40/70 Benchmark

Winter to Potentially Return Later in February Major Disruption of Stratosphere to Ensue There is a growing school of thought that winter is essentially over and that this season will end as one of the mildest and least snowy on record across much of the region. And while that still may be the case, there is reason to believe that winter is not destined to end quietly. Indeed, it was it was expressed in the Eastern Mass Weather Winter Outlook this past November that the latter portion of the season was at an elevated risk for a significant disruption to the polar vortex, which could result in one more round of high latitude blocking. And is now all but a certainty that this will indeed occur. Currently the polar vortex remains very stout and centered, which is keeping the supply of cold constricted over the arctic: However, the weakening of the zonal mean wind anomaly over the polar stratosphere after mid month is very evident on the the European guidance. This weakening of the vortex results in a great deal of warming of the polar stratosphere by 2/19 on both the European: And the GFS suite: However, neither ensemble suite currently reflects this polar disruption in the pattern very well, as evidenced by the forecast H5 anomaly for that same time frame being void of high latitude blocking. European: GEFS: The GFS ensemble maintains this disruption of the polar vortex through the end of the month. With still no notable reflection in the overall pattern. This is possible given the fact that the manner in which major disruptions of the polar vortex do, or do not manifest themselves into the pattern can be difficult to predict. And it is possible that the cold is sent into Siberia as it was for much of January. However, there maybe some early signs of a more ominous end of the month beginning to emerge in the form of a descent of both the AO and NAO. Thus the more likely scenario given analog preference is that the ramifications of said disruption will be slow to materialize on guidance and that ultimately it will in fact influence the pattern to assume a more wintery character to at least some degree. Potential Late Season Analog There are signs of this in the longer range European weekly product, which is now signaling strong blocking ultimately materializing during the last week of February, which resembles one of the primary Eastern Mass Weather 2023 seasonal analogs: This is transition on the European weekly product is a progression that is very similar to that which occurred during February 1956, which is both one of the five primary ENSO analogs and a member of the favored RNA style extra pacific composite discussed in the winter outlook. The season has indeed been a viable analog to date, including a month of December which featured a strong bout of NAO style blocking that resulted in very little snowfall for the region. What can be gleaned from this analog is that the RNA pattern is very likely to persist, so the ability of cold to return to the eastern US for any length of time will depend on whether of not the disruption of the polar vortex can trigger another episode of high latitude blocking. Ultimately what may determine whether or not these changes in the polar stratosphere translate to the surface enough to ensure that the end of winter 2023 will be eventful is whether or not la nina has weakened enough to finally allow a coherent MJO wave entry into phases 7 and 8. But in the mean time, history has taught us that it would be unwise to write it off entirely. In the mean time, enjoy the pleasant weather and get outside before a potentially active late February and first half of March.

https://easternmassweather.blogspot.com/2023/02/winter-to-potentially-return-later-in.html

I like a major late season deal to help bridge the gap from winter to fantasy baseball draft.

I know some may interpret this as me trying to play it both ways, but it's not because I grade what I posted in November, regardless. I'm just trying honestly convey a level of uncertainty. I expect that pattern moving forward to produce some snow, but I also need to acknowledge that the pattern all season has struggled to produce snowfall comensurste with potential.

Right...as in would I be suprised if the rest of the season produced very little? Would I be pissed? The answer to each is "no". But I was trying to convey what I think may happen.

Yea, well like I just illustrated...I just did.

Yea, I get it...which is why I was trying to elaborate to add perspective.

For the season? Yes.

It's really not a huge stretch to have 25" combined for February and March. I mean...I was like +9 for January and had 17.5". Figure less precip, but also less extreme positive temp departures.

I think I see at least another 25-35" this year.

I haven't viewed the weeklies, but I do not expect a very mild pattern during at least the first half of March.

I hear that.

Man, for someone who has queefed historic snowfalls over the past several years of regional despair, you sure are one miserable SOB.

Yea, keep the plows on, Phil.

If someone put a gun to my head right snow, I would say that the cold will not be overly impressive late this month into March, aside from perhaps another glancing blow....and that March will be the snowiest month overall for SNE (low bar), but not like March 2018.

What I had actually called for back in November was for a late season PV disruption that would fall short of official SSW criteria (wind reversal), but would still provide a fairly wintry ending.

I can easily see how this goes either way, which is of zero help, forecast wise. But what I do know is that it is happening and is unlikely to allow futility for anyone...at least in New England, anyway.

That is part of why January was such an epic disaster, despite the fact that it was uber active and SNE snowfall is generally more highly correlated to precip, than temps. Normally, that would have still been a decent to very good month for snowfall, but all of the cold got locked into Siberia and the PNA was constantly west based, which funneled any morsel of cold that managed to sneak onto this side of the globe into the west.

I will say...this is happening. Guidance is locked and loaded on that....how exactly it manifests will dictate whether we ultimately give a flying flake and that is TBD. Should at least be some modicum of validation with respect to the late season portion of my outlook, though. Kind of like how I got the very active January right. That is what is frustrating about seasonal outlooks....you can get important details right, but the sensible result can still turn the forecast to doo doo because either you missed something else, or it didn't quite have the impact you expected. What a mine field.

Yea, agreed.

One thing I am not in love with it that the disruption with the PV seems to send it mostly onto the other side of the globe again.

I think sometimes the emoji reactions are more geared towards the image, rather than the poster.

Cooler version, too. I'll take the under on +8.

May 2009 was brutal....very cool summer.