brooklynwx99

the 50/50 shifted a good bit west as well... hard not to get excited with this look

if only it was a month from now. either way, this is a pretty ideal setup as depicted on the EPS with an anomalous ridge out west, decaying blocking over Hudson Bay, and a deep 50/50 ULL near Nova Scotia. can't draw it up that much better than this the west based -NAO and subsequent 50/50 help force strong HP over SE Canada. if the block is for real, which seems to be the case at this point, then we should see that HP trend stronger in that area as it's downstream of a ridge (promotes upper level convergence and surface divergence -> sinking motion) don't be totally fooled by the time of year. although climo is relatively hostile in late November, this setup can provide ample cold air as shown by the the 00z ECMWF OP, and sun angle is low. there is certainly an elevated risk for winter weather even down to the Mid-Atlantic given all of these pieces in place over the next few days, the most important features to watch will be the blocking and 50/50. if blocking trends stronger or the 50/50 trends farther west, we will see odds for a significant event increase, and vice versa it's still around a week out, so much will change, but it's definitely encouraging to see legit -NAO blocking show up this early in the season happy model watching!

tell me about it. big change in the 50/50 ULL with a stronger ridge out west. nice banana HP starting to show up too

the anticyclonic wave break over Hudson Bay will also force HP into SE Canada, so I'm not worried about a lack thereof this is a really, really nice look. there would be ample cold air verbatim

yeah, it’s basically just an area of below normal heights around Nova Scotia. a legit one forms from a block, and it leads to confluence over SE Canada that locks a HP and cold air in

this west based -NAO and extremely deep 50/50 is pretty textbook for a large coastal storm the signal is there, just still have to fight climo at this point. if this was a month later the alarm bells would already be going off haha

GFS has a legit classic pattern progression with the retrograding -NAO into Canada and the 50/50 pushing off of Nova Scotia... obviously it's far out there, but this is the type of setup where you have a lot of pieces needed for an anomalous event to take place

here were some thoughts I posted in the MA subforum, they're applicable here too. the blocking showing up looks legit and Dec 2010 is looking like a better and better analog recently

it's also quite easy to see how we get from the pattern at the end of the EPS to a pattern like December 2010. yes, I know there was bad luck for you guys down here, but I would take that pattern in the MA every single time all that's really needed is for the blocking to mature and retrograde, which is something that blocking from Scandinavian ridging often does over the course of a few weeks. it takes some time, but it happens more often than not. yes, the Pacific looks "bad" with the -PNA, but it doesn't matter with a west-based -NAO and cross-polar flow established by the poleward Aleutian ridge so, not to hype things up too much, but the chance for a Dec 2010-like pattern is becoming a bit higher looking at the general pattern progression

what a gorgeous look here in the high latitudes. often times the higher heights near Scandinavia retrograde yes, the Pacific isn't amazing yet, but it's reshuffling. the blocking showing up that strongly with a 50/50 and trough into Europe is legit this is also a 5 day mean, which makes this even more impressive

this is actually very similar to the first half of Dec 2010, believe it or not the anomalies are of a much higher magnitude in Dec 2010, but the general waveform is almost a dead ringer

yeah, it would the GEFS might be a little quick with the blocking, but that general pattern evolution makes sense

this is really nice to see. that's a legit -NAO/-AO on a 5-day mean just give the Pacific 7-10 days to reshuffle and that's a great pattern. verbatim that's dry and on the cooler side for you guys around Thanksgiving

dude what are you talking about? the EPS is still well below normal for the same time period and yes, it is, but it's likely just a relaxation before a reload in December just accept the L like a normal person lmao

seethe

cope

that 50/50 and -NAO dipole is already beginning to show up. always very nice to see the deepest negative anomalies in the 50/50 region track that 2 weeks forward - Aleutian LP builds as the Pacific jet extends alongside retrograding Scandinavian ridging and you're looking at a really nice pattern after the first week of December

there will be a 7-10 day relaxation around Thanksgiving due to the Pacific jet retracting, which is pretty well modeled once the jet extends late month into early December (you can see it strengthen late on the EPS here), this becomes a pretty classic look as the Aleutian low strengthens, AK ridging builds poleward, and the Scandinavian ridging retrogrades towards Greenland. the 50/50 and -NAO dipole is already beginning to show up

based on what, exactly?

