Some Midwesterners will wake up to the first frost and freeze of the season this week, while others around the northern Great Lakes may witness the first snow flakes of the season.
Drastically colder air is surging into the Midwest behind a cold front, allowing temperatures to plummet by 20-30 degrees.
Clear and calm conditions behind the front will allow for temperatures to drop near and below freezing across eastern portions of the Dakotas, Minnesota, northern Iowa and northwestern Wisconsin early Tuesday morning.
Fargo, N.D., Aberdeen, S.D., International Falls and Duluth, Minn., are among the cities and towns that will have their first frost or freeze of the season.
Any outdoor plants in pots should be brought inside, gardens should be protected and scrapers should be handy for frosty windshields.
On Wednesday morning, colder air will reach even farther south and east. There is potential for a frost as far south as northern portions of Illinois.
With chilly air moving across the very warm water of the northern Great Lakes, a few snow flakes could fly or mix in with rain showers around the Upper Peninsula of Michigan on Tuesday night. According to the National Oceanographic Data Center, water temperatures are still in the lower 60s in Lake Superior.
While no snow accumulations are expected, seeing snow flakes may catch some off-guard so early in the season.
Tropical Depression Two has formed in the Atlantic and could become the next tropical storm of the season by midweek.
Warm and humid air in place over much of the Midwest and Northeast at midweek will contribute to the risk of drenching, gusty and locally severe thunderstorms on Wednesday.
After temperatures briefly climb to typical midsummer levels, another cooldown will roll into the Midwest and expand to the East for the last part of July.
Severe storms will fire up Tuesday afternoon and evening, threatening outdoor activities and travel for many.
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Unseasonable warmth is expected to continue from the United Kingdom through northern Europe and Scandinavia into the weekend.
Barrow, Alaska (1989)
Thunder reported for the first time since July 1982 (no rain fell with this so-called storm) July 1989 did go on to become the wettest July on record with more than 3 inches of rain.
Thompson, Manitoba (1990)
97 degrees -- record heat wave.
Bom Jesus, Brazil (1990)
About 1" of snow accumulated at elevation of 3,000; this is rare.