Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 223 AM EST Wed Nov 06 2019 Valid 12Z Wed Nov 06 2019 - 12Z Fri Nov 08 2019 ...There is a slight risk of excessive rainfall over parts of the Southern Plains into the Lower Mississippi Valley... ...Snow from parts of the Great Lakes to the Northeast... ...Temperatures will be 15 to 25 degrees below average over parts of the Northern High Plains... ...Air Stagnation Advisories over parts of the Pacific Northwest into the Northern Intermountain Region... A front over the Middle Mississippi Valley westward to the parts of the Pacific Northwest will move eastward off the East Coast and southward off the Gulf Coast by Thursday evening into Friday. Moisture from the Western Gulf of Mexico will stream northward over the Southern Plains intersecting the boundary producing showers and thunderstorms over parts of the Southern Plains into parts of the Lower/Middle Mississippi Valley. Rain with these thunderstorms will be heavy at times producing areas of scattered flash floods that will mainly be localized on Wednesday over parts of the Southern Plains into the Lower Mississippi Valley. Light snow will also develop over parts of the Upper Midwest through Wednesday evening producing a hazard of slippery roads. In addition, light snow will also develop over parts of the Upper/Middle Mississippi Valley into the Great Lakes, likewise, producing slippery roads. Overnight Wednesday as the storm moves eastward, rain and snow will move into the Lower Great Lakes and the Ohio Valley and move eastward into the Northeast by Thursday afternoon. The snow will move into parts of the Northern Mid-Atlantic and New England overnight Thursday into Friday morning. The snow will slowly wane on Friday. On Thursday, rain will move into parts of the Ohio/Tennessee Valleys moving into the Central/Southern Appalachians on Thursday evening into Friday. The rain will move into the Southeast overnight Thursday, too. Meanwhile, behind the front cold high pressure will move into the Northern High Plains by Wednesday evening and into the Southern Plains and Upper Midwest by Thursday evening. Temperatures will be 15 to 25 degrees below average over these areas. Air Stagnation Advisories over parts of the Pacific Northwest into the Northern Intermountain Region as upper-level ridging and high pressure builds over the region causing light winds through Friday. Sinking air and light winds will keep pollutants from mixing out over the region. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php