Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 415 PM EDT Wed Sep 11 2013 Valid 00Z Thu Sep 12 2013 - 00Z Sat Sep 14 2013 ...Relief from the recent heat and humidity is in the forecast from the Midwest and Ohio Valley to the Mid-Atlantic and Northeast... ...Strong to severe thunderstorms will be possible from the Great Lakes into New England... ...Heavy showers and thunderstorms will persist over the Southwest...promoting additional concerns for flash flooding... A slow moving upper low over the southwest will bring an extended period of showers and thunderstorms to the region. While the large scale forcing will not be particularly strong, the presence of a short jet streak combined with the approaching mid level vorticity max will be synergistic enough to spark showers and thunderstorms across the Central Rockies/Great Basin through Friday. Precipitately water across the region is above normal and should lead to periods of heavy rainfall. The persistence of this pattern could result in an extended period of rainfall which could lead to flash flooding. A return to mid summer like weather across the lower Great Lakes, Northeast, and Mid Atlantic should be short lived. A slow moving cold front pushing across the Great Lakes will be reinforced with another cold front entering the Northern Plains. The initial cold front will have a tough time making progress into the Northeast today but the secondary front will bring relief from the heat and humidity Thursday evening. Showers and thunderstorms are expected today across the Lower Great Lakes and Northeast, and some could become severe. The severe risk will shift slightly further east tomorrow to New England and the Mid Atlantic with the cold front approaching the region. Elsewhere, moist easterly flow across will bring showers and thunderstorms to the western Gulf Coast and Florida. The Northwest and Northern Plains will remain dry and pleasant. Krekeler Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php