Stormchaserchuck1

24-25 was the coldest Winter since 14-15. Something similar to last year is possible this year, as lot of the same conditions are reoccurring. We had 2 favorable patterns in 22-23, in December and March. 6/7 times out of 10, those patterns would deliver a SECS. It just didn't happen that way that year - a repeat of 22-23 though may not be as bad as you would think. Jan and Feb were really warm that Winter though: +QBO coupled with La Nina to have a strong 10mb vortex in 22-23.. we have a -QBO this Winter, and the long range Euro ensembles are already looking like they want to do a Stratosphere warming in a few weeks (which would correlate with -AO late Dec into early Jan (about 70% likely)).

Yeah, the Nina is weak sauce right now. Going back to June 2023, 21/29 months have been +PNA (CPC). It's surprising because we've had 2 "most negative monthly PDO on record" periods during that time, and the last 15 months have been cool ENSO.. but tracking 500mb all the time, the -PNA tendency has not been the same since the 23-24 Strong Nino -- it was happening all the time before then, now it's not sustaining more than a short period of time. It would have to kind of come out of nowhere to be a -PNA Winter this year, possible, but not as likely as the 2017-2023 period. Precip is definitely not a El Nino STJ right now, but I don't see why we can't have storms track across the Tenn valley and then into the Mid Atlantic this Winter. I think there is a -AO tendency with negative SLP 60-90N over the warm season (strong Summer -> Winter correlation since 2012) this year. Lots of cold H5 across the N. Hemisphere this year too, including the lowest 500mb reading on record for August this last August. 2020-2023 was not cold at H5 in the Northern Hemisphere at all. The strongest leading correlation I've found to Winter cold/snow is preceding year total H5 cold across the N. Hemisphere.

Is there a place that does the 2-6 week forecasts for GEFS and EPS for free, or do you have to pay for it?

We haven't had a Week 3-4 this cold since January last year.

+WPO is actually cooler pattern in the extreme Southeast. It's main effect is a ridge in SE Canada and around the Great Lakes/Midwest/Northeast. I think the digging trough that was +wpo/+pna related, and the fact that it happened 1 day from the coldest of the year on average (Jan 27). Surprisingly, the NAO/AO was not negative for that event.. so in the optimal scenario, it could have gone even further south!

Nice -NAO pattern Nov 7-23.. through hr384 on the 00z GFS ensemble mean. That's what you want to see as a wintery pattern, constant sustained High pressure west of Greenland and over the Davis Strait through the entire model run. That's a good sign for Winter, and does correlate at about 55% to -AO the rest of the Winter. We aren't super cold in the east because of a N. Pacific High pressure in that time... but since the 23-24 Strong Nino, since June 2023, the PNA has been positive 21/29 months (CPC)! It's been hard for -PNA's to sustain..

There is a really strong timelag between Stratosphere warming and -NAO at different times of the year: Nov 1-15: +45 days Nov 15-30: +40 days Dec 1-15: +35 days Dec 15-30: +30 days Jan 1-15: +25 days Jan 15-30: +25 days Feb 1-28: +20 days March 1-31: +15 days Cold Stratosphere has a +0-day timelag to corresponding +NAO at all times of the cold season.

Some long range confusion on the long range GEFS right now. It's the only model that has a strong MJO Phase 7 wave occurring But it's developing a -PNA look You guys are keeping track of this more than I am.. Has strong Phase 7 in late November been hard to happen the last several years?

We've had a good amount of PNA blocking (-PNA). December 2021 shattered records in this regard. -NAO's have not sustained at all. 15 days or less then it always goes back to neutral or positive, since I think 11-12. The 60s and 70s were not like that at all. EPO has also come in short periods, but that is more typical of the region to be like that than the NAO.

Well the 18z GFS isn't close to any snow. You guys made me look.

That's a time that correlates with -NAO from around Christmas to the 1st week of January

I haven't been talking about it as much because it's been near neutral.. the May-Sept total N. Atlantic SST indicator for Winter (DJFM) NAO came in at +0.08. It has a normal standard deviation of 0.54, so that makes it 50% likely to have a Winter NAO -0.46 to +0.64.

Kind of a big trend on today's models to -NAO conditions in the medium/long range. Yesterdays models had the NAO very positive for the next 15 days. I like that trend, I think we're wanting to go colder this year. Not huge Winter cold but at least a decent shift to normal Winter conditions unlike so many Winters in the last 10 years.

October SOI came in at +12.. which was the highest monthly reading since December 2022! Here's how that rolls forward to the following Winter:

October SOI came in at +12.. which was the highest monthly reading since December 2022! Here's how that rolls forward to the following Winter: Cooler December, warmer February

Lamar has almost a perfect QB rating in Miami in 5 games there.. that's where he grew up. The dude loves warm weather

La Nina effects on the Winter Northern Hemisphere pattern actually puts a High pressure over the North Pacific High, which is just off the west coast of the US. A lot of people think its main effect the PNA, which is actually only the case for extreme west-based events. Last Winter despite +PNA we did see a +NPH pattern. It was Weak-Nina like. I think we could be looking at a similar pattern here, at least to start this Winter, going into November and early December. Beyond early December, I wonder if the now neutral ENSO subsurface will make the La Nina less impactful. If the SOI stays strong through next month (it's been positive now 15 months in a row), we could see more a of a east-based La Nina like composite for the Winter, which is usually cold in the Upper Midwest and sometimes Great Lakes. La Nina December's also have a tendency to be cool in the Upper Midwest, Great Lakes, and Northeast - that's if the SOI stays moderately positive through next month and December.

30-day SOI is now the highest it's been since Feb 2023.. almost 3 years. Now long range models for the 2nd week of November are showing a +NPH (North Pacific High), which is more of a La Nina pattern (+NOI).

It used to not be uncommon to see snow flurries in October.. we aren't seeing anything like that, but Aug 1 - Nov 5 is probably going to be the first time we've been below average for the time period in a while, possibly since 2013.

The troughy pattern really turns into a +NAO out here pretty quickly With it being just after a Solar Max, I do think more +NAO is favored this Winter.

If I were a farmer in the 1800s, looking at sensible weather lately, I would go for a colder Winter. In August it got cool.. I had something like 15/16 days where it didn't get out of the 70s in August, and it's stayed relatively cool through September, October, and it looks like early November. In the last 15-20 years, we have had a lot of very above average Fall's. At the least, I think a blowtorch winter is off the table. The pattern would need to completely change around for that -- we have a little more tendency for -EPO right now.

The NAO is correlated with changes in the AMO at about 0.4, or 70% of the time. +NAO cools the AMO, we saw this in Hurricane season 2024 when there was a lull of activity mid-season during record +NAO. Now since October is -NAO, and the NAO looks to be negative a good 4 weeks, they are saying the AMO is changing. A better way to do that, is just roll forward October NAO, which does not actually have a positive correlation with Winter NAO. Every October has been -NAO since 2019.

Here is what we get the Winter before an El Nino the following year

SOI has been positive now 15 straight months.. -AAM the last few months, -PDO, a few things are lined up for cold-ENSO it seems, but without a big ENSO subsurface cold pool it's going to be hard to get N. Pacific -PNA. The subsurface cooling could come back, it waxes and wanes, but the way it looks right now is pretty far from La Nina analogs.. Crazy thing, although SOI has been positive 15 straight months, it has never gone above +10.. so we've been consistently on this weak-cold ENSO thing. I think the past shows us that when that happens the odds for a future El Nino increase.

Halloween now looks very cold. A few ensemble members bring the 528dm into the Northeast.. there is a pretty good spread and variation for that trough on current models though.