SnowGoose69

The GEPS has the past 2 runs for sure on the 00 last night and 12 yesterday but it has been bad recently...it denied the current warmup vehemently 10-12 days ago when the GEFS/EPS insisted on it in their D12-D16 periods, now it sort of wants to kick the SER as far as 1/8-1/9. The GEFS/EPS have worsened slightly in recent days by making the W ridge shorter and or further east...I said in the NYC forum there is a 04-05ish look in some members in the 500 heights where places like MSP/MCI/OMA torch but DCA-SNE can do okay and be below normal with snow chances. I still prefer the ridge further west though over the Rockies or W Coast

I'd ignore the GEPS if that is what you're referencing as it has been extremely bad the last 4 weeks now beyond D8-10...the EPS/GEFS have not really budged at all now in 5 days...the main problem is some ensemble members either have the ridge out west too short or too far east...to a degree we see a bit of the 03-04/04-05 thing going on which worked for us and SNE but basically the rest of the country straight out torched in both of those winters where the ridge is basically centered over the Plains or just west of there...that pattern can work here, especially if the NAO is negative.

The idea of the -PNA though on the Op run is really an outlier to all the ensembles though...I still think something may happen in that period but more likely in SNE

It sure looks like its gonna get cold and active for a week or two in mid January, its just a question if it flips again...the fact we had the -AO/NAO in December is usually a good sign for the rest of winter, minus 89-90 of course so I feel optimistic this won't just be a January 97/99/00 type of brief flip in a neutral or Nina...La Ninas have a tendency to see whatever the pattern was in December revert back in February alot of the time so we may go back to crappy Pacific again but good Atlantic in February...that works in February way more often for coastal areas than it does in December.

I don't think the amplitude will be enough to really impact things much, this wave has been trending weaker with time on both ensembles...it seems the tendency so far this winter has been for a weaker wave than shown in the long range regardless of what phase its in

Evidently this storm broke the GFS model

December 2015 was like a La Nina, we had a raging SE ridge, normally in a strong Nino you'd have the monster low in the SW GOA, some sort of ridging east of it near the west coast and usually troffy or zonal like flow in the east. That pattern made no sense at the time....I think if I remember right some speculated the crazy MJO wave at the time may have overwhelmed what was even a strong Nino

This Nina is weakening. I still think NYC ends up over 20 inches this winter...the raging -AO/NAO in December outside of 89-90 has always led to 1 or 2 more similar episodes later in winter, its really tough to get a ratter pattern as you get into Jan-Mar with those indices like that, its much easier in December to fail

Unfortunately too the most recent ENSO runs now are less optimistic for a Nino in 23-24, the mean is actually around -0.1C lol...I still think given various factors in recent weeks we are going into at least a very weak Nino next winter, it may just take til spring til the predicting models see it

At least the GEFS sort of caved to the GEPS/EPS to a degree...none really show a SER anymore, the main bad change was they've delayed the vortex in AK moving west and the PNA going positive somewhat but they've at least moved more towards there being no connection between the block over Canada and the ridge anymore. Part of this change is probably the fact the breakdown of the western ridge has been delayed too from 2-3 days ago which is no surprise, the ensembles showed a total breakdown by 12/26-12/27 and now that is delayed which ultimately kicks the entire evolution further down

A storm of the magnitude depicted is just extraordinarily rare so some type of move that way would be expected. I think I'd still rather be in Indy/Grand Rapids etc than say Rockford as of now....to a degree something weaker may be better for whoever is in the ideal zone because the GFS with its bombs has been occluding the low so fast you lose the dynamics and subsequently get showery snow thereafter, a 988 system is sometimes better than a 972 bomb that occludes

If you look at the 06Z GFS and 00Z Euro there really is not even any spot in the Midwest or Lakes which sees epic snows, the GFS simply occludes too quickly and the Euro is just a tad too progressive and then also semi occludes...it may ultimately be somewhere like STL or Peoria who sees the biggest amounts, Indy may snow forever once they get rid of the rain or mix but it may not be heavy by that point

Yeah that isn't a setup where this area sees rain to snow...there are only 2 or 3 setups where that happens and this is not one of them. The closed 500 low like 2/8/13 or 12/25/02 is the most common although the 2 setups were not exactly the same as one was a Miller B and the other was really a strange hybrid, I would not call Christmas 02 a Miller A or B. The other setups are all similar and usually involve some type of surface low formation on a front and require a negative tilt or semi stall...this thing is just progressing too fast

I find it funny that even Detroit and Indianapolis are mostly rain now

It has less influence in the summer months somewhat than it does in winter, you get patterns and teloconnections lining up differently. Also no idea if the inevitable flip to a cold AMO may cool those waters

The ridge IMO was just too far west...we have had big snows from ridges on or off the W Coast but more often later in winter, with a broad/elongated PV that extends from MB to QC, or with the whole pattern breaking down or about to break down and the ridge progressing east with time...I noted both 1/7/96 and 2/16/03 as cases where the ridge was too far west as the pieces began coming together but the Pac was in the process of being about to blast the nation so the whole pattern was shifting east with time and by the time the phasing was beginning the ridge was over the rockies

Really the GEFS only was correct about the pattern switch really happening closer to 12/15 vs 12/10, after that it was sort of owned by the GEPS/EPS, I posted in the SNE thread I'd feel better about January right now as the GEPS/EPS show a +PNA by D14-16 while the GEFS wants to go -PNA...the GEFS failed miserably about 10-12 days ago saying the 12/20-12/25 period would be a -PNA while the EPS/GEPS had it positive

The question is does Canada really torch as fast as the ensembles show...it seems remarkable to me that we are torched by 12/29, usually it takes time when things go to crap for it to effectively muck up things downstream this far...I would not be surprised if the anomalies D10-12 end up cooler than currently shown, albeit above normal as the vortex does not really begin flooding Canada til 12/25

The GEPS is the best obviously while the GEFS is the worst, largely because it seems it does not want to go +PNA whereas even the EPS does...the good news may be that the GEFS denied the +PNA fairly strongly we are currently headed into 10-15 days ago while the GEPS/EPS did not so perhaps its wrong again

They have random years where they severely under perform relative to Syracuse and Buffalo since they don’t get lake effect that easily and synoptic storms can miss them to the east

Monster SE ridge...it made no sense...typically a super Nino has a huge GOA low and big western ridge with the trof in the east with no cold air. If I remember right speculation was a strong MJO wave interfered causing the odd pattern

The 18Z GFS makes about 5 attempts as to where to place the surface low

Chances are with that limited period of the AK vortex we would not flood the country and torch that fast with a mean trof in the east...all 3 ensembles continue insisting that the relaxation is brief and the vortex backs up into the Aleutians D14-16 and we begin going cold again.

I think in a +PNA pattern it works for sure, but with this -PNA now unless we get a good cold AMO the next 20 years we will have an issue

The pattern was lousier most of that month and we had a SER most of the time. I think maybe 12/20-12/25 we briefly went semi trof in the east and a big snow event hit TN/AR/OK but otherwise the SER was dominant