Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 PM EDT Wed Oct 21 2020 Valid 00Z Thu Oct 22 2020 - 00Z Sat Oct 24 2020 ...Winter weather from Northern Rockies to Upper Midwest through Thursday; rain and thunderstorms across Mississippi/Tennessee/Ohio Valleys through Friday... ...Cold air dives south through Plains while warm air lingers in the east over next two days... ...Fire weather threat continues for northern California while Critical Fire Risk develops over Southern Plains... ...New system enters Pacific Northwest on Friday... A deepening upper level trough will generate much of the weather that occurs over the CONUS over the next couple of days. An area of low pressure currently stationed over the Front Range will organize and begin moving east tomorrow. In the meantime, it will continue producing heavy snow across the Northern Rockies of Montana and the Dakotas. Winter Storm Watches and Warnings are in effect for these areas. Moderate rainfall and scattered to isolated thunderstorms are expected to occur along the associated warm front as it lifts into the Middle to Upper Mississippi Valley/Great Lakes. Snow will shift eastward into the Northern Plains and Upper Midwest tomorrow as the low pressure system moves into the Mississippi Valley. Rain and thunderstorms will follow the cold front as it tracks across the Midwest and Ohio/Tennessee Valleys on Friday. A strong area of high pressure will build over the Rockies behind the aforementioned low pressure system. This will filter in cold continental Canadian air into the Plains over the next two days. Meanwhile warm air will remain to the south of the warm front draped along the midsection of the country and will raise temperatures to 15-20 degrees above average from the Southern Plains to parts of the interior Northeast through Friday. The threat for fire weather continues over northern California as dry/windy conditions are forecast to persist over the next few days. The above average temperatures over the Southern Plains tomorrow will contribute to the Critical Fire Risk for parts of eastern New Mexico and the Texas panhandle through Friday. Another low pressure system will enter the Pacific Northwest on Friday. It will bring with it the threat of heavy snowfall to the Cascades Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php