Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 305 AM EST Sat Feb 21 2015 Valid 12Z Sat Feb 21 2015 - 12Z Mon Feb 23 2015 ***Winter storm to affect the eastern U.S. this weekend*** ***Cold front brings more frigid temperatures to northern U.S.*** ***Snow expected from the Rockies to the central Plains*** Arctic air from the Siberian Express (an airmass that originated near Siberia in the Arctic region) that remains over the eastern half of the country and a developing surface low tracking across the Ohio Valley will set the stage for widespread snow and ice on Saturday. A plethora of moisture advecting northward from the Gulf of Mexico will support widespread moderate to occasionally heavy precipitation ahead of the surging warm front. This will expand over portions of the Deep South, Ohio Valley, and eventually towards the Northeast and northern Mid-Atlantic states. The cold and dense air in place over the eastern U.S. will be slow to erode beneath the warm air moving in aloft, leading to widespread wintry precipitation within the northern edge of the precipitation shield. After only a brief warm up late this past week, another arctic boundary dropping down from Canada will reinforce the frigid temperatures for the north central U.S. going into this weekend. In addition to the plunging temperatures and gusty winds, expect light to moderate snow showers along with the blustery conditions. By Sunday and Sunday night, a very strong surface high sliding into the central U.S. behind the cold front should help produce noteworthy upslope snows along the Colorado Rockies and across the adjacent High Plains. A few showers may also try to materialize over parts of California by late Sunday as well. Hamrick Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php