Vog is expected to creep over all islands Friday as a weather system approaches from the northwest, National Weather Service forecasters say.

The cold front is expected to reach the islands over the weekend, bringing some scattered showers to Oahu starting Saturday into the early part of next week.

The cooling trade winds have already started to shift today, becoming light and variable and creating muggy Kona weather conditions. Forecasters say there’s a possibility of afternoon showers today over leeward areas.

By Friday, southerly winds should blow vog over the western islands making for hazy skies.

The trade winds may not return until later next week.