The National Weather Service said visibility may be a quarter-mile or less, with sudden and big changes in visibility possible Wednesday evening.
Drivers are urged to slow down, use low beam headlines and leave plenty of distance ahead of your car in case a sudden stop is needed.
Occasional rain will continue to fall, mainly before 11 p.m., with temperatures dropping to the mid-40s.
Thursday should be partly sunny, with a high near 50 degrees and northwest winds of 6 to 15 mph, with gusts as high as 28 mph.
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