November Medium/Long Range Discussion

[Eskimo Joe]

 

 

[Stormchaserchuck1]

If this verifies, we could be looking at our first winter storm threat around or after Thanksgiving. Maybe more 40N-north. 

18z GFS ensemble mean at 384hr also had a pretty strong -EPO developing.

Basically, the NAO is negative for the next 15 days, then the block retrogrades to NE Canada, just when the Pacific changes to more -epo/+pna around Nov 24-25 and after. That actually creates a window for a trough to track across the US, under the -NAO ridge in NE Canada, giving us a chance for a storm to hit colder air after Thanksgiving. The H5 in the map below is good, but we probably need a few days to flush out the old slightly warmer pattern. Still a long way to go, but it's looking good for at least below average temps beyond Day-15, based on current long range models.  That cross polar ridge, with a GOA trough and 50/50 trough (although both are weak) is what you want to see -- especially good ridging over Alaska. It's a winterystorm pattern, although early in the year.