Hilo

Today: Mostly sunny. Breezy. Highs around 81 near the shore to 66 to 72 at 4000 feet. South winds up to 20 mph.

Tonight: Mostly clear. Lows 60 to 68 near the shore to around 54 at 4000 feet. Southwest winds up to 15 mph.

Wednesday: Sunny. Highs around 81 near the shore to 65 to 73 at 4000 feet. Southwest winds up to 15 mph shifting to the southeast in the afternoon.

Kona

Today: Sunny. Highs around 83 near the shore to around 69 near 5000 feet. Southwest winds up to 10 mph.

Tonight: Mostly clear. Lows around 70 near the shore to 44 to 52 near 5000 feet. Southeast winds up to 10 mph.

Wednesday: Sunny. Highs 80 to 85 near the shore to around 68 near 5000 feet. South winds up to 10 mph.

Waimea

Today: Mostly sunny. Highs around 77 near the shore to 67 to 72 near 3000 feet. Light winds.

Tonight: Partly cloudy. Lows 60 to 68 near the shore to 51 to 57 near 3000 feet. Light winds becoming south up to 10 mph after midnight.

Wednesday: Sunny. Highs around 78 near the shore to 68 to 74 near 3000 feet. West winds up to 15 mph.

Kohala

Today: Mostly sunny. Highs around 77 near the shore to 67 to 72 near 3000 feet. Light winds.

Tonight: Partly cloudy. Lows 60 to 68 near the shore to 51 to 57 near 3000 feet. Light winds becoming south up to 10 mph after midnight.

Wednesday: Sunny. Highs around 78 near the shore to 68 to 74 near 3000 feet. West winds up to 15 mph.

South Big Island

Today: Sunny and breezy. Highs around 81 near the shore to around 68 near 5000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon.

Tonight: Mostly clear. Lows around 70 near the shore to around 49 near 5000 feet. East winds up to 15 mph.

Wednesday: Sunny. Highs around 81 near the shore to around 67 near 5000 feet. South winds up to 15 mph shifting to the southwest in the afternoon.

Puna

Today: Mostly sunny. Breezy. Highs around 81 near the shore to 66 to 72 at 4000 feet. South winds up to 20 mph.

Tonight: Mostly clear. Lows 60 to 68 near the shore to around 54 at 4000 feet. Southwest winds up to 15 mph.

Wednesday: Sunny. Highs around 81 near the shore to 65 to 73 at 4000 feet. Southwest winds up to 15 mph shifting to the southeast in the afternoon.

Waikoloa

Today: Mostly sunny. Highs 79 to 84 near the shore to 63 to 72 above 4000 feet. Southwest winds up to 10 mph shifting to the northwest in the afternoon.

Tonight: Partly cloudy. Lows 67 to 72 near the shore to 46 to 52 above 4000 feet. Southeast winds up to 15 mph.

Wednesday: Sunny. Highs 79 to 85 near the shore to 64 to 72 above 4000 feet. South winds up to 15 mph shifting to the west in the afternoon.

Detailed Forecast

Synopsis

The persistent southerly winds are here to stay through early next week as a series of fronts pass through or nearby to the north. Expect the southerly winds to become strong and gusty tonight through Wednesday as the first front approaches and begins to move through. Increasing moisture associated with the front will bring the rain chances up beginning over the western end of the state later today through tonight, then over the eastern end Wednesday as the front begins to stall and weaken. Drier conditions and light winds will follow over the western end of the state Thursday through Friday. Moderate to breezy southwest winds and increasing moisture will return over the weekend as the next cold front approaches.

Discussion

Satellite imagery showed a persistent plume of moisture being drawn northward nearing Kauai due to a broad cyclonic gyre that has setup over the past week across the northern Pacific. Water vapor imagery depicted a shortwave trough located at the Date Line near Midway this morning that is forecast to rotate through the broad upper trough today through midweek. This upper pulse will drive the attendant surface cold front quickly eastward toward the state today, then through the islands Wednesday through Thursday.
Hi-res model guidance reflects this and shows the pressure gradient tightening over the region with strong and gusty southwest winds evolving over the islands tonight through Wednesday. These winds may become strong enough to trigger a wind advisory in later packages today to account for an increasing potential of damaging downsloping winds tonight through Wednesday. In addition to the winds, guidance shows a line of showers developing along and ahead of the front advancing down the island beginning with Kauai and Oahu late tonight through Wednesday, then the eastern end of the state late Wednesday through Thursday. Although significant accumulations are not anticipated, some showers could become locally heavy at times. Drier conditions and light winds will follow over the western end of the state Thursday through Friday, while some rain chances hold over the eastern end where the moisture axis associated with diminishing front stalls.
Moderate to breezy southwest winds and increasing moisture will return over the weekend as the next cold front approaches.

Aviation

A cold front will continue to approach Kauai from the west today. Ahead of the front, expect light to moderate southerly winds to across the state.
Scattered showers may occur over Kauai and Oahu, closest to the aforementioned front, with partly cloudy skies and mainly dry conditions elsewhere along the island chain.
Southerly/southwesterly winds will increase tonight and become breezy to windy by Wednesday.
No AIRMETS are currently in effect.

Marine

The area is along the western periphery of a surface high centered approximately 1,000 miles northeast of the islands. This is maintaining moderate southerlies over the local waters that will persist through the day. A near-stationary front over the northwest offshore waters will be nudged southeast and down the island chain by the eastern passage of a compact gale low later today. This will tighten the gradient west of the front and result in fresh to locally locally strong south southwesterly winds along and west of the boundary as it moves into the central waters Wednesday. Late week moderate southwesterlies will gradually weaken and veer more westerly this weekend as the front washes out in the vicinity of the east waters and high pressure builds in over the state. The next front is forecast to clip the northern waters this weekend. A series of large, generally medium period west to west-northwest (280-310 degree) swells are expected to arrive through the week. As a result, the nearshore waters surrounding Kauai and windward Oahu waters will remain under a Small Craft Advisory (SCA) through tonight for seas building to, or slightly exceeding, 10 feet.
A west-northwest (290-310 degree) swell is forecast to fill in through the afternoon and evening with an anticipated mid to late morning arrival at the far northwest buoys. A similar swell will be arriving Wednesday night through Thursday. A High Surf Advisory (HSA) remains in effect for double to near triple overhead surf along the north-facing shores of Niihau, Kauai and Oahu…at least double overhead surf along the north-facing shores of Molokai, Maui and the west-facing shores of Oahu. Due to the more westerly component to this swell, the west-facing shores of Molokai, Lanai and Big Island will also experience head high to near double overhead HSA- threshold surf heights. This more westerly swell component will allow for some wrap into southwest and south-facing shores and, along with higher wind waves brought on by stronger south to southwest winds, increase surf along more southern exposures.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 AM HST Wednesday for Niihau, Kauai Leeward, Waianae Coast, Oahu North Shore, Maui Windward West, Kona, Kohala, Kauai North, Molokai Windward, Molokai North, Molokai West, Lanai Leeward, Maui Central Valley North, Windward Haleakala, Big Island South.
Small Craft Advisory until 6 AM HST Wednesday for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Oahu Windward Waters.

Big Island Now Weather is brought to you by Blue Hawaiian Helicopters.

Check out their Big Island Helicopter Tours today!

Data Courtesy of NOAA.gov