Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 346 PM EST Sun Mar 01 2015 Valid 00Z Mon Mar 02 2015 - 00Z Wed Mar 04 2015 ...Snow and freezing rain expected tonight from parts of Ohio valley to the Northeast... ...Heavy rain possible over portions of the Southwest tonight and Monday... ...Heavy snow possible for portions from the higher elevations of the Southwest to the central Rockies tonight and Monday... ...Heavy snow possible across the Upper Midwest and Great Lakes on Tuesday... Moisture streaming northward over a cold air mass in place today from the Ohio valley to the Mid-Atlantic and Northeast is resulting in widespread wintry precipitation -- including snow, sleet, and freezing rain. An upper-level disturbance will cross the Great Lakes tonight and will cause a low pressure system to develop along a coastal front situated near the Mid-Atlantic coastline. As this low moves northeastward it will bring the potential for some heavy snow to southern portions of New England this evening into tonight. This entire system will move offshore Monday morning bringing an end to widespread wintry precipitation. Scattered snow showers may still be possible across New England through Monday. Rain and a few thunderstorms are also possible tonight from the southern plains to the Tennessee valley. Scattered showers and thunderstorms will persist across these areas through Monday and into Tuesday as a frontal boundary becomes stationary over the region. A Pacific low pressure system is moving into the southwestern U.S. this afternoon and will bring widespread precipitation to much of the Southwest through Monday. Heavy rain is possible western Arizona. At the higher elevations, precipitation will fall as snow -- and heavy snow is possible. The combination of rain and potentially heavy snow will shift eastward on Monday, with widespread precipitation possible across much of the Four Corners region, northward across the central Rockies. As an upper-level disturbance and associated Arctic surface front move southward from Canada into the Rockies and northern plains Monday into Monday night, the low pressure system crossing the Rockies will evolve into a more expansive system across the plains. Widespread snow is forecast to develop Monday night across the Upper Midwest and Upper Great Lakes -- and heavy snow is possible. Please refer to products issued by the WPC Winter Weather Desk for specific details on the winter winter weather threats associated with these systems. Ryan Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php