First taste of fall: Cold front to bring season’s coolest air to northern US
Changes in leaves start occurring when trees and other vegetation receive less light. The lack of chlorophyll helps reveal yellow, orange and red pigments.
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Mother Nature is dishing out fall weather faster than Starbucks can launch its seasonal flavors, as a blast of cool air sweeps across much of the country.
The FOX Forecast Center says a significant cold front is pushing through the nation’s northern tier, setting the stage for the coolest stretch of temperatures so far this season.
The front is expected to usher in widespread temperatures in the 40s and 50s, with highs only in the 60s and 70s - marking a sharp departure from the oppressive heat domes that typically dominate the news in August.
Forecast map on Tuesday
(FOX Weather)
Computer forecast models indicate the air mass will have staying power, meaning it won’t be a one-day phenomenon.
Cities including Minneapolis, Chicago, Cleveland and St. Louis will be firmly in the chill zone, where temperatures are forecast to run 10 to 20 degrees below average, with a large section of the northern country running 5-10 degrees below average.
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The cooldown has been anticipated for a while, with more than 100 million people, stretching from the Rockies eastward to the Appalachians, feeling its impacts.
The troughiness will translate into no hurricane concerns for the continental United States for the foreseeable future, as developing cyclones will turn away from North America into the open Atlantic.
In addition to the widespread cooldown, some areas along the U.S.-Canada border and at higher elevations could see their frost and some may even see their first flakes of the second half of the year.
Neither the ice nor snow will impact population centers and will likely not trigger meteorologists at National Weather Service offices to issue advisories.
Unseasonable chill
(FOX Weather)
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A lingering question is how long will the pattern last.
Large-scale patterns tend to remain in place from several days to a few weeks, which means summer 2025 will end on a cool note, with no threat of any direct hurricane landfalls on the horizon.
It is also important to note that with humidity levels dropping and the overall comfort index rising, more people are expected to spend time outdoors and could notice subtle changes in the leaves of trees.
According to experts at ExploreFall.com, most of the current color changes seen across North America are the result of climate-related stress and disease and not related to the seasonal loss of daylight.
The only region of the United States currently experiencing a true foliage season is Alaska, but within just a few weeks, the colors will start to spread into portions of the Lower 48.
As chlorophyll production slows with less sunlight, green pigments disappear, revealing underlying tones of yellows, oranges and reds that define the season and become a spectacle until the hemisphere approaches winter.
Average Peak Fall Foliage
(FOX Weather)