Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 459 AM EDT Wed Mar 11 2015 Valid 12Z Wed Mar 11 2015 - 12Z Fri Mar 13 2015 ...Additional rounds of heavy rains and flash flooding will be possible for the Lower Mississippi Valley... ...Widespread precipitation expected across the Western U.S.... ...Temperatures will remain well above normal over the northern Plains and Upper Mississippi Valley... Showers and thunderstorms will continue to focus along a frontal boundary stretched from the central Gulf coast to the Mid-Atlantic region. High pressure building in over the Great Lakes should gradually press the boundary south and east through the eastern U.S. on Wednesday...and the front and any associated precipitation should push off the Southeast coast by Thursday morning. Farther west...however...persistent southerly flow ahead of an upper trough stuck over the south central U.S. will continue to pump Gulf moisture northward. The anomalous moisture...combined with a surface wave lifting out of the northern Gulf of Mexico...will bring additional rounds of heavy rains and flash flooding across the Lower Mississippi Valley on Thursday. Precipitation will continue to spread inland over the Western U.S. on Wednesday...ahead of a Pacific front approaching the coast. Moderate to heavy rain will be possible along the coastal ranges...but the boundary should dissipate before moving inland...which should keep precipitation totals light over the Intermountain West and northern to central Rockies. An upper ridge sliding in over the north central U.S. will keep temperatures well above normal across the northern Plains and Upper Mississippi Valley Wednesday and Thursday. Gerhardt Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php