psuhoffman

You mean we would have almost every December pattern the last 5 years?

It’s been so long people forget how much a great high latitude pattern can mask other flaws.

That is the best and most significant development so far. The high latitudes seem to want to cycle between ok and great so far. Let’s keep that going. The only thing I’m paying attention to long range is how the forecasted puke pattern of the seasonals continues to get pushed back. A week ago we were saying how it continues to be just outside ensemble range. Another week later and it’s still outside realistic guidance range. Let’s keep that going too. Ive been skeptical but I’m about another week from firmly believing that look is just another seasonal guidance mirage.

The single most encouraging thing I see right now is the tendency for the high latitudes to look generally favorable into early December now. November can be a big head fake month with the volatility of the seasonal changes in the jet going on so while I have generally liked what I have seen the last few weeks, I want to see what happens into December before becoming too confident. That said last year the look up top was already breaking down heading into early December. A crazy EPO ridge kept early December cold and a rogue TPV displacement suppressed a storm south of us...but the signs the AO/NAO weren't going to cooperate were already showing by December. Right now keeping the blocking up top going into December is the single best sign we can have that this winter could be different. Get a more favorable AO/NAO this winter and a lot of those "flaws" that killed us last year won't be as hard to overcome. And those periods when the pacific did cooperate become epic vs just mediocre. One other thought I keep having... better winters tend to tip their hat when even the relaxations and "bad" phases that will happen aren't that bad. USUALLY the better years we avoid month long epic torches. We go through a few days here and there, or a mediocre couple weeks...but we usually don't have weeks and weeks on end of shutout no hope patterns. If we can avoid that type of look setting up shop I don't mind a relax and a couple weeks of a warm/mediocre pattern, especially early. That said...we have had plenty of winters that were super warm early and flipped colder and snowier. But, throwing out the older analogs from a colder climo those years more recently...2004/5, 2006/7, 2014/15, 2015-16, 2018-19, mostly didn't turn into epic years. With the exception of 2015 (which had a LOT of luck) we went from dog crap to mediocre. It's simply hard to make up for losing half of climo and get lucky enough or an epic enough pattern to end up with a +climo year when you lose a significant chunk of what is already a short climo window. So while a slow start doesn't mean this will be a total bust awful year...it is a sign that this probably won't be a good one and we will fight to scratch and claw our way to a mediocre year. So I would like to avoid seeing that no end in sight pacific puke pattern with no high latitude help set in. Every run that avoids that is a win imo. I will start to think about actual snow results once we get into mid December and our climo clock starts to tick.

January 66 you’re thinking of.

There are some repetitive themes I like so far. One is that systems have amplified and traversed the 50/50 domain frequently. Last year too often the WAR held and systems either amplified into Quebec or washed out. It hasn’t helped us yet as you need a perfect setup this early, but if we continue to see that all winter it will pay off.

Even if we don’t score early season, I want to see a generally favorable look up top continue. I doubt the pac kills us all winter. Even the last few we had favorable periods. But what we haven’t had is a cooperative look up top. If we get a winter where the NAO and AO cooperate some of the time we probably can eek our way to climo with a variable pacific. That’s kind of how I was leaning in my WAG.

This is all speculative and I’ve not had time to research it much to verify anything, but I’ve wondered if the decrease in sea ice has encouraged ridging in those regions in November which could favor cold dumping into the conus. Also the increased baroclinicy from the increase in SSTs could cause volatility during the transition to the winter jet pattern. But once wavelengths broaden and the pattern settles into its winter mode, and the waters finally cool and ice over, the pattern flips. Just a thought.

@frd I do think there are legit signs of a pattern shift in early December. However, his timeline and extent of the effects of the mjo wave propagation through warm phases seems dubious to me. Last year we had a record stall in warm phases and even that didn’t take a whole month to propagate out. We started to torch mid December due to the mjo and still got back to a colder regime by the end of the first week of January. So he is expecting another record stall in warm phases to beat last years record? He may be totally right with his numbers but his tone implies a month long warm pattern and if we do enter mjo hell in early December I find it unlikely we are still battling that come holiday week. Now last year the problem was the mjo would blast through cold phases in a week and cycle back to warm phases but that’s another issue. And there was speculation the SSWE muted the benefits of the one decent cold phase mjo wave as well. Just seems to be a lot not being taken into account.

As USAF said the atmosphere is behaving “like” a nino lately. But frankly the climo cycle recently has been a warm December no matter the enso state. I’m not entirely sure if the “warm nino” thing is due to enso or that we have had way more ninos lately which skews the results vs older ninos when colder December’s wasn’t as unusual. We had some pretty cold December ninos in the 1960s and 70s. The Atlantic and Gulf SSTs have been on fire lately. Add in the lag of sst temperatures cooling and that might have as much or more to do with the prevalence of the SE ridge early in winter lately. In essence we might be losing the early 1/3 of winter due to the current warmer SST cycle there. Only reason our mean snowfall isn’t dropping faster is we also seem to have a higher hit rate on big storms when the pattern does rarely get right. Boom and bust cycles seems to be our normal climo now, even more than it was historically.

Depends... last year the great looks would frequently penetrate from the weeklies into the day 11-14 ensembles range. But never past day 10. But when they would repeatedly collapse back and day 14 would look like crap again on the eps the weeklies would still magically flip the pattern by the end of week 3. It did that numerous times. So no matter what the eps shows day 14 if the weeklies is making a mistake based on a factor it’s miscalculating it might be likely to continue making that error so long as the same background state persists. It never corrected itself all winter last year.

