psuhoffman

All we need is another slight bump north and its a warning event for the entire area.

the systems in the 18-22 period are definitely moving away from the cutter idea.

The seasonal trend is we can rain but not snow We haven't been in a cold enough pattern to realize a seasonal pattern yet. We had 2 legit threats during our previous cold periods Mid November and early Dec with nice systems ejecting from the west into a cold airmass. One hit and one got suppressed. This is now the first such threat since. In between the general storm track has been great just no cold thanks to the pacific pattern. Not sure I am ready to declare what you are implying yet.

I agree with all your analysis except this. For the last 3 weeks we have had one perfect track stj system after another inundate us with qpf but there was no cold to work with. So are you basing this off the one threat so far when it was. cold in December? That seems like a small sample. Plus the system wasn't weak or strung out it simply got blocked by an incredibly awful placed lobe of the vortex to our northeast. I agree that this is trending away from an amplified solution but not sure I see a seasonal trend to that yet.

@frd @showmethesnow @Bob Chill Regarding the long range pattern setting up, I was thinking about the discussion the other day regarding to PV or not to PV and I realized we might just be describing things differently. I hate to quote my arch nemesis but yesterday JB was going on about needing to get rid of the PV over Canada. (was he reading here again! LOL) I decided to use the panel of the EPS that was showme had up earlier. First of all this is NOT a bad pattern, we can work with this, and we could get a snowstorm from this, but that PV there is less than ideal. But what we want is to get it from this.... To this.... The PV there isn't the worst thing, there are higher heights under it so there would be a tendency to get higher pressure in southern Canada to our north BUT the westerly flow under that PV will cut off any true cold from getting into the CONUS so during peak climo we can work with that, especially with ideal high locations, but its not going to be a sustained cold look and any storm with a less then perfect high will have temperature issues. Ideally we would want to see that PV weaken and then either elongate or split with a weaker vortex somewhere in central canada with a stronger piece taking up shop in the 50/50 space. Ideally the blocking would retrograde and end up almost where the PV is now. A strong PV like that will be tighter wound and thus more likely to enhance the jet around it making the flow more progressive. If it weakens that is when we can get it to split and elongate and that is when you can get the perfect setup where parts of it can dig into the trough to phase and parts can break off into the 50/50 and get stuck under the blocking. So when I say we "dont want a PV" I don't mean we dont want any vortices up there at all...but not a strong one. When I hear PV I think of the "big blue ball". Ideally we want red all across Canada with weak very weak vortices that do not get in the way of the buckling and amplification of the trough we need for a big storm. The worst thing would be if the PV remains strong and drops down right on top of us. That is cold/dry and kiss any big storms goodbye. If it remains strong and drops down to our west we can get progressive waves along the east coast but any significant storms would be unlikely. But cold with some snow isnt the worst. Ideally we want it to weaken and either get fully squeezed into the 50/50 area or split with the weaker part remaining over Canada. I think when people say "the PV is on the other side" it scares some because we are not used to having both PNA/EPO and NAO help lately. If we have a hostile NAO or EPO then having no strong PV up in canada is a death sentence. Without blocking, if there is no PV there to suppress the pattern the whole NAM will be flooded with warmth and we end up with a total evacuation of cold from our side. That is not what would happen with a -nao, and a favorable combo of the pna or epo. In that case we want high pressure all over canada and home grown cold. Nothing to interfere with the slowing and amplifying of the jet in the east we want for a big storm. It looks like that is where we are headed on the super long range guidance (CFS/Euro weeklies) in February. But we might have to get through a week or so where we have a severely displaced PV first before it weakens. So long as the blocking holds long enough we would get a better look on the other side of that. Our big storm chances might be before and after that period. During that period if the PV sets up in a less hostile location we could be in line for waves and it doesn't take that much qpf to get a nice storm when its that cold. Even a nice clipper can do it. So I am not saying a shutout, and I am not worrying about it until its reality, but the guidance does look kind of suppressive in the Jan 22 on period right now. That could obviously change, and any relaxation puts us in perfect spot and if the blocking holds we would get a window as the PV weakens as it will being so removed from the pole. All in all its a great look, but yea there will be times in that pattern where it might be too much of a good thing, but if blocking sets up and runs the table through February I highly doubt the PV sets up over the Lakes and squashes everything the rest of the winter. That would be a first. A lot of the super cold years that didn't snow much, the blocking wasn't long term enough or there wasn't much of a STJ so it didn't take much suppression. This year doesn't feel that way.

more on this... These are days 1-5, 6-10, and 11-16 on the GEFS. The euro seems to agree in general on this progression. I added where (in general) we want lower pressure and convection and where we do not. You can see the next 5 days are pretty ambiguous with normal to slightly below pressures in both areas. So we are pobably looking at a near neutral SOI over the next 5 days. Days 6-10 become more favorable, pressures are still lower then I would like north of Australia where ideally we would want high pressure but the lower pressures and main area of tropical forcing is definitely out in the central PAC where we want it. This looks like a slightly negative SOI Then days 12-16 the SOI would tank. This is a severely negative SOI look and it coincides with the start of our extreme pattern. So I am not worried right now about the current neutral SOI after the recent crash so long as we don't see a reversion to having the tropical forcing in the wrong locations over a long period. This looks to be temporary before another crash.

