psuhoffman

It’s trending more negative day 10-15 than guidance showed it previously. Not more negative than the -4 stdv it is now. We don’t need the AO to be -4 to snow.

Now that the guidance has resolved the bigger picture Synoptics of the evolution this week, and it makes much more sense given the lack of any antecedent cold, we can start to get a clearer picture of what could come after. As the primary from this week stalls and slowly dies to our north in Canada cold will finally slide east across the Conus. For a time the flow is likely to be progressive and suppressive. Not sure about that first wave around the 20th. That might be a slider. After that it gets interesting Imo. A lobe of the TPV is going to slide south through a temporary weakness in the blocking and end up in Canada. But at the same time the wave breaking from the system this week and that TPV is going to pump the NAO ridge and the blocking strengthens again. After that is when I think is our best shot. The TPV stuck under blocking will provide ample cold source. The key will be exactly how that TPV is situated. Several ways to score. Waves look to continue to eject from the pac and one could run the boundary under the TPV. The big dog potential would be around the 23-27th if something from the NS rotates down around the TPV and phases. That’s risky though. If there happens to be a 50/50 at the right time that’s the setup for a big storm. No 50/50 and too much Atlantic ridge in front and it would be a cutter. Weaker boundary waves would be higher probabilities for frozen but lower high end potential. Just my 2 cents how I think this might play out. Most of what I described the key events happen soon enough that I feel reasonably confident in this general progression.

I see you found a mirror.

Ji hasn’t been that bad Imo, just a frustrated post now and then when a specific storm doesn’t work out. The other guy though…is just straight trolling and contributes absolutely nothing of substance ever.

Agree with Wiggum. Unless you just have a bet the Bay freezes over you don’t actually want the core of that kind of cold centered on top of us. Storms are going to ride the boundary. You want to be on the cold side but not too far. That’s an ideal look Imo.

No matter how many times you say it the usual suspects will still melt down and unleash a rant in tongues when it fails.

if we ask a psychiatrist, probably nothing good

Fwiw UKMET looks like CMC/GFS. Mostly an upstate NY into New England event.

Yup. One think I think some underestimate…we’re too far south to ever have a can’t miss super high snow probability setup from long range. No matter how good the pattern is…we always will still need some luck wrt timing and other synoptic and meso scale details that can’t be seen until medium range at best.

Yea, but they look like we should expect for this type of system. Primary into the Midwest in mid December without an arctic airmass in place…not the way we win. Is it within the realm of possible sure, if we get super lucky in every detail, but we need more than just a block to snow. It gets annoying everytime we get blocking and then some assume every storm has to be snow suddenly. We rain during a blocking pattern all the time. Maybe even still more than snow! We need blocking AND the right synoptic setup. This ain’t it. Root for a fluke but don’t expect anything from this setup. It’s a bonus. Our better chances come after. Waves between the 20-25 need to be watched closely imo.

I tried but he complained that colors are a liberal hoax then ate the crayons.

refresh my memory...is having a -3std NAO and EPO block at the same time a good thing?

All this... There is a path here, but its narrow because the amount of confluence needed to force a system under us starting out that far north is so extreme its also likely to shred the system if thing's don't go exactly right. We saw this a few times back in 2021 where a system originally supposed to cut way north ended up shredded to nothing by the time it got to us. Does not mean it can't work out...but I still think our best bet would be for the system to kinda split and get a healthy front runner wave into the CAD rather then having the energy come out more consolidated and trying to slide under the block. Yea that has bigger upside...but more often then not either the primary mucks up the mid levels OR if there is enough confluence the system gets shredded and washes out. But I am not pessimistic overall... this first wave COULD work...but I think there are likely to be better opportunities later. If we do get any significant snow from this first threat I consider it a bonus.

One way a setup like this could work...is if the primary trends weaker and more disconnected...and we get a front runner wave. We have seen that setup lead to a modest snow/ice event before. Obviously the 6z GFS 12z ICON idea of a primary dying and a secondary bombing is ideal...but also pretty rare. The thing we don't want is for there to be a more consolidated/stronger primary that would wreck the mid levels pretty fast given how far west its tracking initially.

Yes, there are a few examples of that kind of progression. It’s not impossible but it’s rare. Definitely not the typical way we get a snowstorm.

not saying just saying. Keep in mind there was no snow in the cities during this period. There was a nice event NW and a front end snow to rain again NW during this period but the big snow came after when a pna temporarily popped. But I think its worth pointing out a couple things that could be pertinent if this in fact is the type of pattern we end up with. While non having a Nino will limit potential due to less STJ the pattern is the pattern. If a non Nina pattern happens in a Nina the atmosphere isn’t going to be like “no we can’t let it snow cause it’s a Nina”. The challenge is usually getting a non Nina pattern during a Nina! Second, we don’t need a long lived pna ridge. If we can just get a temporary one for a few days that kind of pattern is loaded. That’s how 2009 happened. A pna ridge popped at the right time allowing one of the ejecting waves from the west to dig into the east and not try to cut. And….voila.

@WxUSAF there is actually one fairly recent really good December -epo/AO/NAO/pna pattern match. Not a Nina though.

Not really unless you go WAY back…nothing the last 30 years. The closest comp would be March 2018. This is a lot more typical of a Nino longwave pattern up top actually, but the central pac makes this a super rare look overall. Not a lot of great comps. Even the top analogs aren’t really all that close for the best analog. But the best matches Imo were periods in Dec 1970, 1978, and 1989.

Yes

Euro bout to be like…

@WxUSAF watch the EPS go the other way now

@CAPE we agree 100% on the less ideal NAO look up top...but the reason I said its not hopeless is that while the latest depictions of the high latitudes are not a true block and really just higher heights from the extension of a full latitude ridge... that look can quickly/easily become good. For example...if a system were to amplify into the lakes/northeast...the heat transfer from that into the high latitudes could pump the ridge...and eventually cut it off into a true block. It wouldn't take much. Then we still have to deal with the whole no cold air anywhere problem...but one thing at a time. Just saying...while its disapointing, even if expected, that things aren't perfect...I would much prefer where we are now over seeing some consolidated blue ball of death up top. That would be game over...a central pac ridge with +++AO/NOA is the stuff our total shutout winters like 2020 are made out of. This currently blah pattern at least leaves the door open we could head in a better direction. I have a low bar.

It does...but I have a theory that the MJO has a more symbiotic relationship rather than a pure cause/effect one with the pattern. Convection in regions 8/1 is preferable yes. But convection there is also an effect of a nino pattern. So in a favorable pacific pattern we tend to get the MJO cycling through phases 8/1 strongly...and we get a great pattern...creating the "correlation". Phase 8/1=cold/snow. But I've also noticed that often when the pacific base state is in a bad phase...and the usual suspects are relying on the MJO to get into cold phases to "save us".... what happens is even if the MJO does eventually make it weakly into phases 8/1 it doesn't do us any good. The impact on the pattern isn't as extreme, and often by the time the pattern even starts to evolve from the awful one we are in...the effect wanes and the base state re-establishes. To simplify...waiting on the MJO to save us when we're in a bad pacific base state has mostly been futile over the years.