The average date for the first frost and freeze in Indianapolis takes place on October 11th and 14th, respectively. Right on cue, the first frost of the season will take place for most central Indiana neighborhoods over the weekend. If you happen to miss out on the frosty conditions this week, reinforcing chilly air will descend on the region early next week.
We forecast (3) of the upcoming (7) nights to fall into the 30s. This is, obviously, a significant change from the extended summer like conditions we’ve been dealing with as of late. One primary driver behind the significantly cooler pattern has to do with the change in the PNA. The shift towards a positive PNA will result in the cooler air remaining in place with more staying power than the fleeting cool shots of a few weeks ago.
A series of cold fronts will sweep through the Ohio Valley over the upcoming couple of weeks and each will likely feature progressively cooler conditions.
With the positive PNA in place, it’s no surprise to see the mean trough setting up shop over the eastern portion of the country.
At the surface, we see the cool pattern taking hold into not only the short-term, but the 10-15 day range, as well.
