Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 443 AM EDT Sat Jul 27 2013 Valid 12Z Sat Jul 27 2013 - 12Z Mon Jul 29 2013 ...Unseasonably cool conditions will continue across the eastern half of the Country... ...Showers and thunderstorms will be possible from the Gulf Coast to the Great Lakes and Northeast this weekend... ...Heavy rains and flash flooding will become a threat over the Central Plains... Unseasonably cool conditions will continue over the eastern half of the Nation this weekend as an expansive upper vortex slowly spins through the Great Lakes. New record low temperatures have already been set...and a strong cold front pushing out of the Midwest and towards the Appalachians will bring another reinforcing shot of cool Canadian air into the Eastern U.S.. Along and ahead of the cold front...scattered showers and thunderstorms will be possible from the Gulf Coast states to the Great Lakes and Northeast. The best chance for any organized areas of storms and heavy rains will be across the Lower Mississippi Valley on Saturday as potent energy streaks through aloft and helps enhance rainfall rates. Locations along the Appalachians could also see higher precipitation totals...where moisture surging northward should fuel some moderate to heavy rains. The tail end of the strong cold front pushing through the Eastern U.S. should stall out and linger near the Oklahoma/Texas border this weekend. Convection is expected to break out to the north of the boundary...and as moisture/instability quickly increase across the region...developing storms will become capable of producing severe weather and heavy downpours. Please refer to the Storm Prediction Center for the latest information on severe weather. Widespread showers and thunderstorms will continue across the Southwest...Central Great Basin...and Northern/Southern Rockies this weekend...especially during the peak heating hours of the late afternoon/early evening. Farther north...a cold front dropping southeastward out of Canada will lower temperatures across the northwestern corner of the Country. Towards the later half of the weekend...the front should push out of the Rockies and trigger some scattered convection while crossing the Northern Plains. Gerhardt Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php