The latest in a series of upper-level disturbances will act to amplify a cold trough over the western Great Lakes by Saturday evening resulting in unseasonably low temps across the region. The trough is forecast to progress eastward Sunday and Monday allowing milder, Pacific-origin air to spread across much of the nation by Tuesday.

CORE OF COLD AIR TO SETTLE OVER WESTERN GREAT LAKES AND MIDWEST OVER WEEKEND

Forecast temperature departures from normal

Valid at 6 AM Sunday

MODERATING TEMPERATURES TO SWEEP ACROSS COUNTRY BY TUESDAY

Forecast temperature departures from normal

Valid at noon Tuesday 11/22