Severe Weather potential over parts of the Upper Great Lakes tonight...Heavy to Excessive Rainfall possible over portions of the Southeast andMid-Atlantic.Unsettled weather returns to the Northwest on Wednesday.Heavy snow and blizzard conditions associated with a deep mid-latitudecyclone that impacted the Northern/Central Plains and Upper Midwest thepast few days has ended, but some lingering mainly light snows maycontinue into tonight across parts of the Upper Great Lakes. Behind theassociated cold front, a chilly airmass will continue to spread across theGreat Plains and Midwest into Wednesday. The greatest anomalies onWednesday will be across the Northern Plains/Upper Midwest where daytimehighs 15-25 degrees below average are possible, with temperaturesmoderating thereafter.Widespread showers and thunderstorms are expected to accompany the abovementioned cold front through Thursday as it slowly progresses through theMidwest and East Coast states. Into this evening, the Storm PredictionCenter highlights portions of southern Michigan into Indiana and Ohiowithin a slight risk (level 2/5) of Severe Thunderstorms. On Wednesday,the heaviest rains are expected across parts of north Florida and into theSoutheast as additional moisture gets pulled northward due to a secondwavy front and developing surface low where WPC has a slight risk forexcessive rainfall. Showers and storms will continue across the Northeastinto Thursday, though heaviest rainfall should be confined across portionsof the Carolinas and the DelMarVa, and up the Northeast Coast posing amainly localized flash flood threat.Unsettled weather will continue across the Northwest during the shortrange, with low elevation rain and mountain snows. Favorable upsloperegions may have the greatest threat for heavy to excessive rainfall,particularly across southwest Oregon/northwest California on Wednesday.Accumulating snowfall is possible particularly across the highestelevations of the Cascades, Sierra Nevada, and into the northern Rockies.