With a frigid Arctic high pressure air mass overhead, this past Chicago weekend saw Saturday-Sunday temperatures 16 and 17-degrees below average respectively – so cold that it was 4 to 5-degrees below average even for our climatologically coldest day in mid-January. A reinforcing cold front will pass through from the northwest later Monday preceded by a band of snow that could end up covering the ground and creating numerous slick spots over much of the metro area.
The leading edge of another Artic high pressure will follow Monday night as winds turn northerly and temperatures will again begin to fall. Northerly flow of very cold air the length of Lake Michigan will establish a lake-effect snow event across northwest Indiana into southwest Lower Michigan – in fact the Illinois shoreline of Lake Michigan could also be impacted, if the wind direction varies ever-so-slightly more to the northeast.
With the blustery north winds creating snow showers and steering another shot of mid-January-like cold into this area, temperatures Tuesday will be lucky to warm much above the 30-degree mark. The core of coldest air settles over the Midwest and western Great Lakes Wednesday – and even with abundant sunshine, highs here will probably be very similar to those experienced this past weekend – in the middle 20s.
Finally the steering upper air jet stream flow will gradually shift from northwest to a more west-east orientation Thursday-Friday, allowing a low-level southerly wind flow – albeit on the weak side – to return. We might even observe normal or slightly above normal readings in the lower to middle 40s this next weekend.
The winter storm in the southern U.S. continues to bring a mixture of rain, freezing rain, sleet and snow to those states in its path. After hitting Texas, Oklahoma and Louisiana Sunday – the wintery precipitation was headed for Arkansas, Tennessee and portions of states just to the south Monday. The storm system was expected to make a turn north up the east coast starting Tuesday.