Hilo

Today: Mostly sunny with isolated showers. Highs 82 to 88 near the shore to around 73 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows around 66 near the shore to around 52 at 4000 feet. Northwest winds up to 10 mph. Chance of rain 20 percent.

Thursday: Mostly sunny with isolated showers. Highs 81 to 87 near the shore to around 72 at 4000 feet. Northeast winds up to 10 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 20 percent.

Kona

Today: Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs 81 to 86 near the shore to around 69 near 5000 feet. Light winds becoming west up to 10 mph in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening. Lows 69 to 74 near the shore to around 54 near 5000 feet. Light winds. Chance of rain 20 percent.

Thursday: Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 85 near the shore to around 71 near 5000 feet. Light winds becoming north up to 10 mph in the afternoon. Chance of rain 20 percent.

Waimea

Today: Mostly sunny with isolated showers. Highs around 84 near the shore to 75 to 82 near 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows around 65 near the shore to 52 to 59 near 3000 feet. East winds up to 15 mph. Chance of rain 40 percent.

Thursday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 83 near the shore to 74 to 81 near 3000 feet. East winds 10 to 15 mph. Chance of rain 40 percent.

Kohala

Today: Mostly sunny with isolated showers. Highs around 84 near the shore to 75 to 82 near 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows around 65 near the shore to 52 to 59 near 3000 feet. East winds up to 15 mph. Chance of rain 40 percent.

Thursday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 83 near the shore to 74 to 81 near 3000 feet. East winds 10 to 15 mph. Chance of rain 40 percent.

South Big Island

Today: Mostly sunny. Highs around 87 near the shore to around 76 near 5000 feet. East winds up to 15 mph.

Tonight: Partly cloudy. Lows around 66 near the shore to around 51 near 5000 feet. Northeast winds up to 15 mph.

Thursday: Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 86 near the shore to around 75 near 5000 feet. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 20 percent.

Puna

Today: Mostly sunny with isolated showers. Highs 82 to 88 near the shore to around 73 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows around 66 near the shore to around 52 at 4000 feet. Northwest winds up to 10 mph. Chance of rain 20 percent.

Thursday: Mostly sunny with isolated showers. Highs 81 to 87 near the shore to around 72 at 4000 feet. Northeast winds up to 10 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 20 percent.

Waikoloa

Today: Sunny. Highs around 85 near the shore to 69 to 75 above 4000 feet. Northwest winds up to 10 mph.

Tonight: Mostly clear. Lows around 71 near the shore to 49 to 58 above 4000 feet. Southeast winds up to 10 mph.

Thursday: Mostly sunny. Highs around 84 near the shore to 68 to 74 above 4000 feet. North winds up to 10 mph.

Detailed Forecast

Synopsis

Light to moderate trade winds are expected through Thursday. A few brief trade showers are possible mainly along windward facing sections of the state, especially from late this evening through early Thursday morning. Light and variable winds are expected from Friday through early next week, which will allow local afternoon sea breezes and nighttime land breezes to develop. This may result in clouds and a chance of showers over leeward and interior sections of the islands each afternoon, followed by clearing skies at night.

Discussion

A 1027 mb surface high pressure system is located far east- northeast of Hawaii near 33N 130W. The western end of a surface ridge extends west-southwest from this feature through a point about 400 miles north of Honolulu. The pressure gradient south of this ridge is maintaining light to moderate trade winds across most of the Hawaiian Island chain early this morning. Elsewhere, the leading edge of a band of broken to overcast low clouds with embedded showers associated with a cold front is slightly less than 500 miles northwest of Lihue. This leading edge has been moving toward the southeast at about 20 mph during the past few hours. Closer to home, loops of infrared satellite imagery and radar reflectivity data show scattered to locally broken low clouds and isolated light showers being transported into the windward sides of some of the islands.
The forecast guidance shows the western end of the surface ridge north of the islands will continue to gradually erode as the cold front pushes rapidly southeast. The models indicate the front will eventually stall and weaken about 200 miles north of Kauai by early Thursday morning. Surface high pressure bridging across this feature will likely maintain the light to moderate trade wind flow through Thursday. Note that some sheltered leeward locations of the islands may see local afternoon sea breezes develop later today and Thursday. Local nighttime land breezes will also set up over portions of the islands this evening, and again after sunset Thursday.
The forecast models appear to show the trades may transport additional low clouds and scattered showers down near windward Kauai from this evening through early Thursday morning. A few of these light showers may even reach windward Oahu. Otherwise, it will likely be rather dry over most areas through Thursday, with mainly brief trade showers possible over some windward sections. There will also likely be clouds and a chance of a brief shower or two over some leeward areas where the sea breezes develop each afternoon.
The stalled front will eventually dissipate north of the area by late Thursday, and by Friday a surface ridge is expected to move down into the vicinity of the islands. This will disrupt the trade winds, and produce light and variable background flow into early next week. As a result, expect a weather pattern with alternating local afternoon sea breeze and nighttime land breeze circulations over each of the individual islands for several days. It will also be somewhat dry. but clouds and a few showers may develop over leeward and interior sections of the islands each afternoon. The downslope winds at night will likely result in clearing skies over most of the state.

Aviation

As high pressure weakens across the islands, trade winds have been easing into the light to moderate range. VFR will prevail over most areas most of the time, with only brief MVFR in lower clouds and showers possible in windward and mauka sections statewide through the day.
No AIRMETs are in effect, and none are anticipated through the afternoon hours.

Marine

Surface high pressure remains far northeast of the state, its associated ridge axis extending back to the southwest in the vicinity of the far north Hawaiian offshore waters this morning. This ridging, along with a series of cold fronts approaching the region from the northwest, will support a weak pressure gradient and lighter winds across the islands. These fronts will weaken and become more diffuse as they pass through the northern offshore waters, possibly backing winds more north and west this weekend. Trades will generally remain gentle to moderate through Thursday night before weakening even further to just light and variable breezes Friday into the weekend.
The recent moderate size, medium period north swell will be slowly declining through the day. Today’s north surf heights will only subtly lower as an overlapping small, but slightly longer period, northwest swell fills in through tonight. A slightly larger, shorter period north northwest swell will arrive Thursday, peak Thursday night into early Friday then fall over the weekend. A large northwest swell is timed to reach the island chain Saturday night and peak Sunday. This swell will increase early week surf heights to above High Surf Advisory thresholds, possibly as high as low-end High Surf Warning levels. Looking further out to next week, a potentially even larger swell is possible Monday night into Tuesday. A few slightly larger, medium period south swells will begin arriving today. These swells will bump south shore surf up by another foot or two through the remainder of the week. Surf along east facing shores, with the exception of more northern exposures experiencing a higher north swell wrap, will continue to fall through late week in response to a weaker trade wind regime.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov