Hilo

Today: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 78 to 86 near the shore to around 69 at 4000 feet. North winds up to 15 mph shifting to the northeast in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 61 to 70 near the shore to 53 to 58 at 4000 feet. North winds up to 15 mph. Chance of rain 50 percent.

Wednesday: Partly sunny with scattered showers. Highs 79 to 87 near the shore to around 70 at 4000 feet. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.

Kona

Today: Sunny in the morning then becoming mostly cloudy. Isolated showers. Highs 81 to 88 near the shore to around 67 near 5000 feet. Light winds. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows around 72 near the shore to 48 to 54 near 5000 feet. Light winds. Chance of rain 20 percent.

Wednesday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 82 to 87 near the shore to around 67 near 5000 feet. Light winds. Chance of rain 50 percent.

Waimea

Today: Partly sunny in the morning then becoming mostly sunny. Breezy. Isolated showers. Highs 64 to 84. East winds 10 to 20 mph. Chance of rain 20 percent.

Tonight: Breezy. Partly cloudy with isolated showers. Lows 62 to 70 near the shore to 54 to 61 near 3000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny with isolated showers. Highs 64 to 84. East winds 10 to 15 mph. Chance of rain 20 percent.

Kohala

Today: Partly sunny in the morning then becoming mostly sunny. Breezy. Isolated showers. Highs 64 to 84. East winds 10 to 20 mph. Chance of rain 20 percent.

Tonight: Breezy. Partly cloudy with isolated showers. Lows 62 to 70 near the shore to 54 to 61 near 3000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny with isolated showers. Highs 64 to 84. East winds 10 to 15 mph. Chance of rain 20 percent.

South Big Island

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

Tonight: Partly cloudy. Lows around 73 near the shore to around 51 near 5000 feet. Northeast winds up to 15 mph.

Wednesday: Mostly sunny. Breezy. 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: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 78 to 86 near the shore to around 69 at 4000 feet. North winds up to 15 mph shifting to the northeast in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 61 to 70 near the shore to 53 to 58 at 4000 feet. North winds up to 15 mph. Chance of rain 50 percent.

Wednesday: Partly sunny with scattered showers. Highs 79 to 87 near the shore to around 70 at 4000 feet. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.

Waikoloa

Today: Sunny and breezy. Highs 83 to 89 near the shore to 65 to 74 above 4000 feet. Northeast winds up to 15 mph increasing to 10 to 20 mph in the afternoon.

Tonight: Partly cloudy. Lows around 73 near the shore to 49 to 54 above 4000 feet. Southeast winds up to 15 mph.

Wednesday: Mostly sunny. Isolated showers in the afternoon. Highs 83 to 88 near the shore to 64 to 73 above 4000 feet. North winds up to 10 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Broad high pressure north of the state will weaken, resulting in the breezy trade winds to ease to moderate strength Wednesday through Friday. Stable and somewhat dry conditions will prevail through at least Friday, with light showers favoring windward slopes.

Discussion

No changes to the forecast this morning. A broad high pressure system remains between 30 and 35N, driving locally breezy trade winds to the region. An upper level ridge over the islands is helping to maintain a very stable and mostly dry airmass over the area. Some moisture areas remain within the shallow boundary layer. The night started off with very few light showers riding in on the trades, but a few more spotty showers have been seen on radar over the last couple of hours. Anticipate a few more over the next several hours, mainly over windward and mauka areas, with showers diminishing again this afternoon.
The ridge to the north is expected to weaken, which will allow trades to ease some tonight and Wednesday. Stable conditions will persist with limited moisture in the trade wind flow. As a result, expect modest windward rainfall, and aside from a few afternoon showers on Kona slopes of the Big Island, leeward areas should be dry.
In the long range, trades may strengthen during the weekend, and the GFS and ECMWF suggest that an increase in showers will be possible.

Aviation

Breezy trade winds will persist today, then gradually ease through the end of the week. Light showers and low clouds will favor windward and mauka areas and bring the potential for brief periods of MVFR. Otherwise, VFR will prevail.
AIRMET Tango for moderate low-level turbulence lee of island terrain is in effect and will continue through the day due to strong trades.

Marine

A broad surface high pressure over the central and eastern Pacific will remain stationary through today maintaining fresh to locally strong trade winds. A Small Craft Advisory (SCA) for the typical windier waters around Maui County and the Big Island through has been extended through Wednesday morning. A disturbance will develop far northeast of the state late tonight into Wednesday, weakening the ridge. SCA conditions may drop off as early as Wednesday as winds ease to moderate to fresh then persist through Friday. A high will strengthen north of the state over the weekend as the disturbance weakens and dissipates. Trades may strengthen back to moderate to locally strong over and upstream of the state this weekend into early next week.
The current long period south swell continues to hold in the 16 second range based on near shore and offshore buoy data. Thus have extended the High Surf Advisory (HSA) through today as surf height slowly trend down around or slightly above HSA criteria. This swell will continue to slowly decline through Thursday before dropping to background levels Friday through the weekend.
Rough, choppy surf along east facing shores will remain slightly elevated through today before slowly declining as trades upstream of, and eventually over, the islands weaken. In addition a small pulse of northeast swell energy appears to have arrived at near shore buoys and will continue to fill in today. This small swell could provide a tiny boost along north and east facing exposures. East shore surf will fall below average by Wednesday and will decline further Thursday through Friday as the northeast swell quickly fades and trades over and upstream ease.
North facing shores may see a tiny bump from the combination of a small, medium period northwest swell and the northeast swell mentioned above today into Wednesday but will quickly fade Wednesday night.

Fire weather

The ongoing breezy and dry weather will produce elevated fire weather concerns today, though critical conditions are not forecast. Improvement is expected as winds decline Wednesday into Friday.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST this evening for Niihau, Kauai Leeward, Waianae Coast, Kahoolawe, Maui Leeward West, Kona, Kauai South, East Honolulu, Honolulu Metro, Ewa Plain, Molokai Leeward South, Lanai Leeward, Lanai South, Maui Central Valley South, South Maui/Upcountry, South Haleakala, Big Island South, Big Island Southeast.
Small Craft Advisory until 6 AM HST Wednesday for 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