Thanks, PhilChuck.

I think sometimes events are over-attributed to SSWs. Just because a nice pattern or some blocking occurred near or a bit after an SSW doesn't mean it was necessarily responsible.

There is a lot of literature on the subject, it's pretty well understood. I found that early in the Winter, Nov-Dec, it takes +30-45 days for 10mb warmings to make it to the surface. Late in the Winter, March, it takes +10-15 days for 10mb warmings to make it to the surface. Right in the middle of Winter, it's +20-25 days. They time lag is pretty linear from early to late Winter. It's actually a very strong correlation.

The May Gray is finally burning off here.

I think it was nearly instantaneous in late January 1989.