Hilo

Tonight: Partly cloudy with scattered showers in the evening, then mostly cloudy with showers likely after midnight. Lows 59 to 67 near the shore to 48 to 55 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 70 percent.

Monday: Partly sunny. Showers likely in the morning, then scattered showers in the afternoon. Highs 75 to 81 near the shore to 62 to 67 at 4000 feet. Northeast winds around 10 mph. Chance of rain 70 percent.

Monday Night: Mostly cloudy with showers likely. Lows 59 to 67 near the shore to 48 to 56 at 4000 feet. North winds around 10 mph. Chance of rain 70 percent.

Kona

Tonight: Mostly clear. Isolated showers in the evening. Haze after midnight. Lows around 69 near the shore to 41 to 48 near 5000 feet. Light winds. Chance of rain 20 percent.

Monday: Sunny. Haze through the day. Isolated showers in the afternoon. Highs 81 to 86 near the shore to around 66 near 5000 feet. Northeast winds around 10 mph shifting to the west in the afternoon. Chance of rain 20 percent.

Monday Night: Mostly clear. Haze through the night. Lows around 69 near the shore to 42 to 49 near 5000 feet. Northeast winds around 10 mph.

Waimea

Tonight: Partly cloudy. Breezy. Isolated showers in the evening, then scattered showers after midnight. Lows 59 to 69 near the shore to 51 to 59 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Monday: Partly sunny in the morning then becoming mostly sunny. Breezy. Scattered showers. Highs around 77 near the shore to 66 to 75 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Monday Night: Breezy. Partly cloudy with scattered showers. Lows 60 to 69 near the shore to 52 to 59 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Kohala

Tonight: Partly cloudy. Breezy. Isolated showers in the evening, then scattered showers after midnight. Lows 59 to 69 near the shore to 51 to 59 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Monday: Partly sunny in the morning then becoming mostly sunny. Breezy. Scattered showers. Highs around 77 near the shore to 66 to 75 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Monday Night: Breezy. Partly cloudy with scattered showers. Lows 60 to 69 near the shore to 52 to 59 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

South Big Island

Tonight: Mostly clear. Haze after midnight. Lows around 71 near the shore to around 49 near 5000 feet. Northeast winds 10 to 15 mph.

Monday: Sunny. Haze through the day. Isolated showers in the afternoon. Highs around 84 near the shore to around 67 near 5000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Monday Night: Mostly clear. Haze. Lows around 72 near the shore to around 50 near 5000 feet. Northeast winds 10 to 15 mph.

Puna

Tonight: Partly cloudy with scattered showers in the evening, then mostly cloudy with showers likely after midnight. Lows 59 to 67 near the shore to 48 to 55 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 70 percent.

Monday: Partly sunny. Showers likely in the morning, then scattered showers in the afternoon. Highs 75 to 81 near the shore to 62 to 67 at 4000 feet. Northeast winds around 10 mph. Chance of rain 70 percent.

Monday Night: Mostly cloudy with showers likely. Lows 59 to 67 near the shore to 48 to 56 at 4000 feet. North winds around 10 mph. Chance of rain 70 percent.

Waikoloa

Tonight: Mostly clear. Breezy. Haze after midnight. Lows 67 to 72 near the shore to 44 to 50 above 4000 feet. East winds up to 20 mph becoming 10 to 15 mph after midnight.

Monday: Sunny and haze. Highs 80 to 87 near the shore to 65 to 70 above 4000 feet. East winds 10 to 15 mph shifting to the north in the afternoon. Gusts up to 35 mph.

Monday Night: Mostly clear. Haze. Lows 67 to 73 near the shore to 46 to 51 above 4000 feet. East winds 10 to 15 mph.

Detailed Forecast

Synopsis

Typical trade wind weather is expected during the next several days with scattered showers focused over windward and mountain areas primarily during the overnight and morning hours. The one exception is on Tuesday, when a plume of moisture will move in from the east, which should increase shower activity for windward Big Island and Maui County. Trade winds are expected to dissipate Friday into next weekend.

Discussion

Latest satellite and radar imagery shows a band of moisture over the western end of the state, which is producing passing showers over Kauai and parts of Oahu this afternoon. Rainfall amounts have been mostly light and for tonight we should see a similar trend with more shower activity expected over Kauai with scattered showers elsewhere across the state.
Starting Monday, we should return to our typical fair trade wind weather with some scattered showers over windward and mauka areas. On Tuesday, a plume of moisture will move in from the east which should increase shower activity especially over the windward and mauka areas of Maui County and the Big Island. A dry air mass will follow behind on Wednesday, while the plume of moisture lingers around Kauai.
From Thursday night into Friday, trades will begin to weaken and veer toward the southeast as a front approaches the state. Friday should be a transition day with light southeast flow over the western half of the state and moderate to locally breezy east to east-southeast winds over the eastern half of the state. For next weekend, a light and variable wind pattern is expected with mostly fair weather.
A hot spot over Halemaumau Crater on the Big Island continues to be seen on infrared satellite imagery. The University of Hawaii (UH) Vog Model shows that SO2 emissions have cleared out of the smaller islands and should remain confined to portions of the Big Island and the waters to the southwest through the middle of the week. Vog will likely increase across the state as the trades weaken and veer toward the southeast towards the end of the week.

Aviation

Breezy trades will focus remnant frontal moisture along windward and mauka sections of Oahu and Kauai with some leeward drift of showers, especially during the overnight hours. Conditions have improved during the peak heating hours allowing for a return to prevailing VFR in these locales and for cancellation of AIRMET Sierra for Windward Oahu and Kauai. A return to prevailing MVFR is anticipated tonight for roughly the same areas. A lower coverage of showers prevails elsewhere.
No AIRMETs in effect.

Marine

The current northwest (310-330) swell will continue to gradually decline through midweek. Another northwest (300-320) swell will arrive later in the week and likely produce advisory level surf on exposed north and west facing shores Thursday and Thursday night. Surf along south and east facing shores is expected to remain small through the week.
Fresh to strong trade winds persist this afternoon across local waters and will continue for the next few days as high pressure remains to our north. A Small Craft Advisory (SCA) remains in effect through tomorrow afternoon for the typically windier waters around Maui County and the Big Island, but may need to be extended. The SCA for waters farther to the west have been cancelled.

Fire weather

No critical fire weather conditions are expected for the next seven days. Trade winds will continue to remain at moderate to locally breezy speeds with relative humidities staying above critical levels through most of this week. Trades should dissipate by next weekend.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Monday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

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Data Courtesy of NOAA.gov