Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 315 AM EDT Thu Sep 29 2016 Valid 12Z Thu Sep 29 2016 - 12Z Sat Oct 01 2016 ...Heavy rain expected across the Mid-Atlantic region and central Appalachians... ...Scattered showers and thunderstorms will be possible over the Southwest and southern Rockies... The biggest weather story across the continental U.S. through the end of the week will be a large upper level low that is forecast to track slowly across the Ohio Valley and meander there for a while. Cool conditions and numerous showers are expected in the vicinity of this low with an unstable atmosphere in place. It will certainly feel like fall across these areas. The heaviest rain associated with this disturbance will be well to the east across the central Appalachians and the Mid-Atlantic region. Through Friday morning, a strong surge of deep Atlantic moisture wrapping northwestward into this system will continue to produce a heavy rain event from North Carolina to Pennsylvania as it interacts with a surface boundary lingering over the region. Rainfall totals within this moisture plume are expected to be on the order of 3 to 6 inches. Higher totals will be possible for some areas, especially where heavy showers and thunderstorm activity develop repeatedly over the same areas, and this could lead to flooding issues. Flash flood watches are in effect for many of these areas. Elsewhere across the nation, conditions will be mostly sunny and pleasant across much of the central U.S. and extending westward towards the northern Rocky Mountains with surface high pressure governing the weather pattern. Across the western U.S., modest moisture combined with weak shortwave energy aloft should support the development of afternoon showers and thunderstorms over portions of the Southwest and southern Rockies through Friday. Hamrick Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php