brooklynwx99

holy crap

idk the cold might dump into the west at the very beginning, but this is a loaded setup. about as good as it gets

here is a loop of the preloading pattern for 18”+ events for NYC. it’s easy to see how we get from the EPS to this as the block retrogrades and decays

the EPS is pretty much a dead ringer to the second half of Dec 2010. make of that what you will i’m also inclined to believe that this anomalous west-based -NAO is legit. it’s well agreed upon on all major ensembles, it’s getting stronger and moving forward in time, and retrograding Scandinavian highs often give us our best blocking patterns. this checks all the boxes

yup! the EPS is absolutely loaded. here is a 7 day loop of the preloading pattern for 18”+ snowfalls in NYC, and you can see how you take the EPS around a week later and this occurs. really exciting look! btw, the preloading composites for NYC and BWI for the 18”+ events are very similar, so this is still useful for you guys. many of the storms that gave NYC all time amounts were great for the MA as well (2016 and 1996 come to mind) i’m also inclined to believe that the block is legit since it comes from a retrograding Scandinavian HP… those are known to cause our best periods of blocking

the block and overall pattern showing up on the EPS is very reminiscent of late December 2010 retrograding Scandinavian highs are known to give us our best blocking spells, so I think that the block itself is legit given how models are really picking up on it as we move forward in time

we aren't going to see a -PNA of that magnitude for that long for a long time. that was a record breaking semi-permanent Aleutian ridge we're going to see a -PNA spell to start December, but it should be transitionary rather than anything like that

if we do end up getting a Modoki Nino, which seems more likely, then there would be lots of blocking, especially late

this is what the pattern evolves to. it's pretty loaded for everyone

we're also going to see very strong high pressure move into Mongolia over the next 5-7 days, leading to a +EAMT that will extend the Pacific jet and lead to the anomalous -EPO that's showing up on modeling... so I think that's for real the blocking is a bit more nebulous, but with all the Scandinavian ridging I think that there's a better chance than not of a -NAO after the first week of December

we're also going to see very strong high pressure move into Mongolia over the next 5-7 days, leading to a +EAMT that will extend the Pacific jet and lead to the anomalous -EPO that's showing up on modeling... so I think that's for real the blocking is a bit more nebulous, but with all the Scandinavian ridging I think that there's a better chance than not of a -NAO after the first week of December

this is a really nice evolution with the Scandinavian ridging retrograding into Greenland. that's a signal for a legit block, and they like to leak farther W too

@ORH_wxman look at the Scandi ridging retrograde towards Greenland... that's a legit signal for a potent -NAO. those like to tuck westward too

holy crap

no way to know. just have to see i’m leaning towards the EPS since it’s been more consistent, but who knows

it’s ridiculous. i’m not sure how a huge feature like that is completely different between ensembles at this range

the EPS and GEFS are completely different in how they handle the PV lobe in SE Canada the EPS is similar to the better runs where it acts as a 50/50, while the GEFS leaves it much farther NW and torches everyone now we just need to see which is correct! could go either way. this is a very touchy setup

I know it’s still day 6, but this is a really significant difference in the entire NA pattern the GEFS would be a total wash while the EPS still has the confluent flow in SE Canada now we just have to see which is correct

yeah, the EPS looks quite similar. the 18z GFS looks like a blip as of now

EPS is relatively unchanged from 12z so i’m inclined to believe the GEFS is on crack the 50/50 is a tad weaker but the C Canada ridging is a tad stronger so it seems like a wash

super interesting pattern evolution upcoming and snowman is finding tweets from teenagers that talk about factors that may lead to a warm pattern in the E US love to see it

I know that you guys are worried about climo, and rightfully so at this time of year, but this is a loaded pattern you have a stout +PNA, a decaying west based -NAO, an anomalous 50/50, and a potent shortwave this isn’t your typical November setup, so I think it’s worth watching closely even south of the M-D line

this is absolutely loaded everything is there for a significant storm: strong +PNA ridge, anticyclonic wave breaking in Canada forced by the -NAO, anomalous 50/50, and a potent shortwave can't really look any better a week out, let's see what happens

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!