Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 500 AM EDT Fri May 03 2013 Valid 12Z Fri May 03 2013 - 12Z Sun May 05 2013 ...The same frontal boundary that piled late season snows over portions of the Midwest will edge eastward and bring a threat of flooding rains to the Lower Mississippi/Tennessee valleys... The same frontal boundary that piled record breaking late season snows over portions of the Midwest and plummeted temperatures across the southern plains will continue to edge its way eastward during the short range period. The northern part of the boundary will remain draped across the upper great lakes and midwest...but an upper low closing off over the lower mississippi valley will help intensify a surface low and push the southern portion of the boundary slowly through the Tennessee valley and southeast. The sluggish progression of the front...combined with plenty of moisture streaming out of the gulf and atlantic...should fuel an organized band of moderate to heavy rains along the front. Flooding and flash flooding will be a concern with this system...especially as it dumps rain on the already swollen rivers of the Mississippi. The threat for any significant winter precipitation will diminish early on Friday...however...conditions should be cold enough underneath the closed low to produce some impressive late season snowfall over western Missouri and northwest Arkansas. In addition...temperatures behind this system should remain below normal through the weekend. While rainfall totals add up over the Mississippi and Tennessee valleys...portions of the sunshine state will also see a soaking during the short range period. A weak surface wave exiting the eastern Gulf of Mexico and crossing into the Atlantic should continue to produce showers and thunderstorms over much of Florida. Elsewhere across the nation...strong high pressure nosing down into the Northeast and Mid-Atlantic states should keep precipitation from creeping into the region. Out west...a cold front dropping through the northern plains and northern/central rockies will trigger some light shower activity friday and saturday. Snow will be possible...but should be confined to the higher elevations. Gerhardt Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php