SnowGoose69

One thing is for sure, the GFS Fri/Sat on that run moved towards the Euro or CMC idea which we obviously knew was happening given the block

The GFS Op continues to frequently show a PNA that is like -5, albeit this run it did not, it found a new way in the 11-15 to mess stuff up as was said above the Pac was not that bad although you get the impression D14-16 if it ran to D20 it would blast that ridge across the entire US and go zonal

Air mass was meh but NAO was strongly negative and PNA was positive. It was nearly the same setup as 2/83 more or less http://www.meteo.psu.edu/fxg1/NARR/2009/us1218.php

The one thing I have noticed the last 48 hours is that while the Pac still looks meh 12/10-12/14 the SER is noticeably flatter or more of TN Valley/S Plains ridge which depending where you are in the NE/MA varies how you feel on that

Any winter event next weekend or early the next week will be nearly impossible to forecast beyond 3 days as not only is the strong block a factor but the remaining SE ridge impact. So trying to resolve how far south the storm is pushed due to the block is one issue but then what does the SE ridge do

One notable change the last 48 hours is the GEFS now almost unanimously agree on the PNA going to neutral, the spread with the crazy -2s 12/10-12/15 are now gone

This for whatever reason has been a consistent theme by the GFS the last week...its not unusual as we know to see big differences but its consistently been a torchy Op and cold ensemble on 90% plus of runs

The strangest thing in the last week is how there has not really been more than 1-2 GFS Op runs showing a good pattern past D10 while the GEFS more or less consistently has, the 06Z run disparity between the Op and ensemble is maybe the best example of that

The main I problem I see is the GEFS now have the PNA in some cases as low as -2 in 15 days where most ensembles 4-5 days ago were near neutral. If the GEFS is correct on the PNA and the EPS is not its hard to see even the GEFS mean 11-15 verifying of a trof in the east.

The GFS looping it from 220-290 is hilarious with all the lows retrograding west in NE Canada

Verbatim the 18Z GFS 12/12 on is basically a Gulf Coast snow threat lol...hopefully we do not go that full blown shredder pattern. I believe the 12/10-12/20 period in 2010 was similar to that but not quite that bad

It was a fortunate setup too, we had a setup for a storm about 3 days prior but the shortwave which ultimately caused 12/30/00 ruined the initial event...that event may have been a more widespread Miller Aish KU whereas 12/30/00 was narrowed to a small area. The 5 boroughs actually were not under a winter storm watch a single time from March 1996 until the December 2000 storm. That is a record that probably never will be exceeded again. Obviously in today's meteorological advancement world both 3/20/98 and 1/25/00 likely would have had watches out and probably even 3/14/99 as well

December 2000 came fairly close to a shutout though I think we had a cheap 1.5 inch snow event mid month which would have qualified as something

One strange aspect we are seeing yet again much as we did 7-10-12 days out from the most recent cold stretch is the Op runs of the GFS/EC are/were insanely mild and ridgey in the east relative to the ensembles...not sure why this is the case but indeed we saw this back in early November too when the ensembles showed almost an entirely 180'd pattern in the long range compared to Ops...its not unusual to see that on some runs but it was almost persistent and it is again.

LOL, FOK airport is 20 degrees colder than HWV and 26 colder than E Hampton...I have seen those differences between there and NYC but never the 2 closest airports

The weak PV and the occasionally funky angular momentum numbers in recent 8 weeks more indicative of a Nino may very well result in a different outcome this year. I know we've seen jokes of a La Nino on social media but there are really signs of both to some degree. We've even seen periods where there is a subtropical jet feature the last 4-6 months

Also I think the MJO was moderately strong in phase 6, it probably will be in 7 or 8 or CDO this time

Even if it gets back to 6 it'll probably be January 1 by the time it happens...it looks likely we will be in 7 or 8 and probably nothing for awhile before any 6 happens again

The 06Z GEFS ultimately gets there 360-384 anyway, just takes a different path to do so

Isnt the standard we have noticed in recent years is the GFS in Ninas typically wins these battles due to the northern stream dominance usually playing into these differences at day 4-6. This one is maybe less so solely a result of that but would not shock me if GFS is correct, especially now that the ensembles agree

It probably does end up more troughy/cold BEHIND the system than the Op GFS/CMC show at 12z....they are if you want to get theoretical a bit too flat or ridgey behind a low that deep but as far as the pulling in air cold enough to snow the low in central Canada coupled with no cold high even across E Canada settles that idea, unless you're at high elevation maybe

The one persistent thing has been if the Euro is killing an MJO wave and the GEFS is blasting into the next phase the GEFS has won almost every single time the last 3-4 years. I'd say its 90-10 or so...no question the Euro has issues on MJO amplitude forecasts

Its remarkable though how the Op despite the ensembles not being close on any of the last 3 runs spat out such a vastly different idea than the ensemble mean...at 132 on the 00Z run the GEFS vs GFS difference is maybe the biggest I ever saw at Day 6

I was about to say shift everything 700 miles west and that pattern is fine lol

I'd lean towards the GEFS on the MJO...anytime the last few winters where its "outamplituding" the EPS it has tended to be right so I'd lean on at least a strong 7 if not going into 8