Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 422 PM EDT Thu Oct 22 2020 Valid 00Z Fri Oct 23 2020 - 00Z Sun Oct 25 2020 ...Winter weather in Upper Midwest tonight, then across Pacific Northwest/Northern Rockies into weekend; rain and thunderstorms across Mississippi/Tennessee/Ohio Valleys... ...There is a Slight Risk of severe thunderstorms over the Middle/Upper Mississippi Valley; there is a Slight Risk of excessive rainfall over parts of the Upper Midwest/Great Lakes... ...Cold air dives south through Plains while warm air lingers in the East... ...Critical Fire Risk will be over parts of Northern California and over Southern Rockies/High Plains... An area of low pressure, currently traversing the Mississippi Valley, will be the impetus for rain and thunderstorms over points east of the Mississippi River through the beginning of the weekend. This low pressure system will produce potentially heavy snowfall in its cold sector over the Upper Midwest tonight. Winter Storm Warnings and Advisories are in effect for the Northern Plains and Upper Midwest. This system will also generate potentially heavy rainfall leading to a Slight Risk of flash flooding over eastern Iowa and into Lake Michigan, as well as a Slight Risk of severe thunderstorms over the Middle-Upper Mississippi Valleys tonight. Winter weather will end over the Upper Midwest tomorrow morning, while rain and thunderstorms will continue across the Mississippi, Tennessee and Ohio Valleys before losing much of its moisture component Friday night. Record warmth is forecast for tonight as the rising warm front keeps low temperatures in the 50s and 60s across parts of the Lower Mississippi Valley, Midwest and Northeast. High pressure will continue to build steadily over the Northern Rockies and Great Plains behind the aforementioned low pressures system this weekend. This will drive cold continental Canadian air down into the Plains over the next couple of days. High temperatures will be between 15-20 degrees below average for much of the Plains and Northern Rockies with some isolated areas seeing temperatures fall to 25-30 degrees below average over this period. Freeze warnings are in effect over parts of the Central Plains as a result. Another potent disturbance will enter the Pacific Northwest tonight producing low-elevation rain and high-elevation snow to the Cascades and Northern Rockies tomorrow and Saturday. Another strong area of high pressure is likely to build in behind this system into the beginning of next week, bringing with it, once again, the chance for much below average temperatures to the Plains. The threat for fire weather continues across northern California and the Southern Plains tonight as warm, dry and/or gusty conditions contribute to the Critical Risks in those areas. An elevated risk of fire weather lingers over northern California tomorrow. Kebede Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php