Hilo

Today: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs 79 to 86 near the shore to 64 to 73 at 4000 feet. North winds up to 10 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Lows 64 to 71 near the shore to 54 to 59 at 4000 feet. North winds up to 10 mph. Chance of rain 50 percent.

Thursday: Mostly sunny with isolated showers. Highs 81 to 87 near the shore to 66 to 75 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 20 percent.

Kona

Today: Partly sunny with isolated showers. Highs 83 to 89 near the shore to around 70 near 5000 feet. Light winds. Chance of rain 20 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Lows around 73 near the shore to 48 to 56 near 5000 feet. Light winds.

Thursday: Mostly sunny. Isolated showers in the afternoon. Highs around 86 near the shore to around 71 near 5000 feet. Light winds. Chance of rain 20 percent.

Waimea

Today: Partly sunny with isolated showers. Highs around 80 near the shore to 68 to 79 near 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Lows 64 to 72 near the shore to 55 to 61 near 3000 feet. East winds up to 15 mph increasing to 10 to 15 mph after midnight. Chance of rain 50 percent.

Thursday: Breezy. Mostly sunny with isolated showers. Highs around 80 near the shore to 69 to 79 near 3000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Kohala

Today: Partly sunny with isolated showers. Highs around 80 near the shore to 68 to 79 near 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Lows 64 to 72 near the shore to 55 to 61 near 3000 feet. East winds up to 15 mph increasing to 10 to 15 mph after midnight. Chance of rain 50 percent.

Thursday: Breezy. Mostly sunny with isolated showers. Highs around 80 near the shore to 69 to 79 near 3000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

South Big Island

Today: Partly sunny. Highs around 85 near the shore to around 66 near 5000 feet. Southeast winds up to 20 mph.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Lows around 74 near the shore to around 52 near 5000 feet. East winds up to 15 mph.

Thursday: Breezy. Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 86 near the shore to around 68 near 5000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Puna

Today: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs 79 to 86 near the shore to 64 to 73 at 4000 feet. North winds up to 10 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Lows 64 to 71 near the shore to 54 to 59 at 4000 feet. North winds up to 10 mph. Chance of rain 50 percent.

Thursday: Mostly sunny with isolated showers. Highs 81 to 87 near the shore to 66 to 75 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 20 percent.

Waikoloa

Today: Mostly sunny. Highs 84 to 89 near the shore to 66 to 73 above 4000 feet. North winds up to 15 mph.

Tonight: Mostly cloudy in the evening then becoming mostly clear. Lows around 73 near the shore to 50 to 56 above 4000 feet. East winds up to 15 mph.

Thursday: Sunny and breezy. Highs 84 to 89 near the shore to 66 to 74 above 4000 feet. Northeast winds up to 20 mph.

Detailed Forecast

Synopsis

Stable, moderate trades will focus limited showers over windward and mauka slopes through Thursday. A land and sea breeze pattern emerges from Friday onward in response to further weakening of the trades.

Discussion

Moderate trades and high stability prevail over the islands this morning, a trend that will continue for the balance of the forecast period. Southerly flow aloft associated with a weak upper jet will funnel high clouds across area skies, especially today, which may take the edge off of afternoon heat at times. Otherwise, moderate trades will focus limited/light clouds and showers over windward and mauka zones through Thursday. From Friday onward, the large scale pattern will be dominated by an eastward extension of the Pacific jet. This will force rather flat but very broad ridging to build into the Central Pacific from the west resulting in a trend toward even greater stability as the weekend progresses. Meanwhile, trade winds at the surface will further weaken as they are suppressed south of the area. This leaves the islands in a rather non-descript area of the regional MSLP field characterized by weak ridging at the surface and light to variable winds. Afternoon sea breezes and overnight land breezes will dominate during this time, but inland shower development is likely to be sparse at best given the dearth of moisture and steadily increasing stability.

Aviation

A weak high pressure ridge far north of the Hawaiian Islands will produce light to moderate trade winds through Thursday. Brief showers are possible mainly over windward and mountain areas.
No AIRMETs are currently in effect.

Marine

The western end of a surface ridge about 400 nm north of Honolulu is expected to maintain moderate to locally fresh trade winds over the state today. A new surface high pressure system is expected to move to a position far northwest of the state tonight and Thursday. This feature will move slowly south as a front pushes down from the north-northwest, which will force a weak surface ridge to the east of the surface high to eventually move down closer to the islands. This will result in the trade winds gradually weakening to light to moderate speeds from late Thursday through Friday. By this weekend, expect light and variable winds in the vicinity of the western islands, while weak trade winds may linger near the eastern end of the island chain.
The current small, medium-period northwest (310-320 degrees) swell will continue to produce small surf along exposed north and west facing shores today. A slightly larger, medium-period northwest (310-320 degrees) swell will likely boost surf along exposed north and west facing shores from later tonight through Friday. A moderate, long-period north-northwest (320-330 degrees) swell arriving Saturday is expected to produce moderate surf along exposed north and west facing shores from late Saturday into early next week.
Modest surf is expected to persist along south facing shores this week due to a series of medium- to long-period south to south- southwest (190-200 degrees) swells moving through the area. A fetch of gale force winds southeast of New Zealand is expected to produce a new, long-period south-southwest (200-210 degrees) swell that may arrive Sunday. This may result in above the seasonal average surf along south facing shores from late this weekend into early next week. Elsewhere, the weakening trade winds will result in diminishing surf along east facing shores later this week, with nearly flat conditions possible along most east facing shores by late this weekend.

HFO Watches/Warnings/Advisories

None.

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