StormchaserChuck!

It's a really big -PNA reloading again on Jan 3rd, very strong. How did we do these years. There's actually nothing like Dec 2010 for January Before 1-25-2000 (one of my favorite storms all time), we had a really strong -NAO, +450average for 10 days

Actually, the 6z GFS ensembles have a much stronger -NAO though.. strongest 10-15D run so far. We have +300dm as an ensemble mean over the Baffin Island at 384hr.

The last 21 -NAO's since March 2018 have had no power at all.. I think we are even average to slightly above average temps for that 300 day composite. Every single one has been with -PNA or +EPO, This one's going to do a +4SD -PNA, and probably end near average or above average as well.

GFS ensembles is reloading/strengthening -NAO at hr384 and it's reloading -PNA too. I think the reloading -PNA at 384hr is good because otherwise we may default quickly to +EPO. -PNA also keeps a lot of cold air in N.America (,but although that it sometimes than true, more times than not ~60% of the time SE ridge amplifies when that is the case). I do think we will see the Pacific shift in January, maybe Jan 5-10, and I mean as much of a flip as is possible with predominant -PNA cycle present. We seem to be in this law of averages-evening out thing, so there may be a +PNA period in Jan. Don't broadbrush the whole thing because it's Nina, just maybe expect less precip, as that has been the trend since the Summer anyway.

Only -PNA of the magnitude as this December is 2010 Pacific kind of flipped around in January (+300dm Dec 2010 #1.. #2 is 1955 +230dm)

Hey, December 2010 was the most -PNA by a lot, only really comparable to this year since the early 1900s. This was Jan 2011

Opposite correlation to last year, 15D model

In Dec 1995, we had a strong Kelvin Wave "head fake", and also 79-80,, 96-97 was a Strong El Nino 1 year later, but 96-97 was Neutral. 82-83 was also the 2nd strongest El Nino, 2-3 years later fwiw.

+3 popping up the western subsurface.. ENSO subsurface vs 4-5SD -PNA in December is a -PNA signal for Jan-Feb 2023, and that tends to coincide more with La Nina than El Nino (April-May on). 2010 is the only other year that had such a strong December -PNA (300dm) vs 230dm[2nd], and this is how it evolved. -1.6 2011 -1.4 -1.2 -0.9 -0.7 -0.6 -0.4 -0.5 -0.6 -0.8 -1.0 -1.1 -1.0 2012 -0.9 We will beat 2010 for number 1 this December.

A while back I plotted most extreme -PNA and +PNA times (330+days , and 330+days, since 1948), PNA leads to samePNA out to like 45 days. Less of a signal at 45-60 days. We are so opposite of last year all the time, I'm expecting a Jan-Feb (reverse of 22-23 too) less -PNA (if that makes any sense).

That's a -PNA signal for Winter 22-23 because ENSO central subsurface is warmer than cold right now vs -PNA (57-59, 65-67, 72-74, 97-99). I'd be impressed if we have an El Nino next year.

Furthermore, El Nino's that missed it, and had a -3SD> December -PNA vs ENSO state include 1957, 65, 72, 97, and the following February (Feb 2023 analog)fwiw -PNA next year maybe. I also mention this because the other 2 times 6th year after Strong El Nino, 7th year broke it(this shows not). ^(for ENSO analogs) subsurface ENSO is Kelvin Wave/warm-neutral now(El Nino slight analog, -PNA is 3-4SDsvsENSO right now: -PNA signal next Jan-Feb)

Top 20 -PNA December's since 1948, 2010 was +300dm, which beat 1955 +230dm for 2nd. 2nd dataset

We are on a streak since the 15-16 Strong El Nino that looks like this compared to the rest (Winter PNA): 6years -170 -120 -115 -112 etc

Might be the strongest -PNA on record for December, 12z GFS ensembles have 2 separate reloads of +640dm and +600dm! Enjoy the pure extremes over weather for the next two weeks.. observe what a High pressure in the Central North Pacific Ocean is like here.

Whoa! It might be hard for the NAO to go negative late month. The last few runs of GFS ensembles have kind of backed off a little.

I was looking at records for 500mb

Since 1948, PNA <-1 in Dec, with -NAO, 7 years, seems to shift energy to the NAO later, we'll see. (Of course, you know much of this December was +NAO)

3 pink 500mb anomaly peaks, 18z GFS ensemble mean: That's 582dm ridge in northern England, to start. 2nd image hits almost+600dm as an ensemble mean average, that's top 10-15 all time (I think I found +720dm over the Arctic as the record).

La Nina is weakening, and there should be a PNA shift around Jan 15th. It will be hard to do -PNA with that subsurface structure in the 2nd half of Winter.

It's a really good signal for Arctic cold. NAO block could last into January, too, alot of the roll forward stuff from the Spring, Summer and Fall had this.

At 12z, 8/25 GFS ensemble members had the 498dm Polar Vortex over SE Canada, or the NE at 384hr (12-29).

The last 3 times the PNA was <-1.00 in December, the rest of the Winter was -NAO, -PNA, I've seen that these types of things play out in real time vs later. Before then you have to go to the 1990s to have a -PNA December.

Honestly, -PNA with strong -NAO is not that bad. We do best snowstorms with GOA Low which is -PDO pattern. Problem is probably the STJ. -360dm on a 372hr average of 25 ensemble member is strong.

This really isn't bad.. the -PNA it seems reaches up to pour into -WPO and -EPO regions, with a big -NAO, and I think the cycle become wetter this could be a fun time unless it trends back. http://www.meteo.psu.edu/fxg1/ENSHGTAVGNH_12z/ensloopmref.html By 384hr, that's a really solid-NAO, and -WPO seems to be pinching off