening becoming light.

Wednesday: Sunny. Highs 80 to 87. North winds up to 15 mph.

Upcountry

Today: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 61 at the visitor center to around 68 at the summit. Light winds. Chance of rain 40 percent.

Tonight: Mostly clear. Isolated showers in the evening. Lows around 49 at the visitor center to around 46 at the summit. Southeast winds up to 10 mph. Chance of rain 20 percent.

Wednesday: Sunny. Isolated showers in the morning, then scattered showers in the afternoon. Highs around 62 at the visitor center to around 67 at the summit. Southeast winds up to 10 mph in the morning becoming light. Chance of rain 50 percent.

East Maui

Today: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 80 to 86 near the shore to around 65 near 5000 feet. East winds up to 15 mph. Chance of rain 40 percent.

Tonight: Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows 70 to 75 near the shore to around 55 near 5000 feet. Southeast winds up to 15 mph. Chance of rain 50 percent.

Wednesday: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Highs 81 to 87 near the shore to around 66 near 5000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Lanai City

Today: Sunny. Highs 71 to 79. Northeast winds up to 15 mph.

Tonight: Clear. Lows 66 to 71. Northeast winds up to 15 mph in the evening becoming light.

Wednesday: Sunny. Highs 71 to 80. Light winds becoming east up to 10 mph in the afternoon.

Kaunakakai

Today: Sunny. Highs 70 to 87. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon.

Tonight: Mostly clear. Lows 60 to 74. Northeast winds up to 15 mph.

Wednesday: Sunny. Highs 72 to 88. East winds up to 10 mph.

Detailed Forecast

Synopsis

Slightly weaker trade wind flow today with a few light windward showers. Wednesday into Thursday, light easterly flow will lead to the development of sea/land breezes. Thus, most cloud cover and shower activity will be limited to interior and mountain areas during the afternoons. In addition, deeper moisture moving in from the southeast Wednesday through Friday should bring increased shower chances to the Big Island and Maui.

Discussion

Current satellite and radar imagery shows some isolated to scattered showers moving in on the trade impacting windward and mauka locations with some spillover over to leewards areas. Moderate trades are expected across the state today due to a high continuing to move far to the northeast.
By Wednesday, the local pressure gradient is expected to weaken even further, with background winds becoming light and variable. Daytime heating, combined with weak surface flow, will lead to daytime sea breezes and nighttime land breezes. Clouds and showers should mainly be limited to over the island interiors and mountainous terrain, particularly during the day. By Wednesday night, however, global forecast models remain consistent in a pocket of deeper moisture associated with a weak surface trough moving northward from the southeast towards the Big Island. This feature could act to increase shower coverage, especially along eastern portions of the Big Island. Long range models continue to push this band of moisture up through Maui County and, to a lesser extent, Oahu on Thursday into Friday before lifting it northward. Light southeast flow, combined with this batch of moisture, could lead to an increase in shower activity over the islands interiors during the afternoons. More typical trade wind weather should return by this weekend.

Aviation

Moderate trades today before weakening Wednesday. Low cigs and SHRA will impact windward an mauka locations. MVFR conds possible otherwise VFR prevails. Weakening trades should allow for sea/land breeze development on Wednesday.
No AIRMETs in effect.

Marine

Moderate to locally fresh trade winds will gradually ease to light to moderate speeds through the end of the week as a trough to the northwest weakens the ridge to the north. The ridge will strengthen over weakened as the troughs weaken and lifts far north, allowing fresh to moderate easterly trades to return.
The current large, long period south southwest swell will continue to slowly decline as the swell slowly fades. Swell heights remain elevated as the swell period has begun to decline. The High Surf Warning has been downgraded to a High Surf Advisory (HSA) through tonight for all south facing shores. Another south southwest swell is expected to fill in Wednesday night into Thursday that could push surf back up to HSA levels.
Surf along north facing shores will remain flat to tiny through the forecast period. Surf along east facing shores will remain below average as easterly trade winds ease through the end of the week.
A Coastal Flood Statement remains in effect for minor coastal flooding of vulnerable low-lying coastal roadways, docks, boat ramps and other coastal infrastructure due to King Tides. King Tides combined with water levels that are running higher than predicted will lead to minor flooding potential around the daily peak tide, which will be during the late afternoon and early evening hours, through today and possibly Wednesday. While minor coastal flooding is expected along all shorelines, the combination of the large south southwest swell and peak daily high tides will make low-lying coastal areas along south and west shores susceptible to more widespread coastal flooding through this evening.
A Marine Weather Statement also remains in effect due to the large, long-period south southwest swell producing harbor surges and breaking waves near harbor entrances along south and west-facing harbors.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 AM HST Wednesday for Niihau, Kauai Leeward, Waianae Coast, Kahoolawe, Maui Leeward West, Kona, Kohala, Kauai South, East Honolulu, Honolulu Metro, Ewa Plain, Molokai Southeast, Molokai Leeward South, Lanai Leeward, Lanai South, Maui Central Valley South, Kipahulu, South Maui/Upcountry, South Haleakala, Big Island South, Big Island Southeast.

Data Courtesy of NOAA.gov