Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 351 PM EDT Thu Oct 12 2017 Valid 00Z Fri Oct 13 2017 - 00Z Sun Oct 15 2017 ...Moderate snow over parts of the Cascades and the Northern Rockies ... ...Heavy rain possible over parts of Upper Midwest... ...Severe thunderstorms possible over Central Plains and Midwest... A low pressure system associated cold front will be slow to move through the central U.S. as it will be sandwiched between high pressure over the East and over the West. Moisture will stream northward over the next few days and pool near the front; which, will help generate showers and thunderstorms along the boundary from Oklahoma to the Great Lakes region. The axis of higher rainfall amounts is forecast from eastern Iowa to lower Michigan. Periods of heavy rainfall is expected over the area on Sunday therefore there is a slight risk for excessive rainfall and flash flooding conditions. A cold front will push offshore the Mid-Atlantic coast today but will become mostly stationary by tonight as high pressure expands further south. Onshore flow from the Atlantic will develop over parts of the Northern Mid-Atlantic and move into the Southern Mid-Atlantic by this evening and continuing into Friday evening. This will result in light rain and drizzle. In addition, upper-level energy and easterly flow off the Atlantic will aid in producing showers and thunderstorms over the Florida peninsula into Friday. Rain and higher elevation snow across portions of the Pacific Northwest and Intermountain West will continue with the onshore flow through Friday night... persisting over the Northern Rockies into Saturday. Heavy snow will be possible in the higher elevations of Oregon, Washington and Idaho through Saturday afternoon before decreasing in intensity. Whereas snow and Heavy snow will begin to taper off over parts of Montana and Wyoming during overnight hours/very early Sunday morning. Campbell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php