Hilo

Tonight: Mostly cloudy with scattered showers. Lows 57 to 65 near the shore to 46 to 54 at 4000 feet. Light winds. Chance of rain 50 percent.

Thursday: Partly sunny. Scattered showers in the morning, then showers likely in the afternoon. Highs 72 to 78 near the shore to 58 to 64 at 4000 feet. Light winds becoming northeast up to 10 mph in the afternoon. Chance of rain 70 percent.

Thursday Night: Mostly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows 58 to 66 near the shore to 47 to 53 at 4000 feet. North winds up to 10 mph. Chance of rain 40 percent.

Kona

Tonight: Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows around 67 near the shore to 42 to 47 near 5000 feet. Light winds. Chance of rain 40 percent.

Thursday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 80 near the shore to around 63 near 5000 feet. Northwest winds up to 10 mph shifting to the west in the afternoon. Chance of rain 50 percent.

Thursday Night: Partly cloudy. Isolated showers in the evening. Lows around 68 near the shore to 42 to 49 near 5000 feet. Light winds. Chance of rain 20 percent.

Waimea

Tonight: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Lows 57 to 66 near the shore to 50 to 57 near 3000 feet. Southeast winds up to 10 mph in the evening becoming light. Chance of rain 50 percent.

Thursday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 74 near the shore to 63 to 72 near 3000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Thursday Night: Partly cloudy. Isolated showers in the evening. Lows 58 to 67 near the shore to 50 to 58 near 3000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Kohala

Tonight: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Lows 57 to 66 near the shore to 50 to 57 near 3000 feet. Southeast winds up to 10 mph in the evening becoming light. Chance of rain 50 percent.

Thursday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 74 near the shore to 63 to 72 near 3000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Thursday Night: Partly cloudy. Isolated showers in the evening. Lows 58 to 67 near the shore to 50 to 58 near 3000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

South Big Island

Tonight: Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows around 68 near the shore to around 47 near 5000 feet. Northeast winds up to 15 mph. Chance of rain 40 percent.

Thursday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 80 near the shore to around 63 near 5000 feet. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.

Thursday Night: Partly cloudy. Isolated showers in the evening. Lows around 69 near the shore to around 48 near 5000 feet. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Puna

Tonight: Mostly cloudy with scattered showers. Lows 57 to 65 near the shore to 46 to 54 at 4000 feet. Light winds. Chance of rain 50 percent.

Thursday: Partly sunny. Scattered showers in the morning, then showers likely in the afternoon. Highs 72 to 78 near the shore to 58 to 64 at 4000 feet. Light winds becoming northeast up to 10 mph in the afternoon. Chance of rain 70 percent.

Thursday Night: Mostly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows 58 to 66 near the shore to 47 to 53 at 4000 feet. North winds up to 10 mph. Chance of rain 40 percent.

Waikoloa

Tonight: Partly cloudy. Scattered showers in the evening. Lows around 68 near the shore to 44 to 50 above 4000 feet. Southeast winds up to 10 mph. Chance of rain 40 percent.

Thursday: Sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 78 to 84 near the shore to around 64 above 4000 feet. Northeast winds up to 10 mph shifting to the northwest in the afternoon. Chance of rain 50 percent.

Thursday Night: Mostly clear. Isolated showers in the evening. Lows around 68 near the shore to 45 to 50 above 4000 feet. Southeast winds around 10 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

A disturbance moving through the area will bring an increase of showers through Thursday across the state. The focus of the showers will likely be over interior and leeward areas during the afternoon and windward areas at night. Light winds will persist through Thursday with moderate trade winds returning by Friday afternoon. A drier air mass will move in Friday afternoon with fair weather conditions expected through early next week.

Discussion

This afternoon's satellite imagery shows scattered showers over many interior areas due to the day time sea breeze convergence. These showers will likely linger longer than usual as a short-wave trough moves through the state this evening and tonight. Model guidance has been struggling with this short-wave trough, but they are now in better agreement with the trough enhancing showers tonight especially windward areas. With the added upper level support, we could see some brief downpours tonight. Showers should eventually weaken in intensity and move offshore late tonight as the land breezes develop. For Thursday, we could see some showers lingering along the windward coastline in the morning, but sea breezes will likely develop again by mid day which should lead to another round of afternoon clouds and showers over interior and leeward areas.
Starting Friday, a weak upper level ridge will build overhead and a surface high will build northeast of the state. A ridge extending from the parent high will fluctuate just north of the state into early next week. With the ridge staying just north of the state, we should see stable conditions with generally a trade wind pattern. For the western half of the state, the winds will be lighter with winds out of the east to east-southeast direction. Due to the lighter winds, we could see sea breezes develop over the interior and leeward areas. Over the eastern half of the state, we should see our typical trade wind pattern. Overall, stable with mostly dry conditions are expected this weekend into early next week.

Aviation

Light easterly winds will prevail through tonight, allowing localized land breezes to be common across the state. An area of enhanced moisture will keep some showers and MVFR cigs/vsbys around windward areas tonight. AIRMET Sierra remains in effect for mountain obscurations above 2500 feet for windward sections of Kauai, Oahu, Molokai, Maui and Big Island.

Marine

A weak surface ridge developing over waters just N of Kauai will support light and variable winds as it remains nearly stationary through Thursday. The ridge will move N and strengthen from Friday into the weekend, supporting moderate to locally fresh trade winds that will favor an E-ESE direction.
Combined seas are just below 10 feet in exposed zones, and as they are expected to gradually ease over the next 12-24 hours, thus the Small Craft Advisory (SCA) has been cancelled. Seas will likely reach SCA criteria in zones exposed to NW swell Thursday night/Friday, and again over the weekend. Additionally, E winds may also reach SCA speeds in zones around Maui and the Big Island this weekend.
Ongoing NE swell will receive another pulse of medium-period (12-14 seconds) reinforcement from 040 degrees tonight and Thursday, then gradually diminish Friday/Saturday. A High Surf Advisory (HSA) for E facing shores has been extended through Thursday. Peak surf heights will likely approach but remain below the 15 foot HSA criteria for N facing shores with this pulse.
The current small (and difficult to detect) NW swell will gradually diminish through Thursday. A new long-period NW swell is expected to arrive late Thursday and peak Friday, with peak surf heights likely exceeding HSA-level heights along N and W facing shores. A similarly-sized (or slightly smaller) NW swell is expected from Saturday night into Monday, with a potentially larger WNW swell from late Tuesday into Thursday next week.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST Thursday for Olomana, Kauai North, Kauai East, East Honolulu, Koolau Windward, Molokai Windward, Molokai Southeast, Windward Haleakala, Kipahulu, Big Island East, Big Island North.

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Data Courtesy of NOAA.gov