Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 403 PM EST Tue Nov 17 2015 Valid 00Z Wed Nov 18 2015 - 00Z Fri Nov 20 2015 ...There is a slight risk of severe thunderstorms over parts of the Lower Mississippi Valley... ...Heavy rain possible from the Lower Mississippi Valley to the Southern Appalachians to parts of the Southeast... ...Heavy rain possible over parts of the Cascades... ...Temperatures will be 10 to 20 degrees above average for parts of the Upper Midwest into the Ohio Valley... A storm over the Central Plains will move northward to Northwestern Ontario by Thursday and absorb a low moving eastward along the U. S./Canadian border by late Wednesday night. The system will produce showers and thunderstorms along and ahead of the associated front from the Lower Mississippi Valley to parts of the Upper Mississippi Valley that will retreat to parts of the Southern Ohio Valley/Tennessee Valley and parts of the Southeast/Central Gulf Coast by Wednesday morning. As the boundary move eastward, the showers and thunderstorms will be restricted to parts of the Southeast. Rain will also develop over parts of the Upper Midwest that will expand southward along the boundary into the Ohio Valley by Wednesday and move eastward to the Northern Appalachians/Mid-Atlantic by Thursday morning. In addition, snow will develop over the Central High Plains Tuesday evening into early Wednesday morning. Additional snow will develop over parts of the Upper Mississippi Valley late Wednesday night into Thursday morning. A second front over the Pacific Northwest will move eastward to the Northern High Plains by Wednesday morning. The front will push eastward to the Great Lakes/Ohio Valley and southward to the Southern Plains by Thursday. Additionally, the boundary will reinforce the lead front on Thursday as the associated surface low becomes absorbed into the first storm over South-Central Canada by Thursday. Rain will develop along the Pacific Northwest Coast on Tuesday evening and continue over the area through Thursday due to onshore flow from the Pacific. Snow will develop over parts of the Northern Cascades and the Northern/Central Rockies late Tuesday night into Wednesday, tapering off to snow showers by Thursday morning. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php