Newman

I think many here would take this and run with it for Tuesday. An inch or 2 followed by frigid cold to keep it around.

Good stuff Ralph. Don't take this as a post trying to steal your spotlight. Just trying to share some thoughts. Anyway, I would think a PV split is most likely to occur later on in the winter, as the QBO would have descended enough into the easterly phases which support such a thing occurring. It could still occur even without a favorable QBO, however. But the progression of the QBO is admittedly not occurring as fast as I had hoped. Save for a miraculous uptick (which is very much possible), the QBO might not be too much of a factor this year. That's fine though. Last year it's something that helped kill us. The ENSO is in an overall favorable look - Cooler ENSO regions 1.2 and 3. Regions 3.4 and 4 much warmer. It's very much a Modoki look. A warm Atlantic/AMO is still evident in the data sets and SST maps. The PDO is actually cooling off a bit with the NP warm blob starting to regress to the west a bit south of the Aleutians. What I fear the most this winter is actually what we've got potentially in store for us next week. The ridge out west is just a bit too far west, aided by the warmer SST's a bit further west. We've actually been stuck in a +TNH pattern for a while now which supports my analog set as well. Cold dumps into the central states and Great Lakes, the SE ridge tries to pop, and you get cold before and after each storm, but as the storm comes in the trough axis is just a bit too far west. Now, I've been delving into this upcoming winter since July/August and have stuck with this SST composite and 500mb composite since September. I don't see any reason to change now. As I mentioned above, the cold will be there I believe with the mean trough centered across the central states and Great Lakes. The question is how does it modulate when storms come through? With no HL blocking, you can bet App runners and coastal screamers will be a real threat. Kinda like this upcoming Tuesday/Wednesday storm. It's a battle between the Ridge/Trough orientations, WAR, and incoming cold press. If HL blocking does commence this winter, I truly believe it's off to the races. The Pacific is favorable enough for there to be some hope.

Not sure if some of y'all have seen, but Pivotal Weather now has free Hi-res ECMWF maps. Snowfall, precip type, and all. And in 6 hour intervals, not 24 hours. Just keep in mind for this winter. Sample:

Just a heads up, Pivotal Weather now has free Hi-res ECMWF weather maps, including snowfall, precip type, etc. And it goes in 6 hour intervals, not 24 hours.

I'm not going to pout and complain that it's only late October/Early November BUT if this look can materialize and hold for steady periods throughout the 2019-20 winter, we will be looking at plenty of snow opportunities. Ridge/Trough axis is nearly perfect (perhaps a smidge too far west), high latitude blocking over the top, trough north of Hawaii.... great look. Again, if I had to release an official analog map right now, I'd throw this one out there. And it has similarities to the map above. The difference is just the ridge orientation out west. That affects the trough orientation in the east downstream. But anyway, is it premature to say a 500mb pattern in late October will stick around for 4-5 months? Holy crap yes. You'd have to be a new level of stupid to think you've got a sure-thing touchdown right now. But if we can get stuck in this pattern with the occasional thaw/warm-up? Then it's all-aboard the hype train. Either way its nice to be thinking about winter early this year rather than later.

Getting to be that time of year where we look at the source region. Ridge in SE Canada will funnel down the Northeast flow.

August PDO data: 2019-01-01T00:00:00Z 0.66 2019-02-01T00:00:00Z 0.46 2019-03-01T00:00:00Z 0.37 2019-04-01T00:00:00Z 1.07 2019-05-01T00:00:00Z 1.03 2019-06-01T00:00:00Z 1.09 2019-07-01T00:00:00Z 1.03 2019-08-01T00:00:00Z 0.38 August AMO data: 2017 0.222 0.224 0.164 0.280 0.311 0.305 0.299 0.307 0.347 0.430 0.349 0.361 2018 0.170 0.059 0.129 0.061 -0.004 -0.014 0.015 0.110 0.159 0.141 -0.124 -0.063 2019 -0.018 0.078 0.118 0.121 0.085 0.171 0.349 0.335

ENSO 3.4 continues to dive: ENSO 4 is as well with plenty of easterly wind bursts nearing 180W:

From 2009, talking about changing global circulations including Hadley Cell/Mid-Latitude Cell disruptions, etc.: http://www.inscc.utah.edu/~reichler/publications/papers/Reichler_09_Widening.pdf

Just broke 90 here in Reading so it has now become an official heat wave.

Definitely not fake lol. Reading has reported 88, 92, 90 the past 3 days. The dews have definitely been lower than they were back during the heat of July however. Instead of high 70s dews, we got high 60s dews.