The SOI is calculated by the difference between pressure at Tahiti and Darwin. (I know you know this just laying it out there for everyone). A negative SOI is when the Pressure is higher at Darwin than Tahiti. A daily value is less useful then a longer term average because local pressure features can cause changes in the daily values but in general we want to see pressures lower in the central Pacific then near Darwin. That is because forcing near Darwin correlates to the warm phases of the MJO and a ridge here. Forcing out near Tahiti correlates to colder. This is why a central pacific based nino is good for us. (really simplifying it here but in general that's the thing) At the moment there is a low pressure system right near Darwin so that would account for the daily spike in the SOI. However there are still lower pressures in the Pacific. It looks like it may remain around neutral for the next few days then turn negative again. Pressures look pretty low at both locations actually and that might be a wash. So long as the pressures aren't lower to the west I would think the convection and forcing in the ideal locations for us should win out. Not concerned by a daily value near 0. Just don't want to see another spike up into very positive territory. The negative spike and the MJO into 8 did its job and the pattern is now cascading towards what we want. So long as nothing bad shows up the dominoes should continue to fall in our favor. Ambiguous inst a bad thing when the other factors are lined up in our favor. Just keep those things out of our way.

Yea 77 was brutal cold but not much snow. Suppression city.

That triple trough blocking longwave alignment is just as hard to beak down as the crap Pacific patterns we have suffered through. Could last the rest of winter.

SHUT UP CHUCK sorry Randy

@Bob Chill @C.A.P.E. I guess it makes sense. Modoki nino. Weak PV. Sswe. Low solar. There are reasons to think it might be real.

That bad lol?

I'm hearing the weeklies have even more blocking. Not sure how that's possible. Last run was almost perfect.

@Bob Chill your analysis is spot on but I'm not sure given the progressive flow and multiple moving parts here we are close enough to take too much from one op run. Icon trended better. Fv3 and gfs swapped places. That's about all so far. But yes the gfs at h5 was a bad step toward the euro. But there were gefs members like that so it could be noise.

Ji says lots of things

0z last night was sweet too.

Can't believe I'm even going to bother with the jma but it cuts off too far south and stalls and we are under easterly fetch too long. Adjust it north some and the thermals would be fine. Don't and the precip we get from the initial waa would be over and just snizzle by the time that warm layer invades but the big snow would be central and southwest VA.

No and it looked jacked up but I never doubt a new way to fail.

my wife said it was snowing up in Manchester a little while ago.

Perhaps the euro tendency to hold energy back in the southwest is leading to the weaker more sheared out solution here. It's weird to see some models with a progressive bias overall to be so much more amplified.

She has a very obvious agenda. I doubt it's going to change her spin at all. As of right now...she has been right about the winter...it has been warm. If we flip cold and snowy she will bust, if we don't she was right (about that) but she has been misrepresenting the enso data in a way to support her warm forecast and to very nastily blast everyone who had a cold forecast and to imply they are hyping and attention seeking. I took some offense to that since I am in the "cold/snowy" contingent but I can ensure you I went with that outlook because I honestly believed based on the analogs I think are most pertinent that it will be cold and snowy from mid January on. If I am wrong I am wrong, but to imply I am just saying that because I want it to be snowy or because I want some kind of attention is presumptuous and unnecessary. She could promote her own forecast without personally attacking everyone who disagrees with her. I feel like I have been very adamant about defending my own belief that things would turn colder, but without once attacking or implying a dishonest motive or doubting the integrity of those that disagree with me.

@40/70 Benchmark after all that crap about "it's not a modoki" region 1+2 cooled and the nino seems to be retreating westward after a peak which is classic modoki progression. Lol there is also some cooling to the north which could help provide the gradient needed

so we can analyze more partly cloudy?

Here comes the sh!t show...it's more predictable than the pattern change was!

@mappy @H2O @WxUSAF not that my opinion matters either but I would say its time to break this out into its own thread simply so the long range discussion doesn't get totally overwhelmed. Obviously this will be the most discussed thing (rightfully so) now but there is still some pretty good stuff regarding the upcoming pattern to talk about also.