Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 258 AM EDT Wed Aug 17 2016 Valid 12Z Wed Aug 17 2016 - 12Z Fri Aug 19 2016 ...Heavy rain possible over parts of the Southern Plains... ...Temperatures will be 10 to 15 degrees below average over parts of the Southern Plains into the Lower Mississippi Valley... An axis of tropical moisture along an old boundary over the Southern Plains into the Ohio Valley along with upper-level energy will aid in producing showers and thunderstorms over parts of the Southern Plains into parts of the Ohio Valley through Thursday evening. In addition, daytime heating and moisture rich air extending from the Mid-Atlantic Southward to the Central Gulf Coast and the Southeast will aid in producing showers and thunderstorms over the region during the afternoon into late evening hours on Wednesday and Thursday. Meanwhile, a front over parts of the Northeast into the Mid-Atlantic will move off the coast by late Wednesday night. Showers and thunderstorms will develop along and near the boundary over parts of the Northeast into the Mid-Atlantic on Wednesday morning, ending by Wednesday afternoon till evening. Additionally, upper-level energy over the Upper Mississippi Valley/Great Lakes will move eastward to off the Northeast Coast by Thursday evening. The energy will produce showers and thunderstorms over parts of the Upper Mississippi Valley into the Great Lakes on Wednesday morning that will move eastward to the Northeast by Thursday. A front moving into the Pacific Northwest from Western Canada will move eastward to the Upper Mississippi Valley/Upper Great Lakes and Southward to parts of the Central Plains by Thursday evening into Friday. Showers and thunderstorms will develop along and near the boundary over the Northern High Plains on Wednesday evening that will move to the Upper Mississippi Valley/Central Plains into parts of the Northern Rockies by Thursday evening. Elsewhere, daytime heating and monsoonal moisture will aid in producing showers and thunderstorms over parts of the Southern/Central Rockies and the Southwest into the Eastern Great Basin during the afternoon and evening hours on Wednesday into Thursday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php