The first of two storms systems this week is slowly pulling out of the Midwest. During Monday most of the Midwest was on the mild spring side of the system with highs jumping into the 40s north to the 60s south. The graphic from the MRCC shows the temperatures. Today is just the opposite with temperatures only in the teens north and 20s south.
For the Chicago metro area conditions certainly have rapidly varied over the last 24 hours. From Monday morning sun, to midday highs in the low 50s, to evening rain, and then a light dusting of snow with temperatures dropping into the teens. The official high was 52 at O'hare at 12:53 p.m. CST yesterday. Today at the same time it was 15, a 37 degree drop. The normal high for the two days is 36. .
After two chilly days, today and Wednesday, Thursday will start to moderate as the second storm of the week approaches. The first storms system over southeast Canada will actually act as a block to the second storm. It will be forced to move well west of the metro area. The surface low Friday morning will be over eastern Iowa with the strong upper level dynamics over the Plains. This is where the heaviest snow will fall with local amounts of 18+ inches expected over part of Kansas.
For the metro area, warm advection snow will move in Thursday night after the rush, and turn into a little freezing drizzle by Friday morning. As the system moves through the area the upper dynamics will weaken some so snowfall amounts will not be very heavy, several inches across the area with heaviest west and least southeast. With the surface low moving west of the area during Friday, temperatures will rise above freezing to melt some of the snow and any slight glazing from the freezing drizzle.
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