Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 348 PM EDT Wed Oct 19 2016 Valid 00Z Thu Oct 20 2016 - 00Z Sat Oct 22 2016 ...Severe thunderstorms and heavy rain possible today across the Mid-Mississippi valley... ...Heavy rain possible on Friday for portions of the Ohio valley and the Northeast... Scattered to widespread showers and thunderstorms will develop along and ahead of a front, spanning from the southern Plains to the Upper Great Lakes through Thursday. The swath of precipitation will mainly be along or east of the Appalachians by Friday morning as the front advances through the eastern third of the U.S. Severe thunderstorms will be possible near the Ozarks Mountains of southern Missouri and northern Arkansas through Thursday morning. Some of the storms may also produce periods of heavy rainfall, which may increase the risk for rapid runoff and flash flooding. For Friday, the best potential for heavy rainfall will likely setup over western Pennsylvania and New York. Accumulations in the Northeast of 2 to 3 inches will be common through Saturday evening - isolated areas of 4 to 5+ will be possible near Lake Erie. The recent warm spell will end as a cooler airmass filters in behind the front. Near seasonal average temperatures will return to the central and eastern states by the weekend. Onshore flow associated with an incoming frontal system is producing rain showers across the Pacific Northwest. The system is forecast to move inland by Thursday and rain will spread east into the Intermountain Region - with snow in the highest elevations. Another round of showers are forecast for the Pacific Northwest region as a second front tracks onshore by Friday morning. The lower elevations of western Washington and Oregon are forecast to have 3-day accumulations of less than 1.5 inches, with 1 to 3 inches in the higher elevations of the Olympics and Cascades. Campbell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php