Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 300 PM EST Sat Dec 26 2020 Valid 00Z Sun Dec 27 2020 - 00Z Tue Dec 29 2020 ...Lake effect snow winding down in the eastern Great Lakes tonight, chilly overnight temperatures in the Southeast and Mid-Atlantic... ...Fast moving storm system to usher in wintry weather across the Upper Midwest and northern Great Lakes... ...Upper level trough to bring unsettled weather to California and the Four Corners... The persistent lake effect snow bands off Lakes Erie and Ontario are expected to wind down this evening as the strong low level winds weaken aloft. Several more inches are likely with the heaviest totals just down wind of Lake Ontario. Meanwhile, cold temperatures remain entrenched over the East Coast with the coldest anomalies focused in the Southeast. Hard Freeze Warnings are in place across southern Georgia and northern Florida where temperatures fall well below freezing. Sunday stays chilly up and down the East Coast with high temps struggling to reach the 70s throughout most of Florida. Temperatures rebound to more seasonal levels across the Southeast on Monday. The Northeast witnesses a brief warm-up on Monday as well but colder conditions return to the region on Tuesday. Meanwhile to the west, an upper level disturbance responsible for producing scattered rain and snow showers throughout the Northwest is racing east towards the northern Plains. This feature will spawn a new wave of low pressure in the Midwest on Sunday leading to the development of addition snow showers from the Dakotas to the northern Great Lakes. The storm looks to intensify over the Great Lakes Sunday night and a fresh injection of cold Canadian air rushes in behind it on Monday. The eastern Great Lakes and into the northern Mid-Atlantic may contend with some passing rain showers Monday morning but as the next shot of cold air races over the Great Lakes, more lake effect snow bands are forecast to form throughout the eastern Great Lakes region by Monday evening. In total, most accumulations from the Dakotas to the Great Lakes are on the light side but some totals approaching 3 to 6 inches are possible in the northern Great Lakes Sunday night and several more inches possible down wind of Lakes Erie and Ontario Monday evening. Another upper level trough will dive south through the northeast Pacific and approach the West Coast Sunday night. This storm system will usher in welcomed rainfall and mountain snow to parched areas of California and the Four Corners region Sunday and into the start of the week. Snowfall forecast in the southern Sierra Nevada suggests over a foot of snow is possible with upwards of a foot also possible in the southern Rockies. Over an inch of rainfall is also anticipated along the southern California coastal range through Monday evening. Eventually, this upper level system will become the primary focus for the next winter storm emerging into the Nation's Heartland on Tuesday. Mullinax Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php