After a sun-drenched, warm weekend and start to the week, things are about to change drastically.
The forecast alone may be enough to send a chill down the spines of those who love summer. And it all starts Wednesday.
Today, there is a slight risk of severe storms from the central Plains to the Upper Mississippi Valley. The National Weather Service in Duluth reports chances for showers and thunderstorms tonight with rain possible throughout the rest of the work week. Heavy rain, up to 1 to 3 inches, is possible but is mainly predicted farther east in Wisconsin. Once the storms move through, much colder air arrives Wednesday, to the tune of at least a 30-degree drop in daytime highs.
Daytime highs may only reach the upper 40s and lower 50s through Friday, the weather service reported, and lows are expected to drop into the 30s on Thursday and Friday.
"There is a risk for frost and freezing temperatures on one or both nights," the weather service reported. "People with tender plants outdoors should keep updated on this potential."
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The weather service reports rain will become heavy at times tonight and Wednesday, as "intense northeast winds bring gale force winds to areas bordering Lake Superior. Wave heights of more than 10 feet can be expected across western Lake Superior" tonight and Wednesday.
Flooding or flash flooding is possible, especially in the Arrowhead and in northwestern Wisconsin. Almost all of Cass, Aitkin and Wadena counties along with the northern half of Crow Wing County may get 1.25 to 1.5 inches of rain. From Brainerd and points south, including the southern edges of Wadena, Cass and Aitkin and all of Morrison and Mille Lacs counties may receive an inch to 1.25 inches of rain. A smaller portion of Cass County on the northeastern edge and extreme northwestern edge of Aitkin County may receive closer to 2 inches of rain.
"Temperatures will be much cooler behind the front on Thursday with some frost possible later in the week," the weather service reported.
With clearing skies Friday night, the low is forecast to drop to 35 degrees. The National Weather Service in Duluth issues frost warnings or advisories based on a number of factors, including wind and air temperature. For the frost warning or advisory, the air temperature is typically in the 34-36 degree range.
The weekend and early part of next week should bring back mostly sunny skies, but expect crisp fall-like temperatures with highs in the upper 50s to lower 60s.
"This isn't really an extreme pattern, it's just the first cold front of the season," said Melody Lovin, meteorologist with the National Weather Service in Duluth.
The normal high for this time of year is about 74 degrees with an average temperature of 60 degrees.
Frost can arrive before the temperature drops down to a freezing degree of 32, which typically happens in mid-September. In the last 14 years, according to the National Weather Service's online database, the earliest date for a 32 degree or colder temperature came in 2004 on Aug. 21 and the latest date was recorded just last year on Oct. 14.
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Since 2000, the Brainerd area had a first 32 degree spell in the second to last week of September nine times. On four of those years, the first 32 degree day arrived in early to mid-October. For the past 14 years, the first day with the temperature at 35 degrees or below was largely in second or third week of September. The first day of fall arrives on the last full week of September.
Looking further out, Lovin said the climate prediction center is looking at an equal chance for the lakes area to have a warmer or colder than average pattern into the late fall. While this cold snap may prompt thoughts of winter, Lovin said there is a 60 percent to 65 percent chance of an El Nino developing this fall or winter. If an El Nino develops, it typically translates to a warmer winter in the Midwest.
