Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 450 AM EDT Sat Jun 15 2013 Valid 12Z Sat Jun 15 2013 - 12Z Mon Jun 17 2013 ...Severe weather and flash flooding will be possible across the Central Plains/Middle Mississippi valley on Saturday... ...Unsettled conditions are expected to spread into the northeastern states by later in the weekend... The key feature affecting the country this weekend is an elongated trof extending from the Big Bend of Texas up through the remainder of the Southern/Central Plains. Slow moving impulses within this upper trof will continue to fuel episodes of locally heavy rainfall given the deep-layered moisture feeding in from the Gulf of Mexico. Much of the activity should pick up in intensity during the peak diurnal heating which will lead to numerous showers and thunderstorms. While these storms are discrete in nature, expect episodes of severe weather anywhere from the Front Range of the Rockies eastward through the Central Plains and into the Middle Mississippi valley. As the cells begin to merge during the evening hours, the threat should shift over to more of a flash flooding issue given slow/negligible storm motions. Such an evolution is similarly expected for Sunday although the focus will shift toward the Oklahoma/Kansas border. The beginning of the weekend should be rather tranquil across much of the eastern states as a broad surface anticyclone builds over the region. Ideal radiational cooling effects are underway overnight as lows have plunged well into the 50s with even some pockets of 40s in New England. While Saturday should be a pleasant day for much of the Eastern Seaboard, conditions should slowly deteriorate as the mid-level impulses from the center of the U.S. shift toward the Ohio valley and Mid-Atlantic. Expect showers and thunderstorms to be more commonplace across the Northeast for Sunday with the impacts continuing into Monday. Looking further south, a frontal zone which has nearly stalled along the Gulf Coast should continue to be a focus for scattered convection during the weekend. The thunderstorm activity will peak during the afternoon/evening hours given sufficient solar insolation before waning into the overnight hours. Rubin-Oster Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php