They are uncommon in November but we do have them. Almost half the November’s on record have produced a 70-degree day – at least two per year. Though we went three years without a 70° high in the month, putting together a string of 70° days is much more uncommon.
Checking weather records, the longest spell of 70° days in November is 6 days, which occurred on four occasions. 1953, 1977, 2008 and most recently in 2010. These records date back 89 years per the Midwest Regional Climate Center.
The streak was interrupted on Thursday when mid/high level clouds spread across the state and the official high “only” reached 69°. The current forecast is for temperatures nearly 20-degrees above normal through Tuesday.
So why is it so warm? The jet stream is behaving as if it is September, retreating north and running flat – west to east along the U.S. and Canadian border. The cold is bottled up for now and the pattern doesn’t change here for several days.
It is Indian summer in Indiana – the term used in the Autumn months when a warm spell follows the first hard freeze of the season. Remember how we started the work week? Early Monday morning lows in some locations were in the lower 20s.