Photo Credit: Brittney Cruz

West Side

Today: Mostly sunny with isolated showers. Highs 79 to 88. East winds up to 10 mph shifting to the west around 10 mph in the afternoon. Chance of rain 20 percent.

Tonight: Mostly clear. Lows 69 to 78. Northwest winds around 10 mph in the evening becoming light.

Sunday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 77 to 86. Light winds becoming west around 10 mph in the afternoon. Chance of rain 50 percent.

South Side

Today: Sunny. Highs around 88. North winds up to 10 mph.

Tonight: Mostly clear. Lows 67 to 75. Northeast winds around 10 mph in the evening becoming light.

Sunday: Mostly sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs around 86. Light winds becoming west around 10 mph in the afternoon. Chance of rain 40 percent.

North Shore

Today: Mostly sunny with scattered showers. Highs 77 to 87 near the shore to around 67 near 5000 feet. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 40 percent.

Tonight: Partly cloudy with isolated showers. Lows 69 to 74 near the shore to 48 to 55 near 5000 feet. East winds 10 to 15 mph in the evening becoming light. Chance of rain 20 percent.

Sunday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 75 to 85 near the shore to around 65 near 5000 feet. Light winds becoming north around 10 mph in the afternoon. Chance of rain 50 percent.

Central Maui

Today: Sunny. Isolated showers in the morning. Highs 83 to 90. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 20 percent.

Tonight: Mostly clear. Lows 67 to 72. Northeast winds 10 to 15 mph in the evening becoming light.

Sunday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 81 to 88. Light winds becoming north around 10 mph in the afternoon. Chance of rain 40 percent.

Upcountry

Today: Sunny with isolated showers. Highs around 61 at the visitor center to around 55 at the summit. East winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Lows around 47 at the visitor center to around 44 at the summit. East winds around 10 mph in the evening becoming light.

Sunday: Sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs around 59 at the visitor center to around 53 at the summit. North winds around 10 mph in the morning becoming light. Chance of rain 50 percent.

East Maui

Today: Mostly sunny with scattered showers. Highs 77 to 87 near the shore to around 67 near 5000 feet. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 40 percent.

Tonight: Partly cloudy with isolated showers. Lows 69 to 74 near the shore to 48 to 55 near 5000 feet. East winds 10 to 15 mph in the evening becoming light. Chance of rain 20 percent.

Sunday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 75 to 85 near the shore to around 65 near 5000 feet. Light winds becoming north around 10 mph in the afternoon. Chance of rain 50 percent.

Lanai City

Today: Mostly sunny early in the morning, then scattered showers in the late morning and afternoon. Highs 74 to 81. Northeast winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly clear. Lows around 65. East winds up to 10 mph in the evening becoming light.

Sunday: Mostly sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs 75 to 82. Light winds becoming south around 10 mph in the afternoon. Chance of rain 50 percent.

Kaunakakai

Today: Sunny in the morning then becoming partly sunny. Isolated showers. Highs 70 to 90. East winds up to 10 mph shifting to the north in the afternoon. Chance of rain 20 percent.

Tonight: Mostly clear. Lows 59 to 77. North winds up to 10 mph in the evening becoming light.

Sunday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 69 to 89. East winds around 10 mph shifting to the northwest in the afternoon. Chance of rain 50 percent.

Detailed Forecast

Synopsis

An early season cold front moving into the Hawaii region from the north, will continue to weaken the subtropical ridge just north of the islands. Trade winds will become light today and Sunday for most central and southeastern islands with local scale sea breezes forming. Brief passing showers remain in the short range forecast for these sea breeze areas this weekend. The northwestern half of the state however will see widespread rainfall coverage from Sunday to Monday as this weakening front slows down and passes through each island. Moderate to locally breezy trade winds are expected for Kauai and Oahu after the frontal boundary passes each island on Sunday. The frontal motion will stall out over the central islands from Monday through Tuesday with high shower chances as the front fades away and trade winds return to moderate strength statewide.

Discussion

An early season cold front roughly 300 miles north of Kauai this evening continues to dive south towards the Hawaiian Islands. The frontal cloud band appears fairly convective with some of the highest cloud tops reaching the 40,000 foot level. This front will bring a good round of rainfall to the islands from Sunday through Tuesday. Otherwise, only a few cloud bands are shown on satellite ahead of the approaching front, yielding drier conditions across the state through Saturday afternoon.
The subtropical ridge will continue to weaken over the next 24 hours as the cold frontal trough dives south into the islands. Light large scale trade winds will allow sea breezes to form over each island on Saturday, with sea breezes continuing over Maui, Lanai and the Big Island through Monday. Expect trade winds to strengthen with northeasterly winds in the 10 to 20 MPH range with higher gusts as the frontal boundary passes through each island.
On the weather front, this system will produce widespread rainfall across the northwestern and central islands in the state from early Sunday morning near Kauai and Oahu, then spreading to Molokai and portions of Maui from Sunday night to Monday. Lanai will see scattered showers mainly on Monday afternoon in a sea breeze pattern. Kauai will see improving weather conditions by late Monday morning with passing windward showers. Rainfall amounts will be highly variable and terrain favored with a 0.10 to 0.50 inch range within the frontal zone with locally higher amounts possible. There is enough convective instability along this front for potential isolated thunderstorm activity right along the frontal cloud band from Sunday into Monday.
This front will break apart on Tuesday with lingering instability and moisture extending the enhanced shower activity across most islands into Wednesday in a moderate trade wind weather pattern. Clouds and showers from Tuesday to Wednesday will favor windward and mountain areas with less rainfall forecast over leeward locations.
Trade winds will weaken again on Thursday and Friday as a long wave trough lingers to our north. Land and sea breezes are forecast over all islands with lighter background trade winds. Clouds and a few showers will favor mountain and island interior sections each afternoon with a few windward showers developing each night.

Aviation

Moderate trades will remain on the dry side through Saturday. As a result, clouds and any showers will remain quite limited for the next 24 hours. Nothing more than brief MVFR is expected. Winds will back to a more northeasterly or even NNE direction by Saturday evening as a frontal boundary encroaches on the islands from the north.
No AIRMETs are in effect.

Marine

Light to moderate trades will hold in place through Saturday as a front approaches from the north. The front will sag southward into the islands late Saturday night and Sunday, bringing a return of moderate to fresh trade winds once it moves through. The front will stall out and dissipate over state early next week, with moderate trades generally prevailing through the end of the work week.
The current small medium period north-northwest swell will peak tonight and Saturday, then lower Sunday into early next week. A slightly larger north swell with a shorter period will build tonight then peak over the weekend. A moderate size longer period north-northeast swell should arrive Sunday night, peak near advisory levels along north facing shores Monday, then slowly decline through late next week. Another small medium period northwest swell appears to move through the islands Monday through the middle of next week, with a moderate near advisory level north swell potentially following by the end of the work week.
Surf will remain small along south facing shores over the next few days with mainly background energy from the south and southeast. Another small, more noticeable long-period south swell is expected to fill in Sunday into Monday with a slow and gradual decline through late next week.
East facing shores will remain small and well below normal during the next 7 days due to a lack of strong trade winds over and upstream of the islands.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov