Low pressure will continue to develop over the southern Plains and then head northeastward.  The system looks as if it will come a bit farther north and west than projected yesterday.  That means heavier snow will probably spread farther a little farther west into a good share of the U.P.  It still appears that the heaviest snow will fall over the southeastern half of the U.P. into north-central sections. 

The upper-air chart (500mb) this evening shows a deep trough centered over the Plains (Image 1 above).  At the bottom of the trough over the Texas Panhandle, there’s a brown-colored area with an “X”.  This is the center of the strong disturbance that’s developing the storm.  The low-pressure area develops just to the northeast of that center where the air is rising.  By late tomorrow night, the system is forecast to deepen into a closed upper low over Lower Michigan (Image 2).  This will cause the surface low to really wind up and cause strong winds on its backside.  The low will likely be right near the “X” at that time.  This means snow will spread into the southern U.P. by morning and then spread northeastward.  Snow will become heavy, mainly over the southeastern U.P. 

Accumulations will range from a couple of inches over the far west into the Copper Country, while 6 to 12 inches are likely over the eastern U.P.  Strong north to northeast winds will make for heavy lake-enhanced snow over north-central sections, especially the highlands where up to a foot may fall by Friday morning in the hills around Marquette.  Some enhancement may add to totals in the far west around Ironwood, too.