The first wave of the storm system is already affecting southern parts of the St. Louis region, with snow, sleet, and rain falling overnight, while the more substantial storm is expected to impact Wednesday into Wednesday evening, bringing significant impacts on travel and daily activities.

An updated winter weather advisory was issued by the National Weather Service on Monday at 4:33 p.m. valid from Tuesday 7 p.m. until Wednesday 7 a.m. for Lower Bucks.

Storm Watch was expanded this morning to include all of Southeast Michigan starting Wednesday afternoon through Thursday morning. This watch precedes advisories and warning.