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Early run up to Winter 2020/2021 discussion


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Liking short term strengthening of the PV as we end Oct then PV implode due to massive Siberian high as we start Nov could be some interesting early winter weather mid Nov onwards.

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Edited by booferking
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Just a post for any newbies who have just joined. Musings and posts you WILL regularly come across in the months ahead and going into a winter: 1. October: 'This winter will be front loaded or ba

Says it up top 02/10.   Hot off the press Met office seasonal update OCT 20 for NDJ Considerable changes in favour of a colder Front loaded winter. Gone is the negative low pressur

Last time Liverpool lost 7-2 was apparently in 1962/3. Lets hope the weather remembers

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6 hours ago, booferking said:

Liking short term strengthening of the PV as we end Oct then PV implode due to massive Siberian high as we start Nov could be some interesting early winter weather mid Nov onwards.

gfsnh-0-216.png

gfsnh-0-384.png

I ponder a UK/Scandy high scenario as we move into November.

Certainly high pressure ,Sceuro high perhaps..

Edited by northwestsnow
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50 minutes ago, northwestsnow said:

I ponder a UK/Scandy high scenario as we move into November.

Certainly high pressure ,Sceuro high perhaps..

I know I keep reposting this from Simon Lee last week, but suggests a range of options in to December... 

IMG_20201018_095653.jpg

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1 hour ago, Griff said:

I know I keep reposting this from Simon Lee last week, but suggests a range of options in to December... 

IMG_20201018_095653.jpg

Indeed, I'm not personally looking that far ahead however..

 

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1 hour ago, Griff said:

I know I keep reposting this from Simon Lee last week, but suggests a range of options in to December... 

IMG_20201018_095653.jpg

Yes - what is good to see is even the flatter options into Jan / Feb are not Bartlett territory. Looking more north westerly in origin, could be some cold cyclogenesis mixed in with attempts for the MAH to try and ridge up to Greenland, tilting the jet NW - SE. 

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https://longrangesnowcenter.net/2020/10/20/october-preliminary-2020-21-winter-outlook/ 

Looking like for the European winter IMO: 

Moving onto Europe, we see a colder December for the UK, and a pretty average winter overall, with a weaker backend of the season.
The Northern Alps (Northern Europe) should see an average snowfall season, maybe slightly better than normal. 
The Southern Alps (and the rest of Southern Europe) should see a slightly below average season, with the best conditions early in winter. 

Climatic factors:

  1. A basinwide moderate (possibly strong) La Nina this winter.
  2. A positive QBO
  3. Solar Minimum
  4. Atlantic SSTs favourable for a +NAO
  5. North Pacific SSTs favourable for a Aleutian Ridge.
  6. Average growth of Stratospheric Polar Vortex into winter, potential for SSWs later.
  7. Phase 3-6 MJO centred tropical base state
  8. Low sea ice in Barents-Kara Sea.
  9. Average snow coverage in Siberia.

Technical analysis in link above :) 

 

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https://easternmassweather.blogspot.com/2020/10/mixed-signals-regarding-enso-for-winter.html

Oct%2BENSO%2BPlumes.png
EASTERNMASSWEATHER.BLOGSPOT.COM

 Mixed Signals Regarding ENSO for Winter 2020-2021 Clarity Emerges with Respect to...

One of the most important considerations as we begin to craft the 2020-2021 Eastern Mass Weather Winter Outlook will be that while a modoki la nina evolution is unlikely, this particular cool episode is alive and well across its western flank, as well. It is true that some of the most intense anomalies continue to be across the eastern flank, these anomalies have expanded in coverage to the west, as region 3.4 now reflects the most intense anomaly, at -1.4C as of today.

There are three other cool ENSO events which exhibited this "mixed" distribution of the most intense sea surface anomalies.

It would be prudent for any analog composite this season to include these three seasons.

They are as follows:

1970-1971

1999-2000

2007-2008

From Judah Cohen comes this list:

Winter 2000 and 2008 had a SSW.

Ekuq2A8WkAAnfet.jpg

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It’s very early days really - good to see some outlooks beginning to emerge but in truth very far out to be sure: Snowy’s early plumping for a pretty standard Niña pattern illustrating good gambler’s instincts.

For me the strength of Niña will be the key element and if MJO phases 7/8 are undermined by cold waters in the west/central Pacific then  Greenland heights I think become a long shot. However I do see opportunities for Scandy High development this season, and I think I’m also beginning to sense that an SSW may be a genuine possibility this year. We are all waiting now to see if the moderate Niña mid Atlantic ridge can give a cold and northerly fed December...and at the same time I’m keen to see how embedded a Sceuro High might become through November. If that happens, and if an Aleutian low can establish as some models are suggesting at the same time, then given lag effects we might see pressure on the vortex increase into the New Year. The met office extended forecast suggests to me a sceuro high with effects far enough west to hold off the Atlantic. 
 

We are all just spitting in the wind though at this range. And back to where I started - until we see how strong Niña might be by December then all forecasts are like throwing at a dartboard blindfold. There are quite a few proclaiming that it won’t get much below -1.5. I hope they are right because a strong Niña is likely to give the Atlantic steroids. We will see.

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I am shifting my focus/hopes on to the strong Ural High anomaly that is forecast for beginning of November by GEFS,EPS and CFS weeklies. Dr.Cohen was kind enough to send me full study by Peings 2019 that links the Ural High to -NAO in Dec/Jan through stratospheric warming pathway. Mornings EPS 0Z clustering reveals that 28 out of 51 ensembles - cluster 1 and 3 have nearly perfect match to the Ural High anomaly that is used in that study.  

24N9Cg5e.jpg

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Time for my next CFS monthly predictions for the November to March period

These are the latest 14 days worth of figures off the weather outlook website (Link in earlier updates)

CFS 00Z 500hpa anomalies    Start 07/10/2020    End 20/10/2020        Last 20/10/2020

Temps        Nov    Dec    Jan    Feb    Mar     TOTALS
V Mild            0        0        0        0         0            0

Mild               0        0        0        0         0            0

Average        7        11      12      7         6            43

Cold              7         3        2        7         8            27

V Cold           0         0        0        0         0            0

Precip        Nov    Dec    Jan    Feb    Mar     TOTALS

V Dry            2         1        0       0          0             3

Dry               6         7        3       2          3             21

Average       5         4        4       5          5             23

Wet              1          2       7       5          2             17

V Wet           0         0       0        2          4              6

TOT    14 days worth of data

Key Temp figures    Key Precip Figures
V Mild        +2.00     V Dry          0%
Mild           +1.00      Dry            50%
Average    +0.00      Average    100%
Cold           -1.00      Wet            150%
V Cold        -2.00      V Wet        200%

Now to compare the averages calculated from both sets of data we have the following. The most recent analysis is in bold

07/10/2020 to 20/10/2020 Analysis November CET -0.50C COLDER  November Precip 67.86% OF NOV AV
23/09/2020 to 06/10/2020 Analysis November CET     -0.36C COLDER   November Precip  89.29% OF NOV AV
06/07/2020 to 22/09/2020 Analysis November CET     -0.08C COLDER   November Precip  97.47% OF NOV AV

07/10/2020 to 20/10/2020 Analysis December CET -0.21C COLDER  December Precip 75.00% OF DEC AV
23/09/2020 to 06/10/2020 Analysis December CET    -0.29C COLDER   December Precip   75.00% OF DEC AV
06/07/2020 to 22/09/2020 Analysis December CET    -0.25C COLDER   December Precip   87.97% OF DEC AV

07/10/2020 to 20/10/2020 Analysis January CET     -0.14C COLDER  January Precip      114.29% OF JAN AV
23/09/2020 to 06/10/2020 Analysis January CET         -0.36C COLDER  January Precip         103.57% OF JAN AV
06/07/2020 to 22/09/2020 Analysis January CET         -0.25C COLDER  January Precip         108.23% OF JAN AV

07/10/2020 to 20/10/2020 Analysis February CET   -0.50C COLDER February Precip    125.00% OF FEB AV
23/09/2020 to 06/10/2020 Analysis February CET      -0.43C COLDER   February Precip     125.00% OF FEB AV
06/07/2020 to 22/09/2020 Analysis February CET      -0.24C COLDER   February Precip     115.82% OF FEB AV

07/10/2020 to 20/10/2020 Analysis March CET        -0.57C COLDER  March Precip        125.00% OF MAR AV
23/09/2020 to 06/10/2020 Analysis March CET           -0.43C COLDER   March Precip         110.71% OF MAR AV
06/07/2020 to 22/09/2020 Analysis March CET           -0.11C COLDER   March Precip         112.66% OF MAR AV

07/10/2020 to 20/10/2020 Analysis OVERALL NOV-MAR ANOM -0.38C COLDER  OVERALL NOV-MAR % 101.43% OF NOV-MAR AV
23/09/2020 to 06/10/2020 Analysis OVERALL NOV-MAR ANOM      -0.37C COLDER   OVERALL NOV-MAR %   100.71% OF NOV-MAR AV
06/07/2020 to 22/09/2020 Analysis OVERALL NOV-MAR ANOM      -0.19C COLDER   OVERALL NOV-MAR %   104.43% OF NOV-MAR AV

November 2020

CET - November 2020 is predicted to be colder than average and the anomaly has got just a bit colder again compared with the last update. The latest update shows -0.5C Colder than average compared with -0.36C in the last one and -0.08C in the summer update. Starting to look more and more promising for November if you are a cold fan

Precipitation - November 2020 is now looking increasingly likely to be a drier than average month. The latest 67.86% of average precipitation shows this compared with 89.29% last update and 97.47% in the summer update

November 2020 will not feature any further in these 2 week updates of the monthly CFS charts as the next update of this nature will be after November starts although I will have an in depth CFS 9 monthly runs update for November 2020 at the end of October

December 2020

CET - December 2020 is predicted to be slightly colder than average although for cold fans the latest analysis is a step in the wrong direction for cold with a slightly less cold -0.21C colder than average compared with -0.29C in the last update and -0.25C colder in the summer update. Maybe not all bad as all December updates have been in the -0.20C to -0.29C range

Precipitation - As with all updates December 2020 has come out consistently drier than average and this latest analysis is no different with another repeat of the 75.00% of average precipitation like the last update and drier than the summer update of 87.97% of average.

January 2021

CET - January 2021 latest analysis is the most disappointing in terms of a cold perspective. What looked promising last time has gone away somewhat with this latest analysis. Although -0.14C is still colder than average it is the closest to average update for January 2021 compared with the previous 2 of -0.36C last time and -0.25C in the summer update. Maybe CFS is responding to the Super Nina forecast it has.

Precipitation - January 2021 is now more firmly into wetter than average territory after the latest analysis at a new high of 114.29% of average precipitation. This combined with the lesser colder signal looks like a more zonal Atlantic January 2021 is on the cards.

February 2021

CET - February 2021 has continued to look promising for colder weather and this latest update only reinforces this fact even more as the latest anomaly is an even colder -0.5C colder than average signal compared with -0.43C last time and -0.24C in the summer update. Perhaps a front and back loaded winter is showing up now with the cold for early on, the less cold January then this colder February.

Precipitation - February 2021 has continued to show a wetter than average signal right from the start of my analysis right back in the summer and the latest figure of 125% of average precipitation that matches the last update only continues this. With an even colder CET anomaly showing up then the snow risk for February 2021 has only increased even further.

March 2021

CET - Perhaps the most impressive month in the latest update is March 2021. The latest CET analysis has come out with the coldest anomaly so far of all 5 months with a nice -0.57C colder than average signal which continues the getting colder signal from -0.43C colder last time and -0.11C colder in the summer analysis.

Precipitation - March 2021 is now looking a more firm bet for a wetter than average month too now with the latest 125% of average precipitation value compared with the 110.71% and 112.66% from the previous updates. Even more chance of snow makers now with the even colder CET anomaly.

Overall November 2020 to March 2021 period

CET - Overall the latest average out CET anomaly has come out only a tiny bit colder than the previous update. The latest Nov - Mar CET anomaly is -0.38C colder compared with the last -0.37C colder. Still a lot better than the first update with its -0.19C colder. Overall in the latest update the cold is focused most on November 2020, February 2021 and March 2021. December 2020 and January 2020 are not so cold, especially the January.

Precipitation - Overall the same signal as all updates continues with a generally close to average precipitation signal overall for the whole of the Nov - Mar period. However this masks the pattern showing up with a generally drier start to the period and becoming much wetter later on in the winter.

My next update based on the monthly CFS charts from weather outlook will be as usual in 2 weeks time on 03/11/2020 but as mentioned before will no longer contain any November analysis.

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5 hours ago, jules216 said:

I am shifting my focus/hopes on to the strong Ural High anomaly that is forecast for beginning of November by GEFS,EPS and CFS weeklies. Dr.Cohen was kind enough to send me full study by Peings 2019 that links the Ural High to -NAO in Dec/Jan through stratospheric warming pathway. Mornings EPS 0Z clustering reveals that 28 out of 51 ensembles - cluster 1 and 3 have nearly perfect match to the Ural High anomaly that is used in that study.  

24N9Cg5e.jpg

Agree with this Jules. And even if an SSW doesn’t follow with all the associated dice rolling that would then come into play, a weakening of the trop vortex via sceuro ridging will help create a context for greater blocking potential once the vortex passes its seasonal peak.

We will see. Scouring various forums I’m seeing 2010/11 and 1995/96 mentioned by analog junkies quite regularly. I got snow in both those seasons...so I’d take either. Bar the extraordinary and freakish 2018 Beast we haven’t had a cold outbreak of note in years. Gotta end sometime....

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On 17/10/2020 at 09:46, Rollo said:

Ian was anything but a mild lover, he gave a forecast one winter when there was a very cold snowy spell and he appeared so exited about it. I did meet him once but I am afraid he had had too much too drink and I could not get much sense out of him.

I went to a book signing with him and Paul Hudson in Sheffield. He signed my book with Paul but he did look very ill due to his poor health drinking ete. Great forecaster tho he was bless him 

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2 hours ago, Catacol said:

Agree with this Jules. And even if an SSW doesn’t follow with all the associated dice rolling that would then come into play, a weakening of the trop vortex via sceuro ridging will help create a context for greater blocking potential once the vortex passes its seasonal peak.

We will see. Scouring various forums I’m seeing 2010/11 and 1995/96 mentioned by analog junkies quite regularly. I got snow in both those seasons...so I’d take either. Bar the extraordinary and freakish 2018 Beast we haven’t had a cold outbreak of note in years. Gotta end sometime....

keep your expectations low as its easy to get carried away by these typical october hypes. I ve looked at current NH view of latest GFS for 31.10 then looked back at all archives last 30 years and didnt find any such a diabolical profiles bar 2007 and 2013.The compact vortex and low thickness values of trop vortex upcoming week are truly discusting and years that get mentioned a lot like 1995,1998,2010 or 2016 has much weaker or pertubered for the same date. For me a reality check that hadley cell expansion or abnormally cold mid to high stratosphere bring. No way this is going to be a 1995 or 2010 re-run.more like 2013 or 2019 I am afraid.

