A powerful early-season arctic cold front is expected to carve a path across the United States by mid-to-late next week. Now, just because this is an arctic front, doesn't mean we'll see January-type bitter cold. But temperatures 10-20 degrees below average could be possible!
For mid-Missouri, the chances for frost have decreased (see graphic above!) However, folks in Iowa, Northern IL, and especially Minnesota and Wisconsin will have to contend with the frostiest weather!
Now, on average, Missouri sees its first frost by the middle of October. As next week begins the month, this frost chance is about 2 weeks ahead of schedule. However, when we dig through data of the past 30 years, it's not crazy to see this happen in late-September either.
Temperatures at Columbia Regional Airport fell to a frosty 35 degrees on the morning of September 19th back in 1991. Other dates as early as the 3rd week of September have brought similarly cold temperatures in the last 30 years.
As of right now, our best forecast is still liable to change as we're several days out, but right now the mornings from Wednesday to Friday of next week pose the greatest threat for frost to develop.
As far as how cold we're expecting to get... running 10-20 degrees normal gets us between 57-65 during the day, and 35-45 during the night. While temperatures aren't expected to go below freezing at this time, under the right conditions, air temperatures as high as 38 degrees are cool enough to yield frost and damage sensitive plants this time of year.
We'll continue to track this cold front and update this forecast as needed! Stay tuned!