Hold on to your hats (and coats)! Tennessee Valley is in for a large temperature swing

Yes, it's been really, really hot lately.

Afternoon temperatures have reached the upper 80s to low 90s this week, threatening records that have been set since the 1910s and 1920s. In fact, a record was broken in Huntsville on Tuesday when thermometers registered 90 degrees at the airport.

But as hot as it has been for the early half of this week, the Tennessee Valley is going to experience a major cool down in time for football on Friday and Saturday. This due to a cold front that will be swinging into the region, bringing both the hope for rain as well as cooler temperatures.

(Remember rain? We get reacquainted this week!)

Take a look at this temperature swing! During the day, highs will climb into the upper 80s to low 90s ahead of the front, but when it arrives, it will knock temperatures down into the upper 60s to lower 70s.

Forecast high temperatures for October 19 through 23.

Forecast high temperatures for October 19 through 23.

But that is half the picture. Lately, overnight lows have settled into about 10 to 15 degrees above average. Once the cold front moves, it will usher in a much colder air mass into the Valley -- and you'll be waking up to the 40s over the weekend!

Forecast overnight lows for October 19 through 23.

Forecast overnight lows for October 19 through 23.

If you already put away your hats, coats and scarves, make sure you pull them back out before Thursday night!

Is it an Indian Summer?

The Merriam-Webster dictionary defines the term as "a period of warm or mild weather in late autumn or early winter".

The American Meteorological Society has a slightly more rigorous definition for the phrase:

"A period, in mid- or late autumn, of abnormally warm weather, generally clear skies, sunny but hazy days, and cool nights. In New England, at least one killing frost and preferably a substantial period of normally cool weather must precede this warm spell in order for it to be considered a true 'Indian summer.' It does not occur every year, and in some years there may be two or three Indian summers. The term is most often heard in the northeastern United States, but its usage extends throughout English- speaking countries. It dates back at least to 1778, but its origin is not certain; the most probable suggestions relate it to the way that the American Indians availed themselves of this extra opportunity to increase their winter stores. The comparable period in Europe is termed the Old Wives' summer, and, poetically, may be referred to as halcyon days. In England, dependent upon dates of occurrence, such a period may be called St. Martin's summer, St. Luke's summer, and formerly All-hallown summer."

With the start of winter still a good two months away, it may be a little premature to call the current hot spell an "Indian Summer", but rather just an extension of "normal summer".