First Freeze Of Season For Some Tonight

A band of overcast continues to creep in from the west-northwest, and 1:30pm temperatures offer a clue of where the sun is shining.

temps 24 hour change

Lafayette is parked at 50 degrees under cloud cover while Shelbyville reaps the reward of a brighter sky and mid 60s.


Sprinkles and showers are possible this evening as a cold front moves through Central Indiana.  This front marks the beginning of the well advertised chilly change that produces the coldest temperatures in nearly six months tonight.


Downtown Indianapolis near the freezing mark for the first time since April 20th, and many locations north and northwest of the city (where clouds clear sooner) will dip below freezing.  This is very near the climatological average, which is October 16th, and essentially the growing season.

FROST_FACTS jetstream

A strong dip southward in the polar jet stream delivers the unseasonably cold air mass… and delivers a few “clipper” systems across the Great Lakes and Ohio Valley.


The first clipper arrives late Tuesday into Wednesday morning with rain that may mix with the potential for some snowflakes to mix in on the colder side of the clipper.


A second clipper moves through the I-70 corridor Wednesday night into Thursday.  The atmospheric temperature profile will be colder, and offers a better chance to see some snowflakes mixing in.  Accumulation is highly doubtful…unless it can snow hard enough, and long enough, to overcome a relatively warm ground.


While more of a novelty, the snowflakes serve notice on how we’re fast forwarding to late November-like weather… and the cold is definitely the bigger story this week.  To put the air mass into perspective…. the “high” Thursday of 43 degrees will be what the “average” low is this time of year!  Temperature departures of 15-20 degrees hold heading into the weekend.