Hilo

Tonight: Cloudy with isolated showers. Lows 64 to 71 near the shore to 55 to 60 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.

Saturday: Cloudy with isolated showers. Highs 78 to 85 near the shore to 65 to 70 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 20 percent.

Saturday Night: Cloudy with scattered showers. Lows 62 to 70 near the shore to 53 to 59 at 4000 feet. North winds up to 15 mph. Chance of rain 50 percent.

Kona

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Lows around 74 near the shore to 49 to 55 near 5000 feet. Northwest winds up to 10 mph in the evening becoming light.

Saturday: Mostly sunny in the morning, then mostly cloudy with isolated showers in the afternoon. Highs 84 to 89 near the shore to around 70 near 5000 feet. Light winds becoming west up to 10 mph in the afternoon. Chance of rain 20 percent.

Saturday Night: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Lows around 74 near the shore to 48 to 55 near 5000 feet. West winds up to 10 mph in the evening becoming light. Chance of rain 20 percent.

Waimea

Tonight: Mostly cloudy. Lows 64 to 73 near the shore to 56 to 63 near 3000 feet. East winds up to 15 mph.

Saturday: Mostly cloudy. Breezy. Isolated showers in the afternoon. Highs 66 to 85. East winds up to 20 mph. Chance of rain 20 percent.

Saturday Night: Breezy. Mostly cloudy with isolated showers. Lows 63 to 71 near the shore to 55 to 62 near 3000 feet. East winds up to 20 mph increasing to 10 to 20 mph after midnight. Chance of rain 20 percent.

Kohala

Tonight: Mostly cloudy. Lows 64 to 73 near the shore to 56 to 63 near 3000 feet. East winds up to 15 mph.

Saturday: Mostly cloudy. Breezy. Isolated showers in the afternoon. Highs 66 to 85. East winds up to 20 mph. Chance of rain 20 percent.

Saturday Night: Breezy. Mostly cloudy with isolated showers. Lows 63 to 71 near the shore to 55 to 62 near 3000 feet. East winds up to 20 mph increasing to 10 to 20 mph after midnight. Chance of rain 20 percent.

South Big Island

Tonight: Partly cloudy. Breezy. Lows around 74 near the shore to around 53 near 5000 feet. East winds up to 25 mph.

Saturday: 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.

Saturday Night: Partly cloudy. Breezy. Lows around 74 near the shore to around 52 near 5000 feet. Northeast winds up to 20 mph.

Puna

Tonight: Cloudy with isolated showers. Lows 64 to 71 near the shore to 55 to 60 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.

Saturday: Cloudy with isolated showers. Highs 78 to 85 near the shore to 65 to 70 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 20 percent.

Saturday Night: Cloudy with scattered showers. Lows 62 to 70 near the shore to 53 to 59 at 4000 feet. North winds up to 15 mph. Chance of rain 50 percent.

Waikoloa

Tonight: Partly cloudy. Lows around 75 near the shore to 52 to 58 above 4000 feet. North winds up to 15 mph.

Saturday: Sunny in the morning then becoming partly sunny. Breezy. Highs 84 to 91 near the shore to 68 to 75 above 4000 feet. Northeast winds up to 20 mph shifting to the north in the afternoon.

Saturday Night: Partly cloudy. Breezy. Lows around 74 near the shore to 52 to 57 above 4000 feet. Northeast winds up to 25 mph.

Detailed Forecast

Synopsis

Moderate trades will briefly strengthen late Saturday through Sunday before easing again early next week. Limited showers expected over windward and mauka areas during this time.

Discussion

Today's weather evolved as expected with afternoon visible and radar imagery indicating a few showers along sea breeze boundaries over Kauai and, to a lesser extent, Leeward Oahu. By comparison, the eastern end of the state remains quite dry in the lowest 10kft as evidenced by this afternoon's Hilo sounding. Showers over Windward Big Island are nowhere to be found as dry air continues advancing westward. Most locales will see skies clear with the loss of diurnal heating and the development of land breezes. Little change in the prevailing ESEly wind regime means potential for development of showers along coastal areas of Windward Kauai will be possible again tonight, especially during the first half of the night before drier air begins to make inroads.
Existing 590dm mid-level ridge will expand north and eastward during the next couple of days in advance of the next round of mid-latitude height falls over the central Pacific. This will bring a brief period of stronger/breezy trades to the islands late Saturday through Sunday night as the attendant surface ridge strengthens. By early next week, surface pressure falls spread into the central Pacific bringing a return to light to moderate trades, weakest over the western end of the state. Relatively dry trades are expected throughout this time given the lack of any upstream moisture source or focusing mechanism (i.e. frontal boundary) in the boundary layer.

Aviation

Light to moderate east-southeast trades are expected through tonight, then will gradually strengthen and become more easterly on Saturday. Clouds and showers will generally favor windward and mountain areas. In addition, the lighter wind speeds with a slight southeasterly component will allow for localized sea breezes to bring inland clouds and isolated showers to the more sheltered leeward areas into this evening, followed by land breezes clearing things out overnight. Overall, VFR conditions should prevail with brief MVFR conditions possible in showers.

Marine

An E-W oriented surface ridge along 28N is supporting gentle to moderate ESE winds near Kauai and Oahu, and fresh E winds near Maui and the Big Island. While little change is expected in the short term, the ridge will move N and strengthen late Saturday, leading to fresh to strong ENE trade winds statewide into Monday. Deep-layer lows developing NW and NE of the islands early to mid next week will weaken the ridge, and gentle to moderate ESE winds are likely to prevail by Tuesday.
Surf will remain below High Surf Advisory levels through at least the middle of next week. A dissipating N swell will continue to fade overnight. A small relatively short-period NW swell will arrive tonight and Saturday, then diminish Sunday as it becomes increasingly N. NDBC buoys 51001/51101 NW of Kauai are detecting increasing energy in the 12-14 second bands this afternoon, lending confidence to the forecast. Small long-period S swell will bring small surf to S facing shores, with potential for a small boost early next week.
A Coastal Flood Statement (CFWHFO) for all coastal zones is highlighting the fact that higher than forecast water levels are combining with full moon high tides, bringing the potential for minor coastal flooding, mainly during the early morning hours.

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