psuhoffman

Yea but that was a Nino so more stj and a tpv got displaced into Quebec which acted as de facto blocking on the flow. I wouldn’t expect the same results from that same longwave pattern absent those 2 nuances

Well to be fair the op euro also retrogrades the pac ridge into asia then slides the vortex currently near Japan over into Ak which floods pac puke across the conus. The ensembles don’t favor that as of right now but that would be a disaster. Essentially a bad pac and Atlantic at the same time. I do agree that people are being way too pacific focused lately. It’s recency bias. And I get it. We’ve actually had a favorable Atlantic much of the last 2 years and it’s not done much good. The pac has been so awful, and I do think the warmer base state of the pac and the globe makes it harder to overcome a bad pac. But people are forgetting how frustrating the inverse can be also. There weren’t a lot of dots in the +pna +AO side of that 4” snows scatter plot either! Truth is we need some cooperation from both the pac AND the HL if we want a high probability snow pattern.

The long range has a very 2015 look to it. People like to throw 2014 around as a totally pac driven year but we had a pretty decent look up top most of the first 2/3 of that winter. Certainly not what was driving it but like I’ve said it’s a balancing act. A great pac and decent high latitudes is a good trade off. 2015 was a good pac and pretty awful high latitude look which is similar to what the eps and gefs is spitting out now. I’ve said I thought 2015 was a fluke because there isn’t much historical support for that look working here. But I guess we will put that to the test.

As the background state warms its easy to speculate that we will struggle to over come imperfections more. So setups with one or two things not right that we could have worked with 50 years ago might not now. Applying that logic to the recent struggles with a bad pac but good Atlantic, the inverse isn’t necessarily true. Just because a favorable HL can no longer overcome a warmed pacific doesn’t mean a favorable pac with a bad HL regime will be better for our chances. I fear people are so fed up with what we’ve been struggling with lately they forget how frustrating it can be when the AO is raging positive even with a decent PAC. I don’t think anyone was consoled in 1995 or 1997 that the pac wasn’t that bad. I doubt we would hear a lot of “well it’s warm and snowless but at least the pac pattern is ok”. The truth might be we need BOTH a favorable pac and Atlantic now to overcome the warmer base state.

Maybe preference here. The pacific certainly has more to say about our temps. And maybe if I bothered to do a correlation study on 1-4” snows it probably would show something. But I’m a big game Hunter. I was totally happy with 2016! I’d rather one huge storm and nothing the rest of winter than a zillion 1-3” nuisance snows that add up to twice as much. To get a big snowstorm we really do need Atlantic help. Just getting cold isn’t enough. We need something to resist the return flow that’s inherently part of any big storm. That something is usually blocking. So yea if we just want colder weather and the chance at clippers or weak boundary waves the coming pattern looks good. If you want a 10”+ snowstorm it looks like dog crap.

With the mjo inching closer to 8 in Jan and long range guidance showing the ridge shifting poleward and east it looks like the pac will be in a reasonably favorable phase. But the Atlantic looks to go to crap at the same time. EPS towards day 15 looks similar to 2015 actually. So let’s see. If that actually works again I’m willing to admit that maybe what typically works has changed. But history says a good pac and bad Atlantic isn’t any better for snow than the inverse.

I fear we’re about to be reminded that a good pacific and awful Atlantic doesn’t usually work for us either. Hope I’m wrong.

I doubt that but it’s harder than it should be lately.

@CAPE the problems with the pacific base state have been beaten to death. But my point, and Ji I think, was that occasionally when the pac is not THAT bad and the pattern should be “ok” the SE ridge is still going nuts. This panel is a good example. No the pac isn’t “good” there but it it’s not a train wreck either. Honestly that’s likely as good as we can hope for in the current base state. The pacific ridge is poleward and just far enough east that combined with a favorable AO/NAO that should suppress the SE ridge some. Yea there should be some SE ridge response to the wavelengths out west but it’s still flexing to Canada! It shouldn’t take a perfect wavelength alignment to stop the SE ridge from pumping to the arctic circle.

The TNH loading pattern has been killing us for a while. The fact that the gulf is on fire doesn’t help either. But I’ve also noticed it’s been harder than it should be to suppress the SE ridge from going ape the last 5 years. And I’m not talking about when the EPO is mediocre and the PNA is -4. But even when it seems like it should be a workable look the SE ridge goes nuts.

I’m working on -NAO and neutral pna. It will have to do!

Merry Christmas

@CAPEthe pac changes we observed yesterday continue to move forward on long range guidance. Ensembles have been VERY good from about day 10-12 in so we’re maybe 48-72 hours from some confidence it’s real.

The pac ridge isn’t going to go away. That’s a Nina constant and it’s fed by the pac base state on top of the Nina. But we need it to broaden and be less sharp. Then the western trough could press cold shots east v digging down the west coast.

Some hints at the very end of the gefs/eps of the pac becoming more favorable. Not great but serviceable. Vortex in NW pac weakens. Central pac ridge becomes less amplified and extends poleward. You can see the pna trough is digging less in response. It’s a look that could allow cold to press east more assuming we keep a serviceable look up top. Too far out to worry about details.

It was heading towards 8 but I can’t remember if it actually ever made it. Very similar stall/death as now with the MC warm sst fighting the mjo progression.

