psuhoffman

Lastly, 1 of the 4 storms that ended up a big cold enso snowstorm was maybe the biggest surprise snow ever but 3/4 were storms many on here identified as legit threats well in advance. One was that WAG I got right from 10 days out in 2011. But what all 4 had in common was a trough diving well to our southwest with an amplified wave digging into the TN valley to our southwest. 3/4 also featured a rarity for a Nino which was a mature STJ moisture feed to our southwest. If we see those things it’s ok to think this could be one of the exceptions. And the day 8-9 thing is way too far out to put to bed yet, but runs that show some NS dominant event with a SW that barely digs to our latitude and has to stall and bomb to get us don’t excite me. We all know how those actually play out.

Just so everyone knows I'm not just being a deb... there have been 35 NESIS events during a -ENSO including cold neutrals since 2000. And full discloser I did include 2014 in this, even though you all know how much of an outlier I think that season was...if I excluded it these numbers would be a LOT worse! Of the 35 NESIS events the average snowfall at BWI was 2.8" 71% were 3" or less 29% were 4" 17% were 6" 9% were 10" The max was 15" By far the highest probability of how an NESIS level storm will affect our area during a cold enso is with less than 4" of snow and that its VERY likely the heavy snow will miss us to the north or east. That is just the probabilities based on the records. I am NOT saying it cannot snow or that we can't get a good snowstorm, just that the odds are against it and so I am not getting my hopes up by long range HECS type setups because history says those storms are very likely to miss us. Just for comparison there have been 25 NESIS events in warm enso years since 2000 The avg at BWI is 7.4" only 40% were less than 4" 60% were 4" plus 44% were 6" plus 20% were 10" plus The max was 29" My advice is in a cold enso when we are tracking a major snowstorm at range...expect it to miss us to the north or east and to get a very minor event because that is what the probabilities say are by far the greatest odds...then be happy if it turns out to be the very rare fluke where we get a major event. Even in a warm enso our odds from range at a major threat being a BIG snow are below 50% but they are over double the chances in a cold enso.

Looks a lot like a typical cold enso HECS

The thermal distribution isn’t the issue. That’s general profile is what to expect with a strong -EPO. The issue is the degree of the anomaly. It’s ok if western and central Canada are +3 or +5 but when it’s +10 or more we’ve seen recently that even when we get a favorable long wave configuration the air masses here just aren’t cold enough because our source regions are torched. Southeast Canada isn’t super warm yet but roll that day 15 forward 5 days and it would be. it’s way too far out to worry about the specifics I was just trying to point out that we’ve blamed the hostile pac of the last 8 years for our source regions being torched several times. But there we have the opposite pacific long wave pattern and it’s a similar result.

I’m mildly interested in the window around the 20-22. There is a brief window we might have enough cold and a chance one one the NS waves could get forced south in the squeeze between amplifying troughs. The 12z euro and 0z gfs are ways that setup can realistically work. But it’s not something guidance will pin down at range.

No, but the elephant you’re talking about is there behind all of this. Ya it’s part of the reason 90% of the mid latitude land mass of the whole NHem is torched there. That’s not something you’d see in a more balanced period where “means” weren’t out of calibration. That’s something you see when what is “normal” is changing and the means used to make the blues and reds is constantly behind the curve. But my point was specific to the fact the pacific is 100% opposite of what we have had most of the last 8 years yet NAM is still torched. Yea what little cold there is is in the east but we need a colder profile than that to have a high % of snow. It’s 15 days away, not something to panic about yet, but it’s an ugly look is all.

That was a day 15 plot not 15 years. We’re not talking about the future I’m talking about now.

Good luck getting that to last long with that background thermal pattern across NaM. It’s 15 days out but that’s ugly. But that wasn’t my point. The pacific is good there and the whole continent is still torched. Our cold air source is Fckd.

We just need that cold that’s…wait…where is…ah FCK

So much for “it’s the pacific”

Closest we got was -1.3 for a month. Most of the snowy Ninos were positive pdo. There were some slightly -pdo years in the 60s that were snowy. But in that era a -nao offset a hostile pacific. What’s been happening recently is a hostile pacific causes such an extreme SER that it links with the nao ridge into a full latitude eastern ridge. I don’t think that same equation works anymore. We probably simply need a +pdo Nino.

