The light snow system that moved through the upper Midwest last night and today was just the beginning of a very active pattern over the next few days. The arctic airmass that has been modifying the past few days is going to be replaced by a mild and moist flow straight off the Gulf. The result will be a 30-40 degree high temperature jump. NOAA put together an extremely interesting time loop of the spread of the cold air over the country beginning last Saturday.
Chicago received its first official 1+ inch snowfall, 1.1 inches at O'hare. This one inch snowfall broke two snow records. The latest one inch calender day snow in a winter season, and the most consecutive days without a one inch snow. Amazing, the only word that describes this winter season so far, and really back to last winter. The 1.1 inch total was also my total out in the DuPage river valley, my largest snowfall of the season. The snow blower remains untouched!
The graphic shows the GFS model forecast valid Sunday evening, a strong south flow off the Gulf. As the moist mild air runs over the top of the retreating cold air, a broad area of much need precipitation will form. For Chicago, it looks like a brief shot of snow before several hours of sleet and freezing rain Sunday afternoon and evening before surface temperatures warm above freezing. Surfaces will quickly glaze over Sunday afternoon before the rise in the temperature above freezing later on.
Following the warming surge Sunday, highs both Monday and Tuesday will be quite mild. Highs in the 40s on Monday and the 50s on Tuesday. From Monday through Tuesday there will be some occasional periods of drizzle and showers. Much colder air returns to the Midwest by Thursday and into next weekend as the upper level flow again turns northwest to bring down another batch of cold Canadian air.
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