The first of four clipper systems moved through the Midwest last night and early today. These clipper systems are forming on a baroclinic zone (temperature contrast zone), that is running from northwest to southeast over the Midwest. Cold arctic air to the northeast and milder Pacific air to the southwest. These small storms systems scoot southeast along the zone, each one producing a relatively narrow band of snow. The graphic shows the 24 hour Midwest snowfall through early morning. Heviest was the lake effect snow over Michigan.
The first one has moved through the greater Chicago metro area. Snowfall amounts were generally from 1.5 to 3 inches over the immediate metro area. A fairly complete list here. The far southwest did receive amounts generally less than an inch. This was the largest general metro area snowfall so far this winter. Remarkable! I received 2.1 inches in the DuPage river valleyh, my largest previous amount was only 1.1 inches which fell last week.
The second clipper will move over the metro area late tonight. This is much weaker than the one last night, and has less moisture so snow amounts will range from only flurries to a very light dusting. No big deal. Temperatures that jumped into the low 20s early morning have already fallen back into the teens mid afternoon. Highs tomorrow will only be near 20 with brisk northwest winds.
The third clipper to affect the metro area will move in late Sunday night into the Monday morning rush. This looks much stronger than clipper number two with more moisture. A very early take would be a possible 2-4 inch accumulation. Again it looks like the far southwest sections will receive less than the immediate metro area. Snow water ratio is expected to be about 16 to 1, this morning's system was about 20 to 1.
The fourth and final clipper will move over the northern Midwest during Tuesday. With a much farther northern track than the previous three, warmer air will be able to move over a much larger area. The metro area Tuesday high in the 20s will jump into the 30s for the rest of the week as milder Pacific air will be over the area. The normal high is now rising, up to 32. By the end of February the normal high is up to 40.
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