Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 356 PM EST Thu Feb 20 2014 Valid 00Z Fri Feb 21 2014 - 00Z Sun Feb 23 2014 ...A rapidly deepening cyclone over the Central U.S. will carry a threat of flash flooding...severe storms...ice accumulations...and blizzard conditions... A surface low tracking through the Middle Mississippi Valley is expected to rapidly deepen while it lifts through the Upper Great Lakes and into Ontario Thursday night into Friday. A wide band of moderate to heavy snows will continue to develop to the northwest of the low...and the snow will combine with strong and gusty winds surrounding the intensifying storm to create potential blizzard conditions over portions of the Upper Midwest. Temperatures will soar well above normal with the cyclone's warm front expected to surge northward through the Ohio Valley and Mid-Atlantic states. However...freezing rain will be a concern within precipitation developing to the north of the boundary...where warm air will be overrunning sub freezing surface temperatures. Finally...a strong cold front trailing from the deepening low is expected to trigger a solid line of organized convection while it marches across the Midwest...Tennessee Valley...and Lower Mississippi Valley Thursday evening and then pushes through the eastern third of the Nation on Friday. An abundance of moisture and instability along the boundary will make severe weather and heavy downpours a concern within the developing convection. Widespread shower activity will continue with a weakening Pacific system moving inland from the Pacific Northwest to the Northern/Central Rockies Thursday night into Friday. A decreasing moisture supply should keep precipitation light...and any snowfall accumulations will be confined to the higher elevations. Elsewhere...strong high pressure nosing down from western Canada will spread a fresh supply of Arctic into the northern tier of the Country this weekend. Gerhardt Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php