The last time we had a significant snowfall area-wide was January 7-8. Now, almost exactly a month later, a major winter storm is taking shape which could dump 6"+ for Chicagoland. Two storm systems are approaching... one from the northwest, the other from the southwest. Eventually, the two will merge into another east coast monster, hitting areas from DC northward around midweek. The heaviest snows will be farther north than the last storm which broke records in DC, Philly, Pittsburgh and Baltimore. Before the complete merger, we will taste a partial phasing of the storms. Snow should break out in earnest tomorrow night, and continue at varying intensities into Wednesday morning. The long-duration event will tap into lake moisture which will likely enhance the snowfall, especially late Tuesday. 6"-10" seem highly likely across the board. There is a way out of the heaviest snowfall, if the southern stream Low pressure area robs a big slug of moisture from the northern wave. There is conversely a possibility that the lake could ramp up the snow totals in Cook and Lake Counties to more than a foot. Due to the relative certainty of significant snowfall, a winter storm watch has been hoisted starting late tomorrow night. It will likely be upgraded to a warning or changed to an advisory Monday. Travel will be impacted Tuesday and Wednesday morning as it looks now. Following the storm, arctic air will settle into the region providing a week of cold at least.
Mike
