West Kaua’i

Today: Sunny. Highs 86 to 93 near the shore to around 78 above 3000 feet. East winds up to 10 mph.

Tonight: Mostly clear. Lows around 73 near the shore to around 61 above 3000 feet. East winds up to 10 mph.

Saturday: Sunny. Isolated showers in the afternoon. Highs 85 to 92 near the shore to around 78 above 3000 feet. Light winds. Chance of rain 20 percent.

South Kaua’i

Today: Mostly sunny. Isolated showers in the morning. Highs 84 to 92. East winds around 10 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Isolated showers after midnight. Lows around 73. Northeast winds around 10 mph. Chance of rain 20 percent.

Saturday: Sunny. Isolated showers in the morning. Highs 84 to 92. East winds around 10 mph. Chance of rain 20 percent.

Kaua’i Mountains

Today: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 77 to 86 in the valleys to around 68 above 4000 feet. East winds up to 15 mph. Chance of rain 40 percent.

Tonight: Partly cloudy with isolated showers. Lows 63 to 70 in the valleys to around 59 above 4000 feet. East winds up to 10 mph. Chance of rain 20 percent.

Saturday: Mostly sunny with isolated showers. Highs 77 to 85 in the valleys to around 69 above 4000 feet. East winds up to 10 mph. Chance of rain 20 percent.

North Kaua’i

Today: Mostly sunny with isolated showers. Highs 79 to 88. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Mostly clear with isolated showers. Lows 65 to 73. East winds up to 10 mph. Chance of rain 20 percent.

Saturday: Sunny with isolated showers. Highs 78 to 88. East winds up to 10 mph. Chance of rain 20 percent.

East Kaua’i

Today: Mostly sunny with isolated showers. Highs 76 to 89. East winds around 10 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 65 to 78. Northeast winds around 10 mph. Chance of rain 20 percent.

Saturday: Mostly sunny with isolated showers. Highs 77 to 89. Northeast winds around 10 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Partly cloudy and warm with light to moderate trade winds the next couple of days. The islands are under a stable weather pattern as weak ridging remains situated over and east of the state. Limited showers will be primarily confined to windward upslope mauka and within higher terrain through Saturday. An area of enhanced moisture moving through early Sunday will increase statewide precipitation chances. Primarily windward rainfall will increase in response to approaching Tropical Cyclone Kiko early next week. Kiko is forecast to reach our far eastern offshore waters Monday. There is a fair amount of uncertainly that exists concerning Kiko's eventual track, intensity and possible impacts.

Discussion

The islands remain under the stable influence of an upper ridge planted over the state with its axis extending east-northeast to the U.S. mainland. A open wave trough north of the islands will deepen as an upper low dives south into its base this weekend. The trough will erode the ridge anchored over the state and ultimately be the impetus to providing the necessary wind shear required to weaken Tropical Cyclone Kiko as it tracks north of the state Monday through Wednesday. This trough will also kill the trade belt gradient resulting in a few days of very light winds where daytime sea breezes and overnight land breezes will become more dominant. Any measurable rain will focus along windward exposures and upslope mauka today and tomorrow. Early morning shortwave IR satellite imagery is depicting a nice clustering of low topped moist clouds to the east of the island chain that will pass over the state the next few hours. This will increase morning shower activity over Big Island's windward Hamakua, Hilo and Puna regions as well as across East Maui. After a couple of days of this continued relatively dry and warm summer weather, lighter winds in tandem with a higher slug of mid layer moisture Sunday will produce a muggy start to next week. Rain chances will also increase across most of the state Sunday morning as this mid layer moisture rides in on light trades.
Tropical Cyclone Kiko is moving west at around 10 mph and is forecast to move into our eastern offshore waters, or pass 150W, late Monday. The track of Kiko will be determined by the drier Central Pacific environment it will be moving into the next couple of days as well as its interaction with increasing southwesterly shear brought on by the aforementioned trough north of Hawaii. The official forecast track of TC Kiko has it passing just north of the Hawaiian Islands as a weakening tropical storm Monday through Wednesday. Due to the uncertainly of Kiko's intensity and track as it interacts with the upper low early next week, the messaging for the state is still centered on the potential for greater areal rain or more frequent shower behavior from Monday through early Thursday. Interests in the Hawaiian Islands and surrounding waters need to closely monitor Kiko's official forecasts from the National Hurricane Center.

Aviation

VFR for the majority of the terminals. Light to moderate trade winds will prevail across the Hawaiian Islands. Trades will weaken this weekend as Tropical Cyclone Kiko approaches the area from the southeast. Brief periods of nocturnal low clouds and occasional showers will focus along windward exposures and higher terrain. MVFR ceilings and/or visibilities are possible within more organized, moderate-in-intensity showers.
There are currently no AIRMETs in effect.

Marine

Weak surface ridging just north of the state will continue to produce moderate trades through tonight. A weak trough is expected to develop just north of the islands this weekend and cause trade winds to ease into the gentle to moderate range with localized sea breezes.
Hurricane Kiko, approximately 1100 NM ESE of Hilo, continues to track west northwest in the Eastern Pacific. The latest forecast from the National Hurricane Center has Kiko possibly entering our coastal waters, as a tropical storm, north of the Big Island or Maui County on Tuesday. Keep a close eye on the future National Hurricane Center forecast track updates as the system approaches.
A small, short period, northwest swell will bring small surf to north facing shores through this weekend. In the extended forecast, additional small northwest swells from distant north pacific disturbances will continue to generate rounds of small surf along north facing shores through mid- next week. Expect a bump in surf along south facing shores to near or slightly above seasonal normals Saturday through early next week as a small to moderate, long period, south southwest swell fills in.
Surf along east facing shores will steadily rise Sunday through early next week as swell energy from Tropical Cyclone Kiko arrives. The surf may approach High Surf Advisory Criteria as early as Monday and possibly breach High Surf Warning levels Tuesday. However, surf heights will be highly depended on the track and intensity of Kiko as it nears the state.
Peak monthly high tides, combined with water levels running higher than predicted, may lead to minor flooding along the shoreline and in low-lying coastal areas. A Coastal Flood Statement remains in effect through Sunday afternoon.

Fire weather

Fire conditions will remain elevated, but remain below critical thresholds, within this dry summertime trade wind weather pattern. Afternoon humidities will briefly fall into the upper 30s to middle 40s under dry, warm conditions. Winds will remain below critical fire weather thresholds with light winds forecast through Sunday. Limited rainfall will occur the next couple of days but humidity should generally begin increasing Sunday and Monday. Rain may likely increase in coverage and intensity over many windward exposures early to mid next week as TC Kiko passes north of the state.

HFO Watches/Warnings/Advisories

None.

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