psuhoffman

So are dozens of others that didn’t end up that extreme.

lol. I just said why are you wanting to change anything on a run that gave you 20”! But if storm one becomes a mecs so what. But everything affects everything else so rooting to change a lead wave when that solution lead to 20” 2 days later was odd and risky. That’s all. We have no control so it doesn’t matter.

Not bad for the week

I’ll take it as an appetizer to kick off the pattern.

Ji is right there is definitely potential for the Jan 6 wave to trend south. Slightly less separation between the wave and the 50/50 and it could be a better event. I think the top end potential is lower than the next wave hypothetically but I wouldn’t kick a 4-8” snow out of bed.

I’m somewhere over Montana.

Yes but people don’t want to hear that. But it’s typically how it goes with blocking.

This gfs run has too much blocking day 10-15 and crushes everything. That hasn’t been a typical problem at all recently so let’s wait and see. I’d rather see that than cutters at range.

Ggem suppressed for the opposite reason as gfs. It washes out wave 1 which leaves room wave 2 to amplify and it does but without wave 1 it drops the boundary too far south. Both are a typical error at that range from a hit so Im fine with both.

But wave 2 dying on the gfs has opened the window behind it. Incoming look day 9! The pattern is loaded. Remember what I said though about it often not being the wave we first identify at range.

The biggest issue on gfs is timing. Not enough separation between the two waves. The boundary is close by but the lead wave slowed down 12 hours and really squashes the second. It’s trying to amplify onto the suppressive flow behind wave 1. We need more separation for it to work

Anyone upset at this gfs run is lacking perspective. No single run is likely to be 100% accurate at that range or even close. It’s well within a typical expected error of a hit this run. That’s all that matters.

The further north solutions with wave 1 leaves the batoclinic boundary closer to us which puts us in the game for a bigger event wave 2 which is more of a stj wave coming from a better angle. More miller A. Higher upside. That doesn’t mean there is no path to two hits. A west primary track with better CAD and a 3-6” thump to dry a lot is very much a scenario that could lead to a nice first event and leave the door open to wave 2. But if the lead wave ends up tracking under us and leaves the boundary down through SC we’re probably cooked for the second wave and that becomes a NC SC snow threat. That’s just how I see the permutations here but what I want or say doesn’t matter and won’t affect the outcome so…

Now you listen

I would sacrifice a decade of 3-5” storms for a 50/50 shot at a hecs.

It’s a classic snow/sleet thump to dry slot imo.

Btw I think our chances of a MECs snow for this whole pattern, however long that is, is higher. Maybe closer to 50-60% based on historic results but the guidance doesn’t yet encompass the entirety of the period so I’m just talking about the 2 threats in the Jan 6-12th window.

But do they are are people reading the tool wrong? A few years ago I created an objective tool and posted the 50% snowfall forecast from 24 hour cycles of the geps, gefs and eps to show people were interpreting it wrong due to bias. They get excited about a run that shows snow and ignore the ones that don’t. They also use the mean which is skewed high by a few big snow solutions when the 50% plot snows what it really thinks. Right now for example based on the last 24 hour cycle we have about a 30% chance of a MECS level or higher snow and about a 50% of SECS. And about a 40% chance we get skunked the next 15 days. The most likely median outcome according to the whole guidance package is 1-4” across the area. But that’s really good. Having a better than 50% chance of snow in general but more so having a 30% chance at that range of a mecs level event is a rare high probability chance. But it’s still more likely to fail and that’s not the guidance failing that’s people who see the hecs runs and ignore that most don’t actually show that. At day 10 all we can do is identify threat windows and because we live in a very low snow area many of them will fail. But we spend most of many winters in periods where there is absolutely no chance of a mecs snow. So having a period with 30% is worth noting imo!

I think the mean was an artifact of smoothing due to outliers. The couple times I peeked under the hood the members that did have blocking were pretty nuts about it. But there were members that did the whole SER likage which lead to extreme cutters breaking down the ridge instead of cutting it off.

Last thought from 30k feet. Thinking back on all recent blocking regimes it was almost always not the first threat we identified that ended up the snowstorm. 2021 we missed several chances before that storm Jan31-Feb1 hit. March 2018 we missed 3 storms and I made some huge dumpster fire meltdown post in the panic room then we got the snowstorm! Jan 2016 we were tracking 2 threats that didn’t work out before the hecs. The block set in Dec 2010 and we didn’t get a mecs until late January and had to suffer a couple times bad first! 2009/10 was about the only time we hit every time a threat showed up! Even 1996 the blocking set in a month before we got the epic week of snow! We missed a mecs just to our north right before Xmas then there was a cutter in early January. Every blocking regime of this magnitude in my life did produce snow. Some were epic and some were just some snow. But it’s very likely we get at least a secs somewhere from this. History says that. SimplE probabilities. But don’t be surprised if it’s not the first storm we identify from range. Don’t over react if one or two threats don’t work out. That’s often how we roll. Even in a good pattern.

@CAPE you weren’t wrong about the inception of this blocking regime being a less common evolution. But when I went and looked I did find some examples, a few in the 60s and that 2006 one were very similar. It doesn’t matter how the heat bubble gets to the Greenland area so long as wave breaking takes over with the feedback loop we need to cut off the flow and trap it there with the mid latitude flow “blocked” under it. We’ve seen some attempts at more canonical retrogression induced ridges fail when storms cut west and displaced the attempts at ridging instead of sliding under and reinforcing it. I was skeptical but more so that we might see the SER linkage we saw in recent years and storms would cut into the ridge destructively interfering instead of under it to feed back into the cycle needed. I wonder as we continue to warm of this path to blocking might not become more common. A huge heat ridge migrating so far north that if we get a storm track under it we end up with the same end result as the retrograding Scandinavian heat ridge scenario. The end result on our pattern is the same if you get there.

Combine the temps with the ideal pass of the mid and upper level lows and ratios would be well above 10-1. Silly to worry about at that range but the at run wouldn’t be 10-1.

Something to note, the extended products continue to delay the eventual morphology of the pattern into a canonical Nina look. In two recent ninos they did this, wanting to morph the pattern into a canonical enso look that never happened. It’s very possible they are doing the same now. If we look where the ensembles leave us now day 15/16 it’s still a ways from getting to a Nina look. When this pattern does break down it’s likely through retrogression as the jet extension effects fade and it retracts. We actually would want pattern retrogression from this look. We would have at least another 1-2 weeks of a favorable window from here if this look were to go through retrogression. That gets us almost to Feb! The pattern will eventually morph/end obviously. But it’s setting in early January right at the start of our best snow climo. And I think it lasts at least 3 weeks before a total collapse. And I’m starting to like the over on that! I could see some version of this lingering through much of our cold season, or at least enough to stack our chances of our first positive seasonal bust in a long time!

We haven’t had much to track around here but I keep an eye on multiple regions for skiing interests and the gfs has been a total train wreck anecdotally on almost all the storms I’ve tracked. Flipping around run to run and almost invariably eventually caving to a solution closer to the euro. Btw the gefs still has an issue with under dispersion so if the op goes off on a tangent the ensembles almost always follow it and that makes them kinda useless for what they’re intended.