LakePaste25

10-day ensemble mean for early to mid December looks decent. More favored here in the interior/lakes due to climo, but also can’t rule out one or two a small events and/or front-end for I-95. For you I-95’ers, Boston on N is probably more favored for a moderate event or greater. We will have to see how things evolve.

The effects of the SSW look to completely decouple from the surface (for now).

Yeah, there’s no doubt that the warming climate is increasing the size of the SE ridge regardless of whether it gets over or under modeled. Ridges are getting larger and the breadth of below normal temps from troughs is getting smaller. These are just facts. doesn’t mean it can’t snow or get cold though. But in terms of getting the colder temps, it’s like spinning a prize wheel with less winning spaces to land on.

Fair but we also don’t verify a forecast with a forecast.

The most anomalously cold air in the entire northern hemisphere will reside in Canada, allowing the northern tier of the Eastern US to stay somewhat cool despite the -PNA.

yeah strong nino decembers can “bust cold” such as with 2009 blocking, while nina decembers can “bust warm” such as with 2021. with the new climate, the odds of course are always more favorable to go warm than cold. i don’t think this december ends up torching though, especially northern tier. i can see it going 1-2 above.

For december, one would definitely want to be north of I-80. Even here, probably still dealing with rain from time to time.

People put too much emphasis on the AO/NAO/SPV stuff. You can have a +TNH/Hudon vortex anchored in place all winter coupled with an SPV on roids. This was mostly the case in 13-14/14-15. Then again I am biased towards the great lakes, but I like seeing the indo-pacific warm pool and the -EPO pattern show up.

It is probably just picking up a weak signal from the Indo-pacific warm pool. I would be more worried about it if p8 was not propagating as a strong KW. Note the WWB associated with the P8 pass through, which is what we typically see with weakening Nina’s.

We saw this a few times last winter. Fast pac jet leads to systems undercutting the PNA ridge, causing energy to get buried in the southwest, thus, rolling over the ridge into the east.

not to be too finicky but that new run is not really a classic -nao to begin with. more of a “newfoundland block.” a true bootleg -nao like we’ve seen in recent winters would be the traditional +gph anomalies extending from greenland through the eastern seaboard

yeah it’s not guaranteed by any means. just looking for signs of changes

i would shift the mean trough axis a little further west given the stronger nina and a weaker indo-pacific warm pool this year. still a decent fit though.

poleward shift of the pac jet = an alaskan vortex as far as the eye can see. no shots of arctic or subarctic air through the next couple of weeks, probably longer. mjo does look like it wants to push out into the pacific. eyeing mid to late november for a potential equatorward shift of the pac jet which would increase chances of popping a -epo depending on where this jet exits.

a little surprised by this because it’s more of a strong-storm induced cooler airmass, not canadian-sourced arctic air