Photo Credit: Sebastien Gabriel

West Kaua’i

Today: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs around 83 near the shore to around 72 above 3000 feet. Southeast winds up to 10 mph shifting to the south in the afternoon. Chance of rain 40 percent.

Tonight: Partly cloudy with isolated showers. Lows around 68 near the shore to around 58 above 3000 feet. Northeast winds up to 15 mph. Chance of rain 20 percent.

Sunday: Mostly sunny with isolated showers. Highs around 86 near the shore to around 75 above 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

South Kaua’i

Today: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 80 to 85. East winds up to 10 mph. Chance of rain 30 percent.

Tonight: Partly cloudy with isolated showers in the evening, then mostly cloudy with scattered showers after midnight. Lows around 69. Northeast winds 10 to 15 mph. Chance of rain 40 percent.

Sunday: Partly sunny with scattered showers. Highs 81 to 87. Northeast winds 10 to 15 mph. Chance of rain 40 percent.

Kaua’i Mountains

Today: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 73 to 80 in the valleys to around 65 above 4000 feet. Light winds. Chance of rain 50 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows 61 to 68 in the valleys to around 57 above 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Sunday: Partly sunny with scattered showers. Highs 74 to 81 in the valleys to around 66 above 4000 feet. East winds up to 15 mph. Chance of rain 50 percent.

North Kaua’i

Today: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 75 to 83. East winds up to 10 mph. Chance of rain 40 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows 63 to 71. Southeast winds up to 10 mph. Chance of rain 40 percent.

Sunday: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 77 to 86. Southeast winds up to 15 mph. Chance of rain 40 percent.

East Kaua’i

Today: Partly sunny with scattered showers. Highs 74 to 84. Southwest winds up to 10 mph shifting to the east in the afternoon. Chance of rain 50 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows 62 to 74. Northeast winds up to 10 mph. Chance of rain 50 percent.

Sunday: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 74 to 84. East winds up to 15 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Mostly dry weather will persist for the next day or so, with the exception of a few light showers around Kauai today from a dissipating front. Light and variable winds will continue today, with moderate to locally breezy trade winds returning tonight into early next week. Strong northeast trade winds may develop on Tuesday, with a potential increase in windward showers through Wednesday through the rest of the week.

Discussion

Overnight satellite imagery shows mostly clear skies over the majority of the state, with the exception of some lingering high clouds streaming northeastward over the Big Island at the leading edge of an upper trough advancing eastward through the islands. Recent GOES-West CIRA ProxyVis satellite imagery and radar are showing some showery low clouds over the far eastern coastal waters, moving toward windward areas of the Big Island. These showers are likely the leading edge of the trade winds returning. Elsewhere at the surface, a dissipating stationary front is located just northwest of Kauai, resulting in scattered low clouds and a few showers over and around Kauai. The 12Z sounding from Hilo is still quite dry, while precipitable waters is somewhat higher on the Lihue sounding from the proximity of the fading frontal boundary. Due to the presence of the dissipating front near Kauai, a land and sea breeze pattern will prevail through much of today. Moderate trades will return from east to west later this afternoon into early next week as weak ridging rebuilds north of the state.
A progressive mid-latitude pattern will ensure the next front reaches (or nearly reaches) the western portion of the island chain by later in the day Monday before dissipating Monday night. Post-frontal high pressure will then strengthen northwest of the state beneath building ridging aloft prior to moving into the local area. This will bring a period of breezy to locally strong northeast trades from Tuesday through middle portion of next week. During this period, both the GFS and ECMWF show varying degrees of remnant moisture from the former front converging over the state, while also disagreeing on exactly where this moisture sets up and if/how far it progresses down the island chain. For now, the forecast reflects a blend of the two solutions, with a modest increase in mainly windward showers for the middle and latter part of next week.

Aviation

A decaying stationary front near Kauai has increased clouds and showers near the Garden Isle early this morning. Elsewhere, light background winds have allowed land breezes to clear skies over the islands. High clouds that have been streaming over the Big Island for much of the night are now moving southeast away from the state.
Showers and clouds will remain most common near Kauai today as the decaying front stalls and then dissipates. Sea breezes will develop from late morning into the afternoon, increasing cloud cover and perhaps introducing a few showers over island interiors. However, moisture will be limited, so showers will remain mostly isolated from Oahu to the Big Island. VFR flight conditions are expected to prevail across the central and eastern islands today.
AIRMET Sierra for tempo mountain obscuration remains in effect for Kauai early this morning, but this AIRMET will likely be dropped later today as the front dissipates and clouds and showers diminish. Additionally, AIRMET Tango remains in effect for moderate upper level turbulence statewide as an upper trough moves over the state. This area of turbulence is quickly moving east, however, so this AIRMET may be dropped later this morning.

Marine

A new, medium-period NW (320 degrees) swell will peak today, with swell heights ranging from 6 to 10 feet along the most exposed N and W facing shores, where a High Surf Advisory (HSA) is posted. The swell will gradually become more northerly (360 degrees) as it slowly diminishes Sunday into Monday. Combined seas will peak over 10 feet in windward waters from Kauai to Maui today, prompting an expansion and extension of the existing Small Craft Advisory (SCA).
A stalling front near Kauai will dissipate today as a weak high passes well N of the islands. A surface ridge near the islands will move N and strengthen in response. Today's (very) light to moderate trade winds will become moderate to locally fresh Sunday, potentially requiring a SCA for typical windier waters near Maui County and the Big Island. Another front approaching from the NW may lead to a brief weakening of the trade winds on Monday, but high pressure building NW of the islands will support strong to near-gale NE trade winds Tuesday and Wednesday. These increased trade winds will lead to elevated short-period surf along E facing shores.
A powerful low in the NW Pacific is generating a long-period NW (310 degrees) swell that is expected to arrive Tuesday and Wednesday, with peak surf heights approaching High Surf Warning levels along exposed shores. This long-lived swell will become more northerly (360 degrees) later in the week. With the strong trades and large swell, a SCA will likely be required for all waters.

HFO Watches/Warnings/Advisories

High Surf Advisory until 4 AM HST Sunday for north and west facing shores of Niihau and Kauai and north facing shores of Oahu, Molokai, and Maui.
Small Craft Advisory until 6 PM HST this evening for Kauai Northwest Waters, Kauai Windward Waters, Oahu Windward Waters, Kaiwi Channel, Maui County Windward Waters.

Data Courtesy of NOAA.gov