it's a great match with PDO, MEI, general SST anomaly placement for ENSO - yes, 2010-11 was strong, but the placement of the anomalies is just as important, and they're very similar. this Nina is also no slouch QBO is also a dead ringer. I can see this December going somewhat like that one in terms of blocking, but that was a unicorn of a winter and to expect anything of that magnitude is foolish

it's second behind 2010-11 lmao which still remains a pretty good analog given how December might shake out

I do think the -EPO is legit. big cold dump looks likely and the odds of you guys seeing some kind of wintry precip are good, especially towards NNE we should see a relaxation around Thanksgiving as the ensembles have been showing due to a -EAMT developing around the 15th... would lead to a Pacific jet retraction over the next several days however, ensembles are then showing a descending Siberian HP that would then spark another +EAMT late in the month, encouraging another jet extension and subsequent Aleutian low/-EPO look around the first week of December it's easier to see this occur with the 200mb jet... extension leads to the poleward ridging, then a relaxation due to retraction, and then you can see the Pacific jet strengthen in response to the +EAMT... would extend again over the next few days

yeah, this is a really solid jet extension from the +EAMT at the end of the run

It looks like there are some wheels in motion to lead to a pattern change later on in November... mainly the development of an +EAMT, a flip to +AAM, and hints of Scandinavian ridging. First off, the +EAMT: There is pretty good model agreement on anomalously strong HP moving over Mongolia and the rest of east Asia, which helps lead to a +EAMT. +EAMT events often lead to an extension of the Pacific jet and subsequent poleward ridging around Alaska. This is bolstered by the shift to +AAM in the tropics, which often builds poleward and encourages blocking a few weeks down the line... Scandinavian ridging is also beginning to show up on both the GEFS and EPS in the extended range. This can both help to disrupt the SPV, which is a possibility, but this shouldn't impact the pattern too much unless it couples with the troposphere. Also, notice the beginnings of an Aleutian low beginning to form - this is a result of the Pacific jet extension after the +EAMT begins to form. However, what's more important is that ridging in this area tends to retrograde towards Greenland like so: https://journals.ametsoc.org/view/journals/clim/33/7/jcli-d-19-0447.1.xml So, although the pattern to open the month will be very warm and quiet (enjoy the great weather!), I expect a flip to colder and more active weather around Thanksgiving once all of these pattern drivers really take shape, mainly with the Pacific jet extension around two weeks from now. The Scandinavian ridging often takes longer to retrograde. We want to see these signals move forward in time. The analogs that some have proposed for this winter also featured blocking early on (2000-01, 2020-21, 2010-11), so it's nice to see some pattern drivers support it! We shall see.

It looks like there are some wheels in motion to lead to a pattern change later on in November... mainly the development of an +EAMT, a flip to +AAM, and hints of Scandinavian ridging. First off, the +EAMT: There is pretty good model agreement on anomalously strong HP moving over Mongolia and the rest of east Asia, which helps lead to a +EAMT. +EAMT events often lead to an extension of the Pacific jet and subsequent poleward ridging around Alaska. This is bolstered by the shift to +AAM in the tropics, which often builds poleward and encourages blocking a few weeks down the line... Scandinavian ridging is also beginning to show up on both the GEFS and EPS in the extended range. This can both help to disrupt the SPV, which is a possibility, but this shouldn't impact the pattern too much unless it couples with the troposphere. Also, notice the beginnings of an Aleutian low beginning to form - this is a result of the Pacific jet extension after the +EAMT begins to form. However, what's more important is that ridging in this area tends to retrograde towards Greenland like so: https://journals.ametsoc.org/view/journals/clim/33/7/jcli-d-19-0447.1.xml So, although the pattern to open the month will be very warm and quiet (enjoy the great weather!), I expect a flip to colder and more active weather around Thanksgiving once all of these pattern drivers really take shape, mainly with the Pacific jet extension around two weeks from now. The Scandinavian ridging often takes longer to retrograde. We want to see these signals move forward in time. The analogs that some have proposed for this winter also featured blocking early on (2000-01, 2020-21, 2010-11), so it's nice to see some pattern drivers support it! We shall see.