West Side

Tonight: Mostly clear. Haze after midnight. Lows 62 to 68. Light winds.

Friday: Sunny and haze. Highs 76 to 83. Light winds.

Friday Night: Mostly clear. Haze. Lows 62 to 68. Light winds becoming east up to 10 mph after midnight.

South Side

Tonight: Mostly clear. Haze after midnight. Lows around 64. Light winds.

Friday: Sunny and haze. Highs around 84. Light winds.

Friday Night: Mostly clear. Haze. Lows around 64. Light winds.

North Shore

Tonight: Partly cloudy with isolated showers. Haze after midnight. Lows 62 to 67 near the shore to around 50 near 5000 feet. Southeast winds up to 15 mph. Chance of rain 20 percent.

Friday: Mostly sunny with isolated showers. Haze. Highs 76 to 82 near the shore to around 64 near 5000 feet. Light winds becoming northeast up to 10 mph in the afternoon. Chance of rain 20 percent.

Friday Night: Partly cloudy with isolated showers. Haze. Lows 62 to 67 near the shore to around 50 near 5000 feet. East winds up to 10 mph in the evening becoming light. Chance of rain 20 percent.

Central Maui

Tonight: Mostly clear. Haze after midnight. Lows around 64. Light winds.

Friday: Sunny and haze. Highs 80 to 85. Light winds becoming north around 10 mph in the afternoon.

Friday Night: Mostly clear. Haze. Lows around 64. Northeast winds around 10 mph in the evening becoming light.

Upcountry

Tonight: Mostly clear with isolated showers. Haze through the night. Lows 45 to 53. Light winds. Chance of rain 20 percent.

Friday: Sunny. Haze through the day. Isolated showers in the afternoon. Highs around 58 at the visitor center to around 61 at the summit. Light winds becoming north up to 10 mph in the afternoon. Chance of rain 20 percent.

Friday Night: Mostly clear. Haze. Lows 44 to 53. East winds around 10 mph.

East Maui

Tonight: Partly cloudy with isolated showers. Haze after midnight. Lows 62 to 67 near the shore to around 50 near 5000 feet. Southeast winds up to 15 mph. Chance of rain 20 percent.

Friday: Mostly sunny with isolated showers. Haze. Highs 76 to 82 near the shore to around 64 near 5000 feet. Light winds becoming northeast up to 10 mph in the afternoon. Chance of rain 20 percent.

Friday Night: Partly cloudy with isolated showers. Haze. Lows 62 to 67 near the shore to around 50 near 5000 feet. East winds up to 10 mph in the evening becoming light. Chance of rain 20 percent.

Lanai City

Tonight: Partly cloudy with isolated showers. Haze after midnight. Lows around 62. Light winds. Chance of rain 20 percent.

Friday: Mostly sunny with isolated showers. Haze. Highs 70 to 77. Light winds becoming northwest up to 10 mph in the afternoon. Chance of rain 20 percent.

Friday Night: Mostly clear. Isolated showers in the evening. Haze through the night. Lows around 62. North winds up to 10 mph shifting to the northeast around 10 mph after midnight. Chance of rain 20 percent.

Kaunakakai

Tonight: Partly cloudy. Isolated showers in the evening. Haze after midnight. Lows 59 to 68. Light winds. Chance of rain 20 percent.

Friday: Mostly sunny. Haze through the day. Isolated showers in the afternoon. Highs 78 to 85. Light winds becoming north up to 10 mph in the afternoon. Chance of rain 20 percent.

Friday Night: Mostly clear. Isolated showers in the evening. Haze through the night. Lows 59 to 68. Light winds. Chance of rain 20 percent.

Detailed Forecast

Synopsis

A high pressure ridge remains locked in place over the Hawaiian Islands through Saturday. A dry and stable atmosphere will significantly limit shower potential in this light to moderate southeasterly wind pattern. Brief periods of shower activity will favor the east to southeast slopes of each island. Rain chances may increase from Sunday into early next week, mainly over the western end of the state, as southerly winds from a deep low pressure system west of the state draws up unstable tropical moisture into the western islands. The latest long range forecast guidance shows a trough stalling out before reaching Kauai by Wednesday limiting rainfall impacts.

Discussion

Satellite imagery this afternoon and evening shows a stable cloud pattern under a high pressure ridge with sea breezes producing clouds over island interior sections. Cloud clearing will begin as down slope land breezes begin over each island. A few cloud bands associated with lee side island convergence plumes are producing a few stray showers. Afternoon weather balloon soundings show temperature inversion heights are stabilizing the atmospheric boundary layer at around 6,000 feet.
In the short term weather forecast period we continue to see good agreement in our forecast guidance. A ridge axis will remain locked in place across the Hawaiian Islands through Saturday night, keeping the region in a stable light to moderate hybrid southeasterly wind flow regime. These lighter southeasterly winds will allow sea breezes to develop over all islands each day. Building clouds over island mountain and interior sections. Wind convergence in the lee of island mountains will produce cloud bands and a few showers that will wrap northwestward into western islands producing brief periods of light shower activity. The east and southeast sections of Maui and the Big Island will see some cloud and shower enhancement in the evening hours driven by wind convergence between the downslope mountain/land breezes and the light upsloping southeasterly winds.
On Sunday, we start to transition to a light southerly wind pattern over the western half of the state, as a strong low pressure system approaches Kauai from the northwest and stalls out before reaching the Garden Isle. These southerly winds will bring up additional unstable tropical moisture from the deep tropics, with upper level troughing lifting inversion heights and slightly enhancing shower activity over Niihau, Kauai and Oahu through the first half of next week. Islands over the eastern half of the state in Maui and Hawaii Counties will see little change to this fairly stable weather pattern through next week Wednesday, with the exception of a slight shower enhancement along the east and southeast slopes in the afternoon and evening hours.

Aviation

Mostly dry and stable conditions will persist into the weekend, with light east to southeast winds continuing. Expect light to moderate showers favoring windward and southeast-facing slopes overnight through the early morning hours. During the afternoons, sea breezes will lead to interior and leeward cloud buildups, but any associated showers should remain brief and limited in coverage. Periods with MVFR CIGS/VSBYS are possible in showers, which could lead to AIRMET Sierra for mountain obscuration overnight if the showers become focused in a particular area.

Marine

A surface ridge will remain near or just N of the islands through the weekend, with light to moderate E-SE winds prevailing. No marine headlines are expected, with seas about 3-6 feet. Diurnal land and sea breezes will dominate the flow over nearshore waters sheltered from the large-scale flow. Early next week, deep-layer low pressure far NW of the islands may bring increased SE-S winds, especially to the W end of the island chain.
A relatively small, medium-period NNE swell will gradually build overnight and peak Friday near 4 feet 12 seconds, then gradually diminish through Sunday. A small WNW swell may also arrive over the weekend. More medium-period N swell is anticipated from Tuesday into Thursday next week. Small, long-period SSW swells are expected to provide small surf to S facing shores into next week.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov