SnowGoose69

It would not be the GFS if it did not lose a southern stream storm at some point in the medium range

True but I have to say I don’t recall a case in the last 22-23 years where I’ve really followed these indices where anything like this has happened before. Part of it is that December is probably the only month in winter where this type of alignment can occur and the pattern and air mass nature could suck this much, so you have narrow period to a degree where the stars can align. I think even in early to mid March this set of indices with a bad EPO would produce a markedly colder pattern than this. I think alone the W ATL SSTs being colder in March would likely cause less ridge bridging between that SER and the NAO ridge than we keep seeing models trying to spit out. Whether or not that comes to fruition I don’t know but they’ve been trying to show it

This is a classic pattern where a snow event will appear out of nowhere. It’s a combo of there being enough cold air around and the models really sucking badly beyond day 5 recently

Many think that. Similar to how in the fall several years back that insane remnant west pac tropical slammed into Alaska and brought an absurd cold spell in November and that was basically it for the winter. The remainder of that winter was fairly mild although I think snow wise it was not awful. I cannot recall year that was but ensembles Day 10-16 were very optimistic for a pattern change til that Alaskan situation too place. It seems to an extent an SSW always screws someone because ultimately the process impacts pattern progression to a degree in the whole hemisphere north of 35N. The January 2012 SSW no question screwed NOAM. Models seemed to be hinting a -NAO would develop but the SSW ultimately shifted the pattern to one that favored Europe

Its not unusual at all to see a fairly crappy pattern in December and sometimes in early Jan with the AO/NAO negative. It becomes increasingly difficult on an exponential level for that to happen though once you progressive through January

Just have to see now if it keeps getting kicked. The last 24-36 hours all 3 ensembles more or less show 1/8-1/12 the transition to the -EPO or +PNA look. I think I want to see that come inside 240 before I believe it. No idea either how the SSW which does look legit at this time impacts this. Obviously the major results won't transpire til mid or late Jan but we saw 2 winters ago how the warming process basically effed over what was going to be a good pattern shift for the East.

3/4-94 I think. Big elevation snow event and interior event while coast got rain. The pattern more or less went 2011 on the northeast and MA after 2-20 in 1994 though it did get cold again for a week or two from 3/15-3/30 but overall I always point to 94 04 and 11 as being years where pretty much after early to mid February winter ended. In 04 there was a return again in mid to late March much like 94. 2011 it truly ended and never came back

They also don’t realize that are plenty of storms where a -NAO can actually hurt you. It’s not common but there are mostly definitely cases of storms that produced rain from DCA-BOS where if the NAO was positive might have been all snow events. You have to dig in to find them but they’re there. To an extent 12-25-02 is a storm that if the setup over the Atlantic was less favorable the storm might have been snowier near the coast and that wasn’t a raging negative NAO either

That’s the same pattern more or less as 93-94 though I believe 93-94 the negative heights by Greenland didn’t extend over the pole so we had somewhat of a phony or weak -AO most of the winter. That winter wasn’t particularly good in the MA though. Had the NAO been negative maybe it would have been different but as DT has pointed out before the 93-94 and 14-15 predominant winter patterns it’s next to impossible to have a -NAO

I think most would take the 384 18Z GEFS pattern

We are sort of due for a good one. Last good one was what? January 2012? It didn’t impact us but feels like ages since a fairly effective SSW occurred.

Even the GEFS isn’t exactly a shutout type pattern. All 3 of the ensembles GEFS GPS EPS suggest there’s a period day 8-12 or so where things briefly look bad before more ridging looks to occur out west with the low going back towards the Aleutians

Even with a bad EPO with those that indices that good the pattern wouldn’t be as awful as some of the GFS op runs or ensembles have attempted to spit out

I would also side more EPS. The last few winters it seems whatever ensemble groups handles the first 10-16 day pattern shift in later November or early December ends up being the one that is right the rest of the way. Last winter it was the GEFS for sure

That pattern is more or less physically impossible. I guess it’s simply the averaging out of the members but if you had normal heights or weak ridging like that from SEA to YUK and that sort of block in the Davis Straits you wouldn’t see long duration or stable above normal heights like that near Ohio or Virginia. That’s probably a product of members trying to develop a deep storm over Colorado

The Op GFS had another “glorious” run at 12Z. It basically just continually repeats the same thing over and over Day 7-16 which is almost certainly wrong but it’s funny how many torch cutter Op runs it’s continued to have while the ensembles argue for something totally different

The Pacific is really bad til 1/1 which is partly why but models, especially Op runs can show patterns at day 7-10-14 that don’t look anything like the indices and ultimately correct as you get in closer. We saw that in recent winters where MJO was raging phase 5 and the AO positive and the GFS of Euro Op run at D10 thinks you’ll have -20 850s with a trof in the east

Unlikely. You would need the Niña to remain strong in all likelihood to lose the Atlantic. There are very few if any cases since 1950 where December had a solid AO/NAO that were negative where there wasn’t another long duration negative stretch in January or February without some sort of decent La Niña influence.

Ridge out west too displaced to the east and not tall enough. The only case I know of recently where that pattern produced was 12/25/10. You need a nasty nasty west based block probably to get a DC to Boston snow event with that ridge that displaced east. 2/23/89 was somewhat close as well and we saw that largely failed for most areas other than the immediate coast

I remember thinking the models were going to blow it because I didn’t understand the disconnect up in NJ given how far south the whole transfer and development happened. In the end they did end up blowing how far north the surface low would get by NJ before it kicked east. This caused the CCB feature to impact the NYC metro more than any guidance suggested

As far as I know this was only the second storm on record where BGM and ALB recorded 20 plus inches and NYC also had 10 or more. 3/3/93 was the only other case

The Op GFS for some reason in -AO/NAO pattens has a tendency beyond 180 to love dumping trofs into the plains or west. We saw this back near 12/1-12/5 and it never came close to verifying

Both storms occurred with pretty lousy Pacific patterns but this was much more close to a southwest flow type event than that was

My hunch is the block led to the surface low taking a slightly faster east turn which led to areas down into NYC seeing more snow on the back side than expected

This would probably be the only snow event other than March 1993 where Albany and Binghamton saw over 2 feet and NYC reported double digits as well