psuhoffman

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

Sorry I was busy today. As Ralph said what I see there is a split flow. It's not perfect but I am ok with that look, especially during winter. The southern jet is crashing into the southwest and lowering the heights there but so long as there is riding over the top and a decent pattern to our northeast with lower heights in the Newfoundland regions with ridging over the top of it... those systems should mostly be forced to slide across the south and not cut to our west. That may not work in November, but in mid winter that would be an ok pattern.

I see nothing on any guidance that troubles me much. In about a week we will start to get an idea if this pattern rolls into December. If so I will get more optimistic. So far so good.

Never had mine.

The gefs has actually been doing better lately. But that wasn’t really my point. I’m more excited by the repetitive trends in the pacific in the short term and the signs the PV is being best around in general then I am the fluxuations in the long range NAO.

You only look at the EPS?

RR would have too much fun with that.

Woah slow down. I’m still trying to figure out how to tie my shoes and chew solid foods!

Yea it does. I keep thinking how a lot of the primary and secondary analog years I found features early season snowfall. So given that and what we are seeing it wouldn’t shock me to see an actual threat pop up faster then some might think.

Thanks for posting this! 69/70 was one of my top analogs too. Pretty much agree with your expectations. Your presentation is excellent. It should be required reading as a crash course in pattern recognition and drivers for anyone that wants to get into this! Don’t be a stranger this winter. Love your input here.

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.

Looks familiar

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!

@C.A.P.E. @Bob Chill Euro ens still looks good to me heading towards December. This look probably won’t get it done in late November but I would take it during peak Climo. And still no signs of the flip up top that the seasonal guidance expects.