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Great read brought over from 33andrain The met there hits on everything we have been talking about. Enjoy <<<<< Member Meteorologist 290 54 posts Location: Hackettstown, NJ Report post Posted 1 hour ago I'm going to try to post a final outlook of sorts within the next week along with a longer commentary...no huge changes to my thoughts, though did make it a bit colder in the east. In the meantime, I do have a few general thoughts based on what I've been seeing here and on #WxTwitter. The PDO right now is very close to neutral. The September value from NCDC was 0.00. I've highlighted in blue areas that would suggest a negative PDO, and in red areas that would suggest a positive PDO. It remains very close to neutral, and the "cold" waters near the West Coast aren't particularly cold. I look at it as a neutral PDO but with a highly anomalously warm North Pacific. If anything it may trend a little more positive over the next few weeks, but not enough to really move the needle IMO. For reference, here's the JISAO plot of a negative vs positve PDO: I guess my point is that while it's not a classic +PDO, it's definitely not "tanking" and will likely be close to neutral for the winter barring some fairly substantial changes. I also want to stress that the little sliver of cooler water near the West Coast has no ability to force a pattern in the future. It's more a reflection of the pattern we've seen frequently since September. It's possible that pattern is a sign, but the SSTs themselves don't force anything (it's a small area of near average SSTs in an area where SSTs are too cold to strongly force anything). For instance, the ridge over the next 10 days doesn't seem to mind the little bit of cooler water near the coast: The 6-10 day 500mb in winter (even without longer wavelengths) would already by a pretty chilly and active pattern from the Ohio Valley into the northern Mid-Atlantic and New England. With regards to the western US trough and SE US ridge, I still think it's way too early for it to cause any concern for winter. We just had an exceptionally long-lasting and amplified phase 1 RMM (it was more of a standing wave than true MJO, but registered as a phase 1 MJO). It was in "phase 1" for nearly a month and didn't come close to the "circle of death": When the RMM is phase 1 in the fall it correlates to warmth in the eastern US and cold in the west, which is what we've seen plenty of. Wavelengths are beginning to quickly get longer as we transition to winter...this same forcing would result in a different pattern in winter. Compare the September-November phase 1 temperature correlations to the December-February ones....basically, a SE ridge is what we'd expect with the tropical forcing we've seen and it's what we've gotten. In winter the same tropical forcing on its own supports a much colder outcome for the eastern US: The ongoing and near term intensification of the stratospheric polar vortex is of some concern if it continues unchecked well into November...the upcoming pattern is literally the opposite of what we want for PV disruptions with an Aleutian Ridge and Scandinavian Trough, so it's no surprise we're seeing impressive intensification, which could well lead to a spell of milder weather around the middle of November: With some hints of a +EAMT during week 2 and some ridging developing over Scandinavia...with the CFS and EPS weeklies hinting at some Pacific tropical forcing returning during November to go along with impressive Siberian snow cover supporting a stronger Siberian high, there are ways to disrupt the PV going forward. We'll see if anything comes to fruition. The lack of a classic Aleutian low thus far is likely a part of the longer running -GWO, and if that continues then Wave 1 disruptions may be limited (a Scandinavian ridge is usually wave 2). Most of the analogs that have the most blocking have an Aleutian low by October or November which can disrupt the PV via Wave 1 forcing, so this is going to be interesting to watch and see if we can get enough disruptions elsewhere. Long story short, I still generally like where we sit, but if we don't see disruptions to the PV resume in November then the prospects of a warmer December with a +AO increase. >>>>>>

Please don't think because I put Cohen up there I endorse him, I certainly do not . But, I do endorse the potential that the PV will be put under pressure in some form or fashion as November moves on. Simple referring to the potential warming. I do not want to see a SSWE either and will be perfectly happy with a weak PV.

Hearing a lot of conflicting comments on the PV. Taken from John going very strong, of course, how strong it verifies is not certain. The GFS portrays what @C.A.P.E. mentioned. HM chimes in wisely and takes into account some things the average person doesn't focus on, as well as a previous good read. Here are some of the latest thoughts on this. Little sensational if you ask me. then from HM Anthony Masiello @antmasiello 2h Replying to @jhomenuk The shape of the polar vortex is just as, if not more so, important than u-wind strength... especially during the early season when it's normal to strengthen. John Homenuk @jhomenuk 2h Agreed 100%, and still think there is a degree of uncertainty in anomalous the u-wind gets too. But as you alluded to, many different layers to the actual impact of a strong spv including its shape and location. From a u-wind perspective, forecasts are impressive tho A nice refresher from HM

