Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 234 AM EST Fri Nov 20 2020 Valid 12Z Fri Nov 20 2020 - 12Z Sun Nov 22 2020 ...Rain will develop over the Middle Mississippi Valley... ...Warmer than normal temperatures over much of the Eastern U.S... ...Air Stagnation Advisories over parts of Oregon... Weak onshore flow and upper-level energy will aid in producing rain and higher elevation snow over parts of the Pacific Northwest and snow over the Northern Rockies through Saturday morning. The snow will cause hazardous driving conditions. In addition, upper-level ridging will slowly build over the Northwest and with high pressure at the surface the air over parts of Oregon will become stagnant. Air Stagnation Advisories have been posted over parts of Oregon Through Sunday. Meanwhile, a front extending between the Great Lakes and the Southern High Plains will become quasi-stationary from Friday evening to Sunday. Moisture will pool along the boundary aiding in the development of rain with embedded thunderstorms over parts of the Central Plains into the Middle Mississippi Valley overnight Friday into Sunday. Furthermore, a front moving out of Central Canada on Saturday night will aid in producing areas of rain and snow over parts of the Upper Mississippi Valley on late Saturday night into Sunday. The snow will cause hazardous driving conditions. Additionally, from the Plains to the East Coast, temperatures will be mild for late November with temperature ranging between 10 and 15 degrees above average. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php