psuhoffman

Yes the main pv displacement went to their side. We still benefit from a weakened PV in general and as the pac pattern retrogrades and we get some cold into our side maybe that finally pays off.

The gefs is going bonkers with the Greenland block. this... leads to this look as it starts to relax which leads to that spike in snowfall... if the gefs is right about that the period as the blocking relaxes is commonly when we do score so the progression fits.

Like CAPE I’m mostly just bored with this pattern chasing. Also frustrated we can’t seem to link into just some snow in what shouldn’t be a shutout look. But we look to keep the extremely -AO/NAO for the next 15 days if not longer. I still will be shocked if we get a strongly -AO/NAO for a solid month in mid winter and get shut out. That’s kinda crazy. I’ll bet that somewhere we get lucky.

Naw another Nina coming. 2012 repeat.

I was actually saying that was a pretty good setup. It’s not perfect. More wave separation and a 50/50 would be ideal. But a displaced TPV lobe diving in and phasing just to our west is a way we have scored before. It can cut inland if the trough amplifies too far west so it’s not this sure thing can’t fail look. Get more spacing and a 50/50 and it becomes that. But I was saying that tpv there makes getting higher heights in the lakes impossible. But so long as the low is behind the southern wave and not in front it’s ok. The way that works is the cold is locked in long enough in front then by the time the lakes low would screw us the coastal takes over and the mid levels close off and the lakes low becomes irrelevant. That only works if the NS isn’t dominant like the gfs and ggem showed. The euro was all NS and that won’t work. To make my point look at the 12z gfs run. The mid levels stay cold enough. We’re rain because it is just too warm at the surface despite a closed circulation and saturation. The lakes low wasn’t really a huge issue it was just too warm at the surface. That’s sad for Jan 19 with a bombing low off the coast!

Right where we...ahh forget it

Agree with all this but I think the enhanced pac jet isn’t totally Nina related. Some of the better analogs I mentioned that also featured a similar N PAC pattern were Nina’s. They didn’t produce huge years but decent snowfall and that was always my high end goal.

Much larger landmass at higher latitude and they aren’t downwind of the largest heat source on the planet. It is MUCH easier for deep cold air masses to develop in Asia then North America.

This is subjective. You aren’t wrong. When I say pattern I’m referring more to the broader longwave pattern. And at several times so far this year the pattern analogs have spit out very nice dates of snowstorms. But it failed to produce this time the same as those past similar patterns. I do think I underestimated the harm the enhanced pac jet would do. Maybe some was bad luck. You know who didn’t...isotherm. He nailed this. He predicted favorable indexes for Dec and January yet said we wouldn’t get much snow. He predicted the pacific jet would destructively interfere. Im going to be totally honest here I might have a blind spot there because frankly I want to be an optimist...and I fear the enhanced pac jet might be a more permanent problem if as I suspect it’s partly due to the warmer base state of the pac. And if the effect of that pac jet is that some of our best snow patterns are no longer viable...and we need cross polar flow which is pretty rare to offset it...and that is pac jet feature is a new somewhat permanent feature...well you get where this is going and it’s somewhere I don’t want to go!

Imo the same thing that has been...we just don’t get lucky in a decent to good longwave pattern. This year the problem hadn’t been a failure of guidance to see the pattern. It’s been the failure of mostly a decent to at times good pattern to produce anything. Imo the pathetic lack of cold for the pattern is the culprit. Yea it’s snowed in TX and TN and NC but they were all isolated upper level dynamically driven events with a really narrow expanse. If you were to look at a snowfall mean map so far more places are struggling then doing well. There have been scattered local hits because the track of SWs has been pretty good (good longwave pattern) but without cold and a lack of good baroclinic boundary due to that systems are pathetic at the surface and lack a big expense of snow that makes it more likely for us to cash in.

There is good and bad compared to 0z. It has a bit too much SE ridge. Get a little less trough out west though and that becomes a good pattern with a very minor adjustment. It’s no good for the 19th threat though. Doesn’t dig the trough nearly enough. It’s all NS then because it doesn’t amplify it doesn’t really have the second threat either since everything pulls back without that first wave amplifying east. But even there a fairly minor adjustment makes it better. It doesn’t fully support the garbage op look. It’s kinda in between the GEFS CMC look and the euro op.

You make it hard to miss you

Btw after looking like a wreck the other day the GEPS has trended to the GEFS and has a very nice look days 7-16

There is a lot wrong with that euro op run. It shunts the majority of the next heat flux from the WAR off to the east and does not develop a true Greenland block. The NAO is weakly negative but it’s muted compared to other guidance (and the previous EPS runs frankly). The pna ridge is also shallow. The result of those two factors is the trough in the east has less amplitude (less depth) and so nothing digs enough to tap gulf moisture or amplify. This the all NS result you observe. Let’s see if the EPS agrees. The EPS hasn’t looked as good as the GEFS but it wasn’t that steaming pile of garbage either.

