Randomly came across this article today in my Apple News feed. Short version; the stall is due to evaporative cooling according to Greg Blonder, a professor at Boston College. Interesting read, thought I’d share.
https://arstechnica.com/science/2018/09/let-science-be-your-guide-for-the-perfect-labor-day-bbq/
https://arstechnica.com/science/2018/09/let-science-be-your-guide-for-the-perfect-labor-day-bbq/