Hawaii County Weather Forecast for April 22, 2023
Hilo
Today: Mostly sunny with scattered showers. Highs around 83 near the shore to around 67 at 4000 feet. Southeast winds up to 10 mph shifting to the east in the afternoon. Chance of rain 40 percent.
Tonight: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows around 66 near the shore to around 52 at 4000 feet. Southeast winds up to 10 mph in the evening becoming light. Chance of rain 50 percent.
Sunday: Mostly sunny with scattered showers. Highs around 83 near the shore to around 67 at 4000 feet. Southeast winds up to 10 mph. Chance of rain 50 percent.
Kona
Today: Sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 85 near the shore to around 70 near 5000 feet. Northwest winds up to 10 mph. Chance of rain 50 percent.
Tonight: Partly cloudy with scattered showers. Lows 66 to 73 near the shore to around 52 near 5000 feet. Light winds. Chance of rain 30 percent.
Sunday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 85 near the shore to around 70 near 5000 feet. Light winds. Chance of rain 50 percent.
Waimea
Today: Breezy. Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 82 near the shore to 71 to 77 near 3000 feet. East winds up to 20 mph. Chance of rain 30 percent.
Tonight: Partly cloudy with isolated showers. Lows around 65 near the shore to 50 to 59 near 3000 feet. East winds up to 15 mph in the evening becoming light. Chance of rain 20 percent.
Sunday: Mostly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Highs around 82 near the shore to 71 to 77 near 3000 feet. Northwest winds up to 10 mph shifting to the northeast in the afternoon. Chance of rain 40 percent.
Kohala
Today: Breezy. Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 82 near the shore to 71 to 77 near 3000 feet. East winds up to 20 mph. Chance of rain 30 percent.
Tonight: Partly cloudy with isolated showers. Lows around 65 near the shore to 50 to 59 near 3000 feet. East winds up to 15 mph in the evening becoming light. Chance of rain 20 percent.
Sunday: Mostly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Highs around 82 near the shore to 71 to 77 near 3000 feet. Northwest winds up to 10 mph shifting to the northeast in the afternoon. Chance of rain 40 percent.
South Big Island
Today: Breezy. Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 85 near the shore to around 71 near 5000 feet. East winds up to 25 mph. Chance of rain 40 percent.
Tonight: Partly cloudy. Breezy. Isolated showers in the evening, then scattered showers after midnight. Lows around 67 near the shore to around 52 near 5000 feet. Northeast winds up to 20 mph. Chance of rain 40 percent.
Sunday: Sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 85 near the shore to around 71 near 5000 feet. East winds up to 15 mph. Chance of rain 50 percent.
Puna
Today: Mostly sunny with scattered showers. Highs around 83 near the shore to around 67 at 4000 feet. Southeast winds up to 10 mph shifting to the east in the afternoon. Chance of rain 40 percent.
Tonight: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows around 66 near the shore to around 52 at 4000 feet. Southeast winds up to 10 mph in the evening becoming light. Chance of rain 50 percent.
Sunday: Mostly sunny with scattered showers. Highs around 83 near the shore to around 67 at 4000 feet. Southeast winds up to 10 mph. Chance of rain 50 percent.
Waikoloa
Today: Mostly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Highs around 85 near the shore to 66 to 73 above 4000 feet. Northwest winds up to 10 mph. Chance of rain 50 percent.
Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 67 to 73 near the shore to 47 to 55 above 4000 feet. Northeast winds up to 10 mph in the evening becoming light. Chance of rain 30 percent.
Sunday: Sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 85 near the shore to 66 to 73 above 4000 feet. Southwest winds up to 10 mph shifting to the northwest in the afternoon. Chance of rain 50 percent.
Detailed Forecast
Synopsis
Light to moderate east southeasterly winds will prevail through the weekend. Showers will favor windward and southeast facing slopes at night and during the morning, and interior and leeward areas each afternoon. Winds will weaken Sunday night and Monday as a front approaches from the northwest. A few showers will be possible near the coast at night, with shower coverage expected to increase Monday afternoon as some moisture pools in advance of the front. This front will then move into the western islands Monday night and Tuesday, then gradually stall out and dissipate during the middle to latter part of next week. Some showery weather will likely accompany the front with windward slopes seeing the brunt of the rainfall. A return to more typical trade wind weather is looking more likely for next weekend, in line with what we should expect for this time of year.
