Hilo

Tonight: Partly cloudy with isolated showers in the evening, then clear after midnight. Lows 61 to 69 near the shore to 51 to 58 at 4000 feet. Light winds. Chance of rain 20 percent.

Thursday: Sunny. Isolated showers in the afternoon. Highs 77 to 83 near the shore to 65 to 72 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.

Thursday Night: Mostly clear. Lows 60 to 68 near the shore to 49 to 57 at 4000 feet. Northwest winds up to 10 mph in the evening becoming light.

Kona

Tonight: Mostly clear. Isolated showers in the evening. Lows around 71 near the shore to 46 to 53 near 5000 feet. Light winds. Chance of rain 20 percent.

Thursday: Sunny. Isolated showers in the afternoon. Highs 82 to 87 near the shore to around 70 near 5000 feet. West winds up to 10 mph. Chance of rain 20 percent.

Thursday Night: Mostly clear. Lows around 71 near the shore to 45 to 52 near 5000 feet. Light winds.

Waimea

Tonight: Mostly clear. Isolated showers in the evening. Lows 62 to 70 near the shore to 53 to 61 near 3000 feet. Light winds. Chance of rain 20 percent.

Thursday: Sunny. Isolated showers in the afternoon. Highs 64 to 82. East winds up to 10 mph. Chance of rain 20 percent.

Thursday Night: Mostly clear. Lows 60 to 69 near the shore to 52 to 59 near 3000 feet. East winds up to 10 mph.

Kohala

Tonight: Mostly clear. Isolated showers in the evening. Lows 62 to 70 near the shore to 53 to 61 near 3000 feet. Light winds. Chance of rain 20 percent.

Thursday: Sunny. Isolated showers in the afternoon. Highs 64 to 82. East winds up to 10 mph. Chance of rain 20 percent.

Thursday Night: Mostly clear. Lows 60 to 69 near the shore to 52 to 59 near 3000 feet. East winds up to 10 mph.

South Big Island

Tonight: Partly cloudy with isolated showers in the evening, then clear after midnight. Lows around 72 near the shore to around 52 near 5000 feet. Light winds. Chance of rain 20 percent.

Thursday: Sunny. Isolated showers in the afternoon. Highs around 83 near the shore to around 68 near 5000 feet. Southeast winds up to 15 mph. Chance of rain 20 percent.

Thursday Night: Mostly clear. Lows around 72 near the shore to around 51 near 5000 feet. Northeast winds up to 10 mph.

Puna

Tonight: Partly cloudy with isolated showers in the evening, then clear after midnight. Lows 61 to 69 near the shore to 51 to 58 at 4000 feet. Light winds. Chance of rain 20 percent.

Thursday: Sunny. Isolated showers in the afternoon. Highs 77 to 83 near the shore to 65 to 72 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.

Thursday Night: Mostly clear. Lows 60 to 68 near the shore to 49 to 57 at 4000 feet. Northwest winds up to 10 mph in the evening becoming light.

Waikoloa

Tonight: Mostly clear. Lows 69 to 74 near the shore to 49 to 54 above 4000 feet. Light winds.

Thursday: Sunny. Highs 81 to 87 near the shore to 66 to 73 above 4000 feet. Northeast winds up to 10 mph shifting to the northwest in the afternoon.

Thursday Night: Clear. Lows 68 to 73 near the shore to 48 to 53 above 4000 feet. East winds up to 15 mph in the evening becoming light.

Detailed Forecast

Synopsis

Stable and relatively dry conditions will persist through most of the forecast period, with the possible exception of a brief uptick in windward showers tomorrow and again on Sunday night into Monday as two successive fronts approach the area. Light winds in advance of both of these fronts will result in a land and sea breeze regime today and again this weekend, with afternoon clouds and a potentially a few brief showers over interior and leeward areas. Then trade winds will strengthen early next week.

