Are you sure about that?

This site is very reliable when it comes to the jetstream: [link to squall.sfsu.edu]

I check this maps often, I don't see any reversal. The jetstream is fragmented, but there's no reversal. still the same west to east flow.

here's a little animation:

[link to squall.sfsu.edu]

Select five days and six hours interval.

Nothing unusual.