brooklynwx99

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.

regarding Hunga Tonga, it actually looks like there is a correlation between years with a much cooler than average SH stratosphere and a -NAO early in the year the blog post that highlights this: https://www.severe-weather.eu/global-weather/cold-anomaly-stratosphere-polar-vortex-volcanic-cooling-winter-influence-fa/ this bolsters the analogs that myself and some others have in mind that show early blocking, like 2020-21, 2010-11, 2000-01, 2017-18, and 2021-22

2010-11 also had a severely negative PDO and it's actually a pretty solid analog, so, yes, I don't understand the gnashing of teeth about the topic right now no one variable is the end-all-be-all with seasonal forecasting

doesn't even need to be moderate! here's a composite of all central based Ninos, both weak and moderate... about as good as it gets from NYC southward the Februaries are basically weenie maps. even without Feb 2010 it's still a highly conducive pattern for cold and snow so, if we get that Modoki next winter, which I'm fairly confident of given general ENSO progression after multi-year Ninas as well as subsurface SSTs, it should be a big one

maybe next winter. like actually haha good shot at a central-based Nino

I'm including December and the start of January. yes, I know that the snowfall from those years might be paltry, but all that we can say is that the analogs point towards a 500mb pattern that should provide chances down to the Mid-Atlantic from Dec 1 - Jan 15 It's just that so much snow occurs in February, and since February looks to be a torch, you're going to get winters that end below normal

I'm honestly not really that sure. there is a chance that the next Nino could be strong, but that's obviously a shot in the dark at this point. I'm sure there's a lot of research being done on the super Nino and how it changed the atmosphere with the clippers, I think it's just some bad luck as well as a function of the pattern... the Nina composite doesn't really lend itself to clippers while the Nino one does

we've just been in a persistent Nina base state recently after the super Nino, which is why this stretch has been so mediocre for most over the last several years like pretty much everything in the atmosphere, it'll flip back around in time, and I'm becoming increasingly confident that next year will have the moderate Modoki Nino we've been waiting for from NYC southward look at all of the warm water waiting to emerge near the dateline! it's also quite common to see moderate Modoki events occur after multi-year Ninas (2009-10, 2002-03, 1986-87, 1977-78) here's a composite of all central based +ENSO events in the somewhat recent past and their Februaries: so, yes, it's coming. just have to be patient! I also agree with (and have been agreeing w/ for a while) @40/70 Benchmark that the start of this winter will hold some surprises. early-season blocking is favored by analogs like 2000-01, 2020-21, 2017-18, 2021-22, and even 2010-11! and yes, I know there was some bad luck here with 2010-11, but you guys would roll the dice with that 500mb pattern every single time

also

yeah I do think that the first couple weeks of Jan could be good snow wise if the blocking does come to fruition. after that Nina climo almost overwhelmingly takes over into Feb in the analogs it's never a complete shutout up by you guys, but it definitely looks torchy

December into early Jan still looks good... there's a legit signal for blocking, particularly in the NAO region I do agree that it looks gross as we head into Feb though

whoops. it's actually even stronger lmao

I haven't seen anything peer reviewed or anything like that... just a correlation that could be useful for this winter it seems like a bit too much to be a coincidence. there's a lot of years there and actual analogs based on ENSO/QBO/PDO that back it up

1) I believe they're years that exhibited significant SH strat cooling, not particularly for eruptions the author of the post constructed a SH strat temp index and picked out particularly cold years... here's the link if you'd like to read the entire thing, it's quite detailed: https://www.severe-weather.eu/global-weather/cold-anomaly-stratosphere-polar-vortex-volcanic-cooling-winter-influence-fa/ 2) yes, these are analogs that my coworkers and I agreed on, factoring in ENSO, PDO, and QBO... all of them are weak -ENSO/cold neutral coming off of multiple -ENSO events, besides 1996-97

it's also worth noting that the analogs also had a very weak NH SPV compared to average, which checks out with increased early blocking

yes, for sure

the -NAO correlation from Nov-Jan with the cold stratosphere is even more interesting when you consider the propensity for early blocking in the analogs, as you're saying. this is a legit west-based -NAO signal and when looking at these years' SH strat temperature anomalies from August to September, there is a definite signal for an anomalously cold stratosphere. it's obviously not to the extreme extent as we're seeing this year, but it's certainly similar so, I see no reason to believe that December won't bring some decent winter chances before -ENSO climo takes over as we head into mid January - February

so it turns out that the anomalously cool stratospheric temperatures over the SH actually correlate to a west based -NAO kinda makes sense, I would think that there would be some kind of balancing out with the historically cold SH stratosphere obviously, this is a correlation and these years had other factors influencing the NAO... but this is interesting and it seems that, on average, a very cold SH strat would help a -NAO if anything, not hurt it

for sure. my initial thought is that the flavor of this winter will be similar to last, but we should shift the cold / snowy period up a few weeks. like mid December to early Jan also... the PDO looks much improved thus far. it can change for sure, but this is a good look initially with all the warm water off the WC if this remains heading into November, it bolsters the case for a wintry Dec

2000-01 is a legit analog this year

for the amount I help contribute to LR stuff during the winter (very often times optimistically), I don't exactly feel like this level of snark is warranted over valid meteorological analysis I apologize if my post came off the wrong way, didn't mean to come off as a downer or anything. many should get good winds with the outflow anyway. IAD gusted to 52

lmao trust me, coming from the NYC area, we don't even dream of storms up here you guys have gotten some beefy guys this year though

this looks like a scenario where most in MD north of DC get the bulk of their gusts with the outflow. that line has become outflow dominant very quickly, so I don't see it lasting too long the boundary could fire some new pop-ups tho