Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 252 AM EST Tue Dec 22 2020 Valid 12Z Tue Dec 22 2020 - 12Z Thu Dec 24 2020 ...A low pressure system will track across the northern tier of the U.S. and spread precipitation and gusty winds from west to east through Thursday... A surface low pressure system currently moving across the Northwest is forecast to track eastward into the Northern Plains today and into the Midwest on Wednesday, spreading a variety of weather and hazards to the CONUS. First, snow is likely across the Northwest toward the Northern Plains today, and higher elevations of the Northern/Central Rockies could see several inches of snow. Tonight, winds are expected to ramp up given the strength of the surface low, and High Wind Watches are in place across northern and central portions of the High Plains. By Wednesday, snow is likely for the Upper Midwest and toward the Upper Great Lakes region just behind the low. Accumulations of several inches are expected for northern Minnesota, Wisconsin, and the Upper Peninsula of Michigan through Thursday morning, and snow combined with gusty winds could lead to lowering visibility and thus potentially dangerous travel conditions. Farther south, moisture from the Gulf of Mexico will increase on Wednesday, leading to rain and thunderstorms ahead of the strong cold front associated with the low pressure system. Rain totals of over an inch are expected for portions of the Lower Mississippi Valley into the Tennessee Valley through Thursday morning, and strong thunderstorms are possible as there is a Marginal Risk of severe weather in place from the Storm Prediction Center. In terms of temperatures, much warmer than average temperatures (by 15 to 30 degrees) in the central U.S. today will flip to below normal Wednesday behind the cold front. The Central Rockies could see temperatures of 15 to 20 degrees below average Wednesday, while warmer than normal temperatures are likely to get pushed into the Ohio Valley and Great Lakes ahead of the cold front. Elsewhere, gusty winds and snow could continue across parts of the Appalachians today. Snow showers are also possible today in the interior Northeast. With warm and dry conditions over the next couple days in the Southern High Plains, elevated risks of fire weather are in place there. Additionally, fire weather conditions could become critical over portions of Southern California on Wednesday. Tate Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php