@C.A.P.E. Not very scientific, but comparing week 39 in 2019 to week 39 in 2009. Generally speaking we are doing well. No associations are being made, except the backdrop of a low solar min. If, we can get sea ice to bounce back to a degree, and it should in the next 7 to 14 days, might be interesting weather around these parts later in the year. Row Year Week N. Hemisphere Eurasia N. America N. America (no Greenland) 1 2019 39 8.91 3.52 5.39 3.24 523 2009 39 6.29 1.21 5.08 2.93

Loving the build up of snow ! Bring it on ! Nice visual and even signs of a sea ice recovery. Of note, the area North of Alaska is cooling. Implications for the late December and Jan pattern. I could speculate we are going to end the month on a high note, and only continue to build from there in early November.

Things such as ozone also factor in, as HM mentions this from time to time as well. One Fall many years ago there was chatter among some pros that focused on a sudden ramp up in solar activity near the min. This might have been the solar min prior to the 09 - 10 winter. I was looking at various factors lately and it certainly it appears no worries, we continue to move lower in many of the metrics.

BAMMwx ( good winter seasonal record ) has very high value placed on solar min this winter, while some research has the solar min effects on ocean currents take a multi year lag to manifest itself. As far as I can tell we are close to a bottom.

Well you are in good company , Benchmark thinks we get a -NAO. In 8 days I think isotherm releases his forecast and I am found of his work forecasting NAO phase. From a simply solar min perspective it tends to show up, although some research, as you know, states a lag period.

@showmethesnow good post but I can't stop having concerns for our area in the heart of winter until we see some type of change in the ongoing long duration pattern. I really didn't even notice this in a general sense, but Eric Webb posted recently that what we are seeing is the same general pattern repeating over and over, for a period of years. For the last year I have seen the same issues manifest themselves in the Pacific, the semi permanent Central Pac High, robust WAR, the Pac configuration of SSTS, the very fast Pac jet, lack of West Coast ridging , etc. The areas that are benefiting from this so far are the same as last year, Northern Plains, Rockies, and when it gets deeper into the season areas to our far North will join the list. What are your thoughts when this multi year pattern changes? showme, one caveat IMHO, if get Davis Straights blocking develops, or shift ridging out West East a bit in our favored climo period, then bang you can have a severe winter outbreak here. Here is what Webb said: Eric Webb @webberweather This pattern goes back to 2012-13* and has persisted in some way, shape, or form in every winter besides the 2015-16 Super Nino. There's very little, if any reason to believe it won't be around this year.

Back edge moving in quick here. Going to be a remarkable change from the heavy rain and darkness now to sun later afternoon.

Well now, this is a surprise, really taking off. Granted only a forecast, but still rather concerning in view of some using this data as a means to associate the seasonal models and the crap AO and NAO forecasts. Not what we want to see. courtesy 33andrain posted 3 hours ago from Snowy Hibbo <<<<<<<< Well that throws the forecast for a decent December back to the drawing board. At least: what goes up must come down. >>>>>>>

Interesting he mentioned this , seems a lot of his followers are wondering what the hell he is talking about. Could be he wants some likes of the comment or maybe he believes it. Depends what side of the fence you are one. But, at the 12 hour mark that is a crazy jet stream.

Some folks are talking about why the seasonal models are going with a mostly positive NAO and a + AO in the winter forecasts. Simon believes it is due to the models seeing a stronger winter PV. IMHO I don't see that. Sure, it may, as others stated, get stronger in November, but off the charts strong well I am not so sure. Also, the pattern supports some attempts at weakening the PV and don''t forget the descending QBO as well. Maybe @Isotherm could comment. I read from one source that the signal for the + NAO and + AO also may be related as to how the seasonal models see and resolve oceanic SST profiles. However, a great video from BAMMwx recently mentioned that most model SST forecasts out in time are not correct. I forget the exact wording but he stated they are only correct 19 % of the time. He also mentioned that the model, NMME or close to that, is notorious for being too warm. So since the oceans play such a huge role in driving the pattern if those seasonal models are off in forecasting future SST profiles, then the seasonal temp forecasts will be off along with other outcomes. This is also a great addition to this topic, from Zac.

Maybe November is closer to normal in the states. Here in the East looks average to above based on this. Of course things could change. Don S. thinks the East could be warm after the first week of November. I was really hoping for a colder month. Certainly snow cover should build over Canada, possibly at an above climo rate, and wondering if we get some extreme cold air mass to develop also in time later in the month up North. Looks like continuation of the same old thing to a degree.