If it can get above -1 for Winter we bring some better cold neutral and weak Nina analogs into play. The snowier months in those parameters were above -1. Jan-Mar 2014 averaged about -.3. March 2018 was -.8. 2006 was slightly positive. 1996 was +1. January 2022 is one of the only examples of a snowy month with a severely -pdo so it’s not impossible but most of our snowy months come with a pdo above -1. however we still have a long way to go, yea it’s rising. But it’s coming off a record low it’s still very negative by any other standard and it would be unprecedented to go from -3.5 in the fall to near neutral by winter. That’s the main reason I didn’t include 2014 in my analogs.

We are the furthest southwest of all the major eastern zones affected by HECS storms. Since these storms generally move SW to NE that means we need a storm to develop faster and further west. Everything about cold enso is worse for that. Weaker STJ so storms are less likely to approach with an already developed mature feed to our south. Dominant NS so more chances for there to be the need for stream interaction that can slow down or complicate development. Or a NS dominant wave that simply tracks north or develops too late as it moves east without enough STJ. Really we need an STJ dominant storm to get an HECS here. History shows they NS dominant waves just won’t develop in time for us to her more than low to moderate level snowstorms. In a Nino with blocking our geographic location can be a positive. We can even get storms that track far enough west to be a problem for the immediate cost to our northeast. Or we can get STJ events that peak early or can’t climb due to blocking. In a +PDO Nino the greatest snow anomalies are over us. The opposite is true in cold enso. This doesn’t mean we can’t get an HECS. Nothing is impossible. But in a cold enso Philly northeast is favored and we miss most of them and it’s not a fluke it’s climo.

A more progressive wave is a much more realistic way for us to get a snowstorm.

Obviously it’s way too far out to worry about specific Synoptics yet. But since 2000 there have been 6 cold enso HECS level storms and every one of them missed us east like that. So if we do get a HECS storm this winter it’s highly likely to miss us exactly like that. It’s not a fluke. It’s cold enso climo.

Oh I totally agree. That’s why our goalposts are realistically between a near total dud to best case a slightly below avg year across the area. But some were rooting for an EPO driven pattern even last year in a Nino. I was just pointing out if we ever want a HECS or a truly snowy winter (say widespread 30”+ across the area) an EPO or TNH driven pattern is not most likely to be the way to get it. IMO we need to hope once the PDO flips the temps across NAM can return to a status quo that allows blocking to work again.

We have…but most of those years you mentioned were horrible PDO matches and not good enso either. Remember a stronger Nina is actually better for us oddly enough. 05-06 did barely make it into my analogs and it was the best result among them. But it really wasn’t a great PDO fit. 96 and 2011 both happened during opposite PDO cycles to where we are now. Unfortunately if you look at weak cold enso events in a strongly -pdo cycle there are no snowy years. The best we could hope for would be a year like 2022 that is just a little below avg snowfall across the region. (Yes I know a few local areas bad above normal they don’t need to remind me every time but all the reporting stations were below avg). But the majority of -pdo cycle weak cold enso years were single digit snowfall. It’s frankly the worst combo we can have for snowfall. But we can root for a fluke. We only have a sample size of like 10. I’m sure if we had 100 chances 1 or 2 fluke snowy results would happen. And most years did have at least one snow event so I don’t think a total shutout like 2023 is likely.

It’s also worth pointing out that some have transitioned to rooting for EPO driven cold patterns because lately our more classical ways to snow have failed due to not being cold enough. But this last week was an example of the issue with that. EPO driven patterns are often dry when it’s cold. 2014 and 2015 were anomalies not normal.

For most no. But it’s worth saying that there comes a point, and we aren’t there yet, where it won’t even matter what the pattern is. It just won’t be cold enough unless we get increasingly anomalous setups.

If you pull back and stop focusing on our locations specific snow chances the biggest issue I see is this… We need cold anomalies to snow. Our coldest day of the year has an avg high near 40. But if you simply look at a 5 or 10 day mean temp anomaly for the whole northern hemisphere the warm expanse outnumbers cold by 2 and sometimes 3-1 across the mid latitudes. We got lucky recently that one of the small (globally speaking) pockets of cold did end up over us for a week, but how often are we going to win if we need cold and 2/3 of the whole hemisphere is warm at any given time?

There’s a tiny spec of cold in the NW tip of AK

If the icon is getting this much attention…

Kinda like our winters

They were all below avg snow except 65 but same as 96 I exclude that as an analog due to being an outlier with the PDO and the predominant cycle we were in. Nothing about that period matches this one. If we just look at weak Nina’s that occurred during a strong -pdo they were all really bad wrt snow. Most weren’t complete shutouts though. But no examples that were snowy.