Hawaii County Weather Forecast for April 21, 2024
Hilo
Today: Mostly cloudy with scattered showers. Highs 76 to 82 near the shore to around 65 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.
Tonight: Mostly cloudy with numerous showers. Lows 61 to 68 near the shore to around 54 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 70 percent.
Monday: Breezy. Mostly cloudy with scattered showers. Highs 76 to 82 near the shore to around 65 at 4000 feet. Northeast winds 10 to 20 mph. Chance of rain 50 percent.
Kona
Today: Mostly sunny. Isolated showers in the afternoon. Highs 81 to 86 near the shore to 66 to 71 near 5000 feet. Light winds. Chance of rain 20 percent.
Tonight: Mostly clear. Lows around 70 near the shore to 47 to 52 near 5000 feet. Light winds.
Monday: Sunny. Isolated showers in the afternoon. Highs 81 to 86 near the shore to around 67 near 5000 feet. Southeast winds up to 10 mph shifting to the west in the afternoon. Chance of rain 20 percent.
Waimea
Today: Partly sunny. Scattered showers in the morning, then numerous showers in the afternoon. Highs around 77 near the shore to 65 to 76 near 3000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.
Tonight: Breezy. Mostly cloudy with scattered showers. Lows 60 to 68 near the shore to 52 to 59 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.
Monday: Breezy. Partly sunny with scattered showers. Highs around 76 near the shore to 65 to 74 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.
Kohala
Today: Partly sunny. Scattered showers in the morning, then numerous showers in the afternoon. Highs around 77 near the shore to 65 to 76 near 3000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.
Tonight: Breezy. Mostly cloudy with scattered showers. Lows 60 to 68 near the shore to 52 to 59 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.
Monday: Breezy. Partly sunny with scattered showers. Highs around 76 near the shore to 65 to 74 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.
South Big Island
Today: Mostly sunny. Isolated showers in the afternoon. Highs around 83 near the shore to around 67 near 5000 feet. East winds up to 15 mph. Chance of rain 20 percent.
Tonight: Mostly clear. Lows around 71 near the shore to around 51 near 5000 feet. East winds 10 to 15 mph.
Monday: Sunny and breezy. Isolated showers in the afternoon. Highs around 83 near the shore to around 67 near 5000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.
Puna
Today: Mostly cloudy with scattered showers. Highs 76 to 82 near the shore to around 65 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.
Tonight: Mostly cloudy with numerous showers. Lows 61 to 68 near the shore to around 54 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 70 percent.
Monday: Breezy. Mostly cloudy with scattered showers. Highs 76 to 82 near the shore to around 65 at 4000 feet. Northeast winds 10 to 20 mph. Chance of rain 50 percent.
Waikoloa
Today: Sunny. Highs 80 to 86 near the shore to 65 to 72 above 4000 feet. Northeast winds up to 15 mph.
Tonight: Mostly clear. Lows around 71 near the shore to 49 to 54 above 4000 feet. Northeast winds up to 15 mph.
Monday: Sunny and breezy. Highs 79 to 86 near the shore to 65 to 72 above 4000 feet. Northeast winds up to 25 mph.
Detailed Forecast
Synopsis
Moderate trade winds will hold today with breezy to locally strong trades returning from Monday onward. An increase in moisture is anticipated Tuesday into the middle of the week, especially for the windward areas of Maui County and the Big Island, where showery conditions remain in the forecast.
Discussion
Hawaii radar imagery shows brief passing showers are drifting in on the moderate trade winds this morning. These relatively stable light showers will decrease in coverage just after sunrise as more stable high pressure begins to fill in over the islands. A high pressure center will build into the Hawaii region just north of the islands later tonight. Responding trade winds will increase into the breezy to locally windy range for much of this week. Passing showers are forecast, mainly along windward slopes in the overnight to early morning hours, as trade wind speeds increase from Monday through Tuesday.
From Tuesday night into Thursday morning, model guidance continues to suggest that a small band of unstable clouds will move from northeast to southwest across all islands. Expect increasing shower trends, favoring windward and mountain areas. The bulk of these enhanced showers are expected to fall over East Maui and the windward slopes of the Big Island. From Thursday onward, typical trade wind weather will continue for the rest of the week.
Wind speeds over the highest summits of Mauna Kea and Mauna Loa of the Big Island have fallen over the past six hours below wind advisory thresholds. Forecast guidance continues to show decreasing wind speed trends at summit level, therefore the Wind Advisory for the Big Island summits was cancelled with the morning forecast package.
Aviation
Light to locally moderate trade winds will continue through tonight and into the coming week. Bands of low clouds and light to moderate rain showers will impact mainly windward and mauka areas. Brief MVFR ceilings and visibility are to be expected in passing showers, otherwise VFR conditions will prevail all areas.
Marine
High pressure north-northwest of the state will drift east and keep trade winds moderate to fresh today. The ridge of high pressure should rebuild late tonight, which should produce fresh to locally strong trade winds once again. A Small Craft Advisory for the typical windy waters around Maui County and the Big Island is likely to be issued tonight through the week as trade winds look to remain dominant.
A moderate medium period north swell has begun to rise at the nearshore PacIOOS buoy 51201 overnight bringing an increase in surf for north facing shores today. This swell will peak later today below High Surf Advisory levels and steadily decline Monday. Surf along east facing shores will remain small today, except for shores exposed to the north swell which could see a slight rise. As the trades strengthen early this week, short period wind waves will bring elevated seas. South facing shores will continue at small levels as a series of small, medium to long period energy will persist over the next several days.
HFO Watches/Warnings/Advisories
None.
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Data Courtesy of NOAA.gov