Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 358 PM EST Fri Jan 02 2015 Valid 00Z Sat Jan 03 2015 - 00Z Mon Jan 05 2015 ...A winter storm will impact the Southern High Plains to the Midwest/Great Lakes and Northeast... ...Heavy rains to affect the Lower Mississippi Valley...Tennessee Valley and Ohio Valley... An upper level low pressure system beginning to move east into New Mexico will slowly advance east and should move out into the Southern and Central Plains through Saturday. This energy should then weaken and shear northeast through the Great Lakes region on Sunday as a stronger upper trough begins to advance south from Canada. The energy ejecting out of the Southwest will result in a fairly significant multi-day winter storm that will drive a large area of snow and especially sleet and freezing rain from the Southern High Plains northeast to the Midwest and then spreading through the Great Lakes and interior portions of the Northeast this weekend. Low pressure forming over the Lower Mississippi Valley early Saturday will allow a significant surge of Gulf of Mexico moisture to stream north and overrun much of the Gulf Coast states and into the Tennessee and Ohio Valleys. This should foster a widespread area of moderate to heavy rain along with embedded thunderstorms. Some of the rainfall may be heavy enough to cause some localized runoff problems. On Sunday, this area of low pressure will move into southeast Canada, and will drive a cold front offshore the East Coast. Much milder air will be impacting the eastern seaboard on Sunday ahead of the cold front. In behind the aforementioned storm system developing over the South and impacting the East, a new surge of arctic air will impact the Northern High Plains beginning Saturday and then surge south and east through the Central Plains and Midwest through Sunday. The next surge of arctic air will yield sub-zero temperatures, especially for the Northern Plains, and strong winds that will foster dangerously cold wind chills. This cold air banking up against the higher terrain of the Northern Rockies and will help also foster a new round of upslope snowfall which will spread out into the High Plains. Gradually this cold air will filter into the East by the early next week in a modified fashion along with a return to drier weather. Orrison Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php