The Arctic ridge of high pressure that brought extremely cold conditions to the Central and Eastern U.S. will weaken. As this ridge flattens out, the wind patterns will change to a more westerly orientation. Temperatures will return to seasonable as this cuts off the flow from Canada, but the atmosphere remains dry so precipitation is not likely.
Over the Great Lakes, however, a weak trough of low pressure that skirts across the U.S. and Canadian border will allow for more lake effect snow showers to develop along the downwind shores. Periods of heavy and wet snowfall are likely across western Michigan and the Upper Peninsula, northwestern Pennsylvania, as well as western New York.
Meanwhile, in the South, a cold front slowly moves southeastward from the Gulf of Mexico, but lingers over the southern tip of Florida. This will trigger more scattered rain showers with rainfall totals ranging around an inch.
Out West, a ridge of high pressure dominates over the West Coast and allows for more sunny and dry conditions. A strong low pressure system spinning in the Gulf of Alaska pushes a front toward British Colombia and the Pacific Northwest, bringing increasingly cloudy skies, but does not yet kick up any rain showers.
Temperatures in the Lower 48 states Thursday ranged from a morning low of -32 degrees at Cook, Minn., to a high of 87 degrees at Opa Locka, Fla.
Weather Underground: http://www.wunderground.com
National Weather Service: http://iwin.nws.noaa.gov