Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 459 AM EDT Sun Jun 09 2013 Valid 12Z Sun Jun 09 2013 - 12Z Tue Jun 11 2013 ...Active and wet weather is expected from the Mississippi Valley to the Atlantic Coast... ...Another day of record breaking heat is in store for the Desert Southwest... An active and wet period is expected from the Mississippi Valley to the Atlantic Coast as an upper trough closes off over the Midwest and progresses eastward towards the Eastern Seaboard. Numerous showers and thunderstorms are expected from the central Gulf coast to the Great Lakes on Sunday...ahead of the associated surface front advancing through the Mississippi Valley. An abundance of moist and unstable air surging northward out of the Gulf of Mexico will allow for some storms to become organized and potentially produce heavy downpours and severe weather...especially over portions of the Middle to Lower Mississippi Valley. On Monday...much of the shower and thunderstorm activity will shift into the Eastern U.S.. Out west...another day of recording breaking heat is in store for the Desert Southwest...and excessive heat warnings remain in effect where daytime temperatures will yet again soar well into triple digits. Conditions should begin to cool on Monday as the upper ridge in place slides eastward and a closed low off the California coast moves inland. In addition to relief from the heat...the upper low could also trigger a few isolated thunderstorms as it lifts northeastward through the Great Basin. Gerhardt Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php