On another forum one met claimed the GFS should not even be used. Stated that by incorporating the GFS into your forecast for your clients it reduces your overall performance and accuracy. I know yesterday I posted about verification against the Euro, but when I read that comment I was surprised. Seems the general idea is the GFS is extremely cold biased, reacts slowly to changes and when you have time periods such as this where we are transitioning between seasons it does badly.

Although there appears to be some similarities I doubt we go down that same path again. As I mentioned a simple elongation towards us or at the least keeping the PV in check is fine with me. As you know , many blamed the SSWE last December and what lead up to it as one reason, among many , ( QBO . meager Nino, weal Pac jet , etc. ) for the poor performance of the seasonal models and many mets as well. Personally the one thing I like to see change is for the PNA to go positive, and for ridging to develop closer to the West Coast. It seems the way things are playing out the jet then reacts to this flow with a pumping up of the WAR , so a trough out West and a ridge in the East. This needs to change in the weeks ahead or at least transition to a better Pac. I know bluewave mentioned the SST configuration in the PAC and how the warmer waters out there may feedback this. Borrowing a image from a crankyweather post you can see those warmer waters. But things are changing again with the SSTS and will see what happens when we get later into the Fall . The image shows the trough in the East but currently it is more so in the West. I use the image simply to view the warmer water configuration. Lastly, when you think about that image below it is more so related to what Paul describes here ( see below ) So when we go more towards a Nino look hopefully the East will benefit. Paul Roundy @PaulRoundy1· Oct 23 You get the direction of causality mostly backwards. The high SSTs in that region are a consequence of ridging there, more than the other way around.

I see even HM graced Judah's post, not something you see everyday :-) Wonder whether this roll out is somewhat different from last year in a way, as it may yield a colder early December , similar to early December last year , but where this year may differ is that we do not return to a warmer regime like last December when things looked great in late November and early December and then BAAM we lost the good pattern in mid-December. Also, the caveat here for this December again may be what some referred to last year as a bootleg - NAO, and the interplay of the Scandinavia block.

True, but as a follow up. The GFS is falling out currently. Both models were challenged though by the huge amplifications in the Pac jet with the recent Typhoons. Seems the GFS always trends towards the Euro, however recent verification scores point out the GEFS doing better. And of course no model is perfect, and a blend seems to be a smart move to utilize each model's inherent strength.

Well, someone is wrong here

Less warm , is the new cool

A possible evolution regarding the PV going forward, seems plausible. I see HM posted on the topic as well. So, generally speaking a strengthening, but hopefully not going crazy. Then after this a weakening again. Well, time will tell. Of course after last year's SSWE debacle I would be happy a a simple and favorable elongation of the PV and a general weakening, no need for anything further than that IMHO. And HM's recent post:

Thanks, very interesting. I concur regarding the NAO. Do you see us eventually exiting the persistent - PNA pattern to one more Nino like in time? The contrast of players currently is enough to make your head spin. Very high IOD ( but think it is past the peak ) , high PMM , crazy TNI number, very fast PAC jet and a lack of West Coast ridging. Maybe things re-shuffle to a colder pattern in the East as we get to December. Surprisingly a couple private met commodity forecasters are calling for a cold December in the East with snow potential. That is contrary to many whom have stated the winter gets off to a slow start. On a side note, simply using longer wavelengths in December with the current PMM provides a very cold month in the East.

Cool animation , simply happy to see we are gaining snow coverage up North, pretty much in all areas. Also, note the big gains in Eastern Canada later in the loop. Courtesy 33andrain by Snowy Hibbo << Posted 5 hours ago Large increase in the Siberian and North American snow cover over the next week or so FWIW. And this happens as Arctic sea ice is at a record low... >>>>>>>

This is a great visual , simply click the image for a close up and scroll You can see some of the things Ray spoke about in his update. The kelvin waves, as Ventrice has posted on the past month, are having an effect. The warming in general and the Eastern Areas warming slightly. I am still very interested in the TNI as well.

