Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 338 AM EDT Sun Oct 18 2020 Valid 12Z Sun Oct 18 2020 - 12Z Tue Oct 20 2020 ...Temperatures will be 10 to 30 degrees below average across the Northern High Plains into the Northern/Central Plains, while temperatures will be 10 to 20 degrees above average from California into the Southwest/Great Basin... ...Poor Air Quality conditions persist across portions of California... ...Frost Advisories extend from Southern New England to the Central/Southern Appalachians... ...Winter Weather Advisories across parts of the Northern Rockies/Northern High Plains... Cold high pressure will move southward from Canada over the Northern High Plains and move southeastward to the Middle Missouri Valley by Sunday evening, then into the Great Lakes by Monday. The high will bring temperature that will be 10 to 30 degrees below average across the Northern High Plains into the Northern/Central Plains. Along the leading edge of the cold air is a cold front that will extend from the Great Lakes southwestward to the Southern High Plains that will move eastward to the Lower Great Lakes to the Lower Mississippi Valley into the Southern Plains by Monday evening. The system will produce rain and snow over parts of the Upper Great Lakes through Sunday night. Snow will develop across parts of the Upper Mississippi Valley into the Central Plains and the Northern Rockies on Sunday. This snow has prompted Winter Weather Advisories across parts of the Northern Rockies/Northern High Plains. The snow will end over the Upper/Middle Mississippi Valley by Sunday evening, while continuing over the parts of the Central Plains and the Northern High Plains through Monday evening. In addition, another front will move onshore over the Pacific Northwest on Sunday evening into Monday. The system will produce rain over the parts of the Pacific Northwest into parts of the Northern Intermountain Region from Sunday into Monday evening. As the storm moves inland, snow and rain will return to the Northern High Plains/Northern Plains overnight Monday into Tuesday. The hot dry weather will provide no big relief to ongoing fires across portions of the West. Air quality issues will persist into early next week in the vicinity of ongoing fire, especially in the Central California Valley region. Furthermore, temperatures will be 10 to 20 degrees above average from California into the Southwest/Great Basin. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php