frd

Seems Delta may trigger chain of events leading to polar blocking and arctic intrusion.

interesting zonal wind forecast https://mobile.twitter.com/MattHugo81/status/1314440730534989824

Noticed the shorter days, and less solar heating, means it takes much longer to dry things out. Found out when looking at grass seedlings and checking soil moisture. It was still rather wet ad moist.

I am starting to like the idea of a mini front loaded winter , however, in our case/area that may simply mean normal temps with a minor event. Meanwhile trends with the PV at this time maintain a normal seasonal progression, along the line of the ERA5 mean. Along with a supported - AO. Even though recent Octobers have exhibited a - AO more so than in the heart of winter. Already spoken here is the possibility of a more so - NAO early in season . Although maybe more East based. And very interesting is this post, and the possible variations of the Nina and the effect on the NH

Looking for a last season beach trip, surf zone temps still in upper 60 s

Sounds DT- ish

Saw that this morning when the WPC made come changes that would effect my area. Not thrilled it is a weekend, but we will see. Mount Holly did not go into a lot of discussion about it with the AM AFD, as it is 6 days away. Meanwhile, parts of New England remain in an extreme drought.

Similar to last year, the Chukchi Sea presently has extremely low sea ice extent. . This my have some role in our late Fall weather. Another thing to look for regarding clues to the upcoming winter is what phase(s) the MJO mostly travels in during the month of October. As bluewave and Don S. have referenced there appears to be a connection to the following winter's EPO and AO state. From Don S. < In addition, from the larger pool of La Niña winters following El Niño winters, there were four cases where October saw the MJO in Phases 4-6 for 20 days or more: 1983-84, 1988-89, 1998-99, and 2016-17. All four cases featured an EPO+/AO+ winter. Three cases saw the MJO in Phases 4-6 for less than 20 days: 1995-96: 12 days, 2007-08: 6 days, and 2010-11: 6 days. Both 1995-96 and 2010-11 featured a predominantly negative AO. The latest ensemble guidance favors October 2020 falling into the former pool. Among that pool, October 1983 and 2016 featured above normal and near normal rainfall respectively. October 1988 and 1998 saw below normal and much below normal rainfall respectively. > Meanwhile the West Pac warm pool appears to be at near record temps. If you recall there was a study posted last winter https://www.nature.com/articles/s41586-019-1764-4 Here is a tidbit from the abstract. Here we show that rapid warming over the tropical oceans during 1981–2018 has warped the MJO life cycle, with its residence time decreasing over the Indian Ocean by 3–4 days, and increasing over the Indo-Pacific Maritime Continent by 5–6 days. We find that these changes in the MJO life cycle are associated with a twofold expansion of the Indo-Pacific warm pool, the largest expanse of the warmest ocean temperatures on Earth. The warm pool has been expanding on average by 2.3 × 105 km2 (the size of Washington State) per year during 1900–2018 and at an accelerated average rate of 4 × 105 km2 (the size of California) per year during 1981–2018.

Nina or Nino simply does not matter. As mentioned before the small area of cooler Pac waters is nothing compared to the HUGE global ocean impact specifically the Pacific. And the CFS sucks. Even the monthly CFS is horrible until you get to the 20 th of the present month for the next month's forecast.

I believe there are -NAO cycles or periods when winter blocking in the NAO domain continued for several winters in a row. Lately as you know the -NAO during the heart of winter has been lacking. The real game changer for us and for a large part of the country has been the fast Pac jet causing warmth to dominant and responsible for a lack of phasing storms ( think East Coast , and Miller A s ) and the breaking down of West Coast ridging.

I know it is early, but I go with 2015-2016

Are we not in a new era ? In my opinion winter analogs present little value currently, and there is a tendency for the warmer climate to our South to be nudging North. Saying we are due for an average winter, or there is no history of something is not a wise train of thought. We could go multiple years with a few inches of snow or a fluke blizzard may hit us.

I see no real reason why it has to be better than last year. Could be another very poor winter if you are after cold and snow. Of course, as we have seen the last few years, there could be a fluke event within a period of cold that turns the stats toward , "wow that winter wasn't so bad,we got a lot of snow" , I give you 2016 for example. A one hit wonder, or fluke if you may. It would certainly appear more likely that if you want to venture a forecast going with a false start to winter seems a decent idea at the moment. I would think maybe something along the progression of last year. Whether it is in November or December, remains to be seen. Would have to think earlier versus later. I based this on upon SST forcing to our North, ie. less sea ice, and the still evolving and growing Nina. Whatever favorable elements can happen , would occur early in my opinion. There is talk among some mets, and seasonal modeling, that the coming winter will be back loaded. We thought that would happen last year but it did not , blocking came together too late and brought a cold portion of spring. In March 2018, that was back loaded with the mother of NAO blocks and brought us a memorable late period of snow and cold to our region.

2 weeks of winter in late November to early December then we firmly get implanted on Nina pattern and roast . Accuweather with similar thoughts. As you might have read they feel winter could come in early and then moderation. They are going with typical Nina Climo. Nothing we didnt know already.

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.