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BWI: 11/9 IAD: 11/7 DCA: 11/11 RIC: 11/10 TB: 85°

The GEFS and CFS both keep the pv along the normal growth trajectory during the next 35 to 45 days . Just saying, because it means very little, but interesting to follow along and see how this turns out a month from now.

Latest CanSIPS To be expected in a Nina , whether it is correct not sure.

Another interesting reflection from grit regarding AO and the NAO both being negative ( .40 or lower ) during the period Dec to March since 1990.

Simon just added this to his cool reference site. GEFS: 35-day 10 hPa 60°N The new GEFSv12 now features a 35-day run every day at 00Z. Shown here is the output from the previous day’s run, due to the time taken for the data to appear on NOMADS. Note that, because of the length of the forecast, systematic model biases are more likely to impact the output. These are not accounted for here.

I read a couple posting from TIP that events in a general shotgun area of the NE can be more extreme, in the winter, for example ....I think the idea was a fast PAC flow all the time, but when we funnel that energy into an extreme low pressure area it slows and it becomes one for the ages. So to me that implies, and seems backed possible by the last 10 years, that we are getting more intense storms.

Granted the seasonal models, Glosea included, all have what appears to be a + NAO. Not as robust as last winter, but I place little faith in long range and medium range NAO domain outlooks. All about timing, etc. I look forward Tom's NAO outlook. I enjoy your insights as well.

Sample size is small and we would require a - NAO , especially in our region here for any hopes of significant snowfall. But, the idea of a poleward High during the winter and even extending into the EPO regions has been mentioned by a few pros and mets. Of course, as you know, being in a Nina combined with the location of the Northern Mid Atlantic will take some divine intervention for significant snowfall opportunities.

Great post by @bluewave this morning, I wanted to share it here. As mentioned in the post here, a very small sample size indeed, but still worth following to see what transpires with the Western Ridge during the month of October. I wonder if we enter a feedback loop and how the evolving Nina will effect long term Western ridging later in the year. Here is bluewaves's post: < The sample size for La Niña Octobers with a Western Ridge and Eastern Trough is very small. So we will have to see if the strong ridge to start the month persists like it has in September. There was only 1 La Niña year since 1950 with a pattern like this. It was October 1988. The dominant Pacific feature that winter was that the NEPAC ridge extended north into Alaska. Main problem for us in 88-89 was the very strong +NAO. 08-09 had an almost identical Pacific La Niña pattern with a better Atlantic and more snowfall. So maybe a strong ridge out West in October would be hinting that the Pacific Ridge will extend into Alaska.This would be unlike the last 2 winters with the flat La Niña Ridge North of Hawaii. But we would have to wait and see how the NAO evolves . Still too early to know if any of this pans out. Just something to think about. >

@CAPE Interesting

Speculation on my part that maybe the pattern is possibly showing a tendency for a different outcome at times during the winter regarding the North Pac ridge and Western ridging. Again not sure how things evolve as we get deeper into the Fall season. It seems the last 3 years were all November and EARLY December head fakes, as the real winter pattern did not take hold until post December 20th.

We are getting our winter now and in early October. By the way, Western fires are not the only location in the NH spewing aerosol and other elements into the atmosphere.

I could be mistaken, but I believe he was attempting to match the progression that could be possible this late fall and the upcoming winter . Granted it was a feeble Nino last winter, but I believe that was his goal. Future QBO numbers will be very interesting as we move deeper into the Fall season. Are you looking at where the IO forcing set ups later this month, and in October, for any winter clues? I ask because bluewave posted a week or so back that depending where the forcing sets up, it has a role in the upcoming winter's temperatures and I imagine the background state. I have to go back and locate it . Well worth the read. I found it , here you go : < We would need to see all that IO forcing shift east toward the Maritime Continent in October. The big amped up MJO 5 in October 2017 came before the snowy La Niña 17-18 winter. The strong IO MJO 1 in October 2011 preceded the 11-12 La Niña winter. There is some research that early IO forcing can excite the PV like we saw last winter. >

@CAPE remember what we learned the last two years........ no matter the perceived clue and no matter the head fake , especially good ones that might entice your positive winter vibes, don't be fooled! Ha ha...... I know you know this, but here we go again. And we are talking it is September 22 nd. How things evolve remain uncertain. Saw this last year in October and especially that November period, when postings here commented and reflected that maybe we would get - AO periods and HL blocking, even though the NAO look was not that great.

We have new records.