The rest of the winter will be so bad they will record a negative number.

BWI: 0.3" DCA: 0.1" IAD: 0.7" RIC: 0.00001

Try the long range thread

@Bob Chill BTW...2002-3 shared a lot in common with those years after the blocking in December faded. From Jan on the NAO was positive with a weakly - AO and yet the pacific bullied the pattern very similar to those other years. I bring that up because 2002-3 is a great match wrt north pac SST, IOD sst, QBO, and Atlantic SST profile. The only flaw is enso. And some of those other years share some commonality to the pattern now also.

1960-61 Raging positive NAO. 40” at DCA. And the rare trifecta of above avg snow all 3 winter months. 8.7”, 13.6”, 18”. 1961, 1994, 2014 all had the commonality of extreme ridging in either the epo or pna domain that bullied the pattern downstream. They also all shared that the AO was neutral or slightly negative because the ridging in the pacific domain was so extreme it encroached into the AO domain. 1994 didn’t end as well wrt snow but it was only a slight adjustment on a few storms from being an epic snow year in DC. 1994 though featured the furthest west of the ridge axis on the pac side of all 3 years and so more SE ridging. 2014-15 was perhaps the true oddball. Yea 3 instances in 50 years is rare but 2014-15 is the only example of a raging positive NAO and AO all 3 months and still above average snowfall. We got super lucky with a consistent pna ridge and a PV often parked over Quebec for much of Feb and March. That extreme and rare combo overcame the most hostile high latitudes possible. There are no good comps to that in the last 50 years and we will probably not see it again.

The thing is usually storms run the temperature boundary. So it’s hard to get a ton of precip and be under a monster ridge all winter. It’s also hard to be near the boundary all winter and never end up on the right side for any of the storms. We only need a few to hit Climo. Rare years like 1998 can happen where the whole continent is void of cold so storms ride the boundary between sun tropical and cool but not cold enough air but that’s rare On the flip side it’s also hard at our latitude to be consistently so far north of the boundary all winter that we are just cold/dry for a very long stretch. Yea 1977 can happen but that’s equally rare. What’s more common in a bad pattern is that we get transient cold where we never make it that far into the cold airmass and there is no mechanism (blocking/displaced PV/ 50/50) to resist the push of warmth that will naturally come with the next “wave” in the atmosphere. Without any resistance once the flow backs ahead of the next wave the boundary races to our north and the storm cuts as it rides that boundary. Hence warm wet cold dry. But other than having fun with the running joke that’s not really a problem of “dry during the cold”. It’s a problem of the longwave pattern not being right to offer enough resistance to the WAA that’s comes with 99% of any precip event (other than that rare late bombing perfect coastal we get once every blue moon while a white elk runs by and a leprechaun does a jig on the roof). Usually we can see hints of that problem in the pattern. Any really cold pattern is likely to be a little “dryer” since storms run the boundary and if we are that cold the boundary isn’t likely close. But sooner or later a wave will come and of there is enough resistance in the flow then...boom. Give me the right longwave pattern from range and I’ll take my chances on the details once the short range comes.

Guidance hints at a split flow to me with energy crashing into the west that occasionally lowers heights there. That can work. Probably not in late November but give me that setup between about Dec 15 and March 5 and I’ll roll the dice.

Eps had no appreciable change from the last few runs.

I see nothing alarming on today’s ensemble guidance.

Agree. Right now I am cautiously optimistic. For the last several weeks the monthly and seasonal guidance has been showing a flip to a raging positive AO blowtorch pattern coming just outside the "somewhat believable" 2 week ensemble range. But as we progress that change keeps getting pushed back in time so that it is always just outside that 2 week range. November was supposed to be a torch. Now December. As long as that flip keeps getting pushed back and stays outside the 2 week range where ensemble guidance has had some skill lately I am starting to feel more and more hopeful that its a mirage and the seasonal guidance is miscalculating a key pattern driver and coming up with the wrong conclusions, similar to last year. This year is a bit more puzzling to me wrt seasonal guidance though imo. Last winter I totally understood their mistake, it was the same one almost all the humans made. We all saw the global sst patterns and what past analogs looked like and there was almost unanimous support for a winter that looked like the seasonal guidance suggested. But the atmosphere failed to behave according to expectations. Certain things went haywire, the MJO decided to go ape into warm phases through the core of winter and the enso failed to couple with the atmosphere. But I wasn't one to be crapping on the guidance because I made the same error. The error was easy to see though. This year I am not even sure what the seasonal guidance is seeing. The analogs now are a lot harder to find, and less obvious, with way more conflicting signals this year. So perhaps I am missing something. A lot of the mid and high latitude signals match up more with an el nino than a neutral so its hard to find good matches. A lot of the best pattern matches in other ways are stronger el nino years like 2002/3 so its hard to put much stock into them. But I have seen nothing in the analogs to this current pattern to suggest we are heading towards a raging dumpster fire year. Most of the best matches were decent years with a lot of variability. None of them looked like the seasonal guidance. So if they are wrong again, hopefully, I am less sure why they are doing what they are doing this time.

I’m not buying them either...just pointing out the new weeklies already push back the flip to an awful pattern.

New weeklies (based on last nights EPS) continue to push back the seasonal idea. Weeks 3-5 look ambiguous now but not hostile. Things go sideways week 6 but that’s where they have had no skill for a long time so I dont care. Week 3 week 4 week 5

Cross polar flow is great if you want to go ice fishing. But we don’t need it for snow. Air that originated in northern Canada will be cold enough to snow even if it was above normal for them!