Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 351 PM EDT Fri May 16 2014 Valid 00Z Sat May 17 2014 - 00Z Mon May 19 2014 ...Heavy rains and the threat for flash flooding will impact the Northeast... ...Temperatures will remain below average across portions of the Midwest... ...Cooling trend will continue in the West... An organized area of heavy rains ahead of a slow moving cold front will lift into the Northeast Friday evening. The sluggish progression of the boundary and rich supply of moisture will cause concerns for flash flooding...especially over the upslope side of New England's terrain. Conditions will quickly dry out and cool off behind the front; However...skies will be slow to clear across northern Maine where the front is expected to stall out and cause continued unsettled weather. A large vortex closed off over the Upper Mississippi Valley and Great Lakes will keep temperatures below normal across a large portion of the Midwest this weekend. Weak impulses rotating around the base of the upper vortex should encourage widespread...but light...shower activity from the Ohio Valley to the Central Appalachians. A piece of energy diving down from Canada will trigger scattered showers and possible thunderstorms across the northern to central Rockies and adjacent High Plains Friday night. As the energy continues on a southeastward track on Saturday...it should streak light to moderate rains to the north of a frontal boundary set up over the Lower Mississippi and Tennessee Valleys. A cooling trend will continue for the Western U.S. while an upper ridge breaks down and a closed low in the northeast Pacific approaches the coast. Light shower activity should begin impacting the Pacific Northwest by early Saturday...and precipitation will become increasingly widespread and heavy as the approaching low inches closer to the coast this weekend. Gerhardt Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php