Photo Credit: Jason Weingardt

West Kaua’i

Today: Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs 81 to 87 near the shore to around 72 above 3000 feet. Light winds. Chance of rain 20 percent.

Tonight: Mostly cloudy. Lows around 67 near the shore to around 56 above 3000 feet. Light winds.

Saturday: Partly sunny in the morning, then mostly sunny with isolated showers in the afternoon. Highs around 84 near the shore to around 73 above 3000 feet. Light winds. Chance of rain 20 percent.

South Kaua’i

Today: Mostly sunny in the morning then becoming partly sunny. Highs 78 to 85. Northeast winds up to 10 mph.

Tonight: Mostly cloudy. Lows around 67. North winds up to 10 mph.

Saturday: Partly sunny in the morning, then mostly sunny with isolated showers in the afternoon. Highs 79 to 86. Northeast winds up to 10 mph in the morning becoming light. Chance of rain 20 percent.

Kaua’i Mountains

Today: Partly sunny with isolated showers. Highs 71 to 79 in the valleys to around 64 above 4000 feet. Light winds. Chance of rain 20 percent.

Tonight: Mostly cloudy with isolated showers. Lows 58 to 66 in the valleys to around 54 above 4000 feet. Light winds. Chance of rain 20 percent.

Saturday: Partly sunny with isolated showers. Highs 72 to 80 in the valleys to around 65 above 4000 feet. Light winds. Chance of rain 20 percent.

North Kaua’i

Today: Partly sunny. Isolated showers early in the morning. Highs 73 to 84. East winds up to 10 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with isolated showers. Lows 60 to 68. Light winds. Chance of rain 20 percent.

Saturday: Partly sunny early in the morning then becoming mostly sunny. Isolated showers. Highs 73 to 84. Light winds. Chance of rain 20 percent.

East Kaua’i

Today: Partly sunny. Highs 71 to 83. Northeast winds up to 10 mph.

Tonight: Mostly cloudy. Isolated showers in the evening. Lows 59 to 68. Light winds. Chance of rain 20 percent.

Saturday: Partly sunny early in the morning, then mostly sunny with isolated showers in the late morning and afternoon. Highs 72 to 84. Light winds becoming northeast up to 10 mph in the afternoon. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Trade winds will weaken today and become light and variable during the weekend. The atmosphere will be stable and rather dry with minimal rainfall expected. A shallow and dissipating front move may across portions of the island chain Sunday night and Monday, bringing only modest showers and likely maintaining light winds. Light trades may return by the middle of next week.

Discussion

A stable and rather dry trade wind flow will diminish through Saturday. Trades will continue to drop as a surface high, currently sitting roughly 250 miles north of Oahu, moves east and weakens. With trades on the decline, localized overnight land breezes and daytime sea breezes occurring today will become more prevalent on Saturday. A weak mid-level ridge will maintain stability, and swath of rather dry low-level air around the region will keep precipitable water below an inch. As a result, expect minimal windward rainfall, and leeward sea breezes will produce afternoon clouds over terrain, but little, if any, shower activity is expected. Dew points will hold in the lower 60s, helping to push overnight low temperatures into winter-like range of the mid to even lower 60s in some locations. In addition, a developing weak jet streak aloft will generate increased thin high clouds today and Saturday.
Sunday and early next week, the overall pattern favors light disrupted trade winds and a weak front passing over the northern end of the island chain. For Sunday, trades will become light and variable or northerly as a weak front approaches. A dry land and sea breeze pattern is likely, though a small pocket of moisture could produce some active showers on the Big Island. Timing in the deterministic GFS and ECMWF have come into better agreement, showing a weak front bringing modest showers to windward and northern slopes of Kauai Sunday night and to Oahu and possibly Molokai on Monday.
Details become elusive by Tuesday due to model differences. The GFS and ECMWF are showing the potential for another weak front passing near or over the state followed by an upper-level ridge moving westward into the region around Wednesday. Ensemble guidance shows that the potential for significant rainfall is low, with light northerly winds becoming trade winds around Wednesday.

Aviation

Trades expected to be on the lighter side thought the weekend. In the lighter trades regime we could see some localized land/sea breezes. Any SHRA and low cigs should be confined to windward and mauka areas. Brief MVFR conds can be expected in any SHRA but otherwise VFR should prevail.
No AIRMETS are in effect.

Marine

A weak ridge of high pressure north of the state is producing light to locally fresh winds. This ridge will gradually weaken and shift south late tonight and over the weekend as a weak front approaches from the northwest. In response, winds will gradually become light and variable Saturday into early next week. A weak transient high will build north of the state by the middle of next week allowing gentle to fresh northeasterly trade winds to briefly return.
A small, medium period, north northeast swell (010-030 degrees) is filling at CDIP Hilo and Pauwela near shore buoys early this morning. This should produce some small surf along north facing shores today. Another more moderate, medium period pulse from the same source is expected Saturday along with a similar size overlapping northwest swell (320 degrees). These combined swells will elevate surf along north and west facing shores just shy of High Surf Advisory (HSA) criteria on Sunday before subsiding early next week. A Marine Weather Statement remains in effect for harbor surges, particularly at Hilo and Kahului harbor, generated by the more northerly swells.
Surf along east facing shores will see some energy from the northeasterly swell wrap today into the weekend. Surf along east facing shores will become more elevated over the weekend, especially Saturday into to Sunday as the swell peaks and shifts more easterly, wrapping into exposed areas.

Fire weather

KBDI values remain high across the state, and an overall dry weather pattern is expected through at least Sunday over most islands. With dry air moving overhead, relative humidity values will have the potential to drop below the critical 45% threshold during the late morning and afternoon hours. However, lighter winds will mitigate fire weather concerns.

HFO Watches/Warnings/Advisories

None.

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