INDIANAPOLIS — Here we go again. Central Indiana is under a Frost Advisory again overnight tonight, the second in three days, and the set-up is much more favorable for frost formation than Sunday night.
This is due to the closer positioning of the center of high pressure by Wednesday morning. The clear sky and calming wind near the center promote maximum radiational cooling. Current dewpoints in the lower 30s suggest that's where low temperatures will be Wednesday morning.
The record low Wednesday morning in Indianapolis is 33° set in 1978 and it appears that will be rivaled.
Either way, we expect widespread frost away from downtown Indy and you'll want to protect any vegetation you're concerned about.
This air mass is 10-20 degrees below average and part of a May that's currently some six degrees below average and 11th coldest May to date.
Modification of the air mass occurs gradually heading into the weekend, but additional frost is possible Thursday morning.