I’m generally pessimistic until we see base state changes in the pac. I see a lot of similarities to 2019 when guidance tried again and again to progress the pattern in a logical way but the western pac base state continually thwarted it. That’s a pretty logical mistake for the NWP. It’s important to understand why they are wrong sometimes. Fool me once shame on you… That said there will be fluctuations. The guidance is weakening the NW pac vortex in January. That would help. The location of the pac ridge isn’t likely to change much. It’s well telleconnected to the Nina and western pac base state and TNH combo. However, we can do good if the pac ridge is less amplified and broader. It’s plenty poleward but it’s way too sharp which is digging the pna trough way too much. Even in 2019 there were some instances when the western trough shifted east just enough to get chances with waves. On a more specific front, one way I could see an opportunity in early January would be a scenery similar to the storm in Jan 2019. After the likely cutter we could get enough cold stuck under the block/50/50 for something to attack from the west. The ridge is far enough west for a time to maybe allow enough space for something to squeeze through. Wouldn’t be an amplified system but neither was that 2019 one. That’s one way to get something in this coming pattern.

That’s actually what a typical Nina h5 when the pac ridge is poleward and blocking looks like. But the relentless TNH has been pumping the SE ridge and altering the typical Nina pattern

Good discussion/speculation. If we really are in a phase of increased HL blocking as I suspect (we were long due) and we get a Nino while still near the solar minimum there is obviously potential for a blockbuster winter. We are overdue for one of those also. But there are variables as you all pointed out. I suspect maestro is correct that it would require more than a weak Nino to shake up the incredibly dominant pac base state since 2016. The weak Nino of 2019 didn’t even dent it. How much did the SSW influence that? Dunno but the Nino wasn’t having much affect on the pac even before the SSW. Of course we don’t want a super Nino either as that just floods tropical warmth across the continent. But there are no signs of that and a fairly strong Nino like 1958 can still have a kick ass second half. Even a mediocre Nino for the mid Atlantic like 2004-5 would be a godsend at this point! What type of Nino also matters. An east based Nino is a crap shoot. Some are good some are really bad (see 1992 & 1995!). Basin wide is better so long as it’s not a super Nino and modoki west based is the only super high almost can’t miss indicator of a cold/snowy winter in the mid Atlantic. Hopefully people remember though that many ninos, even ones that end up good like 1958, 1966, and 1987 or decent like 2004-5 or 2015-16 are pretty mild until mid January. I’m ok with the fact our December snow climo sucks but that seems to bother some a lot. But a Nino isn’t necessarily a cure for that. Moving to Vermont or Colorado would be a better plan!

The point of my last post was mostly missed. I wasn’t actually worried about the day 16 op Gfs being right but showing how that run was a good example of how a Nina can be frustrating even if we do get all the pretty h5 colors in the right places.

This is just to highlight why Nina’s can suck even when we get cold. The long range 6z Gfs does dump the trough into the east with as much depth as we can reasonably hope for…but there is no stj so the resultant system is going to miss us to the north.

Just to add to this…we have to be careful using the numerical indexes. The AO is calculated using the 1000mb level which isn’t the most influential on our weather and can be skewed by conflicting anomalies in its domain. I’ll content we had more “help” up top in 2014 then many give that winter credit. This is the mean winter h5 The lower heights in Canada and Iceland effect the AO index but there was a tendency to get ridging over the top from the epo to Scandinavia. Again it’s about degrees. That alone with a bad pac wouldn’t help much. But with an excellent pac, WPO/epo/pna ridge that’s plenty helpful. The net effect if that is a great look Imo. The tpv is displaced in a great spot to get systems rotating around and just under us. And here are 2 of our warning events that had a lot of HL help… Later in Feb and March there was less HL help but by then cold was established and things were set in motion. That also happens. 1996 the blocking broke down before the 2 big storms in January but the wheels were set in motion. 2015 was actually the more anomalous pattern. But as you pointed out it was really only about 2 weeks in Feb and one storm in March (which was a weird trailing wave which almost never works) that delivered all the snow. Maybe it was just luck! But there was an extremely displaced PV in Quebec that acted to simulate similat longwave characteristics that HL blocking would. Those indexes are cheap shortcuts but you really still have to look at the longwave pattern because there are exceptions and times the numbers don’t do reality Justice. I know you know that just wanted to add to your post.

When have I said it’s not a big concern? I’ll make these statements. 1) If this pac base remains it will be really hard to get consistent snow in this area. The last 5 years are very typical of what we should expect in this pac regime. It can snow but it will be slim pickings and storms will be few and far between. 2) I can’t say for sure how much is cyclical and how much is “you know what”. There are some logical possibilities on how warming has made this worse. I’ve mentioned the changes in the typical SST profile in the IO and western PAC favoring convection in hostile locations for cold here AND the expansion of the pac Hadley cell as possible warming related contributing factors. But I can’t prove anything. 3) should I say this everyday 5 times? Scream it’s never going to snow again and cry? Or do what I do and simply get over it and look for whatever opportunities we can manage despite the crappy base state that seems stuck.

@CAPE @Ji this is why I think there is more to this than Nina. The closest example of what we’re dealing with now was actually 2019 which was a Nino! Truth is this has been a consistent pac issue for 5 years through 2 neutral, 1 Nino and 2 Nina’s. This year it’s just even more out of control!

No but neither does a +AO. Most of the snows are when the AO is neg or neutral. Only a few near the top of that graph also. But look at the real issue…none if the AO is +4/5 just like none if the pna is -4/5 like now! If the PNA was +2 but the AO was +5 we would be screaming how we need the AO right now. Truth is we need more than one thing to have a good chance. ETA: there is also a big difference between DCA where that chart was made from and the NW burbs. Places in our forum can do ok snow wise with a -pna -NAO so long as the NAO is more neg than the pna. Lots of 1-3” storms at DCA that were 4-8” not far NW of the beltway. DCA REALLY sucks. It has to be so perfect for it to snow a lot there.