A dramatic pattern shift will bring the chilliest air since spring to millions of people in the central and eastern United States this week, making areas that have struggled so far to shed lingering warmth feel more like November than October.
Extended periods of fall chill have been hard to come by for much of the country since the season began last month. But the combination of an expansive cold front and an upcoming surge of cold, Canadian air, will change that and temperatures could drop to 10 to 15 degrees below average by midweek.
The first aspect of this cooldown — a far-reaching cold front — began over the weekend. This cold front swept from the north-central US and will cross the eastern half of the US by late Monday, ushering in a true autumn chill for some along the way.
The coldest temperatures will remain in the Plains and Midwest Monday, before even chillier air out of Canada gets pushed much farther south.
High temperatures from the Midwest and Northeast to the South will be seasonably cool Monday but trend downward Tuesday. Tuesday could be the coldest day of the week in Chicago, where the high temperature could struggle to reach 50. Chicago hasn’t had a high in the 50s since April.
Temperatures will drop again on Wednesday for many areas outside the Midwest. Wednesday is likely to be the coolest day since spring for millions, and in many locations, it’ll feel more like late November than October.
“Truly fall-like weather is forecast … through the start of the weekend” farther south, the National Weather Service in Atlanta said Monday.
The high temperature in Washington, DC, on Wednesday could struggle to reach the mid-50s — 10 to 15 degrees lower than normal for mid-October.
Atlanta could struggle to break into the low 60s on Wednesday and remain in the 60s through Friday. The city hasn’t had a high temperature reading below 70 degrees since May and typically tops out around 75 degrees this time of year.
Wednesday will also be the chilliest day of the week for large portions of the Northeast, with highs in the 40s and 50s for many. With daytime temperatures this chilly, it leaves room for overnight temperatures to possibly dip below freezing.
“Frost and freeze conditions are probable for several nights and in many areas this week,” the National Weather Service in State College, Pennsylvania, warned Monday.
Freeze alerts are in effect through Tuesday morning for parts of Pennsylvania. More could be issued in the coming days for other parts of the Northeast and chillier spots of the mid-Atlantic.