Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 411 AM EDT Wed Sep 13 2017 Valid 12Z Wed Sep 13 2017 - 12Z Fri Sep 15 2017 ...Wet snow possible over parts of the highest elevation of the Northern Rockies Thursday evening into Friday... ...Temperatures will 10 to 15 degrees below average over parts of the Tennessee and Ohio Valleys... Low pressure over the Middle Mississippi Valley will slowly wind down and move to the Western Ohio Valley while dissipating by Thursday afternoon. Rain will develop over parts of the Ohio/Tennessee Valleys that will move into parts of the Central/Southern Appalachians by Thursday evening. Moisture will flow off the Atlantic over parts of the Mid-Atlantic and aid in developing showers and thunderstorms over parts of the area that will move into parts of the Northern Mid-Atlantic Coast by Wednesday evening. Upper-level energy once associated with Irma will move over parts of the Northeast on Thursday into Thursday evening. The energy will aid in producing showers and thunderstorms over parts of the Northeast on Thursday. Meanwhile, tropical moisture will slowly creep northward over the Florida peninsula that will move into parts of the Southeast by Wednesday evening. The moisture will move off the Southeast Coast by Thursday morning. Showers and thunderstorms will develop over parts of the southern peninsula of Florida on Wednesday that will continue over parts of the Southern Florida through Thursday evening. In addition, showers and thunderstorms will develop over parts of the Southeast by Wednesday afternoon that will move off the Southeast Coast by Thursday morning. Additionally, a quasi-stationary front extending from the Upper Mississippi Valley into the Northern/Central Plains then into parts of the Northern High Plains/Great Basin will aid in developing showers and thunderstorms over parts of the Northern/Central Plains on Wednesday that will end by Wednesday evening. Showers and thunderstorms will also develop over parts of the Northern Rockies/Northern High Plains by Wednesday afternoon that will move into parts of the Northern/Central Plains and the Upper Mississippi Valley by Thursday morning continuing over the region through Thursday evening. An upper-level troughing will move into the Northern Rockies on Thursday into Thursday evening. Rain will develop over parts of the Northern Rockies overnight Wednesday and continue into Thursday evening. On Thursday evening, wet snow will develop over parts of the highest elevations of the Northern Rockies. Furthermore, an upper-level low moving onshore over Central California will move inland while weakening to parts of the Southwest/Great Basin by Thursday evening. Circulation around the upper-level low will aid in pulling moisture off the Gulf of California/Pacific into parts of the Southwest that will weaken by Thursday afternoon. The moisture and the energy will aid in producing showers and thunderstorms over parts of Central California into parts of the Great Basin/Southwest and parts of the Southern/Central Rockies through Thursday evening. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php