Hilo

Tonight: Mostly cloudy with scattered showers. Lows 65 to 70 near the shore to 53 to 58 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 50 percent.

Friday: Partly sunny with scattered showers. Highs 77 to 83 near the shore to 63 to 69 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Friday Night: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 62 to 69 near the shore to 52 to 57 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 70 percent.

Kona

Tonight: Mostly cloudy in the evening then becoming mostly clear. Lows around 71 near the shore to around 51 near 5000 feet. Light winds.

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

Friday Night: Partly cloudy. Isolated showers in the evening. Lows around 72 near the shore to 46 to 53 near 5000 feet. Light winds. Chance of rain 20 percent.

Waimea

Tonight: Breezy. Partly cloudy with scattered showers. Lows 65 to 70 near the shore to 56 to 61 near 3000 feet. East winds 10 to 25 mph. Chance of rain 40 percent.

Friday: Breezy. Mostly sunny with scattered showers. Highs 62 to 83. East winds 10 to 25 mph. Chance of rain 50 percent.

Friday Night: Mostly cloudy in the evening then becoming partly cloudy. Breezy. Scattered showers. Lows 62 to 71 near the shore to 54 to 62 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Kohala

Tonight: Breezy. Partly cloudy with scattered showers. Lows 65 to 70 near the shore to 56 to 61 near 3000 feet. East winds 10 to 25 mph. Chance of rain 40 percent.

Friday: Breezy. Mostly sunny with scattered showers. Highs 62 to 83. East winds 10 to 25 mph. Chance of rain 50 percent.

Friday Night: Mostly cloudy in the evening then becoming partly cloudy. Breezy. Scattered showers. Lows 62 to 71 near the shore to 54 to 62 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

South Big Island

Tonight: Partly cloudy. Lows around 71 near the shore to around 53 near 5000 feet. Northeast winds up to 15 mph.

Friday: Sunny and breezy. Highs around 85 near the shore to around 67 near 5000 feet. East winds up to 20 mph.

Friday Night: Mostly clear. Isolated showers after midnight. Lows around 73 near the shore to around 51 near 5000 feet. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Puna

Tonight: Mostly cloudy with scattered showers. Lows 65 to 70 near the shore to 53 to 58 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 50 percent.

Friday: Partly sunny with scattered showers. Highs 77 to 83 near the shore to 63 to 69 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Friday Night: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 62 to 69 near the shore to 52 to 57 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 70 percent.

Waikoloa

Tonight: Clear and breezy. Lows 69 to 74 near the shore to around 54 above 4000 feet. Southeast winds up to 25 mph.

Friday: Sunny and breezy. Highs 82 to 89 near the shore to 66 to 71 above 4000 feet. Northeast winds up to 25 mph.

Friday Night: Mostly clear. Lows around 72 near the shore to around 52 above 4000 feet. East winds up to 10 mph.

Detailed Forecast

Synopsis

A band of low clouds and showers will keep showery conditions in place as it shifts slowly westward through the smaller islands tonight through early Saturday. From Saturday afternoon through late next week, fairly typical trade wind weather will prevail with bands of low clouds and showers occasionally moving through the islands. The showers will favor windward slopes and coasts, particularly at night and during the early morning hours, with a few showers reaching leeward areas at times as well. Breezy trades will continue through the period with only minor day to day fluctuations in strength.

Discussion

Currently at the surface, a 1026 mb high is centered around 500 miles north-northwest of Kauai, with the remnants of the front which entered the islands yesterday, now draped across Maui County. Infrared satellite imagery shows partly to mostly cloudy conditions across the state, with cloud coverage the highest over windward and mauka areas. Radar imagery numerous showers over windward sections of Oahu, Molokai and Maui, along with quite a bit of leeward spillover. Shower coverage is not as great on either side of the washed out front, with scattered showers mostly limited to windward sections of Kauai and the Big Island. Main short term focus revolves around rain chances during the nest couple days.
High pressure north-northwest of the state will shift northeast during the next couple days, eventually merging with a new building high to the distant northeast of the islands by the end of the weekend. Breezy trade winds will prevail through the weekend, with perhaps a slight easing in speeds as the weekend progresses. The trades may ease a bit more into the moderate to locally breezy range early next week as a front approaches and stalls out north of the state. A new strong high building north of this front could ramp the trades back up to breezy and locally windy levels again Wednesday through late next week.
As for the remaining weather details, the band of moisture associated with the old front will linger over Maui County and Oahu tonight and Friday morning, keeping showery conditions in place, particularly over windward and mauka areas. The moisture band then appears to begin shifting west, with some decrease in showers expected for Maui County, and increase in showers for Kauai, and a continuation of showery weather for Oahu. Friday night into Saturday morning, the band appears to focus over Kauai, with a return to a more typical trade wind pattern expected over the remainder of the state. From Saturday afternoon onward, fairly typical trade wind weather will prevail with bands of low clouds and showers occasionally moving through the islands with the trades. Showers will favor windward slopes and coasts, particularly at night and during the early morning hours, with a few showers reaching leeward areas at times as well.

Aviation

The remnants of an old front will continue to spread low clouds and showers across the Hawaiian Islands, mainly over Oahu and the islands in Maui County. Periods of low clouds and showers with MVFR conditions will continue tonight for Kauai, Oahu, Molokai, Lanai and Maui, mainly over the north through east sections of each island. The Big Island will also see periods of MVFR CIGs due to low clouds along the north through east slopes. These unstable weather conditions will linger into Friday morning with improving trends from late morning to afternoon.
AIRMET Sierra for mountain obscuration was expanded in coverage to include Kauai, Oahu, Molokai, Lanai, Maui and the Big Island. These conditions will improve a few hours after sunrise.
AIRMET Tango remains in effect due to low-level turbulence over and downwind of terrain, with satellite indicating an abundance of low-level wave clouds extending well SW of the islands. A sharp upper trough near Maui will produce moderate turbulence between FL250 and FL350, likely continuing overnight hours as the trough stalls and become E-W oriented over the area.

Marine

High pressure centered north-northwest of the state will reposition itself to the north of the state by Sunday morning. Moderate to fresh northeast trade winds will veer to a more easterly direction on Saturday and persist into the coming week. A Small Craft Advisory remains in effect through Friday for all waters with the exception of the Windward Big Island waters.
The current medium period NW (310-330) swell will gradually decline over the next couple days, but a new reinforcing moderate long period NW (320-340) swell will build in later tonight, peak on Saturday, then gradually diminish as well. Surf along north and west facing shores will thus remain elevated through most of the weekend.
The first half of next week will then feature a moderate long period NW (320) swell that will peak Monday into Monday night only to be quickly followed by a borderline large NW (320) long period swell the forerunners of which should begin arriving late Tuesday. This latter swell will likely elevate surf to the High Surf Advisory threshold for N and W facing shores on Wednesday.
Surf along east-facing shores will remain elevated and choppy through the middle of next week due to the strong trade winds.
Surf along south-facing shores will remain small and near the seasonal average through the middle of next week

HFO Watches/Warnings/Advisories

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