A noticeable shift toward autumn weather is set to arrive early this week across the Midwest and Northeast. Saturday night a pool of cold, dry air moved into the Northern Plains and Upper Midwest and will continue sweeping eastward.
What to expect in major cities
Chicago will see temperatures in the 70s today, dropping to the upper 50s Monday night as the cold front pushes onward. Detroit will follow a similar pattern, with highs staying in the mid‑70s.
In the Northeast, New York City will fall to around 60°F overnight Monday and only climb back into the 70s on Tuesday. Boston and Providence will be cooler, with overnight lows in the 50s and daytime highs staying below 70°F through Wednesday morning.
Humidity and atmospheric effects
The incoming air mass is also much drier, especially along the East Coast, where cool, dry air will move south into the Mid‑Atlantic and settle against the eastern slopes of the Appalachians. This “cold‑air damming” effect traps the dense air against the mountains, reinforcing the cooler temperatures.
Southern outlook
Meanwhile, the South and central United States will remain locked in summer heat, with highs still reaching the 90s and even the 100s. The Southeast likely won’t feel a true taste of fall until later in the week, possibly extending into next week.
Why the change matters
As the Northern Hemisphere moves into the darker half of the year, cold outbreaks like this become more frequent. Major cities such as Chicago, Minneapolis, New York, Washington, D.C., and Boston have already lost over two hours of daylight since the summer solstice and are now losing daylight at a rapid pace—over 17 minutes per week. Longer nights give the atmosphere more time to cool, allowing cold air masses to expand across North America.
Original reporting: El Paso News (HLL/CB) — read the source article.
