Cool temperatures Thursday morning are likely to turn muggy by Friday as Kona winds bring vog and humidity to the state.

The National Weather Service said an approaching weather system northwest of the state will cause the cooling north and east winds to turn southerly, bringing moisture from an earlier front back over the islands.

“This front has the potential of being a wet one. The front’s slow movement eastward once it reaches Kauai Saturday is worrisome for there is the potential for locally heavy showers and flooding,” forecasters said in an advisory.

The front is likely to reach Kauai on Saturday and move down the island chain.

Vog is likely on Oahu and Kauai Friday with a slight chance of showers.

The chance of rain increases Friday night through Sunday.

The front should clear the the state by Monday.