West Side

Tonight: Mostly cloudy. Haze. Lows 66 to 73. South winds up to 10 mph in the evening becoming light.

Tuesday: Partly sunny. Haze through the day. Isolated showers in the afternoon. Highs 77 to 83. Light winds. Chance of rain 20 percent.

Tuesday Night: Mostly cloudy. Haze. Lows 65 to 72. Light winds.

South Side

Tonight: Mostly cloudy. Haze. Lows 64 to 75. South winds up to 10 mph in the evening becoming light.

Tuesday: Partly sunny. Haze through the day. Isolated showers in the afternoon. Highs around 85. Light winds becoming southwest up to 10 mph in the afternoon. Chance of rain 20 percent.

Tuesday Night: Mostly cloudy. Haze. Lows 63 to 74. North winds around 10 mph.

North Shore

Tonight: Mostly cloudy with scattered showers. Haze. Lows around 69 near the shore to around 51 near 5000 feet. Southeast winds up to 10 mph in the evening becoming light. Chance of rain 30 percent.

Tuesday: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Haze through the day. Highs around 80 near the shore to around 67 near 5000 feet. East winds up to 15 mph. Chance of rain 30 percent.

Tuesday Night: Mostly cloudy with scattered showers. Haze. Lows around 68 near the shore to around 50 near 5000 feet. East winds 10 to 15 mph. Chance of rain 30 percent.

Central Maui

Tonight: Mostly cloudy. Haze. Lows around 66. South winds up to 10 mph in the evening becoming light.

Tuesday: Partly sunny. Haze through the day. Isolated showers in the afternoon. Highs 81 to 86. Light winds becoming east up to 10 mph in the afternoon. Chance of rain 20 percent.

Tuesday Night: Mostly cloudy. Haze. Lows 64 to 69. Northeast winds around 10 mph.

Upcountry

Tonight: Mostly cloudy. Haze. Lows around 45 at the visitor center to around 47 at the summit. South winds up to 10 mph.

Tuesday: Partly sunny. Haze through the day. Isolated showers in the afternoon. Highs around 62 at the visitor center to around 69 at the summit. Light winds becoming east up to 10 mph in the afternoon. Chance of rain 20 percent.

Tuesday Night: Mostly cloudy. Haze. Lows around 45 at the visitor center to around 48 at the summit. East winds around 10 mph.

East Maui

Tonight: Mostly cloudy with scattered showers. Haze. Lows around 69 near the shore to around 51 near 5000 feet. Southeast winds up to 10 mph in the evening becoming light. Chance of rain 30 percent.

Tuesday: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Haze through the day. Highs around 80 near the shore to around 67 near 5000 feet. East winds up to 15 mph. Chance of rain 30 percent.

Tuesday Night: Mostly cloudy with scattered showers. Haze. Lows around 68 near the shore to around 50 near 5000 feet. East winds 10 to 15 mph. Chance of rain 30 percent.

Lanai City

Tonight: Mostly cloudy with isolated showers. Haze. Lows around 64. South winds up to 10 mph in the evening becoming light. Chance of rain 20 percent.

Tuesday: Mostly cloudy. Isolated showers in the morning, then scattered light showers in the afternoon. Haze through the day. Highs 72 to 79. Light winds becoming southwest up to 10 mph in the afternoon. Chance of rain 30 percent.

Tuesday Night: Mostly cloudy with isolated showers. Haze. Lows around 64. West winds up to 10 mph. Chance of rain 20 percent.

Kaunakakai

Tonight: Mostly cloudy with isolated showers. Haze. Lows 56 to 72. South winds up to 10 mph. Chance of rain 20 percent.

Tuesday: Mostly cloudy with isolated showers. Haze. Highs 70 to 86. South winds up to 10 mph in the morning becoming light. Chance of rain 20 percent.

Tuesday Night: Mostly cloudy. Haze. Lows 55 to 71. Light winds.

Detailed Forecast

Synopsis

Rain chances will steadily increase through the week as moderate southerly winds associated with an approaching cold front and upper-level disturbance draws moisture northward into the islands. The front may reach the western end of the state later this week, potentially leading to more widespread showers. Trade winds look to return by the weekend.

Discussion

The latest surface analysis shows a gale low approximately 900 nm northwest of the state moving slowly towards the southeast. Its associated cold front is approximately 400 nm northwest of Kauai this afternoon. Meanwhile, satellite imagery continues to show partly cloudy skies across the islands, with isolated showers streaming in from the south on east to southeasterly flow. In the near-term, the main impact will continue to be humid and voggy conditions due to the southerly winds.
Guidance continues to remain in good agreement through the week and shows the gale low and associated cold front slowly shifting southeast towards the state. Moderate southerly winds will hold through Tuesday. Meanwhile, hi-res guidance continues to show an increase in moisture advected northwards with the southerly winds over the next few days allowing for isolated to scattered showers mainly for areas exposed to the southerly winds.
Winds look to gradually ease on Wednesday and Thursday as a deep moisture axis and frontal boundary approaches and moves over Kauai before stalling and weakening and across the western end of the state Friday. This moisture, combined with broad upper- level troughing and instability, will support more widespread showers later this week, especially across Kauai and Oahu. Trade winds look to fill in across the region by late Friday as the front dissipates, with breezy trade wind developing over the weekend. Lingering moisture will keep chances of rainfall high mostly along windward and mauka areas, with a few showers spilling over into leeward areas on occasion due to lingering instability. A more typical breezy tradewinds pattern shall return next week with drier conditions.

Aviation

Southerly winds will continue to strengthen to moderate levels over the western side of the state due to a front approaching the island chain from the northwest. Over the eastern side of the state, moderate to breezy southeast winds will continue. Increasing SHRA expected over the western side of the state with sea breezes expected over Maui and the Big Island. Brief MVFR conds are likely within any heavier SHRA.
No AIRMETs currently in effect however Sierra may be needed overnight for Kauai and Oahu for mtn obsc.
All locations can expect to see some VOG with the degassing of Kilauea. It is not expected to impact vsbys enough to warrant mention in the TAFs.

Marine

A frontal system approaching the state from the distant northwest will help maintain moderate to locally breezy southerly flow across the local waters through Tuesday. Localized terrain enhancement around the Big Island and Kauai will continue to result in advisory level winds, and a Small Craft Advisory (SCA) remains in effect for these areas through Tuesday evening. The winds will gradually ease Wednesday and Thursday as the aforementioned front nears the islands. As the front dissipates Friday through the weekend, moderate to locally strong northeast trades will begin to fill in.
A series of small overlapping north and northwest swells will keep some surf in place along exposed north and east facing shores through late Wednesday. A new north swell is expected to arrive on Tuesday, along with some smaller northwest energy. A moderate north- northwest swell should arrive on Friday and could produce advisory level surf. A large to extra large north to north- northwest swell is progged to arrive this weekend and would likely produce warning level surf along north and possibly west and east facing shores.
Surf along south facing shores will gradually lower through the middle of the week with mainly background energy by the second half of the week.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Tuesday for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Big Island Windward Waters, Big Island Leeward Waters.

Data Courtesy of NOAA.gov