Projected 500mb heights of around 530-535dam for UIL at 18z 10/19 would rank among the coldest October airmasses on record.
— Aidan Teall (@meatyorologist) October 5, 2021
Average is ~563.7dam.
October record is 524.6dam. Such heights are projected just 50-100 miles north of UIL at the same time. (A little more digging pls!) https://t.co/oUBxbMYgmQ pic.twitter.com/WVWtauxml9