cctxhurricanewatcher wrote:wxman57 wrote:I don't like the look of the European (deterministic & ensembles) for past mid month. Another Polar vortex rotating southward west of Hudson Bay by the 17th. I'll enjoy the above-freezing temps up until then...
I suppose that since Joe Bastardi posted the 240hr EC 500mb chart for the general public on twitter that I can post the image here (from WeatherBELL).
https://pbs.twimg.com/media/BdZx9ulCcAAGomm.png
All speculation at this point, but would this position of the Polar Vortex send a more direct shot south vs the "swipe" we are currently enjoying?
I've heard a lot of this on the media and such so lets clarify some things. Yes the coldest air is associated with the vortex field, and yes slight direction of it can effect who gets coldest and what not. But the controlling mechanism (and the reason it is even going that much south at all) is the NW NA ridge or EPO(-). Strength and location of this ridge largely determines the downstream flow of cold. Early winter it was more in the vicinity of Alaska and dumped in the west and plains while the recent shot it was located along the west coast so a bit more east. So in short, yes the polar vortex is there but the real culprit is the Pacific. After the past 5 seasons, is there any doubt the East Pacific controls creation and delivery of cold?
Even in the long range (decade trends), it's well seen that +EPO will flood the country with Pacific air while -EPO sends us Alaska. Cold blasts here in Texas lines up with the EPO almost to a T. What you want to see is a -EPO and a -PNA<- this will dig major energy down the west and kick out in the plains. This is why in large part I've come to disagreement with so much focus on the NAO/Greenland block this is something that plays a bigger role for the eastern conus, we mostly have to look west.