I believe Ninas may tend to have colder Decembers versus Jan. and Feb. Means nothing, and I am not endorsing a cold December at this point. However, exposed waters above Alasaka and general SST forcing way up North may have a role in our sensible early winter weather before the most powerful and direct pattern weather drivers take hold for the East.

Does make sense. The exact location of anomalies and how strong in mid to late Fall will be very important in attempting a December forecast.

BAMWX put together a very detailed and research based presentation rich with relevant data and analogs for the winter outlook of 19-20. The presentation was over 30 minutes long, given in November of 2019 for the winter of 19-20. Guess what, they blew it, they had to back pedal until stating they were wrong. They were very confident in a cold winter. Going too cold and too snowy overall. Of course they spin it, by stating they adjusted their winter forecast to counter their early seasonal forecast. In my opinion, that is still a fail. No one really knows what is going to happen. After two years of incredible busts regarding winter outlooks by everyone, the bottom line is that you should never put faith in a winter seasonal forecast that depends on cold air intrusions. It is a different climate now, with new evolving drivers on a global scale. You can even share the insights and opinion of tip over in the New England forum, whom states that regardless of Nina or Nino it does not matter at all, because a small area of the Pacific cannot counter the global warmth and the corresponding accelerating global warmth drivers.

In the short term yes. As in today, temps in this region will average 2 to 5 degrees lower versus without the smoke effect on solar energy. However, this is an interesting thread below discussing the effects of Western fires on the stratosphere. As Anthony points out some interesting outcomes on the winter AO and even the development of the early season PV. The thing that interests me the most is that in the Nature. com abstract below it discusses the 2017 " Pacific Northwest event " . Keep in mind that the current fires on the West Coast and other areas are far more impressive in terms of release. Also, keep in mind the similarities , as mentioned in the abstract of volcanic intrusions. Also there is this literature https://www.nature.com/articles/s41612-018-0039-3 Abstract Intense heating by wildfires can generate deep, smoke-infused thunderstorms, known as pyrocumulonimbus (pyroCb), which can release a large quantity of smoke particles above jet aircraft cruising altitudes. Injections of pyroCb smoke into the lower stratosphere have gained increasing attention over the past 15 years due to the rapid proliferation of satellite remote sensing tools. Impacts from volcanic eruptions and other troposphere-to-stratosphere exchange processes on stratospheric radiative and chemical equilibrium are well recognized and monitored. However, the role of pyroCb smoke in the climate system has yet to be acknowledged. Here, we show that the mass of smoke aerosol particles injected into the lower stratosphere from five near-simultaneous intense pyroCbs occurring in western North America on 12 August 2017 was comparable to that of a moderate volcanic eruption, and an order of magnitude larger than previous benchmarks for extreme pyroCb activity. The resulting stratospheric plume encircled the Northern Hemisphere over several months. By characterizing this event, we conclude that pyroCb activity, considered as either large singular events, or a full fire season inventory, significantly perturb the lower stratosphere in a manner comparable with infrequent volcanic intrusions.

Where have we seen this before. Will be interesting to observe and speculate on the late Fall implications, in conjunction with SST forcing.

JMA for next 3 months. If the Nina's most significant measured drop occurs in the period late October to early December, with a possible lag effect , December could indeed be a cold month in the East. Followed by the real winter pattern of warmth dependent on other factors of course. Still feel the positioning on the High pressure in the Pacific will be the driver, and any appearence of HL blocking. GLoSea mean may indeed be skewed. Also as HM stated the model may have sniffed out the extreme + IOD last winter as the driver to little if any NAO and HL blocking during the 19=20 winter. This year is the IOD is opposite, so what to expect is uncertain in my opinion. As mentioned previously, the poleward High and positioning, in a Nina with a + QBO as Griteater mentioned may have a role in our weather. The sample size has to be considered.

I have seen neutral, Nino and Nina comparison snowfall scatter plots for December through February in the Northern Mid Atlantic which shows we tend to achieve the highest snowfall in a moderate to even skewed stronger Nino. Possibly, as you mentioned, in a Northern stream dominated Nina and dependent on where the cool anomalies are located in the Pacific the temp profile in our area versus a Nino may be colder. The image itself lends to confusion and has little value if you ask me. Just as all Ninos are not the same, the same can be said of Ninas. Of course, as mentioned here previously you really need the establishment of NAO and HL blocking for true winter block buster events in a Nina background state.

The GloSea5 did well last year. However, to me that means little for this winter.

