Blast of late-season cold sweeps across Midwest, Southeast as millions fall under frost and freeze alerts
Frost and Freeze Alerts cover more than 19 million Americans as cold temperatures spread across the Ohio Valley and Southeast. FOX Weather breaks down the delayed first freeze and El Niño-fueled warmth.
THE TAKEAWAY
Cold temperatures, clear skies and light winds will bring another morning of widespread frost and sub-freezing conditions to millions across the Ohio Valley and Southeast on Sunday.
Following a chilly Saturday morning, a larger area is expected to experience freezing temperatures and frost by daybreak Sunday.
More than 19 million Americans are under Frost Advisories or Freeze Warnings, with alerts expanding south and west into portions of Oklahoma, Arkansas, Tennessee and northern Alabama, in addition to the heart of the Ohio Valley.
WHY DO BRIDGES AND OVERPASSES FREEZE BEFORE ROADS?
Temperatures by daybreak Sunday are expected to fall into the upper 20s and low 30s across much of Ohio, Kentucky, Indiana and Illinois.
The Mid-South and Ozarks, including portions of Arkansas, Oklahoma and Missouri, will see temperatures drop into the low and mid-30s.
Widespread frost is expected to cover lawns, vehicles and windshields, with near-freezing conditions lasting for several hours around sunrise.
The Tennessee Valley and northern Alabama will experience the coldest air of the weekend Sunday morning. Temperatures will fall into the mid-to-upper 30s across northern Alabama and approach the freezing mark across middle and eastern Tennessee.
WHAT’S THE DIFFERENCE BETWEEN FROST, A FREEZE AND A HARD FREEZE?
That will bring the first significant patchy-to-areas of frost of the autumn to many communities.
For many locations, the arrival of freezing temperatures is occurring notably later than average.
Persistent upper-level ridging and a dominant El Niño pattern helped lock in record-breaking warmth across the central and eastern U.S. earlier this fall. Nearly 50 weather stations recorded their warmest start to autumn on record, significantly delaying typical first-freeze dates.
The FOX Forecast Center said the sudden weekend chill serves as an important reminder that while large-scale climate drivers like El Niño influence broad weather patterns over months, day-to-day conditions are driven by short-term weather features.
Even during an exceptionally warm season, Canadian cold fronts can still sweep across the country and deliver brief bursts of true late-autumn air.
Residents in areas under Frost Advisories or Freeze Warnings should take precautions against the cold before temperatures fall Saturday night.
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