psuhoffman

2015. 2016 was bad for a different reason though. We got the typical Nino north pac trough but in typical super Nino style it was too strong and encroached on the west coast too much and this flooded the Continent with mild pac puke much of that winter. 2017 to now the dominant pac base state has been a central pacific ridge which is bad. Our best way to offset that would be the HL but right now the pac is sooooo bad, literally the worst EVER coming up…that’s it’s just a no win no matter what else is in our favor.

If the pacific was REALLY good and the AO wasn’t a train wreck that would work. But the NAO would work if the pac wasn’t flaming poop also. It’s all a balancing act. Fact is it the AO is raging positive or the pac is hot poo we probably aren’t snowing in either scenario. Even when we scored in 2014 @ 2015 absent a great Atlantic it wasn’t garbage. There was often ridging over the top onto the AO domain in 2014. 2015 we had a displaced PV suppressing on the Atlantic side. We can’t score when either is a hot mess on wheels. We need one to be good and the other not to be a floating flaming dumpster fire.

Wrt these “what single factor is most important” arguments it depends on the degree and what combinations were talking about. For instance a mildly positive pna with a +epo/AO/NAO wont to us any good. What I can say is this, historically the -AO/NAO is the single factor that shows up the most in our warning level snows. Again I think we’re falling victim to recency bias because we’ve had a few -NAOs ruined by flat out awful atrocious pacific patterns recently. That’s not necessarily how it would always work. But the pac base state has been so bad lately…yea we need that to relax. But it won’t necessarily do any good if the AO goes to crap. Truth is we need more than just any one thing to be somewhat favorable to get snow.

Dude

Trying to ask this as respectfully as possible. So if you think there is no value to long range forecasting why do you come into the long range thread?

Follow up on the pna. It’s about degrees. Everything is a trade off. See saw wave game! We can do well in a -pna if the equation is balanced by the AO/NAO. That’s not possible when the pna is 5 std dev lol.

Skip to the bold paragraph if you just want the simple simple simple abridged answer… I think we’re falling prey to both recency bias and some attempts to over simplify with the “it’s the Nina” stuff I’m seeing. Let me again post the mean Dec-Feb h5 for all Nina’s the last 30 years to use as a frame of reference. Actually a crazy -pna isn’t a common problem in a Nina. At least no more so than it can be for a time in any enso phase. You can see the tendency for lower heights in western Canada but notice on the means heights are avg in the east and the pac ridge extends into the southwest. Also our temps avg near normal in Nina’s which is actually colder than if you take all other winters but exclude the 3 modoki ninos we’ve had during that time. The 2 major correlations with a Nina are the central pac ridge and weaker STJ. You’re seeing the smoothing of 2 different Nina patterns there though. In a Nina when there is a flatter pac ridge and no HL help we see the pac jet blast N America. But Typically in a Nina pattern when there is a more poleward pac ridge and or some HL blocking we see the cold spread out across N America centered in western Canada but extending into the northeast. Neither typically features what we’re seeing now though! And the current pna is bordering on possibly setting the December record. Last I saw it was just behind as the lowest pna but with what’s forecast the rest of the month I would bet it ends as the most neg pna December ever. Just that fact alone shows we’re dealing with something anomalous that we can’t just attribute to “typical Nina”. This hasn’t happened in any other Nina lol. Now let me simplify our snow chances as I see them based on major phases. It’s the STJ. Both Nina’s and ninos can have variable longwave features and both favorable and negative features and in the last 30 years there isn’t much difference in mean temps in a Nina v Nino. Both can feature cold and warm periods. But a Nino favors more stj and we need that! That stacks the deck that if/when we do get some cold we get a big snow. Look at 1983 and 2016! And if we get lucky and get a good longwave pattern and blocking in a Nino then we get 1987/2003/2010! But that’s not all ninos either. But if you remove all the big stj driven snows from ninos the snow climo wouldn’t look any better than Nina’s! The problem in a Nina is often when we do get long cold stretches without the STJ it’s just dry. We’re too far south to get a lot of snow from pure NS storms. Last thought: we’ve all noticed the pac base state of the last 6 years. And even the Nino of 2019 couldn’t disrupt it much. Maybe this is what happens when you add a second year Niña in top of that base state and so maybe this is the new “typical Nina” if the pac is going to remain in this phase. But we didn’t have this amount of issue with the pna last year once blocking set in. But this is a second year Niña so…

Cyclical. We had 4 Nina’s in 6 years from 1996-2001. Then only 1 in the next 7 years. 4 in 5 years from 2007-2012 then none from 2013-2017.

