Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 329 PM EDT Thu Sep 14 2017 Valid 00Z Fri Sep 15 2017 - 00Z Sun Sep 17 2017 ...Heavy rain possible over parts of the Upper Mississippi Valley/Upper Great Lakes and parts of the Northern Plains... ...Heavy wet snow for parts of the highest elevations of the Northern Rockies... Upper-level energy over the Ohio Valley that was once associated with Irma will slowly weaken and move eastward off New England Coast by Friday evening. Showers and thunderstorms will persist this afternoon and through the overnight hours from the Carolina coast to southern New England. Rain showers are expected to develop along a stalled frontal boundary during the day on Friday across the Ohio Valley and east to the Mid-Atlantic region and northward into the Northeast. A low pressure system over the the Central and Northern High Plains will deepen by this weekend as upper-level energy over Southern California will move northeastward. As this energy travels across the Great Basin, Four Corners and Rockies it will trigger showers and thunderstorms today through Friday... with showers and thunderstorms for Southern High Plains through Friday evening. Rain is forecast to spread across the Northern Rockies with snow falling in the higher terrain. Heavy wet snow will be possible over portions of the highest elevations of the Northern Rockies... which will likely expand into lower elevations as the freezing level lowers. Elsewhere, tropical moisture over parts of Florida and the Southeast will aid in developing showers and thunderstorms over the region into the Weekend. Campbell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php