Upper-level 30,000-ft jet stream flow and low-level/surface temp distribution

  • Short Wave will move NE, triggering cold frontal passage in Chicago area Friday night
  • Cold air will then sink south and east – covering the Great Lakes/Chicago area Saturday

Late Friday afternoon Chicago area set-up

Cold front approaching from the west will pass through the Chicago area Friday night. Temps peak in the 50s Friday afternoon/evening.
Temps fall behind the cold front – highest temps Saturday will occur shortly after Midnight Friday night. Temps to drop into the 20s Saturday with strong winds dangerous wind chills

Decidedly colder pattern taking shape heading into December despite a brief surge in temperatures Friday

Full day temperature departures from normal