Hilo

Today: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 82 to 88 near the shore to around 73 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 30 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows around 68 near the shore to around 54 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 70 percent.

Sunday: Partly sunny in the morning then becoming cloudy. Scattered showers. Highs around 85 near the shore to around 72 at 4000 feet. East winds 10 to 15 mph decreasing to up to 15 mph in the afternoon. Chance of rain 50 percent.

Kona

Today: Sunny in the morning, then mostly cloudy with isolated showers in the afternoon. Highs 82 to 87 near the shore to around 70 near 5000 feet. Northwest winds up to 10 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening. Lows 70 to 75 near the shore to around 57 near 5000 feet. North winds up to 10 mph in the evening becoming light. Chance of rain 20 percent.

Sunday: Mostly sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 82 to 87 near the shore to around 70 near 5000 feet. Light winds. Chance of rain 50 percent.

Waimea

Today: Mostly sunny in the morning then becoming mostly cloudy. Breezy. Isolated showers. Highs around 84 near the shore to 75 to 82 near 3000 feet. East winds 10 to 25 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with isolated showers in the evening, then partly cloudy with scattered showers after midnight. Lows around 67 near the shore to 54 to 61 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Sunday: Mostly cloudy with scattered showers. Highs around 83 near the shore to 69 to 80 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Kohala

Today: Mostly sunny in the morning then becoming mostly cloudy. Breezy. Isolated showers. Highs around 84 near the shore to 75 to 82 near 3000 feet. East winds 10 to 25 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with isolated showers in the evening, then partly cloudy with scattered showers after midnight. Lows around 67 near the shore to 54 to 61 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Sunday: Mostly cloudy with scattered showers. Highs around 83 near the shore to 69 to 80 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

South Big Island

Today: Sunny in the morning then becoming partly sunny. Breezy. Highs around 86 near the shore to around 73 near 5000 feet. East winds up to 25 mph.

Tonight: Partly cloudy. Breezy. Lows around 71 near the shore to around 54 near 5000 feet. East winds 10 to 20 mph.

Sunday: Breezy. Mostly sunny in the morning, then mostly cloudy with isolated showers in the afternoon. Highs around 86 near the shore to around 73 near 5000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Puna

Today: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 82 to 88 near the shore to around 73 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 30 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows around 68 near the shore to around 54 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 70 percent.

Sunday: Partly sunny in the morning then becoming cloudy. Scattered showers. Highs around 85 near the shore to around 72 at 4000 feet. East winds 10 to 15 mph decreasing to up to 15 mph in the afternoon. Chance of rain 50 percent.

Waikoloa

Today: Sunny in the morning then becoming partly sunny. Breezy. Highs around 86 near the shore to 70 to 76 above 4000 feet. Northeast winds up to 25 mph.

Tonight: Partly cloudy. Lows around 73 near the shore to 52 to 60 above 4000 feet. Light winds.

Sunday: Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 86 near the shore to 70 to 76 above 4000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

A weak disturbance moving westward through the islands will continue to briefly enhance showers across the state through the morning hours. Otherwise a series of high pressure systems far north to northeast of the region will keep Hawaii in a moderate to breezy trade wind pattern through the rest of next week. Expect typical passing shower activity through the week, mainly affecting windward and mountain areas in the overnight to early morning hours.

Discussion

The regional satellite picture this morning shows a band of unstable low clouds, associated with a weak low level trough, drifting westward through the islands of Oahu and Molokai. This band of enhanced showers will continue to drift westward, spreading shower coverage from Kauai to Molokai through the morning hours. These showers will mainly affect windward and mountain areas with brief drying trends after the cloud band passes each island. Periods of high level cirrus clouds are also expected to pass over the islands through the week enhancing tropical sunrise and sunset colors.
Moderate to breezy trade winds remain in the forecast through the end of next week as a series of high pressure systems far north to northeast of the islands will keep the subtropical ridge moderately strong through the week. Atmospheric stability will vary from day to day with more stable conditions forecast today following the passage of the current low level trough. Periods of showers will develop from Sunday through Thursday, and enhanced showers are forecast in the long range from Thursday night into Saturday due to a passing unstable upper level low. Not much changes to the forecast grids this morning with only slight adjustments to wind and precipitation coverage across the region.

Aviation

High pressure building far northeast of the islands will strengthen trade winds into the moderate to breezy range beginning later today and beyond. Showers and accompanying MVFR conditions will mainly affect windward and mauka sections.
AIRMETs for mountain obscuration are in effect over windward sections of the Big Island and Maui as showery low clouds have been moving onshore.

Marine

A trough northwest of Kauai will continue to weaken and dissipate through the weekend. Meanwhile, a ridge of high pressure near Kauai will shift further north and will allow the breezy trade winds to spread westward across the state. A Small Craft Advisory remains posted for the windier waters around Maui County and the Big Island. Additional strengthening of the trade winds is possible Tuesday into Wednesday as a new high builds far north of the state.
The current north (350-010 degree) swell will continue to steadily decline today. A series of small northwest swells is expected during the first half of next week followed by small north swells during the second half of the week. No significant swells are expected for the foreseeable future.
Small long-period south swells will maintain above average surf along south facing shores through today. This swell should begin declining later today into Sunday. Another run of small south swells is expected Thursday through end of next week. The return of breezy trade winds will produce small and choppy surf along east facing shores through the weekend. A gradual increase of windswell is expected towards the middle of next week as the trade winds strengthen over the state.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Sunday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

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Data Courtesy of NOAA.gov