Courtesy to Isotherm, he and I had a small conversation on the disruption of the global jet stream patterns due to the emergence of changing Hadley Cell and Mid-Latitude Cell circulations. As SSTs continue to warm poleward due to the background state and changing climate, we see more convection which acts to disrupt the typical Hadley Cell circulations we know. Typically we see rising air at the ITCZ which spreads poleward and subsides around 30N which creates the Horse Latitudes. With convection being able to fire further north, the Hadley Cell circulations expand which create stronger gradients and subsequently strengthen the mid-Latitude cells. For the United States, that means the Pacific Jet stream becomes stronger. What I mean as "this isn't new" is the warmth of the Pacific and overall global oceans. We've seen warmth of our oceans for awhile now. However, are we finally entering the critical time where we truly do start to see global jet stream changes? Are winters going to be the same again? Or will we see more variability resulting in bigger and more extreme winter events? Have we already seen those changes? I don't know the answers to those questions, but I do know that in theory the global jet stream patterns should be or have already changed in the changing climate.

The PAC jet is still raging due to Pacific Warmth spreading poleward and subsequently expanding Hadley Cells and strengthening the mid-Latitude cell (Pacific Jet). This isn't new, though. The Pacific overall has been warm for the past couple years to a decade. The question is how will the strong Pacific jet trend and/or affect the upcoming winter. Last year the Pacific was so hostile. Could we see a repeat?

ENSO region 4 has cooled in the past week and is at its coolest since a month ago: Likely due to a strong burst of easterly wind stress. The GFS forecast of a burst of westerly wind stress could help to bring the temperatures back up again:

Here's a look at how the SST's have changed since June:

16 years ago was the Northeast Blackout of 2003. Was anyone here affected by that?

1993-94 anyone? The ONI progression looks similar to what we could see this winter. Perhaps this winter is a touch warmer. Lets say we throw in 1993-94 for a similar west based warmish Neutral regime with its warm PDO and a cool 1+2, 2013-14 for its warm blob south of Alaska (I'm not sold on that blob going away just yet. 2013-14 had a cool Neutral/weak Nina), and 2005 just for its warmer and positive Atlantic/AMO.

Severe threat coming up Tuesday. Plenty of shear, low level jet will be in play, instability not too bad. Here is berks county area:

We will see how the warm pool south of Alaska progresses into the fall and winter, but it was certainly quite warm in July: Let's say that the warm pool doesn't migrate and/or lessen over the coming months, 2013-14 could be a semi-decent analog for the PDO/EPO region specifically:

New IRI/CPC ENSO probabilities have been posted: El Nino has ended: Here is what the July SST's looked like: The July AMO value finished at 0.350, up from 0.171 in June and the most positive AMO value since Dec 2017.

Correct going into 09-10 the QBO was in a rather strong easterly regime which bodes well for the high latitude regions. This year we will likely be transitioning from westerly to easterly. I saw a tweet that said the most probable and similar QBO analog year is 1995-96. Keep in mind last year's QBO transitioned easterly to westerly, this year will be the opposite.

The current look, featuring cooling in the east based regions of the ENSO with western regions remaining warmer. The PDO is positive with a warm pool south of Alaska, but not to the extent of 2013-14 obviously. A cold pool east of Newfoundland in the Atlantic with warm waters immediately south of Greenland.

Thanks to some help from another forum, I found the 2003-04 winter and it looks like a semi-decent analog right now. We were coming off a prior El Nino winter, ENSO turned weak Nino/Neutral for the winter, Positive PDO, Positive AMO, and there was low solar activity. I expect all of the same for this upcoming winter. However, the summer of 2003 transitioned into a neutral phase much quicker than what is currently forecasted for this summer/fall/winter. I would throw in 2004-05 in case we remain more El Nino, rather than completely neutral. I like 2004's QBO transition into winter as well. It's much better than 2003 and it's close to what I think we could see this winter. A later transition of the QBO could yield later stratospheric impacts deep into winter (February and March, but things like that are fickle and require other variables to look at). 2004-05 also had a warm Atlantic and low solar, but not as warm of a Pacific. 1966-67 is a solid analog with regards to the positive ONI values maintaining closer toward fall/winter. And in case we go more Nina/neutral, it's even greater. I thought about 1959-60 as well. That winter was very very similar to 2003-04 with a transition to neutral much quicker than what is expected this year. It was coming off a weaker El Nino, +AMO, +PDO, low-ish solar activity. But again, the QBO went easterly to westerly during the winter. I like a 2003/1959 winter looking at a warm Atlantic, a fairly warm Pacific, weak El Nino/Neutral ENSO, lower solar, and then throw in a similar QBO progression seen entering the 2004-05 winter with a switch from westerly to easterly and a later transition from weak El Nino to neutral conditions seen in 1966-67 and you have something like this: Obviously, be aware there is more to a winter than just the variables I pointed out. AAM tendencies, the NAO background state, etc. all are important variables among others. Last year we got killed with a Pacific that would not slow down. We'll see how the Pacific cooperates this year. A lousy Pacific is always more concerning over a lousy Atlantic pattern. I'm excited for fall and the introduction of winter to see what we got on our hands this year.