DUDE...did you just imply the NAM state doesn’t correlate to snowfall here? (For the record it is the #1 correlation to DC snow).

The euro doesn’t that’s for sure

And yet the ground truth is about the same in many spots lol

Last observation for now...the Uber long range look with a western trough but a west based -NAO and 50/50 is one where we can get front end thumps to dry slot type storms. The mean track will try to be to our west but that’s a pretty good CAD setup and not just weak insitu type that would lead to the type where it’s really hard to dislodge and we can do some frozen with a track pretty far NW track. Before that I see 2 discreet threat windows. The one around the 19 and another a few days later. The TPV gets further displaced and slides into SE Canada or even into the 50/50. That’s a more canonical (recently) big snowstorm look. The look is much better on the GFS guidance then the euro so hopefully it scores the coup here. The euro isn’t awful and a slight adjustment away but it sets up the trough too far west for the 19th and then goes too heavy with the trough out west after that. It’s a balancing act like a see saw. With a -NAO we can overcome a -pna to a point but if the western trough goes totally ape it becomes harder. Luckily the euro still has a bias I believe of doing that, I’ve noticed it still seems that way recently anecdotally. So for now Im cautiously optimistic in a more gfs like progression.

Para gfs fringes us with back to back storms because the TPV dives in slightly further east which is possible too at that range. A good longwave pattern gets us in the game but details that cannot be seen at range will determine the specific outcome of synoptic events.

Rain is a legit threat in this type setup BUT so long as the trough doesn’t go negative before our longitude and the surface low gets to the coast before turning north we would be ok. We have had plenty of nice snowstorms with this look. ETA: what I mean is yea if the storm cuts inland because the trough went negative too far west it would rain. And that “could” happen. But the scenario the GFS showed where everything went exactly how we want and the storm came up off the coast and it still rained...that’s nonsense.

This is a different longwave setup then the one you’re describing. We haven’t had this look much recently, it’s not that uncommon historically but it’s been virtually extinct lately. But the TPV displaced in south central Canada will promote lower heights in the lakes and ridging to our northeast. And if we didn’t have a huge western ridge and a -NAO with a decently cold antecedent airmass that would be a death sentence which is what we’re used to lately. But with a trough of that depth/longitude/axis we actually need that. Anything that forms down south would end up way OTS otherwise. That’s the kind of look where a storm runs the coast. Us being the furthest west of the megalopolis actually is favorable here. These type setups were more common in the past and can leave eastern NE more susceptible to a flip sometimes if it takes an inside track. The key for us is the trough not going negative too early or trending further west. There was a high to our northeast. Weak but it’s there. The lakes low is behind the dominant southern wave and the coastal develops a closed mid level circulation before that should interfere. But that’s another detail we need. The northern stream needs to feed into the southern wave not the other way. If the NS is the dominant SW this won’t work. Ideally if future runs trend towards a 50/50 low this goes from a very good look with MECS potential to a perfect HECS one but with the TPV in southern Canada that’s a tough ask as that’s going to promote ridging in front. But it also is going to dig the trough just to our west so it compensates for that issue some also.

The signal for the 19/20th has only become more pronounced in the last 24 hours. All the parts are there. Severely displaced TPV in southern Canada. Colder antecedent airmass. -NAO. Very nice wave depth and alignment signature. But the details models will not get accurate at this range will determine exactly how it plays out. No sense getting upset over those details that will change every run for another couple days. 150 hours seems to be about the magic spot where the globals start to hone in on some synoptic level details. We’re still 2 days from that. I will say this about the 12z gfs. If we get a big rainstorm on January 19th from a 984 low 75 miles east of Ocean City with a closed h5 low track across southern VA and a TPV just north of Michigan I am done for the year and I mean it. That’s absolutely ridiculous. And don’t someone tell me how this or that was 2.5 miles off from being perfect. If that setup doesn’t get us a snowstorm we’re wasting our time.

SHOCKING

I don’t know if you were pointing this out or not, sometimes I suck at context clues, but this is exactly what I’m talking about. We are downwind of the pac! Almost always our airmass will be pacific in origins. And before it was in the pacific it was probably over Asia! But air masses do change characteristics some. There is a huge difference between a pacific Maritime airmass that originated in the tropical or subtropical pacific blasting straight across the US at mid latitudes and a pacific airmass that originated in the colder north Pacific then traversed Alaska and the Yukon before diving into the US. The former will never work. The latter better darn well work because that’s responsible for 90% of our snow. How common do you think a direct cross polar flow from Siberia is? And guess what more often then not when we get those arctic blasts once in a blue moon it’s a cold dry pattern then warms before any storm comes because typically to get that you need a full latitude wave 1 EPO ridge configuration and that is NOT good for getting a favorable storm track here. If we need a direct flow from Siberia to get snow we (as DT would say) are fooked.