Hilo

Tonight: Mostly cloudy. Occasional showers in the evening, then numerous showers after midnight. Lows 60 to 68 near the shore to 49 to 56 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 90 percent.

Wednesday: Breezy. Mostly cloudy with numerous showers. Highs 76 to 81 near the shore to 62 to 68 at 4000 feet. North winds up to 20 mph. Chance of rain 70 percent.

Wednesday Night: Mostly cloudy with occasional showers. Lows 61 to 68 near the shore to 49 to 56 at 4000 feet. North winds up to 15 mph. Chance of rain 80 percent.

Kona

Tonight: Clear. Lows around 70 near the shore to 42 to 49 near 5000 feet. Light winds.

Wednesday: Sunny. Highs 82 to 87 near the shore to around 68 near 5000 feet. West winds up to 10 mph.

Wednesday Night: Mostly clear. Lows around 70 near the shore to 44 to 51 near 5000 feet. East winds up to 10 mph.

Waimea

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Windy. Scattered showers. Lows 61 to 70 near the shore to 52 to 60 near 3000 feet. East winds 10 to 35 mph with gusts to 60 mph. Chance of rain 50 percent.

Wednesday: Mostly sunny in the morning then becoming partly sunny. Windy. Scattered showers. Highs 62 to 82. East winds 10 to 35 mph with gusts to 60 mph. Chance of rain 50 percent.

Wednesday Night: Mostly cloudy in the evening then becoming partly cloudy. Windy. Scattered showers. Lows 61 to 70 near the shore to 53 to 60 near 3000 feet. East winds 10 to 35 mph with gusts to 60 mph. Chance of rain 50 percent.

Kohala

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Windy. Scattered showers. Lows 61 to 70 near the shore to 52 to 60 near 3000 feet. East winds 10 to 35 mph with gusts to 60 mph. Chance of rain 50 percent.

Wednesday: Mostly sunny in the morning then becoming partly sunny. Windy. Scattered showers. Highs 62 to 82. East winds 10 to 35 mph with gusts to 60 mph. Chance of rain 50 percent.

Wednesday Night: Mostly cloudy in the evening then becoming partly cloudy. Windy. Scattered showers. Lows 61 to 70 near the shore to 53 to 60 near 3000 feet. East winds 10 to 35 mph with gusts to 60 mph. Chance of rain 50 percent.

South Big Island

Tonight: Clear and windy. Lows around 73 near the shore to around 49 near 5000 feet. Northeast winds up to 30 mph increasing to 10 to 30 mph after midnight.

Wednesday: Sunny and windy. Highs around 85 near the shore to around 68 near 5000 feet. East winds 10 to 30 mph.

Wednesday Night: Mostly clear. Windy. Lows around 73 near the shore to around 51 near 5000 feet. Northeast winds 10 to 30 mph.

Puna

Tonight: Mostly cloudy. Occasional showers in the evening, then numerous showers after midnight. Lows 60 to 68 near the shore to 49 to 56 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 90 percent.

Wednesday: Breezy. Mostly cloudy with numerous showers. Highs 76 to 81 near the shore to 62 to 68 at 4000 feet. North winds up to 20 mph. Chance of rain 70 percent.

Wednesday Night: Mostly cloudy with occasional showers. Lows 61 to 68 near the shore to 49 to 56 at 4000 feet. North winds up to 15 mph. Chance of rain 80 percent.

Waikoloa

Tonight: Mostly clear. Breezy. Lows 68 to 74 near the shore to 47 to 52 above 4000 feet. Southeast winds up to 25 mph with gusts to 50 mph.

Wednesday: Sunny and windy. Highs 81 to 87 near the shore to 66 to 72 above 4000 feet. East winds up to 35 mph with gusts to 60 mph.

Wednesday Night: Mostly clear. Windy. Lows 68 to 74 near the shore to around 50 above 4000 feet. East winds up to 30 mph with gusts to 60 mph.

Detailed Forecast

Synopsis

Strong trades focus limited showers windward and mauka through Thursday. Trades then ease for the weekend.

