Ralph Wiggum

"The North Atlantic Oscillation (NAO) is a weather phenomenon in the North Atlantic Ocean of fluctuations in the difference of atmospheric pressure at sea level (SLP) between the Icelandic Low and the Azores High." Source: https://www.google.com/url?sa=t&source=web&rct=j&url=https://en.m.wikipedia.org/wiki/North_Atlantic_oscillation&ved=2ahUKEwiVpf_FgfblAhWDdN8KHSCAAQAQFjAAegQIARAB&usg=AOvVaw0GhwXcCwaPNo9xghqVw1lN Obviously I would be more inclined to side with CPC and how they determine the NAO but I found that wiki article contradictory of what the CPC uses to measure. It seems odd that two of the big oscillation patterns would be gauged on 2 different atmospheric levels....apples to apples sort of thing.

Is it correct that the AO and NAO phases are actually based on surface pressures more than 500mb/geopotential heights?

But I heard November snows in Iran yield a mild rest of the winter there....kiss of death sorta thing

Taking a beating is an understatement. But a SSWE is extremely volatile and unpredictable. Could throw the entire trop into one hostile mess which is anyone's guess which areas that could potentially favor. I guess it is better than one massive stacked SPV/TPV combo over Santa's hometown but I take these SSWE's with a grain of salt. Sometimes they work out beautifully for us but more often then not it lays an egg.

Typical pattern change/reload/transition look. That is no doubt coming....most ens show this at least starting by day 10. Some bring the current looks back, some flip it.....certainly .mixed signals. Should have some idea about where Dec may head on or around Thanksgiving. I do like some of the recurring themes we have seen most of the fall. Doesnt mean they will hold as a background state this winter though. Lots to be answered.

What's a "gym"?

I like when you talk dirty....in a purely scientific kinda way!

Dafuq is this?

CPC is backing down on the severe -ao/- nao it had been showing for several days. Ao, nao, and pna look neutral towards late Nov. Again, could be worse I suppose.

Was discussing in another forum how the Euro weeklies and seasonal stuff keeps throwing out a strong +NAO/+AO yet the EPS day 10 is completely disagreeing. After last year, I'm trying to mainly focus on Day 10 and under this year...which looks decent. I keep asking myself can such a decent fall pattern with blocking tendencies really hit a wall and flip on itself to such an extreme as the weeklies and seasonal depict? I suppose the answer is yes. However, last year the weeklies and seasonal were touting the epic unicorn of patterns and it never materialized. Could this be the opposite of last year? Lots of questions and we should see some answers over the next several weeks.

More interested in D1-D10 and nothing farther than that for now. At least trying lol. With that said EPS has a building -NAO and by day 10 looks decent. So unless the pattern collapses on itself, which it could in a few weeks, take what we can get for now.

18z gfs has a nice storm next Sunday

Man if we could get this look to stay all winter or something remotely close it would just be a matter of time. Anyone else see the 95-96 similarities in this flow?

Didn't see this posted. NAM is pretty far NW irt other guidance. Probably the typical bias at this lead time but interesting to note nonetheless.

If you look at the PV both at the trop and strat levels signs indicate the majority of the cold is actually going to be deep into Siberia and on the opposite side of the N Hemi. With that said, if we somehow continue to have the BN cold show it's hand with the PV where it is forecast to propogate, I dont think we will be worrying about it too much as there are signs now (really far out there but something getting sniffed out?) that CPF may establish in December allowing for the Siberian cold to follow behind. I'm sure it wont be wall-to-wall BN temps all winter....we will undoubtedly see the reloads and relaxing at times. But the signals are looking promising for more cold and less 'mild' this winter. We can only hope the looks continue.

Rather active pattern moving forward the next 10 days with several impulses riding the NS and some active disturbances in the stj. Climo says still a little early to get overly optimistic but all the players are entering the field that we would want to see at this time moving towards late November. A few coastal systems and a few reinforcing shots of cold air (think clippers) next week to 10+ days. If this was 3 weeks later and this potential background state can hold, some happy people gonna be posting in here.

I think we might be seeing some early repeating signs of what the background state will be this winter. Not looking like a dud, I'm pretty sure many will agree with that. Still some mixed signals but honestly couldn't ask for what we are seeing at this point.

GFS has the strong vortex and shows alignment between trop and strat fwiw. Not the biggest fan of seeing the cold air locked up in Siberia but I'll roll the dice with marginal/borderline temps if it means storm chances vs arctic cold and dry as a bone. I know there can be an argument made for good storms on the backside of a retreating PV but not much we can do if it sets shop over on the other side of the N Hemi in early winter. Still TBD tho obviously. Split camps as you noted.

EPS, GEFS, and GEPS all unanimously advertise a similar day 10 500mb pattern with BN temp regime and the late November "warmup" delayed yet again. Low heights near Aleutians, higher heights in the NAO region and NW coast/W Canada, BN heights Northeast US. Slowly gaining confidence that this is going to be a recurring theme this season. Still a few weeks early though confidence is growing that as we enter December we are going to be tracking.

Urging cautious optimism. Let us never forget the LR ens winter 2018-19. Agreed tho, if it holds then that's a solid look going forward.

I'm not upset with the 12z GEFS:

By 144 hrs an argument could be made that the SPV is being pinched and has 2 centers but the GFS ens seems to recover quickly so much so by 180 hours has one strong center anchoring near the Kara Sea while anti cyclonic flow strengthens over AK and W Canada. TPV remains banged up but the only negative takeaway I had this cycle was by 240 the TPV has consolidated (for the most part) near old Russia. Granted, the charts are more smoothed out the longer the lead time and this is the day 10 prog chart, so there's that.

38F Warminster with flurries

Strat PV continues to get knocked around like a flyweight in a heavyweight fight fwiw.

Weatherbell subscription: $59.95/month Internet service/data plan to contribute to americanwx: $39.99/month Spending countless hours tracking wet mangled non-accumulating snowflake/white rain potential: Priceless