Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 405 AM EDT Tue Jul 19 2016 Valid 12Z Tue Jul 19 2016 - 12Z Thu Jul 21 2016 ...Heavy rain possible over parts of the Western Ohio Valley into parts of the Upper Mississippi Valley... ...Heavy rain possible over parts of the Carolina Coast... A front extending from the Mid-Atlantic Coast across the Southern Ohio Valley to the Middle Mississippi Valley will move southeastward to Southern Carolina/Georgia while the western portion of the boundary dissipates by Wednesday evening. Showers and thunderstorms will develop along and ahead of the front from parts of the Mid-Atlantic to the Western Ohio Valley that will sink southeastward to the Southeast by Wednesday. In addition, moisture rich air over the Gulf Coast States and daytime heating will aid in producing showers and thunderstorms along the Gulf Coast with a maximum in areal coverage during the afternoon and evening hours on Tuesday and Wednesday. Meanwhile, a wave of low pressure over the Northern High Plains will move eastward to the Northern Plains by Wednesday evening into Thursday. The system will produce showers and thunderstorms over parts of the Northern High Plains southeastward to parts of the Central Plains that will move into the Upper/Middle Mississippi Valley by Tuesday evening. The showers and thunderstorms will expand into parts of the Upper Great Lakes on Wednesday. Additionally, upper-level energy circulating around a deep upper-level low just off the Northwest Coast will aid in triggering showers and thunderstorms over parts of the Pacific Northwest on Tuesday afternoon and evening, ending overnight Tuesday. Elsewhere, monsoonal moisture and daytime heating will aid in producing showers and thunderstorms over parts of the Southwest/Eastern Great Basin and parts of the Central/Southern Rockies on Tuesday and Wednesday afternoon and evening. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php