Except what you’re describing isn’t a La Niña. This is the comp of all Nina’s in the last 30 years. And that’s skewed by a couple of the ninas like 2008 and 2012 that were that way. But those are try outliers. Most Nina’s (if they have blocking) have a suppressed SE ridge and it’s just cold/dry. This isn’t a typical Nina. What you’re describing sounds more like 2002, 2017 and 2020 which were all enso neutral winters.

@CAPE unfortunately the eps is predictably pulling the rug again. I say predictably because it’s not changing anything except the strength of the SE ridge. And we’ve seen that’s being supported by the pac pattern. This is the old day 13.5 Note I’ve identified the placement of all key longwave features. The SE ridge is there but suppressed. However look at the pac. Why is it suppressing the SE ridge? We’ve still not seen any positive changes to the upstream factors. here is the new day 13. Nothing changes in the placement of all the key features. But as it’s getting closer and less smoother out, and the features come into better clarity, predictably the SE ridge is pumping more. That will continue to happen until something changes with the equation of the 3 features I circled in the pac. One of them has to move to shake that up. Or the equation between the Aleutian ridge and NAO needs to flip. If the Aleutian ridge weakens and the NAO ridge is the more dominant that can also work. But so long as those 3 features remain AND the Aleutian ridge is stronger than the NAO ridge we’re going to continue to see the SE ridge trend stronger and kill our changes imo.

I’ll admit not having the expertise to necessarily parse this accurately. Maybe someone else can add value. But one of the things driving the colder expected pattern was that mjo phase 7 is cold in a Nina. However, the soi has been tanking and today is at -27, more Nino than Nina. Just pointing this out because phase 7 in a Nino is warm and looks a lot like what we’re seeing. However, I know the mjo also affects the soi so…

Normally poleward helps, it was one of my optimistic observations. It’s been a more poleward ridge than a mid lat Nina type. But when it is poleward it doesn’t help, it’s so strong it just sharpens the ridge/trough and digs the trough even deeper in the west. We really need it to either shift east a few degrees and extend into western Canada OR simply weaken some. Either works. But I see neither happening until that vortex north of Japan moves. It’s feeding into the already hostile pac base state.

I’d feel better if that vortex north of Japan would move at all. It’s parked there on everything for the next 2 weeks and that feeds into the Aleutian ridge.

Like I said no towel throwing. You all know when I think it’s time to have an epic meltdown and nuke the season I won’t shy away. I can Ji with the best of ‘‘em but I wait until it’s REALLY time. My pessimism is more for the period from Dec 27-Jan 3 which I initially pegged a while ago as a period of opportunity. But ~10 days ago guidance had the equation slightly off. It had the N pac ridge but not to the actual amplitude. We could have worked with this look it that pac ridge was less anomalous. But it’s just too dominant and the downstream effects are more than the NAO can offset for places south of 40. After they is still ambiguous as it should be at that range. History still suggests eventual progression. Also, all we really need is for the pac to back off some. Not a full reshuffle. Even just a period where the pac ridge lessens somewhat and we could work with it. But…I would caution to continue to look at the amplitude and location of the features in the pac and be hesitant to buy the trough in the east until we see adequate signs that equation is changing.

That ridge is living on borrowed time. The pacific ridge and NAO have linked. We no longer have a monster ridge off the west coast to lock the trough in the west. Roll that forward 48 hours and there is a deep trough in the east. Apply basic wave physics. Think of the troughs and ridges as waves. Think of the basic see saw effect. Ridge digs next trough which pumps next ridge…but what if there is a rock thrown in the pond to create conflicting waves? See saw war! Right now the ridge in the pac is stronger than the NAO one. So it’s digging the pna trough too much and pumping the SE ridge more than the NAO can suppress. At least if you’re south of 40. That’s actually one detail guidance got slightly wrong. Overall the day 15 ensembles have been great at the longwave features. People expect too much. We still aren’t that far removed from when anything past 72 hours was a crap shoot. We’ve made amazing progress Imo. But when the current pattern was 15 days away the pac ridge was a little less anomalous and so the NAO ridge had a better chance of winning that see saw fight. Now apply all that to the plot I posted. Look how rye equation has changed. Where are the dominant features and ridges now? What’s happened to the pac ridge/trough relationship that’s been impeding the effects of the NAO? All this is just meant to be a mental exercise because we shouldn’t be analyzing a day 16 op prog like this. But that look would roll forward into a trough in the east.

