Photo Credit: James Grenz

Hilo

Today: Partly sunny with scattered showers. Highs 78 to 84 near the shore to around 69 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 61 to 69 near the shore to around 54 at 4000 feet. Southeast winds up to 10 mph. Chance of rain 50 percent.

Friday: Partly sunny with scattered showers. Highs 78 to 83 near the shore to 66 to 71 at 4000 feet. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.

Kona

Today: Mostly sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 81 to 87 near the shore to around 67 near 5000 feet. West winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with isolated showers in the evening, then partly cloudy after midnight. Lows 67 to 72 near the shore to 45 to 53 near 5000 feet. Light winds. Chance of rain 20 percent.

Friday: Mostly sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 80 to 87 near the shore to around 68 near 5000 feet. North winds up to 10 mph shifting to the west in the afternoon. Chance of rain 50 percent.

Waimea

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 64 to 85. Northeast winds up to 15 mph. Chance of rain 40 percent.

Tonight: Mostly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows around 62 near the shore to 51 to 60 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Friday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 66 to 85. East winds 10 to 15 mph. Chance of rain 50 percent.

Kohala

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 64 to 85. Northeast winds up to 15 mph. Chance of rain 40 percent.

Tonight: Mostly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows around 62 near the shore to 51 to 60 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Friday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 66 to 85. East winds 10 to 15 mph. Chance of rain 50 percent.

South Big Island

Today: Mostly sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs around 82 near the shore to around 67 near 5000 feet. East winds up to 15 mph. Chance of rain 40 percent.

Tonight: Partly cloudy. Lows around 70 near the shore to around 49 near 5000 feet. East winds 10 to 15 mph.

Friday: Mostly sunny. Isolated showers in the afternoon. Highs around 82 near the shore to around 66 near 5000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Puna

Today: Partly sunny with scattered showers. Highs 78 to 84 near the shore to around 69 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 61 to 69 near the shore to around 54 at 4000 feet. Southeast winds up to 10 mph. Chance of rain 50 percent.

Friday: Partly sunny with scattered showers. Highs 78 to 83 near the shore to 66 to 71 at 4000 feet. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.

Waikoloa

Today: Mostly sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs 80 to 86 near the shore to 65 to 71 above 4000 feet. Northeast winds up to 10 mph shifting to the northwest in the afternoon. Chance of rain 50 percent.

Tonight: Partly cloudy. Lows 65 to 73 near the shore to 45 to 53 above 4000 feet. East winds up to 10 mph.

Friday: Mostly sunny. Isolated showers in the afternoon. Highs 80 to 86 near the shore to 65 to 71 above 4000 feet. East winds 10 to 15 mph shifting to the north in the afternoon. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Gentle to locally moderate trade winds are expected today, with an uptick in trades Friday into the weekend. Daytime sea breezes will bring afternoon clouds and some showers over the interior of the islands today A more stable trade wind pattern is expected to focus modest showers over windward slopes Friday into early next week.

Discussion

No changes to the forecast this morning, with the updates last night seemingly on track. Some showers came onshore on windward Oahu last evening in a trade wind flow, and although briefly heavy, were quick moving.
The general forecast philosophy remains the same. The overnight soundings from Lihue and Hilo continue to show precipitable water (PW) values at or slightly below normal for March. Light to locally moderate trade winds are expected to give way to some afternoon sea breezes again this afternoon which will allow for some afternoon clouds and showers to develop. Not expected the rigorous showers and thunderstorms we saw yesterday as stability is starting to increase with an upper level ridge building in.
Trade winds are expected to increase on Friday with a stable airmass overhead, which should return us to a more typical trade winds pattern. A surface ridge to the north of the state will continue to build and the nearby surface trough, that has been helping to keep our winds on the lighter side, will dissipate. The above mentioned upper level ridge will become better established, helping to stabilize the airmass. Moderate to locally breezy trades will produce typical windward rainfall, and aside from afternoon showers over the South Kona slopes, dry conditions will dominate over leeward areas. Little change is expected through Monday.
Trade winds may weaken Tuesday and Wednesday as the surface ridge north of the state is pushed toward the islands. The ridge aloft will erode, but overall, stable conditions will likely hold.

Aviation

Satellite and radar trends show showers and cloud cover scattered across the state, as moist and unstable conditions linger over the islands this morning. Otherwise, the transition toward more persistent easterly trade winds continues to strengthen across the state through tonight. This pattern will focus a majority of clouds and showers over windward and mountain areas through Friday. However, during the transition toward strengthening trades, lighter background winds will still allow for some sea breeze development, with clouds and isolated showers possible in sheltered leeward zones later this afternoon. Mainly VFR conditions are expected through the TAF period with possible MVFR cigs in developing showers.
No AIRMETs are currently in effect, however a period of potential moderate upper level turb remains possible this morning as upper jet dynamics diminish over the region.

Marine

A weak east-northeast to west-southwest oriented surface ridge north of the state is maintaining light to moderate trade winds across the area early this morning. Expect trade wind speeds to remain in this range through early Friday morning. The surface ridge is forecast to build north of the islands by late Friday, which will likely allow the trade winds to strengthen slightly. Therefore, a Small Craft Advisory (SCA) may be required starting Friday or Friday night for the typically windier waters adjacent to the islands of Maui County and the Big Island. This SCA may be needed for these waters into this weekend based on the latest forecast guidance.
The current northwest swell will slowly lower this morning. The National Data Buoy Center buoys located northwest of Kauai are already showing signs of the initial energy due to forerunners associated with a new west-northwest swell that is aimed toward Hawaii. This swell is expected to arrive in the islands later today, and then build overnight before peaking on Friday. This west-northwest swell will gradually lower from Friday night through Saturday night. A third slightly larger northwest swell is forecast to arrive on Sunday, and peak from Sunday night into early Monday. Surf produced by this swell may reach the High Surf Advisory criteria along some north and west facing shores of the smaller islands based on the latest wave model guidance. This swell is expected to slowly lower from late Monday through next Tuesday.
A small, long-period south swell is expected to arrive later today, and persist into Friday. This swell will likely provide a slight boost in surf heights along south facing shores. Small background surf will likely return along south facing shores from this weekend into early next week. Expect modest, choppy surf to persist along east facing shores into 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