Great read from @40/70 Benchmark over in the New England forum. His main winter outlook is set to be released on 11/12/19 . OCT 24 Confidence Grows in Late, Marginal El Nino Rapidly Evolving ENSO At the turn of the month, when ENSO neutral conditions were all but a foregone conclusion for winter 2019-2020, it was noted on this site that the warmth in ENSO region 4 was a fairly strong climatological indicator of a burgeoning el nino. As the month of October has evolved, the support has grown stronger. As of October 16th, region 1.2 has increased from -1.0c to -0.2c, region 3 from -0.1 to +0.4c, region 3 from +0.4c to +0.8c and region 4 from +0.9c to +1.1c. Not only has the western flank of region 3.4 and 4 continued to approach moderate levels, but the eastern flank has also began to warm. The implication of this are twofold: 1) Although it will likely take until the NDJ tri monthly period to verify, a weak el nino ONI will likely by achieved. Since 1990, 1991 (strong), 1997 (super), 2002 (moderate), 2009 (moderate) and 2015 (super) have registered equal or greater magnitude of warmth on the western flank of the ENSO regions in mid October. Significant el nino events ensued in all five of these seasons. 2) The subsurface warmth is penetrating the eastern regions of 3 and 1.2, thus a decline in the modoki value has ensued. Even a cursory glance at the subsurface provides a clear depiction of why this has taken place, and will likely continue. Morphologies Driven by Subsurface Much like the fall of 2018, not only are we observing a continued trend toward a marginal el nino, but we are also seeing it build from west to east. Thus the structure is gradually becoming more cannonical as it develops. The continuation of this trend is not only portended by the translation of the warmest subsurface waters eastward through region 3.4 and towards region 3, but also by modoki guidance. Note that on the annotation above, the current burgeoning warm ENSO event registers as roughly +.75c on the modoki scale, which is strongly modoki on par with the 1977-1978 event. However as the warmer subsurface waters continue to translate eastward, it is forecast to descend to approximately a +.40, which registers as moderate and on par with seasons such as 1979, 2006 and 2015. As the moderate classification would suggest, the result for the ensuing winters is very variable across the area, ranging from meager snowfall to the snowiest winter on record. While 2015 appears to be the best ENSO match at this time, one important distinction is that this particular event grew into a modoki, whereas this event, much like this past season's, is forecast to trend potentially more cannonical as it evolves. Conclusions This will be the final installment before the Eastrern Mass Winter outlook is released on 11-12-19, but there remains a great deal to ponder in the interim. Although the Climate Prediction Center has curiously reduced the odds of an el nino event to a mere 29% as of the Friday 10/18 update, we have grown ever more confident of a very delayed and modest el nino event that will likely peak in the NDJ tri monthly timeframe. The warm ENSO event will likely register moderately on the modoki index during its tri monthly peak, which implies mixed results with regard to its implications for winter. SEASON Peak Tri Monthly ONI Value Peak Tri Monthly Modoki Value Boston, MA Snowfall Wilmington, MA Snowfall Worcester, MA Snowfall New York City Snowfall Baltimore , MD Snofall 1951-1952 +1.2C SON +.04 39.6” 62.5" 63” 19.7” 14.1” 1953-1954 +.08C OND +.19 23.6” 23.5" 31.2” 15.8” 22.1” 1958-1959 +.06C NDJ +.52 34.1” 52.7” 64.7” 13.9” 4.0” 1963-1964 +1.4C OND +.43 63” 91.7” 66.6” 44.7” 51.8” 1968-1969 +1.1C DJF +.92 53.8” 86.5” 75.7” 30.2” 18.6” 1969-1970 +.09C SON +.20 48.8” 74.6” 72.1” 25.6” 21” 1976-1977 +.09C OND -.14 58.5” 97.3” 74.5” 24.5” 11.1” 1977-1978 +.08C OND +.79 85.1” 99.5” 85.9” 50.7” 34.3” 1979-1980 +.06C NDJ +.43 12.7” 19.9” 19.1” 12.8” 14.6” 1986-1987 +1.2C NDJ +.52 42.5” 77.7” 93.6” 23.1” 35.2” 1994-1995 +1.1C NDJ +.69 14.9” 22.5” 24.9” 11.8” 8” 2002-2003 +1.3C OND +.48 71.3” 86.8” 117.3” 49.3 58.1” 2004-2005 +.07C OND +.55 86.6” 107.5” 114.3” 41.0” 18.0” 2006-2007 +.09C OND +.32 17.1” 34.5” 49.1” 14.7” 9.1” 2014-2015 +.07C NDJ +.49 110.6” 115.5” 119.7” 53.8” 28.4” 2018-2019 +.09C OND +.52 27.4” 47.5” 51.4” 20.5” 18.3” The best ENSO analog just so happens to be the snowiest winter on record for the vast majority of Massachusetts, given both the anticipated intensity, delayed onset and moderate modoki value of the developing warm ENSO event. However this particular event has developed a bit later, and is also descending in modoki value, as opposed to ascending as the 2014 event did. We will explore possible implications of these subtle differences, as well as a myriad of other global factors that will account for the composite variability in the winter outlook set for release on 11/12/19