So we had snow falling from the sky again today. This has been what feels like an unusually cold spring here in Wisconsin. Looking at the graph from the weather underground, it looks like last month (March) was at or just below the average1 for our neck of the woods - but much cooler than usual just a bit further north and west
Note also that there were warmer than average temperatures for much of the southwest. I find it interesting how much warmer Siberia was at this time (while on the opposite side of the hemisphere, the temperature anomalies were split - both higher and lower than average. Yesterday's strong storm outbreak was impressive, frightening, and a result of these contrasts in warm and cold temperatures. Storms get much of their strength from the contrast between warm and cold air (moisture, temp, pressure, etc). The stronger the contrast, the stronger the storms. I'm not surprised that we have powerful April storms given the big differences in North American temps in March. I am surprised at how quickly and how devastating they were. I'll be very curious to see what the temperature anomalies for April and May are like.
1"Average" in this case is defined as the net total data from 1901-2000. Some "averages" use a 30-year moving window to calculate average temperatures and such.