Photo Credit: Jeni Ji Cousins

West Side

Today: Sunny. Isolated showers in the afternoon. Highs 75 to 80. East winds up to 10 mph shifting to the west in the afternoon. Chance of rain 20 percent.

Tonight: Mostly clear. Lows 64 to 70. Light winds.

Tuesday: Sunny. Isolated showers in the afternoon. Highs 75 to 81. Northeast winds up to 15 mph. Chance of rain 20 percent.

South Side

Today: Sunny. Highs around 83. North winds up to 10 mph shifting to the west in the afternoon.

Tonight: Mostly clear. Lows 62 to 72. Light winds.

Tuesday: Sunny. Highs around 83. North winds 10 to 15 mph.

North Shore

Today: Mostly sunny with isolated showers. Highs 76 to 81 near the shore to around 66 near 5000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows around 67 near the shore to around 50 near 5000 feet. South winds up to 10 mph in the evening becoming light. Chance of rain 20 percent.

Tuesday: Mostly sunny with isolated showers. Highs 76 to 81 near the shore to around 66 near 5000 feet. North winds up to 10 mph shifting to the northeast in the afternoon. Chance of rain 20 percent.

Central Maui

Today: Sunny. Highs around 82. Northeast winds up to 15 mph.

Tonight: Mostly clear. Lows 63 to 68. Light winds.

Tuesday: Sunny. Highs 79 to 84. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon.

Upcountry

Today: Mostly sunny. Isolated showers in the afternoon. Highs around 62 at the visitor center to around 60 at the summit. Southeast winds up to 10 mph in the morning becoming light. Chance of rain 20 percent.

Tonight: Mostly clear. Lows 42 to 53. Light winds.

Tuesday: Mostly sunny. Isolated showers in the afternoon. Highs around 62 at the visitor center to around 58 at the summit. Light winds becoming northeast up to 10 mph in the afternoon. Chance of rain 20 percent.

East Maui

Today: Mostly sunny with isolated showers. Highs 76 to 81 near the shore to around 66 near 5000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows around 67 near the shore to around 50 near 5000 feet. South winds up to 10 mph in the evening becoming light. Chance of rain 20 percent.

Tuesday: Mostly sunny with isolated showers. Highs 76 to 81 near the shore to around 66 near 5000 feet. North winds up to 10 mph shifting to the northeast in the afternoon. Chance of rain 20 percent.

Lanai City

Today: Mostly sunny. Scattered showers in the afternoon. Highs 70 to 78. Light winds. Chance of rain 30 percent.

Tonight: Partly cloudy. Lows around 63. Light winds becoming northwest up to 10 mph after midnight.

Tuesday: Mostly sunny. Scattered showers in the afternoon. Highs 72 to 79. Northeast winds 10 to 15 mph. Chance of rain 30 percent.

Kaunakakai

Today: Mostly sunny. Isolated showers in the afternoon. Highs 68 to 83. East winds up to 10 mph in the morning becoming light. Chance of rain 20 percent.

Tonight: Mostly clear. Lows 54 to 70. Light winds becoming northwest up to 10 mph after midnight.

Tuesday: Sunny. Isolated showers in the afternoon. Highs 68 to 83. Northeast winds up to 15 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Light to moderate winds and mostly dry conditions will prevail through Tuesday night, with a few showers possible along windward slopes and coasts at night and over the island interiors each afternoon. A cold front will approach from the northwest Wednesday and Thursday, shifting winds more southerly and bringing an uptick of showers, particularly over the western end of the state. The front should lift northward on Friday, with some lingering moisture keeping some scattered shower activity in place over the western islands, with mostly dry and stable conditions expected over the upcoming weekend.

Discussion

Currently at the surface, a 1024 mb high is centered around 1000 miles northeast of Honolulu, with a weakening stationary front between the high and the islands. Meanwhile, a new cold front is located around 1000 miles west-northwest of Kauai. Light to moderate trade winds prevail across the state early this morning. Infrared satellite imagery shows partly to mostly cloudy conditions, with cloud cover most prevalent in windward and mauka areas. Radar imagery shows a few very light showers, mostly affecting windward Maui and Big Island. Main short term focus revolves around wind trends and rain chances.
The high northeast of the state will shift eastward today, as the front northwest of the islands continues its approach. This will gradually ease the trades winds with sea breezes becoming common over the western islands by this afternoon. Winds will ease further tonight, followed by a return of light to moderate trades Tuesday and Tuesday night as a new high builds eastward to the north of the state. A new stronger front will approach from the west Wednesday, shifting winds southerly at moderate speeds, with the south winds then easing a bit on Thursday as the front stalls out northwest of the islands. Light to moderate southeast to south winds appear to return Friday and Saturday as the stalled out front lifts back northward and away from the area as a warm front. Light to moderate trade winds could return on Sunday.
As for the remaining weather details, mostly dry and stable weather will prevail through Tuesday night, with a few light showers possible over windward slopes and coasts at night, and over the island interiors each afternoon. Rainfall amounts are expected to remain minimal as low and mid level ridging will keep inversion heights suppressed. As winds turn southerly Wednesday and Thursday in advance of an approaching front, the boundary layer should moisten up a bit and inversion heights should rise slightly, bringing an increase in showers, particularly over the western end of the state. As the front lifts northward as a warm front on Friday, some lingering moisture may keep some scattered shower activity over the western islands, followed by a return of mostly dry and stable conditions for next weekend.

Aviation

A weak high pressure system north of the Hawaiian Islands will keep a light east to southeast wind pattern with hybrid daytime sea breezes over each island. VFR conditions will prevail with periods of cloud ceilings building over island mountain and interior sections with converging sea breezes each day.
No AIRMETs are in effect.

Marine

A ridge of high pressure will slowly drift over the islands today as a front to the northwest will pass north of the islands giving way to light east to southeast flow during the afternoon across most waters. A weak building high pressure north of the state will produce light to gentle north to northeast flow on Tuesday. Another front approaching the islands Wednesday will cause the winds to shift out of the southeast to south through Friday before the front lifts northward.
The current west-northwest swell continues to remain above guidance and the High Surf Advisory (HSA) has been extended for all existing north and west facing shores. The HSA has also been expanded for west facing shores of the Big Island through today too. The Small Craft Advisory (SCA) however, has been cancelled as observations have shown seas just below 10 feet and will continue to decline through the day.
A similar sized northwest swell is expected to build in late Tuesday and linger through Wednesday, resulting in peak surf heights at or slightly above HSA for north and west facing shores. An even larger northwest swell is expected to build late Thursday into Friday potentially getting to High Surf Warning level criteria for select north and west facing shores. Surf along south facing shores will remain tiny with mainly background energy through the week. Surf along east facing shores will also remain tiny to small through the week with a potential slight uptick on Tuesday due to gentle trade winds.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST this evening for Niihau, Kauai Leeward, Waianae Coast, Oahu North Shore, Maui Windward West, Kona, Kohala, Kauai North, Molokai Windward, Molokai North, Molokai West, Maui Central Valley North, Windward Haleakala.

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Data Courtesy of NOAA.gov