West Kaua’i

Tonight: Mostly clear. Isolated showers after midnight. Lows 70 to 75 near the shore to around 61 above 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Friday: Sunny with isolated showers. Highs 86 to 92 near the shore to around 78 above 3000 feet. East winds up to 15 mph shifting to the south in the afternoon. Chance of rain 20 percent.

Friday Night: Mostly clear. Isolated showers in the evening. Lows 70 to 75 near the shore to around 62 above 3000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.

South Kaua’i

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows around 74. Northeast winds 10 to 15 mph. Chance of rain 40 percent.

Friday: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 83 to 91. East winds 10 to 15 mph. Chance of rain 40 percent.

Friday Night: Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows around 73. Northeast winds 10 to 15 mph. Chance of rain 30 percent.

Kaua’i Mountains

Tonight: Mostly cloudy with scattered showers. Lows 64 to 70 in the valleys to around 59 above 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Friday: Partly sunny with scattered showers. Highs 77 to 85 in the valleys to around 68 above 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Friday Night: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows 64 to 70 in the valleys to around 59 above 4000 feet. East winds up to 10 mph. Chance of rain 40 percent.

North Kaua’i

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 65 to 74. East winds up to 15 mph. Chance of rain 40 percent.

Friday: Mostly sunny with isolated showers. Highs 79 to 88. East winds up to 10 mph. Chance of rain 20 percent.

Friday Night: Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows 65 to 74. East winds up to 10 mph. Chance of rain 40 percent.

East Kaua’i

Tonight: Partly cloudy with isolated showers in the evening, then mostly cloudy with scattered showers after midnight. Lows 65 to 78. Northeast winds up to 10 mph. Chance of rain 50 percent.

Friday: Mostly sunny with scattered showers. Highs 76 to 88. East winds up to 10 mph. Chance of rain 50 percent.

Friday Night: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows 65 to 77. Northeast winds up to 10 mph. Chance of rain 40 percent.

Detailed Forecast

Synopsis

Light to moderate trade winds can be expected through the weekend as weak ridging remains north of the islands. A normally dry summertime shower pattern can be expected for the next few days until Sunday when an area of enhanced trade wind moisture moves through. After that, uncertainty remains elevated regarding potential impacts from Hurricane Kiko, but thus far, increased showers are expected statewide.

Discussion

A dry and stable summertime trade wind pattern is currently in place supported by mid level ridging and a 1021 mb high to the northeast. Satellite and radar data from this morning showed partly cloudy skies with a few showers moving through the area on the trade winds. This pattern will continue through the weekend with periods of showers impacting mainly windward and mountain areas, as well as favoring the night time and early morning hours. Winds will remain moderate and then local sea/land breezes can be expected by Saturday as trade winds weaken slightly. The strong mid level ridging which is currently inhibiting shower intensity is forecast to gradually weaken beginning Saturday evening as an upper level low to the far north of the islands becomes cut off from the jet stream and moves south towards the islands. As stability gradually decreases due to the upper low, a mid level trough with enhanced moisture looks to move through the islands Sunday afternoon through Sunday evening, enhancing trade wind showers.
Following the passage of the mid level trough and its associated moisture on Sunday night, uncertainty in the important forecast details remains high due to the evolution of Hurricane Kiko. Currently, it looks like a band of dry air will fill in on Monday before moisture associated with Hurricane Kiko fills in from the east on Monday night. The NHC is currently forecasting Kiko to pass just north of the Big Island as a Tropical Storm on Tuesday. Kiko's wind field is forecast to stay mostly confined to the northern half of the center. Statewide, flash flooding is a possibility, conditional on Kiko's track, intensity, and its interaction with the upper level low that is expected to remain in the area through much of next week. At a minimum, increased showers are expected through much of next week. Additional details are forthcoming as forecast confidence increases; for official forecasts regarding Hurricane Kiko, refer to the National Hurricane Center.

Aviation

Moderate trade winds will prevail over the island chain throughout the next several days, and will continue to become lighter by Friday night into the weekend. Although brief periods of low clouds and showers will be possible over windward slopes during the overnight hours, VFR conditions will prevail throughout the forecast period at most locations. Only brief MVFR ceilings and visibilities will be possible within any showers that do form.
There are currently no AIRMETs in effect, and none are anticipated through tonight.

Marine

A weak surface ridge just north of the state will remain nearly stationary through Friday and will maintain moderate trade winds. A weak trough is expected to develop just north of the ridge over the weekend and will cause the winds to decrease to gentle to moderate speeds with localized sea breezes.
Hurricane Kiko, approximately 1400 ESE of Hilo, continues to track westward in the Eastern Pacific, and is forecasted to move into our offshore waters as a Tropical Storm Monday night. Tropical Storm conditions are possible over the offshore waters starting Monday and could linger through the middle of the week as it tracks west-northward. As far as our coastal waters, the latest forecast from the National Hurricane Center has Kiko centered very close to the Big Island Windward waters on Tuesday. Although it is too early for any specifics, Tropical Storm conditions will be possible around the Big Island waters as early as Monday.
Surf along north facing shores will remain tiny to small over the next few days as reinforcing small short-period north-northwest swells are expected. In the extended forecast, the northwest Pacific looks to get active as low pressure systems traverse the basin over the weekend sending the potential for a few small to moderate northwest swells during the middle of next week. Surf along south facing shores will see background energy through the week before a small to moderate long-period south-southwest swell fills in and peaks over the weekend. Below average surf is expected to continue along east facing shores through the rest of the week. In the extended forecast, easterly energy from Tropical Cyclone Kiko is possible as early as this weekend. This will bring the potential for surf to reach High Surf Advisory criteria as early as Sunday or Monday. Warning level surf will be possible as Kiko moves closer to the Hawaiian Islands on Tuesday. Surf heights for Tuesday will be highly dependent 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

Typical dry summertime trade wind conditions will remain in place through the next few days, keeping fire weather conditions elevated, but below critical thresholds. By Sunday afternoon, a passing trough could bring some increased moisture, elevating relative humidities before drying out again on Monday. By Monday night, moisture associated with Hurricane Kiko will start to fill in and depending on the track and intensity, could significantly lower fire weather conditions.

HFO Watches/Warnings/Advisories

None.

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