Hilo

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows 63 to 70 near the shore to 51 to 57 at 4000 feet. Southeast winds up to 10 mph shifting to the west after midnight. Chance of rain 50 percent.

Monday: Partly sunny with scattered showers. Highs 79 to 85 near the shore to around 66 at 4000 feet. Southeast winds up to 10 mph shifting to the northeast in the afternoon. Chance of rain 50 percent.

Monday Night: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows 63 to 69 near the shore to 50 to 57 at 4000 feet. Northeast winds up to 10 mph shifting to the west after midnight. Chance of rain 50 percent.

Kona

Tonight: Partly cloudy with isolated showers. Haze. Lows around 72 near the shore to 47 to 53 near 5000 feet. Light winds. Chance of rain 20 percent.

Monday: Mostly sunny with isolated showers in the morning, then mostly cloudy with scattered showers in the afternoon. Haze through the day. Highs around 85 near the shore to around 66 near 5000 feet. Light winds. Chance of rain 50 percent.

Monday Night: Mostly cloudy. Scattered showers in the evening, then isolated showers after midnight. Haze through the night. Lows around 72 near the shore to 48 to 53 near 5000 feet. Light winds. Chance of rain 40 percent.

Waimea

Tonight: Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Haze through the night. Lows 63 to 71 near the shore to 54 to 61 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Monday: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Haze. Highs around 80 near the shore to 69 to 78 near 3000 feet. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.

Monday Night: Partly cloudy with isolated showers. Haze through the night. Lows 62 to 70 near the shore to 54 to 61 near 3000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Kohala

Tonight: Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Haze through the night. Lows 63 to 71 near the shore to 54 to 61 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Monday: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Haze. Highs around 80 near the shore to 69 to 78 near 3000 feet. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.

Monday Night: Partly cloudy with isolated showers. Haze through the night. Lows 62 to 70 near the shore to 54 to 61 near 3000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

South Big Island

Tonight: Partly cloudy with isolated showers. Haze. Lows around 72 near the shore to around 51 near 5000 feet. Northeast winds up to 15 mph increasing to 10 to 15 mph after midnight. Chance of rain 20 percent.

Monday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Haze through the day. Highs around 85 near the shore to around 65 near 5000 feet. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.

Monday Night: Mostly cloudy with isolated showers in the evening, then partly cloudy after midnight. Haze through the night. Lows around 72 near the shore to around 52 near 5000 feet. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Puna

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows 63 to 70 near the shore to 51 to 57 at 4000 feet. Southeast winds up to 10 mph shifting to the west after midnight. Chance of rain 50 percent.

Monday: Partly sunny with scattered showers. Highs 79 to 85 near the shore to around 66 at 4000 feet. Southeast winds up to 10 mph shifting to the northeast in the afternoon. Chance of rain 50 percent.

Monday Night: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows 63 to 69 near the shore to 50 to 57 at 4000 feet. Northeast winds up to 10 mph shifting to the west after midnight. Chance of rain 50 percent.

Waikoloa

Tonight: Partly cloudy with isolated showers. Haze. Lows around 72 near the shore to 50 to 55 above 4000 feet. Southeast winds up to 10 mph. Chance of rain 20 percent.

Monday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Haze through the day. Highs 84 to 89 near the shore to 63 to 71 above 4000 feet. Northwest winds up to 10 mph. Chance of rain 50 percent.

Monday Night: Partly cloudy with isolated showers. Haze. Lows around 72 near the shore to 49 to 54 above 4000 feet. North winds up to 10 mph shifting to the east after midnight. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Light to moderate trades will persist over the next few days with moderate to locally breezy trades returning around mid week. Generally fair weather is expected throughout the week with batches of moisture riding in with the trade winds at times. Breezy to locally strong trades are expected for next weekend.

Discussion

This afternoon's satellite and radar imagery shows some scattered showers across the state, which are producing some light rainfall. Trade winds will continue to gradually weaken through Monday in response to a weak surface trough passing to our north. With light trades in place, land breezes will be possible for select areas tonight and sea breezes will be possible during the day on Monday. Shower activity could be slightly more active than your typical summer day on Monday due to a weak trough passing to our north and afternoon sea breeze development across select leeward areas. Also satellite imagery does show some high level clouds streaming over the western half of the state, which should linger into Monday.
By Tuesday or Wednesday, the trough should be away from our area with moderate trade winds returning across the state. Drier conditions with less cloud cover is expected for Tuesday and Wednesday.
For Thursday and Friday, we do have a weak upper level trough that will be moving through the island chain from the east, which could bring an uptick of shower coverage. But confidence remains low at this time, due to the lack of low level moisture.
Over the weekend, there is good agreement within the GFS and ECMWF ensembles for breezy to locally strong trade wind weather across the state. Stronger trades generally lead to more passing showers due to greater orographic lift. But any showers should remain on the lighter side due to stable conditions aloft.

Aviation

Moderate to locally breezy trade winds will gradually weaken into tomorrow as a broad surface trough moves overhead, weakening the local pressure gradient and veering the winds out of the east- southeast. With this lighter flow, sea breezes will begin to become more prevalent tomorrow afternoon, building clouds and showers over leeward and interior areas. Otherwise, passing showers will focus primarily over the usual windward and mountain areas, favoring the nighttime/early morning hours. Brief periods of MVFR conditions will remain possible with any showers but overall VFR conditions should prevail.
No AIRMETs are in effect this afternoon, but AIRMET Sierra for mountain obscuration may be needed overnight as shower coverage picks up across windward areas.

Marine

Moderate to locally breezy trades are expected to gradually decrease through Monday as a couple of troughs far to the north and northwest weaken the ridge to our north. Trades should veer slightly toward the east-southeast and weaken to gentle to moderate speeds as a result. Moderate to fresh trades could return as early as Tuesday as the troughs move away and high pressure rebuilds far north of the state.
Surf along south facing shores should see a small, long-period south swell slowly fill in through tonight, with surf peaking near or slightly above the summertime average late Monday through Tuesday. This swell will then gradually decline through the rest of the week. A smaller long-period south swell could move through toward the end of this week for a slight boost to south shore surf.
Surf along east shores will gradually decline over the next several days due to the trade winds weakening. Surf along north facing shores will remain tiny throughout next week.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov