Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 PM EDT Fri Oct 30 2020 Valid 00Z Sat Oct 31 2020 - 00Z Mon Nov 02 2020 ...Cold air will be the main theme across much of the East this weekend... ...Lake-effect snow will be possible across the Great Lakes region by Sunday... ...Generally very warm and dry weather is expected across much of the West which will maintain the ongoing and widespread drought situation... In the wake of a nor'easter exiting southern New England which helped bring a locally record-setting early-season snowstorm, much colder temperatures will be filtering south across much of the eastern U.S. as a cold dome of high pressure advances down across the Great Lakes and Ohio Valley. Temperatures will be below normal as a result, with daytime high temperatures on Saturday as much as 10 to 15 degrees below normal. Areas of frost, and some sub-freezing temperatures will be possible tonight and early Saturday as far south as the Ohio and Tennessee Valleys, along with the Mid-Atlantic states. Frost and freeze warnings are in effect as a result. Some brief warming of temperatures will be expected across these areas on Sunday as high pressure exits quickly offshore of New England. Elsewhere, a strong area of low pressure will be quickly advancing across southwest and south-central Canada on Saturday, and then southeast Canada on Sunday. This low center will drive a cold front very quickly down across the Intermountain West, the Plains, and Midwest by Saturday night, and will move through the eastern U.S. by late Sunday. The front will be generally dry as it crosses the Plains and Midwest, but will encounter sufficient moisture as it approaches the East Coast on Sunday for some rain to break out, and especially across the Mid-Atlantic and New England. In behind this initial Pacific cold front will be a reinforcing Canadian cold front that will drop southeast across the northern Plains, Midwest and Great Lakes region. Strong northwest flow will bring notably below normal temperatures down with it, including some sub-freezing temperatures that will help set the stage for accumulating lake-effect snow downwind of the Great Lakes Saturday night and Sunday. By Sunday night, this renewed shot of cold air will arrive across the Ohio Valley, Mid-Atlantic and Northeast. Meanwhile, temperatures at least across much of the West will be rebounding and will be well above normal with some areas seeing high temperatures as much as 10 to 20 degrees above normal, and especially across the Great Basin. Unfortunately, this will be accompanied by a continuation of very dry weather which will only reinforce the ongoing and widespread drought situation. Orrison Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php