Discussion
Currently at the surface, a weak trough of low pressure is located just north of the state, a cold front is positioned around 650 miles west-northwest of Kauai, and a 1029 mb high is centered around 1600 miles northeast of Honolulu. Light to moderate trade winds prevail in unsheltered areas early this morning, with land breezes present elsewhere. Infrared satellite imagery shows mostly clear to partly cloudy conditions in most areas, with a few pockets of enhanced cloud cover scattered about the islands. Radar imagery shows scattered showers affecting the Big Island, leeward coastal waters, and windward sections of Maui, with nothing more than isolated shower coverage elsewhere. Main short term focus revolves around rain chances and wind trends.
The trough north of the state will shift west today, allowing light to moderate trade winds prevail across the island chain, strongest over the eastern end of the state. The winds over the western islands will be light enough to allow for land and sea breeze development in most leeward areas however. An approaching front will then ease the trades from northwest to southeast down the island chain tonight and Sunday, with light and variable winds expected statewide Sunday night and Monday. A weakening front will push southward into the islands Monday night and Tuesday, allowing for a return of light to locally moderate northeast trades to develop. The front will stall out over the central islands and gradual dissipate during the middle to latter part of next week, with light to locally moderate northeasterly trades persisting.
As for the remaining weather details, the trailing moisture from the lingering trough will shift northwest through the weekend. This should lead to fewer showers over the eastern islands today, while coverage of daytime heating driven showers will be higher over Kauai and Oahu. Showers should fizzle out in most leeward areas by 8 or 9 pm, with a few showers continuing to affect windward and southeast facing slopes overnight. We should see even fewer showers on Sunday across Oahu and Maui County, with scattered daytime heating driven showers expected to affect Kauai and the Big Island once again.
The front moving in from the northwest should shift a higher precipitable water airmass back over the entire state Sunday night and Monday. This should bring an increase in shower coverage, with showers favoring areas near the coast Sunday night and early Monday, and interior and leeward areas Monday afternoon. The front is then forecast to move into the islands Monday night and Tuesday, then stall out somewhere over the central islands during the middle to latter part of next week. Some showery weather will likely accompany and stick with the front as it stalls out and gradually dissipates over the island chain, with windward slopes and coasts expected to see the brunt of the rainfall. A return to more typical trade wind weather is looking more likely for next weekend, in line with what we should expect for this time of year.
Aviation
Light to locally moderate east to southeast flow will continue for the next couple days. Sea breezes will prevail by day and land breezes at night in the more sheltered areas. Clouds and showers will prefer east facing slopes and coasts during the late night and morning hours. On the Big Island, expect cumulus build-ups over the island's interior in the afternoons and early evenings, then partial clearing overnight. Brief MVFR conditions are likely in passing showers. Otherwise, VFR conditions are expected statewide.
Marine
A trough just north of the state will help support moderate to locally strong east to southeast winds through the day. A Small Craft Advisory is in effect for those notoriously windier marine zones surrounding Maui County and Big Island, including the windward Maui and Big Island waters, where sustained easterlies will hold at between 20 and 25 knots. As a front approaches from the northwest early next week, winds will become light and variable Sunday and Monday before turning moderate northeast as high pressure builds in behind the passing weak front Tuesday.
A moderate size, long period northwest (310 degree) swell moving in this morning will lift surf from chest to slightly over head high along many north-facing shores through Sunday afternoon. A similar size, medium period northwest (320 degree) swell will come in late Sunday into early Monday. This reinforcing northwest swell will result in a slight boost to already elevated early week north and west-facing shore surf through Tuesday. A small, long period south (190 degree) swell that arrived this morning will bump south-facing shore surf up to around chest high this weekend. This swell will keep seasonable south surf in place through Monday. Lighter weekend trades will allow for relatively lower eastern exposure wind wave chop.
HFO Watches/Warnings/Advisories
Small Craft Advisory until 6 PM HST this evening for Maui County Windward Waters, Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Windward Waters, Big Island Leeward Waters, Big Island Southeast Waters.
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Data Courtesy of NOAA.gov