Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 302 PM EST Sun Dec 27 2020 Valid 00Z Mon Dec 28 2020 - 00Z Wed Dec 30 2020 ...Fast moving low pressure system to produce areas of snow and rain from the Great Lakes to northern New England... ...A strong storm system to track through the Southwest on Monday, then into the Heartland by Tuesday... An area of low pressure is passing through the Midwest with snow falling across parts of the Upper Mississippi Valley. The storm will track through the Great Lakes tonight with several inches possible overnight across the northern Great Lakes. On the southern side of the storm system, spotty showers are set to track across the Lower Great Lakes and Ohio Valley. As the storm advances into southeast Canada on Monday, so will areas of rain and snow showers over the eastern Great Lakes and interior Northeast. Meanwhile, much of the Northeast and Mid-Atlantic will enjoy a brief warm-up with seasonably mild temperatures expected Monday afternoon. However, colder temperatures return Monday night as a cold front swings through the region. The cold temperatures and breezy winds mean there will be lake effect snow showers downwind of the Great Lakes through Tuesday morning. Snow totals under the heaviest lake effect bands could mean 3 to 6 inches of snow with locally higher amounts possible. After the brief rebound of above normal temps in the Northeast on Monday, the cold front ushers in yet another round of below normal temperatures on Tuesday. To the west, the next headlining weather story is a potent upper level trough tracking across the Southwest. Beneficial rain and mountain snow arrives in southern California this evening as a low pressure system slams into the Golden State tonight. Winter Storm Warnings have been posted for the Transverse Ranges and portions of the southern Sierra Nevada where as much of a foot of snow is possible through Monday. In addition, a few thunderstorms are even possible along the coast of Southern California. The storm and its corresponding shield of snow heads east into the the Great Basin and central Rockies on Monday while spotty rain showers dot the Desert Southwest. By Monday night, periods of snow are forecast to blossom over the central High Plains with a larger precipitation shield engulfing much of the Great Plains by Tuesday. The southern half of the Plains can expect scattered showers and thunderstorms while the northern half contends with wintry weather. The latest snowfall forecast through Tuesday evening calls for 4 to 8 inches of snow in parts of central Nebraska and southern South Dakota while light but potentially disruptive freezing rain could lead to over a tenth of an inch of ice accretion. All areas expected to receive measurable snowfall; from southern California to the central Plains, may experience treacherous travel conditions due to wintry weather. Interests in the Upper Mississippi Valley should keep tabs on this storm system as they are likely to receive measurable snowfall Tuesday night and into Wednesday morning. Mullinax Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php