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Long Range Pattern Drivers & Evolution Thread


Message added by 33andrain,

The 33andFive...Day Outlook -- Monitor here

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Hi @Pulsar,  I'm not sure if you are directing your question at me.  I'll attempt a partial reply and let others comment further. I see that you read my long post on the Tele thread and thanks for your feedback and comment just now.  I've actually been in email contact with Victor Gensini a few times but that's in relation to his website and discussing future development ideas.  He's very knowledgeable, well qualified and has written some important papers.  His main focus has been on Tornadoes and hailstorms.  His website is being revamped and most of his AAM and GWO charts are not currently being updated.  The link to his home page:   http://atlas.niu.edu/   His email address is there and although he's always very busy he can be contacted with occasional queries.

 

I must admit that I haven't been paying that much attention to NPAC temps but apart from a general warming trend, several recent years have seen active Typhoon seasons.  The systems that track northwest close to Japan generally curve northeastwards.  If they remain powerful storms and stay on the far western side of the Pacific, they can then pump up some very warm air and near surface waters into the far NPAC and "can" leave a legacy of even higher SSTs there throughout the following winter.  This can in turn prevent the Bering Sea from freezing up at all and leave that side of the Arctic ice free until much later in the winter.  That's the context in which I've generally considered those -ve SST anomalies.  

 

Next, we need to see exactly how big the anomalies are and what's the recent trend:

1npac1.JPG

In my ENSO post I noted that, following a very warm phase, SST anomalies were falling again in much of the SPAC and I noted that the +ve anomalies were starting to ease in the NPAC. This chart is just a day later than Victor's chart in his tweet albeit from a different source. 

1npac2.JPG

 Now it's the 7 day anomaly change showing the trend that looks so different to just 3 or 4 days ago. For the first time for quite a while, anomalies are falling across far more of the whole Pacific than in areas where they are rising.   The +ve values in the far NPAC have fallen by around 1c this week (well between 0.5c and 1.5c).  "if" this recent trend continues, the high anomalies in the NPAC generally will become rather less significant. Things can easily change.

 

Finally, wrt to impacts on Europe.  This depends upon the trough and ridge alignment and the wavelength of the jet stream. Victor suggests that this may well produce an unseasonably early cold snap in much of central and eastern CONUS as we move into early November. Several other posters have alluded to that.  I do not have time to check all the models and I'll just show two GFS/NCEP charts for both NAM and Europe.  I always prefer to look at trends, so I'll show the "7 days hindcast" followed by  "7 day forecast trend" charts" - not actual forecast temps which can be checked anywhere. Others can do that and you can compare ECM/UKMO etc.  Have a look on the sister thread to this one -  Eastern US Met Autumn 2019 Observations and Discussions and of course the new UK and European Discussion thread that I started two weeks ago.

1npac6.JPG

 

1npac4.JPG

Well the trend looks encouraging and the colder conditions are likely to spread further east as this chart only takes us up to Nov 1st.

 

1npac5.JPG

 

1npac3.JPG  On this occasion it looks like Europe will cool down even more than CONUS but that's from a warmer starting point for central and eastern Europe.

 

That's more than enough posting from me for several days as I need to catch up with my business activities.  David :)  

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Hey Tom. I did not favor a warm Nov or Dec. I thought the effects of the NPO-induced cold would first start out West in December; and when the NAO eventually relaxes for a time, we would get some warm

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Back on December 26, composite date for MJO passage at high amplitude in Phase 4 and historic data associated with strong AO+ patterns in combination with a positive EPO implied that the GEFS was miss

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33 minutes ago, Event Horizon said:

 

More info on what's a +TNH and the difference between a -TNH and +TNH.

 

https://www.cpc.ncep.noaa.gov/data/teledoc/tnh.shtml

Thank you for posting this. I've heard TNH thrown around by pro mets, but never knew what it signified. At least now I know what attributed to the 70 degree weekend in mid January of 1995. 

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I've just completed another comprehensive Arctic update on the Arctic thread click on the title for a direct link:

 

GENERAL ARCTIC UPDATE - A DRAMATIC ACCELERATION IN THE RATE OF ICE EXTENT RECOVERY

 

Just to whet your appetites, have a look at this chart:

1.2710a.JPG.2a0894c21267c05a495825fac6f1

Loads more charts, analysis and explanations in the post.

 

Turning to Eurasian/Siberian snow cover - it's continuing its rapid increase:

 

Sunday, Oct 27th:

1.2710i.JPG

 

Sunday, Oct 20th:

ims2019293_asiaeurope.gif

 

Well above average now for late october and matching several outstanding recent years.  Let's look ahead to the next 7 days:

anim_lgf2.gif

 

Further heavy snowfalls and rapid accumulation, with (as many of you already know) Canada and parts of CONUS joining the party. In many parts of Siberia and north Russia some very impressive depths are building up - so much of this snow cover is here for the winter season now.  

 

Overall the last 2 weeks have seen some incredibly fast changes. David :)  

 

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I was very much against the Halloween week cool down as my thoughts 8 days ago was that the ridge being that far back would ultimately pull the WAR west and that turned out ok.

 

Now I am on board with the trough getting into the east from the 10th onward. I have November as a BN month with the core of the coldest anomalies continuing through the UMW. 

 

Nov 2013 type at 2 meters comes to mind.

 

The EPO deepening will be a result of the main axis of the positive retrograding west out of Alaska and LP developing East of Hawaii.

That will funnel the trough into the lakes. 

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Simulations I've run based off my winter outlook for this coming winter:

December: -1 to -3

January: +1 to -1

February: -2 to -4

March: -4 to  -6

Now, I didn't run November, because I don't consider that part of winter, but if I had to take a guess as of today, I'd go -1 to -3.

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1 hour ago, Analog96 said:

Simulations I've run based off my winter outlook for this coming winter:

December: -1 to -3

January: +1 to -1

February: -2 to -4

March: -4 to  -6

Now, I didn't run November, because I don't consider that part of winter, but if I had to take a guess as of today, I'd go -1 to -3.

I would like everything but March.  

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4 hours ago, swamplover56 said:

Been so long since we pulled off a nyc metro December storm. 

I think we do it this December, probably within a week before Christmas. 

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3 minutes ago, 33andrain said:

Agree! Not as extreme though. 

Yeah I am not talking a blizzard or anything but a nice 6-10" storm would be a great way to kick off the winter.

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