Discussion

Observations over the last several hours indicate gusts at or near the wind advisory threshold limited to the most favored downslope areas in the Kohala District of the Big Island and Leeward Maui. Gusts so far are generally in line with expectations for a borderline wind advisory type of event. Strong easterlies will strengthen as the low southeast of the islands deepens and migrates westward, remaining south of the islands through the end of the week. This will in turn result in a deep layer of strong easterlies to the tune of 35 kts at 925mb over most of the area by Wednesday. At the surface, this will generally translate to sub- advisory level gust potential with the exception of the windiest locales of Maui County, the Big Island, and perhaps Kaena Point on Oahu. Therefore, the wind advisory remains in tact as is through tomorrow with low confidence precluding an expansion in coverage at this time. With deep easterlies extending up to summit level, the Wind Advisory there has been upgraded to a High Wind Warning that remains in effect through tomorrow as well.
Elsewhere and otherwise, a rather typical stable trade wind pattern remains in place with little indication of any upstream shower activity for Oahu and Kauai. Over the eastern end of the state, particularly in the vicinity of the Big Island, convective depths appear slightly deeper and shower coverage is slightly greater than the remainder of the state, likely a result of closer proximity to the developing closed closed low. The northern portion of the envelope of the cyclonic flow aloft will remain over the Big Island through Thursday. This will raise the inversion locally and enhance shower activity particularly as ESE mid-level flow draws deeper moisture northward Wednesday night through Thursday night. Trades weaken by this weekend as the low south of the island dissipates.

Aviation

Strong trade winds will continue to strengthen in the short term, delivering randomly distributed low cloud clusters that will briefly drop a few showers windward, producing ISOL MVFR VIS/CIG. AIRMET Tango highlights the ongoing likelihood for low-level turbulence to the lee of the terrain.

Marine

Strong high pressure to the north and northeast of the islands will continue to build and expand westward. Easterly trade winds will continue to strengthen to gale force within Maalea Bay, the Pailolo and Alenuihaha Channels, and waters south of the Big Island this evening, and a Gale Warning has been issued with this afternoon's forecast updates for these locations. A Small Craft Advisory remains in effect for the remaining waters where winds will still be strong to near-gale strength and seas are expected to hover near 10 feet or slightly higher. The strong winds will remain in place Wednesday through Thursday, then gradually diminish through the rest of the week.
Surf along north and west-facing shores will peak early this evening as a northwest reinforcement moves through the islands. A High Surf Advisory (HSA) remains in effect for north and west facing shores of Niihau, Kauai, Oahu, and Molokai, and north facing shores of Maui through tonight. However, this swell is expected to drop during the overnight through early morning hours, and surf is expected to fall below advisory criteria by early Wednesday. North and west shore surf will then gradually decline through the end of the week.
Surf along south-facing shores will return to seasonal normals tomorrow as a small south swell diminishes. A small southeast bump in surf is possible on Wednesday for windward Big Island due to a small southeast reinforcement, but this will have little effect elsewhere.
Surf along east-facing shores will rise through Thursday in response to the strong trade winds. Lower surf is expected for the weekend.

Fire weather

Gusty trades will be accompanied by slightly drier conditions Wednesday and Thursday compared to today. Afternoon RH values may briefly dip below 50% but the probability of reaching the fire weather threshold of 45% appears low. No headlines anticipated at this time.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 AM HST Wednesday for Niihau, Kauai Leeward, Waianae Coast, Oahu North Shore, Maui Windward West, Kauai North, Molokai Windward, Molokai North, Molokai West, Maui Central Valley North, Windward Haleakala.
Wind Advisory until 6 PM HST Wednesday for Lanai Mauka, Kahoolawe, Maui Windward West, Maui Leeward West, Kohala, Big Island Interior, Lanai Windward, Lanai Leeward, Lanai South, Maui Central Valley North, Maui Central Valley South, South Haleakala, Big Island South, Big Island Southeast, Big Island North.
High Wind Warning until 6 PM HST Wednesday for Big Island Summits.
Small Craft Advisory until 6 PM HST Thursday for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Kauai Channel, Oahu Windward Waters, Oahu Leeward Waters, Kaiwi Channel, Maui County Windward Waters, Maui County Leeward Waters, Big Island Windward Waters.
Gale Warning until 6 PM HST Thursday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

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Data Courtesy of NOAA.gov