After a chilly start to last weekend, we have warmed up in a hurry and have a mild week on tap around the region.  While the weather won't be the greatest tomorrow afternoon and on Thursday night into Friday, temperatures will be quite a bit milder this week than they were last week.  Also, since many of us had a frost on the pumpkin or on the peppers in our garden, this week's weather is somewhat synonymous to what's found in a typical "Indian Summer" regime.

The term's usage was first attributed to the 18th Century and a French-American writer named John Hector St. John de Crevecoeur.  de Crevecoeur wrote "Then a severe frost succeeds which prepares it to receive the voluminous coat of snow which is soon to follow; though it is often preceded by a short interval of smoke and mildness, called the Indian Summer."  

Other accounts, including one of Catherine Parr Traill (a Canadian settler), wrote in the 1830's that the warmer weather pattern was due to fermentation of vegetation in Canadian forests in October and early November, predicting that as North American became more settled over the coming centuries that Indian Summer would become a less common phenomenon.   I think we can safely say she was somewhat wrong on this assertion!

Other equivalent phrases to describe the late season warm-up, such as St. Martin's Summer, are typically used to describe the Fall warming trend in parts of Europe.

For us, voluminous coats of snow aren't always likely in the winter to follow but in New England and around the Great Lakes, the snowy reference is much more apt to apply.  In many cases, an Indian Summer pattern typically includes high pressure anchored off of the East Coast or in the Southeastern US and includes the jet stream's position to our north.  This allows us to bask in fleeting warmth before the pendulum swings colder.  This upcoming round of milder weather will include some variation in temperature -- with Tuesday cooler than Monday -- but it will generally feature above average temperatures for the course of the week.

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Tom Thunstrom is the editor and publisher of Phillyweather.net. You can also follow Phillyweather.net on twitter @phillywx or on Facebook.