The recent cold spell's been impressive, not only in its magnitude but in its longevity. Including Thursday's 30° high temperature in Rockford, the coldest here in exactly eight months, each of the past 17 days have produced temperatures at or below normal. You'd have to go back to October 21 to find the last time the Stateline had an above normal temperature.
In November's opening week, temperatures are running a mind-boggling 10.1° per day below normal. Such a deficit, if sustained over the remainder of the month, would likely place November, 2019 in the top three coldest on record, dating back to 1906. Another cold day's on tap Friday, with temperatures nearly 20° below normal expected.
A brief shot of Pacific air is to drive temperatures closer to normal, if only for a day, on Saturday, before the next round of Arctic air strikes late Sunday, bringing record or near record-level cold conditions our way for the opening of the next workweek. Temperatures Monday and Tuesday aren't likely to get out of the middle 20s, and, should we lay down even a minimal snowpack before then, those readings may need to be adjusted downward! That's a development worth monitoring.
The chill is projected to ease slowly next week, and there could be more encouraging news beyond then. Long-range projections off of the European Center for Medium-range Weather Forecast's Extended Range Ensemble Prediction System have been advertising a notable pattern shift beyond the middle of the month for some time. That trend appears in the latest run of that forecast model issued Thursday.
The trend illustrated by the model, showing in the animation below, suggests a return of more seasonable temperatures in the days leading up to Thanksgiving. From Thanksgiving on, model projections are honing in on a prolonged period of above normal temperatures for much of the Midwest taking us well into December. It's a trend that's been captured by the past several runs of this long-range ensemble forecast model, which lends increased credibility to the projection.
It's, at the very least, a promising development worth monitoring!