Medium range models show a +PNA of some significance occurring around May 12.
https://ibb.co/CssytcK
I had noticed constant cold in Russia 12 months ago, and this has continued more often than not for the last 12-months. Roll forward research shows that cold, or colder than normal, Russia evens out to more +PNA conditions in the following months(9-12 months).
We also continue to run this ridiculous NAO-PNA correlation (+NAO, happens or trends with more +PNA's, -NAO happens or trends with more trending -PNA's.)
https://ibb.co/YZ0sccj
That will hold until further notice. (I say that because in my observation it has a EC, and imo population- could be wrong, correlation). Let the clouds grow high up in the atmosphere