Ntxw wrote:While lots of focus has been the beginning changes middle to late week (rightfully so as the North American pattern flips via the Pacific) the actual poleward progression of the -EPO isn't until Dec 10th-15th frame. That's likely when we will be watching for the first big high pressure dome of the season and will be of origin much further north.
As for the first front in a few days depending on what guidance you look at appears to be a Tuesday passage. GFS blast it through over night Monday and has been trending a bit chillier than prior runs with a strong North/Northwest wind. NAM doesn't go full out that far yet but looking upstream it is much tighter with the gradient, 30s behind the front and 60s just ahead of it so it suggests we may be in for quite a drop.
I still stand by the above post from last week. The pattern has changed over the weekend and it's becoming more clear. The models were right the core of the cold will be east but they underestimated the breadth of cold coverage. The strong block in W-NW America has shifted the pattern. It's still looking like the retrogression of the ridge is likely with nearly all guidance still showing it moving offshore as it marches towards the favored Nina configuration in the Aleutians.