Hawaii County Weather Forecast for October 20, 2024
Hilo
Tonight: Partly cloudy with isolated showers in the evening, then mostly cloudy with scattered showers after midnight. Lows around 66 near the shore to around 54 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 50 percent.
Sunday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs around 85 near the shore to 68 to 73 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.
Sunday Night: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows around 66 near the shore to around 54 at 4000 feet. North winds up to 10 mph. Chance of rain 50 percent.
Kona
Tonight: Partly cloudy with isolated showers. Lows 69 to 75 near the shore to around 55 near 5000 feet. Light winds. Chance of rain 20 percent.
Sunday: Mostly sunny with isolated showers. Highs 81 to 86 near the shore to around 68 near 5000 feet. Southwest winds up to 10 mph. Chance of rain 20 percent.
Sunday Night: Partly cloudy with isolated showers. Lows 69 to 75 near the shore to around 55 near 5000 feet. Light winds. Chance of rain 20 percent.
Waimea
Tonight: Breezy. Partly cloudy with isolated showers. Lows around 66 near the shore to 54 to 62 near 3000 feet. East winds up to 20 mph increasing to 10 to 20 mph after midnight. Chance of rain 20 percent.
Sunday: Breezy. Mostly sunny with isolated showers. Highs around 83 near the shore to 70 to 80 near 3000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.
Sunday Night: Partly cloudy with isolated showers. Lows around 66 near the shore to 54 to 62 near 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.
Kohala
Tonight: Breezy. Partly cloudy with isolated showers. Lows around 66 near the shore to 54 to 62 near 3000 feet. East winds up to 20 mph increasing to 10 to 20 mph after midnight. Chance of rain 20 percent.
Sunday: Breezy. Mostly sunny with isolated showers. Highs around 83 near the shore to 70 to 80 near 3000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.
Sunday Night: Partly cloudy with isolated showers. Lows around 66 near the shore to 54 to 62 near 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.
South Big Island
Tonight: Mostly clear. Breezy. Lows around 70 near the shore to around 53 near 5000 feet. Northeast winds up to 20 mph shifting to the north up to 10 mph after midnight.
Sunday: Sunny and breezy. Highs around 85 near the shore to around 72 near 5000 feet. East winds up to 20 mph.
Sunday Night: Mostly clear. Lows around 70 near the shore to around 53 near 5000 feet. Northeast winds 10 to 15 mph.
Puna
Tonight: Partly cloudy with isolated showers in the evening, then mostly cloudy with scattered showers after midnight. Lows around 66 near the shore to around 54 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 50 percent.
Sunday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs around 85 near the shore to 68 to 73 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.
Sunday Night: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows around 66 near the shore to around 54 at 4000 feet. North winds up to 10 mph. Chance of rain 50 percent.
Waikoloa
Tonight: Mostly clear. Lows 70 to 75 near the shore to 51 to 58 above 4000 feet. East winds up to 15 mph.
Sunday: Mostly sunny. Breezy. Highs around 85 near the shore to 69 to 75 above 4000 feet. Northeast winds up to 20 mph.
Sunday Night: Partly cloudy. Lows 70 to 75 near the shore to 51 to 58 above 4000 feet. Light winds.
Detailed Forecast
Synopsis
Moderate to breezy trades will continue through the rest of the weekend, with limited clouds and showers favoring windward and mauka locations. Trades will ease into the light to moderate range Monday through Tuesday, then begin to increase slightly through the remainder of the week.
Discussion
A lingering weakness in the surface ridge north of the state is allowing another afternoon of leeward sea breeze development under the weaker trade wind flow over the western half of the island chain. Meanwhile, drier air and locally breezy easterly trades are returning over the eastern half of the state and will fill in elsewhere through this evening through Sunday as the surface ridge strengthens and expands westward slightly. At the same time, mid- level heights will continue to rise over the region, increasing the stability and keeping rainfall totals limited. The best shower chances will still favor windward and mauka areas.
A pattern transition is expected next week due to two broad gale lows forecast to form far northwest and northeast of the state. The surface ridge will weaken in response, allowing the trades to taper back into the light to moderate range and land/sea breezes to occur. Global models are keeping most of the weather associated with these systems far west and north-northeast of the area, so mostly dry conditions should persist locally. Shower activity will be mainly light and focused on windward slopes, as well as over leeward areas in the afternoons where localized sea breezes develop. Trade winds look to rebound slightly through the second half of the week as the strong lows to the north weaken.
Aviation
The ridge to the north of the islands will continue to bring light to moderate easterly trade winds to the region into Sunday, with a bit of an uptick in winds expected. Clouds and showers riding in on the trades will favor windward and mountain areas. Overall, VFR conditions should prevail with brief MVFR conditions possible in showers.
While no AIRMETs are in effect this afternoon, an AIRMET for mountain obscuration cannot be ruled out tonight.
Marine
Fresh to locally strong trade winds will continue through the rest of the weekend. Winds will taper off beginning Monday as low pressure systems develop to the northeast and northwest of Hawaii. The northwest low will linger through much of next week keeping winds gentle to moderate out of the east southeast.
A small, short-period north to northwest swell will gradually diminish Sunday and early next week, shifting to a more northeasterly direction by midweek. North facing shores will see the surf from the swell then shifting to east facing shores as the direction changes. Elsewhere, background south swell will keep surf from going flat along south shores. A small, long-period reinforcement is expected to arrive Monday night and decline through the week followed by another on Friday.
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
Small Craft Advisory until 6 PM HST Sunday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.
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Data Courtesy of NOAA.gov