Our very early taste of spring has ended. We are back to more seasonal temperatures for a while as the upper level pattern has switched from a southwest flow to a northwest flow. The winds will bring down colder air from Canada vs the warm air from the Gulf.
While the normal high for Chicago is 31, we just had two days of highs into the lower to middle 50s over the metro area. We also received anywhere from an inch to 1 1/2 inches of precipitation. Very welcome rain with the continuing drought. Much better for our plants and rivers that the precipitation was mostly rain which soaked into the ground vs snow which would have just sat on top for a while.
Last night the warmth ended as a cold front moved through the area. A second area of precipitation moved northeast over the area overnight. This was from a broad upper level trough that turned the upper level winds southwest to bring in the mild air. NWS Chicago has a very nice loop on their web site showing the movement of both the precipitation and the freezing line at the surface.
A mixture of freezing rain, sleet, and a little snow spread over the metro area as the temperature dropped. As I said in my Friday article, the timing of the cold air aloft would determine how much snow fell. It turned out the GFS model was correct with its slower timing vs the WRF-NAM model. The slower change held snow amounts down with only the area roughly from around Woodstock to DeKalb westward receiving from 1/2 to 1 1/2 inches of snow. Details here and here. The NWS graphic shows some of the snowfall.
The coming week will see temperatures more seasonal with highs bouncing around from the upper 20s to upper 30s. Notice nothing real frigid at the time when sub zero readings are not uncommon. Little if any precipitation is expected. Chicago has yet to receive an official 1+ inch snowfall. The record lack of snow continues to grow.
You can follow my articles by clicking on the “Subscribe” link on top.
Comprehensive weather articles and discussion can be found at http://www.storm-central.com