Photo Credit: Braden Jarvis

West Kaua’i

Today: Mostly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Highs 79 to 86 near the shore to around 74 above 3000 feet. North winds up to 10 mph shifting to the southeast in the afternoon. Chance of rain 40 percent.

Tonight: Partly cloudy. Isolated showers in the evening. Lows around 68 near the shore to around 59 above 3000 feet. Light winds. Chance of rain 20 percent.

Friday: Mostly sunny. Highs 79 to 86 near the shore to around 73 above 3000 feet. Light winds.

South Kaua’i

Today: Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs 79 to 86. Light winds becoming southeast up to 10 mph in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows around 69. Northeast winds up to 10 mph. Chance of rain 30 percent.

Friday: Mostly sunny. Highs 79 to 86. East winds around 10 mph.

Kaua’i Mountains

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 74 to 80 in the valleys to around 66 above 4000 feet. Light winds becoming north up to 10 mph in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Lows 60 to 68 in the valleys to around 57 above 4000 feet. Light winds. Chance of rain 40 percent.

Friday: Mostly sunny with isolated showers. Highs 72 to 79 in the valleys to around 65 above 4000 feet. Light winds becoming southeast up to 10 mph in the afternoon. Chance of rain 20 percent.

North Kaua’i

Today: Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs 74 to 82. North winds up to 10 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 62 to 70. East winds up to 10 mph in the evening becoming light. Chance of rain 20 percent.

Friday: Mostly sunny. Highs 74 to 83. Southeast winds up to 10 mph shifting to the northeast in the afternoon.

East Kaua’i

Today: Mostly sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs 74 to 84. North winds up to 10 mph. Chance of rain 40 percent.

Tonight: Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows 62 to 73. North winds up to 10 mph in the evening becoming light. Chance of rain 40 percent.

Friday: Mostly sunny with isolated showers. Highs 73 to 84. Light winds. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Stable and relatively dry conditions will persist through most of the forecast period, with the possible exception of a brief uptick in windward showers today and Sunday night into Monday as two successive fronts approach the area. Light winds in advance of these fronts will bring periods of land and sea breezes, with afternoon clouds and a few brief showers over interior and leeward areas. Trade winds will strengthen early next week.

Discussion

The latest surface analysis shows a weak cold front approximately 100 miles north-northwest of Kauai, with a surface ridge draped across the islands. Radar and satellite imagery early this morning show a few low clouds and light showers across mainly the western half of the state in the convergence zone between the front and the ridge. Elsewhere there are little to no clouds. With the ridge across the state expect rather light winds to continue into the afternoon. This will allow sea breezes to develop during the day bringing low clouds and a few showers to leeward and inland areas.
Fairly dry and stable conditions will persist through the week with minimal rainfall expected despite a couple of fronts moving near the area. Guidance continues to show the weak cold front dissipating later today as it sags across the western end of the state. Conditions look to remain rather dry along the front, with only a slight uptick in showers expected across mainly windward and mauka areas of Kauai and Oahu. Light to moderate trade winds will briefly fill in behind the dissipating front on Friday before winds weaken in response to the next approaching front. Will see a return to a land and sea breeze regime over the weekend with afternoon clouds and a few showers over the interior clearing out overnight. Another front looks to approach the state Sunday night into Monday, then dissipate over or just north of the area. Once again, don't expect to see much rain with the front.
Easterly trades winds will fill in behind the front and strengthen through Tuesday as high pressure builds to the north of the state and slides eastward. Pockets of moisture will move in on the trades, but generally dry and stable conditions will persist as ridging aloft dominates.

Aviation

Light trades will allow the sea/land breeze regime to continue. With a front approaching from the north an uptick in SHRA coverage is possible especially to the western end of the state. While SHRA should be on the lighter side, its possible to have some brief MVFR conds. VFR conds should prevail.
No AIRMETs in effect.

Marine

No significant changes to the forecast early this morning. The gentle and variable winds will continue through much of the upcoming weekend with a ridge near or over the islands. The ridge is over the central islands early this morning, with a dissipating front north of the islands. A weak but fast moving high pressure system currently west-northwest of the islands will help to push the front over the western end of the state today. Light and variable winds across the coastal waters this morning will become northerly the afternoon, and then give way to light easterly flow Friday. As the ridge moves back over the islands Friday night through Sunday, expect more gentle and variable winds. Fresh trades may redevelop Sunday night or Monday.
A series of large to extra large northwest to north-northwest swells will continue through the weekend, peaking Sunday. The current swell has been running 13 to 14 ft at 14 to 15 seconds overnight, which continues the trend of being about 2 ft above guidance. The forecast continues to reflect this, and see no reason to deviate at this time. The PacIOOS buoys at Hanalei has shown a mix of the 17 and 15 second swells, while Waimea is predominately still picking up on the initial 17 second swell. Both are running around 10 to 11 ft. Anticipate the 15 second swell to build in today. The High Surf Warning (HSW) remains in place for most north and west facing shores from Kauai to Maui through Friday. Given the direction of the swell (315 to 325 degrees) elevated surf is not expected along leeward portions of the Big Island through this morning. A High Surf Advisory may be needed later today, but at this time will be holding off to see how and when that pulse reaches the islands. A series of storm lows passing northwest of Hawaii will send additional overlapping northwest (320 to 330 degrees) swells that should keep surf near or above HSW levels most of the time through the weekend, and the HSW will likely be extended beyond its current expiration on Friday afternoon. The latest guidance continues to show the largest swell arriving on Sunday, with the ECMWF model advertising in excess of 18 feet. While winds will remain rather light through the weekend, seas will be above the 10 foot Small Craft Advisory threshold for waters exposed to the large swells.
Aside from areas exposed to wrapping northwest swell, surf along east and south facing shores will remain small through much of the week. The best chance for a small rise in southwest swell will be on today and Friday.

Fire weather

No critical fire weather conditions anticipated through the rest of the week due to a combination of light winds and relative humidity (RH) values above 45 percent. Trades will strengthen early next week, but RH will remain above critical levels.

HFO Watches/Warnings/Advisories

High Surf Warning until 6 PM HST Friday for Niihau, Kauai Leeward, Waianae Coast, Oahu North Shore, Maui Windward West, Kauai North, Molokai Windward, Molokai North, Molokai West, Maui Central Valley North, Windward Haleakala.
Small Craft Advisory until 6 PM HST Friday for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Kauai Channel, Oahu Windward Waters, Kaiwi Channel, Maui County Windward Waters, Big Island Windward Waters.

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