Today: Mostly cloudy. Scattered showers in the morning, then scattered showers and slight chance of thunderstorms in the afternoon. Highs around 82 near the shore to 63 to 68 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.
Tonight: Partly cloudy in the evening then becoming cloudy. Scattered showers. Lows 62 to 67 near the shore to around 52 at 4000 feet. Northwest winds up to 10 mph. Chance of rain 50 percent.
Sunday: Cloudy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 82 near the shore to 63 to 68 at 4000 feet. Northeast winds up to 15 mph shifting to the east in the afternoon. Chance of rain 50 percent.
Kona
Today: Mostly sunny with slight chance of thunderstorms and isolated showers in the morning, then mostly cloudy with numerous showers and slight chance of thunderstorms in the afternoon. Highs 79 to 84 near the shore to around 63 near 5000 feet. West winds up to 10 mph. Chance of rain 70 percent.
Tonight: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Lows 67 to 74 near the shore to around 53 near 5000 feet. Light winds. Chance of rain 20 percent.
ARTICLE CONTINUES BELOW AD
ARTICLE CONTINUES BELOW AD
Sunday: Mostly sunny in the morning then becoming mostly cloudy. Isolated showers. Highs 79 to 84 near the shore to around 63 near 5000 feet. Light winds becoming west up to 10 mph in the afternoon. Chance of rain 20 percent.
Waimea
Today: Partly sunny. Breezy. Scattered showers in the morning, then scattered showers and slight chance of thunderstorms in the afternoon. Highs around 81 near the shore to 66 to 75 near 3000 feet. East winds up to 20 mph. Chance of rain 50 percent.
Tonight: Partly cloudy in the evening then becoming mostly cloudy. Breezy. Isolated showers. Lows around 64 near the shore to 52 to 60 near 3000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.
Sunday: Breezy. Mostly cloudy with isolated showers. Highs around 81 near the shore to 66 to 75 near 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.
Kohala
Today: Partly sunny. Breezy. Scattered showers in the morning, then scattered showers and slight chance of thunderstorms in the afternoon. Highs around 81 near the shore to 66 to 75 near 3000 feet. East winds up to 20 mph. Chance of rain 50 percent.
ARTICLE CONTINUES BELOW AD
Tonight: Partly cloudy in the evening then becoming mostly cloudy. Breezy. Isolated showers. Lows around 64 near the shore to 52 to 60 near 3000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.
Sunday: Breezy. Mostly cloudy with isolated showers. Highs around 81 near the shore to 66 to 75 near 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.
South Big Island
Today: Breezy. Sunny in the morning, then partly sunny with scattered showers and slight chance of thunderstorms in the afternoon. Highs around 81 near the shore to around 67 near 5000 feet. East winds up to 20 mph. Chance of rain 50 percent.
Tonight: Partly cloudy. Breezy. Lows 66 to 72 near the shore to around 52 near 5000 feet. Northeast winds up to 20 mph.
Sunday: Mostly sunny in the morning then becoming partly sunny. Breezy. Highs around 81 near the shore to around 67 near 5000 feet. East winds up to 20 mph.
Puna
ARTICLE CONTINUES BELOW AD
Today: Mostly cloudy. Scattered showers in the morning, then scattered showers and slight chance of thunderstorms in the afternoon. Highs around 82 near the shore to 63 to 68 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.
Tonight: Partly cloudy in the evening then becoming cloudy. Scattered showers. Lows 62 to 67 near the shore to around 52 at 4000 feet. Northwest winds up to 10 mph. Chance of rain 50 percent.
Sunday: Cloudy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 82 near the shore to 63 to 68 at 4000 feet. Northeast winds up to 15 mph shifting to the east in the afternoon. Chance of rain 50 percent.
Waikoloa
Today: Breezy. Mostly sunny with slight chance of thunderstorms and isolated showers in the morning, then mostly cloudy with scattered showers and slight chance of thunderstorms in the afternoon. Highs around 83 near the shore to 64 to 70 above 4000 feet. North winds up to 20 mph. Chance of rain 50 percent.
Tonight: Mostly clear. Breezy. Lows 68 to 74 near the shore to 49 to 56 above 4000 feet. East winds up to 20 mph.
Sunday: Sunny in the morning then becoming partly sunny. Highs around 83 near the shore to 64 to 70 above 4000 feet. North winds up to 15 mph.
Detailed Forecast
Synopsis
A band of moisture associated with a trough moving through the islands will keep the chances for showers and thunderstorms up for most windward areas through the morning hours today. Drier conditions with moderate to breezy easterly trade winds will return across the entire state later today through Sunday. Winds will shift out of the southeast and briefly weaken early next week as another upper disturbance and front set up west of the state. Stronger trades are expected Wednesday.
Discussion
Satellite and radar showed a band of clouds with embedded heavy showers developing along a surface trough moving through the islands from east to west. Added instability associated with a weak trough aloft is triggering a few thunderstorms within this band, mostly over the windward areas and waters. Some of this activity could translate to localized flooding concerns this morning where it becomes focused as it moves ashore. Morning upper air soundings confirmed this and depicted modestly steep mid-level lapse rates due to cooler air aloft.
As the trough and residual moisture shift west of the area later today and tonight, expect a drier and more stable pattern to fill in through the second half of the weekend. Easterly trades will return to moderate to breezy levels with high pressure passing to the north, which will keep the best chance for showers over the typical windward and mauka locations overnight through the morning hours. A slight increase in moisture moving through within the trades late Sunday through Sunday night will support better windward shower coverage overnight and into the early Monday morning hours.
Trade winds will shift out of the east to southeast through the day Monday as a deep trough develops several hundred miles west of the state. Instability associated with the trough may enhance cloud cover and shower activity around Kauai and Oahu into Tuesday, with afternoon leeward showers possible. Otherwise, expect showers to favor windward slopes.
Trade winds should strengthen Wednesday as the trough to the west weakens and surface high pressure builds far north of the state.
Aviation
Low clouds associated with a weakening surface trough near Kauai and Oahu will continue to produce brief periods of showers, isolated thunderstorms and localized MVFR conditions this morning in a light wind pattern. Day time sea breezes along the terrain sheltered western slopes will converge with increasing easterly trade winds, building clouds over island mountains and interior sections. Mostly VFR conditions will prevail.
AIRMET Sierra remains in effect for mountain obscuration over Kauai and Oahu due to low clouds and showers.
Marine
A trough near Kauai will gradually weaken and shift west today, allowing trade winds to strengthen to moderate and locally strong levels across the island chain. As a result, a Small Craft Advisory (SCA) has been issued for the typically windy waters around Maui and the Big Island through 6 PM Sunday. Winds may ease and tip east-southeast, particularly over the western islands Monday and Tuesday as a trough develops west of the state. Trades will then fill back in on Wednesday as the trough shifts westward and away from the island chain.
Small surf along the north and west facing shores will hold through the weekend from a pair of small north and northwest swells. A moderate sized long period northwest swell will arrive Monday, peak Tuesday, then gradually lower Wednesday through next weekend. This swell will give a noticeable boost to north and west shore surf late Monday through Wednesday, potentially close to advisory levels on Tuesday.
Near to just below average surf along south facing shores is expected through the weekend from small overlapping south swells. A new long period south swell will build Monday and Tuesday, and peak Wednesday and Thursday near advisory levels. This swell will then gradually lower Friday through next weekend.
Surf along east facing shores will trend up slightly this weekend into early next week as the trades strengthen upstream of the state. East shore surf will build close to seasonal levels by the end of the upcoming work week.
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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