As many here already know, the QBO is currently positive and looks to continue to become more so in the months ahead. There is some research that points out a tendency for a more poleward based and oriented North Pacific Ridge during +QBO winters. HM mentioned that, along with a couple other mets as well. @griteater recently mentioned it too in a detailed and revealing post. I found it so interesting as to share it here. Nice job with this ! Here is the post below : . The QBO is utilized in various ways with respect to seasonal forecasting, but IMO, it's best use with winter forecasting is not so much with the AO/NAO, but rather, with the configuration of the North Pacific High/Ridge that is common during La Nina winters. A North Pacific ridge is almost certain to be present in the mean pattern during Cool ENSO / La Nina winters when the Jul-Oct averaged AAM is negative (which has been the case thus far for Jul-early Sep). Anthony Masiello's findings from 2012 showed that more poleward north pacific ridges were favored during +QBO winters, while north pacific ridges that were suppressed to the south were more favored during -QBO winters. A key element here is that the designation of the QBO for this purpose was in the lower stratosphere (roughly Nov-Feb averaged at 45mb) as opposed to the typical level used with QBO analysis which is at 30mb. While the QBO began to behave much more erratic than normal at the first part of 2020, it appears to have resumed with a more typical progression as the positive QBO has more firmly established itself in recent months in the middle stratosphere and descending into the lower stratosphere. For the upcoming winter, I would anticipate the QBO to average positive for Nov-Feb averaged at 45mb - most similar to the winter of 2010-2011 when compared to other cool ENSO winters. See QBO Charts: NASA QBO Chart Free Univ of Berlin QBO Chart Below is a list of what I have for the last 11 La Nina winters that followed El Nino, along with the Nov-Feb avg 45mb QBO, then the placement of the north pacific ridge averaged for Dec-Mar. La Nina Winter That Followed El Nino Winter / Jan-Feb avg QBO at 45mb / Placement of North Pacific Ridge avg for Dec-Mar 2010-2011 / Positive QBO / north/poleward north pacific ridge (specifically, displaced to the NW) 2007-2008 / Negative QBO / south/suppressed north pacific ridge (specifically, displaced to the SW) 2005-2006 / Negative QBO / south/suppressed north pacific ridge (specifically, displaced to the SW) 1998-1999 / Negative QBO / south/suppressed north pacific ridge (specifically, displaced to the SW) 1995-1996 / Positive QBO / north/poleward north pacific ridge (specifically, displaced to the NW) 1988-1989 / Positive QBO / north/poleward north pacific ridge (specifically, displaced to the NE) 1983-1984 / Neutral QBO / no clear distinction overall in the north pacific 1973-1974 / Positive QBO / north/poleward north pacific ridge (specifically, displaced to the NW) 1970-1971 / Negative QBO / north/poleward north pacific ridge (specifically, displaced to the NW) 1964-1965 / Positive QBO / north/poleward north pacific ridge (specifically, displaced to the NW) 1954-1955 / Negative QBO / south/suppressed north pacific ridge (specifically, displaced to the SW) Of the 11 winters, the only one that didn't follow the QBO/North Pacific Ridge placement theory was the winter of 1970-1971. Here are 500mb Height / U.S. Temperature composites of the Positive QBO winters from the list: And here are 500mb Height / U.S. Temperature composites of the Negative QBO winters from the list (I left off the 70-71 winter): Clearly, the Positive QBO composite with the more poleward north pacific ridge offers more potential for cold air intrusion into the lower 48 east of the Rockies compared with the Negative QBO composite. One other thing to look for is the Oct-Nov 500mb pattern over the NE Pacific / Alaska / NW Canada. Winters with a more poleward north pacific ridge tend to be absent of negative height anomalies in the Bering Sea, Alaska, and NW Canada during Oct-Nov....while, winters with a more southward displaced north pacific ridge tend to contain solid negative height anomalies in the eastern Gulf of Alaska extending up into portions of the Bering Sea, Alaska, and/or NW Canada. Bottom Line: I would expect the upcoming winter to exhibit a more poleward north pacific ridge in the mean pattern as long as: 1) the QBO progression continues in a more typical manner as seen in the past few months, and 2) the Oct-Nov averaged 500mb pattern doesn't contain negative height anomalies in the eastern Gulf of Alaska extending up into portions of the Bering Sea, Alaska, and/or NW Canada

Appears the modeled December to February NMME precip forecast closely resembles that of a typical Nina.