By mid-February standards, it's a remarkably mild Monday Evening in the Stateline, but the warm temperatures don't come without a cost. In this case, fog's become an issue in much of the area, and it may get worse before it gets better.
The combination of widespread precipitation Monday and milder temperatures allowing for some snowmelt to take place, low-level moisture's abundant in our atmosphere. Relative humidity values over 90% are being noted all over the Stateline, and with generally light winds in place, the environment's ripe for the development of fog.
Visibility has been dropping rapidly as the evening has progressed, falling well under a mile at a myriad of our local reporting stations. Short-range high-resolution forecast models continue to maintain a projection that visibility may drop to 1/4 mile or less over much of the Stateline through the very early hours of our Tuesday.
Shortly after midnight, a cold front will swing through the Stateline, allowing winds to shift to the northwest and to strengthen. As this takes place, drier air will begin to push into the area, and the stronger winds will be an effective mechanism to stir up the atmosphere and thin out the fog. The end result will be a rather rapid improvement in visibility between 2:00 and 4:00 Tuesday Morning.
While a thin veil of fog may still linger beyond sunrise, it remains highly unlikely that it will have any substantial impact on the morning commute.