West Side

Today: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Highs 78 to 83. Northeast winds up to 15 mph. Chance of rain 40 percent.

Tonight: Mostly cloudy. Breezy. Numerous showers in the evening, then scattered showers after midnight. Lows 67 to 73. Northeast winds 10 to 25 mph. Chance of rain 70 percent.

Sunday: Partly sunny. Windy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 75 to 81. Northeast winds 15 to 30 mph. Chance of rain 50 percent.

South Side

Today: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs around 85. North winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Breezy. Mostly cloudy with isolated showers. Lows 67 to 75. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Sunday: Partly sunny. Breezy. Isolated showers in the afternoon. Highs around 82. Northeast winds 15 to 25 mph. Chance of rain 20 percent.

North Shore

Today: Mostly cloudy with scattered showers. Highs 79 to 84 near the shore to around 64 near 5000 feet. Northeast winds up to 10 mph. Chance of rain 50 percent.

Tonight: Frequent showers. Lows around 70 near the shore to around 52 near 5000 feet. Northeast winds up to 15 mph. Chance of rain near 100 percent.

Sunday: Breezy. Mostly cloudy with frequent showers. Highs 77 to 82 near the shore to around 61 near 5000 feet. Northeast winds 10 to 20 mph. Chance of rain 90 percent.

Central Maui

Today: Partly sunny with scattered showers. Highs 79 to 86. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy. Frequent showers in the evening, then numerous showers after midnight. Lows 67 to 72. Northeast winds 10 to 15 mph. Chance of rain 90 percent.

Sunday: Breezy. Partly sunny with scattered showers. Highs 77 to 83. Northeast winds 15 to 20 mph. Chance of rain 50 percent.

Upcountry

Today: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 60 at the visitor center to around 67 at the summit. Light winds. Chance of rain 50 percent.

Tonight: Mostly cloudy with frequent showers. Lows around 47 at the visitor center to around 43 at the summit. Northeast winds up to 15 mph. Chance of rain 90 percent.

Sunday: Partly sunny. Frequent showers in the morning, then isolated showers in the afternoon. Highs around 57 at the visitor center to around 65 at the summit. East winds up to 15 mph. Chance of rain 90 percent.

East Maui

Today: Mostly cloudy with scattered showers. Highs 79 to 84 near the shore to around 64 near 5000 feet. Northeast winds up to 10 mph. Chance of rain 50 percent.

Tonight: Frequent showers. Lows around 70 near the shore to around 52 near 5000 feet. Northeast winds up to 15 mph. Chance of rain near 100 percent.

Sunday: Breezy. Mostly cloudy with frequent showers. Highs 77 to 82 near the shore to around 61 near 5000 feet. Northeast winds 10 to 20 mph. Chance of rain 90 percent.

Lanai City

Today: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs 72 to 81. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 65. Northeast winds 10 to 25 mph increasing to 20 to 25 mph after midnight. Chance of rain 50 percent.

Sunday: Windy. Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 70 to 78. Northeast winds 20 to 30 mph. Chance of rain 30 percent.

Kaunakakai

Today: Mostly sunny with isolated showers in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 71 to 88. Northeast winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Breezy. Numerous showers in the evening, then scattered showers after midnight. Lows 57 to 73. Northeast winds 10 to 25 mph. Chance of rain 70 percent.

Sunday: Breezy. Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 68 to 85. Northeast winds 15 to 25 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

A cold front will move down the island chain through Sunday, bringing an increase in showers, especially along windward slopes. Breezy to windy east-northeasterly trades will fill in behind the front and persist through much of next week as strong high pressure builds north of the islands. Typical windward and mauka showers will prevail under the trade flow, with generally drier conditions leeward.

Discussion

Infrared satellite imagery early this morning shows a cold front approaching the western end of the state, with light winds and isolated to scattered light showers in advance of the boundary. The front is expected to reach Kauai by mid-morning, Oahu later this afternoon or evening, and progress down the island chain to the Big Island by early Sunday morning. Light and variable winds will prevail ahead of the front, shifting to breezy to windy east- northeasterly trades in its wake.
Moisture pooling along and just ahead of the boundary will bring an uptick in showers as it moves southeast, primarily affecting windward and mauka areas, but some showers may also blow over island terrain to reach leeward areas of the smaller islands as well. Mid-level ridging in place over the region will act to limit vertical development, keeping rainfall rates modest overall. In addition, the relatively quick-moving nature of the front will also help to limit flooding concerns. However, model guidance is still showing that certain windward areas (particularly across Maui County and the Big Island) could receive a couple of inches of rain Saturday evening through Sunday, so have continued to reflect that in this mornings forecast package.
Breezy to windy east-northeasterly trades will become established across the state early next week as high pressure builds to the north. Another reinforcing front with an even stronger high pressure system will arrive midweek, providing another boost in the east-northeasterly trades. With mid level ridging persisting over the region, inversion heights will remain low, keeping the moisture confined to lower levels and focusing clouds and showers over windward and mauka areas.

Aviation

Light and variable winds will continue ahead of an approaching cold front that will move across Kauai later this morning and progress down the island chain to reach the Big Island by sometime Sunday morning. Enhanced shower activity is expected along the frontal boundary as it passes through, along with breezy east- northeasterly trades. VFR conditions will generally prevail ahead of the front, with MVFR conditions expected with the showers as they pass through.
No AIRMETs are in effect this morning, but AIRMET Tango for low- level turbulence over and downstream of island terrain and AIRMET Sierra for mountain obscuration across windward areas may be needed as the cold front advances across the island chain.

Marine

A cold front, currently residing just outside of our coastal waters, will press southeast and proceed down the island chain through Sunday. Fresh to locally strong north-northeast winds will develop in the wake of this front along with building seas. A Small Craft Advisory for both winds and seas will likely be needed for most marine zones tonight and beyond to account for these hazardous conditions. Northeast winds are forecast to remain fresh to strong through mid next week as high pressure builds north of the area.
The current small to moderate, medium period, northwest swell (330 degrees) will remain steady this morning and keep surf near seasonal averages along north facing shores. A north to south oriented fetch, generated from a gale force low far north of the state, will send a large, medium period, northerly swell our direction by late today. This swell will help build surf heights to near or above High Surf Advisory thresholds along north facing shores tonight through Sunday. This swell will also favor harbor surges in north facing harbors such as Kahului and Hilo on Sunday. Moderate to large north- northeast swell will keep surf elevated along north facing shores through at least early next week.
Light and variable winds will maintain small surf along east facing shores this morning. As the front moves down the island chain through Sunday, winds will shift northeasterly and increase in strength. This, combined with a large, moderate period, north- northeast swell (010-030 degrees) will bring elevated surf and choppy conditions to east facing shores through at least early next week. A High Surf Advisory may be needed during the peak of the event.
A small, long period, south-southwest swell will keep surf heights near seasonal averages along south facing shores today. Expect a bump in south shore surf Sunday through mid next-week as a couple more small, long period, south swells arrive.
Peak monthly tides combined with water levels that are running higher than predicted will lead to minor flooding along the shoreline and in low-lying coastal areas during this mornings high tide. A Coastal Flood Statement remains in effect through noon today.

Fire weather

Critical fire weather conditions are not expected through the forecast period. Winds will remain light across most of the state today ahead of the approaching front, with elevated relative humidity values. The front will reach Kauai later this morning and make it to the Big Island by sometime Sunday morning. Breezy to windy trades are forecast to fill in behind the front and persist through next week, but low-level moisture embedded within the trades will help keep relative humidity from reaching critical thresholds.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov