Good Tuesday morning all! A wintry ****tail of precipitation ranging from rain to sleet and snow has switched to heavy snow. The 2nd winter storm to affect the area in less than a week is responsible--and things are likely to get worse before they get better. The storm is larger and windier than last Thursday night's storm and has produced as much as 5.3" at Versailles, IL--3" of which came down in 30 minutes as a result of thundersnow. We're predicting 3 to 7" by the time snow eases to lighter more occasional snow later tonight. Some of our models suggest locally heavier totals. Visibilities at 12 noon Tue have plunged to 1/4 mile in heavy snow at Auroa, Bartlett, Morris and 1/2 mile at DeKalb and 3/4 mile at O'Hare and Midway. Our WeatherBug cameras have shown dramatic deterioration in the weather as a mix of ice pellets and freezing rain have transitioned to heavy snow. The transition has been nicely handled by our in-house RPM model. Here's that model's snowfall forecast.