Some areas of northern Wisconsin, the Upper Peninsula of Michigan, and Minnesota have over half a foot of snow on the ground! In fact, a wide swath of real estate across southern Canada and the extreme northern United States is covered with snow. That can and often does have an effect on our weather in Rockford and across the Stateline.
If the predominant jet stream pattern is out of the northwest, the cold 32°F snowpack can have an impact on the airmass and temperatures downstream. Surface winds will blow across the snow-covered land, modifying temperatures (in this case, enhancing the cold). The opposite is true if the jet stream pattern flows over areas of land without any snow cover. Sunday will be a prime example of this. With a predominately westerly wind over the snow-free central Great Plains, our air temperature will warm to near normal (lower 40s).
On Monday, a center of high pressure will slide south out of the northern Great Plains, through Iowa, and eventually into Missouri. Since the flow of wind is always clockwise around high pressure, our wind in northern Illinois and southern Wisconsin will be out of the north-northwest (originating from the cold and snowy north). Not surprisingly, our high temperature will struggle to reach freezing!
Posted under cold blast, snow, weather, Wind
This post was written by Joe Astolfi on November 24, 2012