Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 420 PM EDT Tue Oct 20 2020 Valid 00Z Wed Oct 21 2020 - 00Z Fri Oct 23 2020 ...Active weather pattern through the middle of the week... ...Elevated Fire Risk continues for northern California... A deepening upper-level trough will generate a range of weather types across the continental U.S. through Thursday. An area of low pressure is forecast to develop in the Midwest tonight along a frontal boundary draped from the Southern Plains into the Northeast. This low is forecast to strengthen and help enhance rain and scattered to isolated thunderstorms along its boundary tonight. It's also forecast to produce snow and mixed precipitation across the Upper Midwest. Rain and thunderstorms should continue across the Lower Great Lakes and interior New England through Wednesday night. The upper-level pattern will amplify over the Northern Rockies on Thursday and strengthen a surface low pressure system over the Central Plains. This dynamic system will produce heavy snow over the northwestern Montana Rockies, and rain/snow across the Northern Rockies/Plains tonight through Wednesday evening before the upper-level amplification occurs and plunges a very cold airmass into the region. This shot of cold air is forecast to be 20-30 degrees below average over the Northern Rockies/Plains which will transition the mixed precipitation to all snow on Thursday. The low will cross into the Upper Midwest on Thursday while continuing to generate heavy snow from the Northern Rockies into the Northern Plains. Rain and scattered thunderstorms are expected to continue along the northern part of the Midwest boundary through Thursday evening. The Critical Threat of Fire Weather continues across northern California through Friday due to the persistence of warm/dry conditions over the region. While temperatures are forecast to be much below average over the northern Rockies/Plains on Thursday, warm air should build across the southern boundary of the low pressure system. This will lead to a swath of much above average temperatures on the order of 15-20 degrees extending from western Texas up and into the Midwest. Meanwhile scattered to isolated thunderstorms should continue across Florida and parts of the Southeast through Thursday. Kebede Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php