Photo Credit: Braden Jarvis

West Kaua’i

Today: Mostly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Highs around 88 near the shore to around 76 above 3000 feet. Light winds becoming southwest up to 10 mph in the afternoon. Chance of rain 50 percent.

Tonight: Mostly clear. Scattered showers early in the evening. Lows 64 to 69 near the shore to around 55 above 3000 feet. Light winds. Chance of rain 50 percent.

Sunday: Mostly sunny. Scattered showers in the afternoon. Highs around 88 near the shore to around 76 above 3000 feet. Light winds. Chance of rain 50 percent.

South Kaua’i

Today: Mostly sunny with isolated showers. Highs around 85. Northeast winds up to 10 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Isolated showers early in the evening. Lows 62 to 68. Northeast winds up to 10 mph in the evening becoming light. Chance of rain 20 percent.

Sunday: Mostly sunny. Isolated showers in the afternoon. Highs around 85. Light winds. Chance of rain 20 percent.

Kaua’i Mountains

Today: Mostly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Highs 75 to 82 in the valleys to around 66 above 4000 feet. Light winds. Chance of rain 50 percent.

Tonight: Partly cloudy. Scattered showers early in the evening. Lows 55 to 60 in the valleys to around 50 above 4000 feet. Light winds. Chance of rain 50 percent.

Sunday: Mostly sunny. Scattered showers in the afternoon. Highs 75 to 82 in the valleys to around 66 above 4000 feet. Light winds. Chance of rain 50 percent.

North Kaua’i

Today: Mostly sunny with scattered showers. Highs 78 to 87. Northeast winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly clear. Scattered showers early in the evening. Lows 58 to 68. Light winds. Chance of rain 50 percent.

Sunday: Mostly sunny. Scattered showers in the afternoon. Highs 78 to 87. Light winds. Chance of rain 50 percent.

East Kaua’i

Today: Mostly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Highs 78 to 86. Northeast winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly clear. Scattered showers early in the evening. Lows 56 to 70. Light winds. Chance of rain 50 percent.

Sunday: Mostly sunny. Scattered showers in the afternoon. Highs 78 to 86. Light winds. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Humid conditions with light and variable winds are expected through early next week as low pressure remains positioned north of the islands. Clouds and showers will favor island interior and leeward locations during the afternoon and early evening hours and areas near the coast at night. More widespread rainfall will become a possibility Tuesday through midweek as a cold front approaches from the north and southerly winds fill in. The cold front could move through the islands late next week, bringing a return of trade winds and some more wet weather.

Discussion

Currently at the surface, a cold front extends from a deep 992 mb low well north of the islands, southwestward to a location around 350 miles north of Kauai. Meanwhile, a pair of highs are positioned to the west and east of the deep low, and well displaced from the island chain. These features have weakened the gradient, with land breezes dominant in most areas early this morning. Infrared satellite imagery shows partly to mostly cloudy conditions in place in most areas. Meanwhile, radar imagery shows scattered showers over the coast waters with a few of these showers brushing the island coasts. Main short term focus revolves around rain chances during the next few days.
The cold front several hundred miles north of the state will make steady progress southward during the next couple days, before stalling out and dissipating near or just northwest of Kauai early next week. This will keep a light wind regime in place across the islands over the weekend, with land and sea breezes common statewide. The flow is expected to tip more southerly at light to locally moderate speeds during much of the upcoming work week, with a cold front potentially ushering in a return of trade winds by Friday.
As for the remaining weather details, not much change to the weather pattern is expected through Monday. A largely land and sea breeze driven pattern should keep showers confined primarily to interior and leeward sections of the islands during the afternoon and evening hours, and locations near the immediate coast at night. Additionally, with mid-level moisture and instability in place over Maui County and the Big Island during the next several days, a few downpours can't be ruled out each afternoon, with a thunderstorm or too not out of the question on the Big Island as well.
Beginning Monday night, a deep closed low north of the islands appears to draw some deep tropical moisture northward into the state. This closed low will open up and lift northward on Tuesday, but will quickly be replaced by a potent shortwave trough closing off into another nearly stationary closed low north of the islands on Wednesday, before opening up and shifting eastward Thursday and Friday. Overall, this set up has the potential to bring a steady influx of deep tropical moisture into the islands with precipitable water values in excess of 2 inches for multiple days. There remains some differences in the model guidance regarding how wet this pattern may get and how much of the state could see some heavier rainfall totals, although the western islands appear to be the main targets at the moment. The deeper moisture should begin to exit the region to the northeast on Thursday, although a potential front moving southward into the islands late next week, could delay a return of more typical drier trade wind weather.

Aviation

Light land breezes will linger through mid-morning. Gentle sea breezes will redevelop along most coastlines in the afternoon. Early morning satellite and radar imagery reveal areas of mid-topped stratocumulus and weak showers affecting all the smaller islands and northern Big Island. Conditions are likely to persist through mid- morning. In the afternoon, showers will increase and become focused over island interiors. For the Big Island, there is also a slight chance of heavy showers or thunderstorms in the afternoon and early evening hours.

Marine

A strong and nearly stationary low pressure system will remain in place far north of the region into the early part of next week. This system will send two additional north swells into the Hawaiian Islands over the next seven days. Trade winds around and upstream of the islands will remain light for the next seven days keeping wind conditions below Small Craft Advisory thresholds.
The current north swell (340-360 degrees) is starting to trend lower this morning as reported by the buoys, therefore the High Surf Advisory (HSA) was cancelled this morning. This north swell will continue to produce elevated surf heights just below HSA thresholds today along all north facing shores. A second north swell (340-360 degrees) arrives later tonight. This second swell may briefly exceed HSA levels on Sunday and then slowly fade through Wednesday. A third swell from the north-northwest direction (330-350 degrees) may once again build surf heights along north facing shores into the HSA range on Thursday and Friday.
A small, long period south swell will peak this weekend before slowly subsiding early next week. Another similar-sized south swell may arrive around the middle of next week. Surf along east facing shores will remain small due to diminished wind swell, except for some select east facing shores exposed to the north swell wrap.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov