Two days before we enter the new year, a burgeoning storm system will charge over the Great Plains while another sturdy system runs north of the Northeast.
The low pressure system responsible for recent bouts of severe weather in the South will continue its northeastward trek across the Great Lakes on Monday, concluding its frontal sweep of showers over the Northeast by New Year's Eve. Some wintry mix will fall in Michigan and the Adirondacks in the morning, and although some early morning thunderstorms could awaken folks in the Mid-Atlantic, any flashes are expected to cease by dawn. By late Monday afternoon, showers will be restricted to the interior Northeast.
Another low pressure system that has been rushing the northwestern Rockies with snow and wintry mix will jump down onto the Great Plains on Monday. Revolving into the Mississippi Basin by the day's end, its swath of showers will be extensive, dropping some form of precipitation from Washington all the way into Ohio. Mostly wintry mix, changing into snow with height, is expected in the northern and western Rockies, which will shrink and weaken through the day. Light to moderate rainfall ahead of the storm's center will transition into light backend flurries in the Great Plains.
Slight Pacific moisture will speckle showers through the Pacific Northwest on Monday, and outside of more isolated showers in South Florida, much of the U.S. Southern Tier can expect a clear start to their work week. Anyone hoping for a cooldown in South Texas will have to set those hopes aside to anomalous high temperatures soaring into 80s and even blistering lower 90s. Warm 70s will continue to heat South Florida, the far southern Plains, southern California, and the Desert Southwest.
Mild 60s and 50s will arise in the South and the East Coast, while 40s and upper 30s cool Appalachia, the interior Northeast, the Great Lakes, the Pacific Northwest, the Intermountain West, and the north-central Plains. Subfreezing highs will be relegated to the far north-central U.S. and western slopes, with the northern Plains and far Upper Midwest hitting just 20s while some Front Range peaks only hit the single-digits.