Hawaii County Weather Forecast for April 21, 2022
Hilo
Today: Cloudy. Showers likely in the morning, then scattered showers in the afternoon. Highs around 80 near the shore to 64 to 69 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.
Tonight: Cloudy with showers likely. Lows 62 to 67 near the shore to around 52 at 4000 feet. West winds up to 10 mph. Chance of rain 70 percent.
Friday: Cloudy. Showers likely in the morning, then scattered showers in the afternoon. Highs around 80 near the shore to 64 to 69 at 4000 feet. Northwest winds up to 10 mph shifting to the east in the afternoon. Chance of rain 70 percent.
Kona
Today: Partly sunny with isolated showers in the morning, then cloudy with scattered showers in the afternoon. Highs 79 to 84 near the shore to around 64 near 5000 feet. West winds up to 10 mph. Chance of rain 40 percent.
Tonight: Mostly cloudy with isolated showers. Lows 66 to 71 near the shore to around 53 near 5000 feet. Light winds. Chance of rain 20 percent.
Friday: Partly sunny with isolated showers in the morning, then cloudy with scattered showers in the afternoon. Highs 79 to 84 near the shore to around 64 near 5000 feet. West winds up to 10 mph. Chance of rain 40 percent.
Waimea
Today: Breezy. Mostly cloudy with scattered showers. Highs around 79 near the shore to 64 to 74 near 3000 feet. East winds up to 25 mph increasing to 10 to 25 mph in the afternoon. Chance of rain 50 percent.
Tonight: Breezy. Cloudy with scattered showers. Lows around 64 near the shore to 52 to 60 near 3000 feet. East winds up to 25 mph. Chance of rain 50 percent.
Friday: Breezy. Cloudy with scattered showers. Highs around 79 near the shore to 64 to 74 near 3000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.
Kohala
Today: Breezy. Mostly cloudy with scattered showers. Highs around 79 near the shore to 64 to 74 near 3000 feet. East winds up to 25 mph increasing to 10 to 25 mph in the afternoon. Chance of rain 50 percent.
Tonight: Breezy. Cloudy with scattered showers. Lows around 64 near the shore to 52 to 60 near 3000 feet. East winds up to 25 mph. Chance of rain 50 percent.
Friday: Breezy. Cloudy with scattered showers. Highs around 79 near the shore to 64 to 74 near 3000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.
South Big Island
Today: Mostly cloudy. Breezy. Isolated showers in the afternoon. Highs around 82 near the shore to around 68 near 5000 feet. East winds up to 25 mph. Chance of rain 20 percent.
Tonight: Mostly cloudy. Breezy. Isolated showers in the evening. Lows around 67 near the shore to around 52 near 5000 feet. Northeast winds up to 25 mph becoming 10 to 20 mph after midnight. Chance of rain 20 percent.
Friday: Mostly cloudy. Breezy. Isolated showers in the afternoon. Highs around 82 near the shore to around 68 near 5000 feet. East winds up to 25 mph. Chance of rain 20 percent.
Puna
Today: Cloudy. Showers likely in the morning, then scattered showers in the afternoon. Highs around 80 near the shore to 64 to 69 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.
Tonight: Cloudy with showers likely. Lows 62 to 67 near the shore to around 52 at 4000 feet. West winds up to 10 mph. Chance of rain 70 percent.
Friday: Cloudy. Showers likely in the morning, then scattered showers in the afternoon. Highs around 80 near the shore to 64 to 69 at 4000 feet. Northwest winds up to 10 mph shifting to the east in the afternoon. Chance of rain 70 percent.
Waikoloa
Today: Mostly cloudy. Breezy. Highs around 83 near the shore to 65 to 71 above 4000 feet. Northeast winds up to 25 mph.
Tonight: Mostly cloudy. Breezy. Isolated showers in the evening. Lows around 69 near the shore to 49 to 56 above 4000 feet. Southeast winds up to 25 mph. Chance of rain 20 percent.
Friday: Mostly cloudy. Breezy. Highs around 83 near the shore to 65 to 71 above 4000 feet. North winds up to 20 mph.
Detailed Forecast
Synopsis
Breezy easterly trade winds will continue into next week, with showers favoring windward and mauka locations. Expect some showers to carry over into leeward areas periodically as bands of moisture move through. Some high clouds associated with a weak upper disturbance lurking to the south will lift northward into the area today through Friday, then clear out over the weekend. A return of drier trade wind conditions is expected next week.
Discussion
Guidance remains in good agreement and supports the breezy trade wind conditions prevailing into next week as the ridge remains strong to the north. Showers will favor windward and mauka locations, with the best coverage being overnight through the early morning hours. A residual band of clouds associated with the tail-end of an old front that has drifted into the area will support better shower coverage into Friday as it stalls and slowly diminishes – best coverage over the smaller islands. This band of moisture combined with the gusty trades will drive some showers into our leeward areas periodically. In addition to the trade wind conditions, a decent sized area of high clouds associated with an upper low lurking south-southwest of the state is forecast to lift northward over the area today through Friday which may lead to cloudy conditions. These high clouds should clear out by the weekend. Drier air moving into the area next week will limit shower coverage.
Aviation
A high pressure cell north of the state will help generate moderate to breezy trades across all islands through the remainder of this morning and into the afternoon. Low level moisture caught up in the flow will bring scattered to numerous showers along the windward coasts with isolated showers elsewhere. Expect brief periods of MVFR ceilings and visibility to accompany any heavier activity.
AIRMET Sierra remains in effect above 2500 feet for north through east sections of Kauai and Oahu due to low clouds and showers.
AIRMET Tango remains in effect below 8000 feet over and immediately south through west of mountains due to tempo moderate turbulence.
Marine
Moderate to strong trade winds will prevail into early next week as a robust surface high passes far north of the islands. The high will move east over the next few days and settle far northeast of the state during the weekend, keeping the trades elevated. A Small Craft Advisory (SCA) is in effect for the typically windy waters around the Big Island and Maui, and has been extended through Saturday. The SCA will almost certainly need to be extended through Sunday and will likely be in effect through early next week as high pressure builds to the northeast.
A pair of north-northwest swells are due this week. The first swell will be peaking today near seasonal average, then slowly lower Friday and Saturday. The next, slightly larger, swell will arrive Saturday, and north shore surf may approach the advisory level during its peak Sunday. This swell will gradually decline Monday and fade by Tuesday.
South shore surf will remain near to below seasonal average during the next couple of days. Forerunners of a south-southwest swell will arrive Saturday. The swell will likely peak above seasonal average Sunday and decrease Monday and Tuesday.
The steady trade winds discussed above will generate rough trade wind swell and keep east shore surf near seasonal average.
HFO Watches/Warnings/Advisories
Small Craft Advisory until 6 PM HST Saturday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.
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Data Courtesy of NOAA.gov