As long as it ends like this

The last couple Gfs runs sucked but they did get to a place we wanted at the end. If getting a huge cutter and rain to Int Falls is what it takes to shake this up so be it.

The effects of low level heat added can be thwarted by the pattern to an extent. I’m not saying if we had a trough in the east it would still be warm. But what I’ve noticed is every ridge ends up going ape. I suspect the added heat simply adds fuel to attempted ridging.

I think that’s a factor but more so the other thing I said. In a -NAO/epo/pna pattern we need the trough to be broad and spread out. The cold will center west but press east. There will naturally be attempts at ridging in the east in that wavelength and we need the ridge to be suppressed. But the more you warm things in general logically the harder it is to suppress attempted ridging. The more heat you add the more ridges will win in that fight.

I’m sure many will interpret my posts as towel throwing even though I said it’s not…but one thing I’d advise caution looking at that there is with how it’s likely to adjust. That is what historical analogs suggest this should evolve too so it’s east to buy into it. But we’ve seen lately that 2 things, so long as the dominant pac longwave features are the same the trough will struggle to fight off the SE ridge and the guidance is missing this past day 10 because some members do put the trough in the east which muted the SE ridge signal in the means. But what happens as we get closer is the guidance is nailing the longwave features and the troughs and ridges just sharpen up. That little muted se ridge will very likely become more of a problem in future runs until we see something upstream change. On that I still see the n pac ridge slightly too far west, trough west of Hawaii. I don’t see anything has changed that would lend confidence it’s not again underestimating the SE ridge response. I don’t know what he said but I mentioned 2 specific ways warming could logically be impacting this pattern. The high latitudes aren’t our problem and I’m not sure how much impact the strat can have on the mid latitude pacific pattern which is our main problem.

It is

The ensembles are definitely kicking the csn now. Psu cant really argue that. That se ridge a monster The last 72 hours was a definite change. But you can’t just jump on things the first run something hints, and it happens non linearly with some good runs mixed back in, but it’s undeniable the guidance is backing away from any progression of the pacific pattern and that the N pac ridge will be too dominant for the NAO to have enough impact. I wouldn’t necessarily say it’s kicking the can as much as just stalling the pac progression. Speculating on what’s gone wrong, yes some of the mjo wave makes it into 8 but it’s really weak and now there are other areas of convection in less ideal locations so maybe the mjo won’t have the influence needed to fight the Nina base state. Additionally the pac ridge pna trough combo isn’t just typical Nina. It’s near record breaking. Early in winter thats too much for the NAO to fight off. If we repeated this in Feb/March we might have a better chance. Heavy speculation but could climate change play a factor? The gulf is on fire and adding latent heat to ridging in the east. When there is less cold globally it also stands to reason the cold will be less expansive where it is concentrated. That’s a problem when we have a -NAO -epo, -pna because the cold will dump west initially then we need it to eject and spread east under the block. Analogs suggest that’s typical. It’s not happening this time. At least not yet. Lastly I’m not tossing winter. This isn’t my post in Dec 2019 when I pretty much trashed our chances the whole season. There are still enough positives to work with in the base state to hope we get some periods of opportunity. I still have not given up on January if the pac can either back off or progress some. But the NAO won’t stay negative forever and we’re wasting prime time right now. What to look for that would be a sign this season was going in the tank like 2002 or 2020…if the pac ridge continues to be as strong and sinks into the mid latitude and AO goes raging positive it’s game over. That’s a stable pattern that often lasts months snd would eat away what’s left of winter. There is no sign of that yet but that’s a way this could evolve where I would admit it’s game over.

So if it keeps moving at this speed we’re good!

Still riding history that suggests amplified waves that start in 6/7 almost always make it to 8. Just the % 8/1

The guidance nailed the longwave pattern. And there was variability with some runs hinting the blocking would suppress the SE ridge and other runs saying the ridge would flex too much. The latter won. But how much suppression was always iffy.