Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 455 PM EDT Mon May 20 2013 Valid 00Z Tue May 21 2013 - 00Z Thu May 23 2013 ...Widespread severe weather and potential flooding are expected with a cold front moving through the Nation's mid-section... ...Windy and wet conditions are in the forecast for the northwestern corner of the country... ...Scattered showers and thunderstorms will continue over Florida and up into the Mid-Atlantic region... A cold front edging eastward through the Nation's mid-section will continue to be a big weather maker during the short range period. Anomalous amounts of moisture surging northward out of the Gulf...combined with strong dynamics aloft...should help fire up an organized line of convection along/ahead of the boundary. Flooding rains will be possible with this system...and widespread severe weather is expected from the Southern Plains to Upper Midwest/Upper Great Lakes. The greatest threat for severe storms will be from northeast Texas into the Lower/Middle Mississippi Valley...but please refer to the SPC for the latest information on severe weather. Farther north...moisture getting wrapped around the anchoring surface low slowly crossing the Upper Mississippi Valley and moisture overrunning an east-west oriented frontal boundary stretched through the Great Lakes and southern New England should fuel some light to moderate rains with embedded thunderstorms for the next few days. A vigorous upper vortex settling in over the Pacific Northwest will slowly push a cold front inland over the Western U.S.. Moderate Pacific moisture associated with this system will allow for scattered showers across the northwestern corner of the country...and strong winds with the passing cold front should really help enhance amounts along the favored slopes of the terrain. Conditions will be noticeably cooler behind the front...and falling temperatures should lead to snow showers over the Washing/Oregon Cascades by Wednesday morning. In the East...weak energy aloft should keep conditions ripe for scattered showers and thunderstorms over Florida and up into the Mid-Atlantic states. Gerhardt Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php