Discussion

Current radar and satellite imagery show clouds and a few showers building up over island interiors due to sea breeze activity this afternoon. Additional showers can be seen streaming across the western end of the state due to increased moisture and low level convergence ahead of an approaching cold front. Winds will remain light across most of the island chain through tomorrow afternoon as the front continues to slowly approach from the northwest, disrupting the trade wind flow. This pattern will allow for the development of land breezes overnight that will help to clear out clouds and showers across land areas by morning, and sea breezes during the day that will bring low clouds and a few showers to island interiors by the afternoon.
Fairly dry and stable conditions will persist through the week with minimal rainfall expected, despite a couple of fronts that are expected to approach the area. The first front will dissipate as it sags across the western end of the island chain tomorrow and model guidance continues to keep this a rather dry front, with only a slight uptick in showers expected across windward Kauai and Oahu. Gentle to breezy northeast winds will briefly fill in behind the dissipating front before winds weaken in response to the next approaching front. As such light winds are expected across the island chain through most of the weekend, allowing for a land and sea breeze regime to redevelop. This second front will approach the state Sunday night into Monday and possibly dissipate over or just north of the area. Easterly trades winds will fill in behind the front and strengthen through Tuesday as high pressure builds to the north of the state and slides eastward. Pockets of moisture will move in on the trades, but generally dry and stable conditions will persist as ridging aloft dominates.

Aviation

Afternoon sea breezes give way to stable offshore land breezes this evening through tonight. Deeper moisture approaching Kauai will bring a modest uptick in shower coverage to western portions of the state, but land areas are forecast to remain dry owing to the established land breeze. The light gradient once again gives way to sea breezes late Thursday morning into Thursday afternoon. VFR prevails through the period.
No AIRMETs in effect.

Marine

A surface ridge will remain over or near the islands into Sunday, maintaining mainly gentle and variable winds. The ridge will remain parked over the central portion of the island chain into Thursday morning, leading to gentle westerly winds around Kauai, light and variables across Oahu and Maui County waters, and gentle southeasterlies around the Big Island. A fast-moving and weak surface high approaching from the northwest will produce gentle north to northeast winds by tomorrow afternoon and will push a shallow dissipating front near Kauai Thursday night. The high will generate a very brief period of trade winds Friday, followed by mainly gentle and variable winds as a trailing surface ridge moves back over the islands Friday night through Sunday. Fresh trades may redevelop Sunday night or Monday.
A series of large to extra large northwest to north-northwest swells will continue through the weekend, peaking on Sunday. The first swell has been holding around 12 ft at 17 seconds since last night at NOAA buoy 51001 and has been at 9 to 10 ft at 17 seconds through much of the day at the Hanalei and Waimea Bay PacIOOS buoys. A High Surf Warning (HSW) remains in place for most north and west facing shores from Kauai to Maui and has been extended through Friday. Given the direction of the swell (315 to 325 degrees) elevated surf is not expected along leeward portions of the Big Island through tonight, though a High Surf Advisory there will be needed as early as Thursday afternoon when a potentially larger pulse arrives. A series of storm lows passing northwest of Hawaii will send additional overlapping northwest (320 to 330 degrees) swells that should keep surf near or above HSW levels most of the time through the weekend, and the HSW will likely be extended beyond its current expiration on Friday afternoon. The latest guidance continues to show the largest swell arriving on Sunday, with the ECMWF model advertising in excess of 18 feet. While winds will remain rather light through the weekend, seas will be above the 10 foot Small Craft Advisory threshold for waters exposed to the large swells.
Aside from areas exposed to wrapping northwest swell, surf along east and south facing shores will remain small through much of the week. The best chance for a small rise in southwest swell will be on Thursday and Friday.

Fire weather

Critical fire weather conditions are not anticipated through the rest of the week due to a combination of light winds and relative humidity (RH) values above 45 percent. Trades will strengthen early next week, but RH will remain above critical levels to continue to preclude critical fire weather conditions.

HFO Watches/Warnings/Advisories

High Surf Warning until 6 PM HST Friday 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.
Small Craft Advisory until 6 PM HST Friday for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Kauai Channel, Oahu Windward Waters, Kaiwi Channel, Maui County Windward Waters, Big Island Windward Waters.

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Data Courtesy of NOAA.gov