gfsnh-0-264.png

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3 minutes ago, jules216 said:

keep your expectations low as its easy to get carried away by these typical october hypes. I ve looked at current NH view of latest GFS for 31.10 then looked back at all archives last 30 years and didnt find any such a diabolical profiles bar 2007 and 2013.The compact vortex and low thickness values of trop vortex upcoming week are truly discusting and years that get mentioned a lot like 1995,1998,2010 or 2016 has much weaker or pertubered for the same date. For me a reality check that hadley cell expansion or abnormally cold mid to high stratosphere bring. No way this is going to be a 1995 or 2010 re-run.more like 2013 or 2019 I am afraid.

gfsnh-0-264.png

A large part of vortex has found its usual home around Greenland and Europe and western Russia is already stripped of any cold source.What cold source will there be to tap in to in Sceuro high it even we manage some? Had a look at nearest city to my in Slovakia on GEFS extended or EC monthlies and mean didnt even get below +2C at 850hPa! and that is decent elevation at 700m.asl. Only like 5 members out of 80 went lowest to -5C 850hPa. 

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Well 95/96 was pretty legendary and had very cold November and extremely cold March on top of that.  Don't think that's even remotely possible in the current climate. We will be lucky to get one below average month.

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1 hour ago, jules216 said:

A large part of vortex has found its usual home around Greenland and Europe and western Russia is already stripped of any cold source.What cold source will there be to tap in to in Sceuro high it even we manage some? Had a look at nearest city to my in Slovakia on GEFS extended or EC monthlies and mean didnt even get below +2C at 850hPa! and that is decent elevation at 700m.asl. Only like 5 members out of 80 went lowest to -5C 850hPa. 

Even a strong vortex doesn't preclude a spell of very cold weather. Are we going to get a severe winter? Almost certainly not. We might scrape a couple of decent snowfalls somewhere though. 

One thing that has become notable in recent years is the lateness of the onset of winter across the NH. Places like Moscow should be seeing their first snows of the winter by now, but yet again it will be well into November. The warming trend marches on 🥵

 

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Just now, Jason M said:

Even a strong vortex doesn't preclude a spell of very cold weather. Are we going to get a severe winter? Almost certainly not. We might scrape a couple of decent snowfalls somewhere though. 

One thing that has become notable in recent years is the lateness of the onset of winter across the NH. Places like Moscow should be seeing their first snows of the winter by now, but yet again it will be well into November. The warming trend marches on 🥵

 

But we're seeing increasingly frequent cold incursions quite far S across Canada and the states.

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6 minutes ago, CreweCold said:

But we're seeing increasingly frequent cold incursions quite far S across Canada and the states.

There was an unusually early cold plunge into Denver last month.

Central Canada has finally gone cold (ie Winnipeg). Ottawa is forecast to be 23c on Friday. Moscow max temps stay well into high single figures right into early Nov based on current output. None of this of itself is proof but it now happens year after year. Anyway, lets leave there as don't want to derail the thread. 

Current output looks like typical fare in our part of the world. In truth anything synoptically good is an utter waste until we get into the middle of Nov anyway.

If your still going for a cold winter, I (genuinely) wish you well with that 😀

 

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1 hour ago, jules216 said:

keep your expectations low as its easy to get carried away by these typical october hypes. I ve looked at current NH view of latest GFS for 31.10 then looked back at all archives last 30 years and didnt find any such a diabolical profiles bar 2007 and 2013.The compact vortex and low thickness values of trop vortex upcoming week are truly discusting and years that get mentioned a lot like 1995,1998,2010 or 2016 has much weaker or pertubered for the same date. For me a reality check that hadley cell expansion or abnormally cold mid to high stratosphere bring. No way this is going to be a 1995 or 2010 re-run.more like 2013 or 2019 I am afraid.

gfsnh-0-264.png

How about this from 1978? 

 spacer.png

Not suggesting we'll get a repeat of 78/19, but plenty of time for things to change at this stage.

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5 minutes ago, Jason M said:

There was an unusually early cold plunge into Denver last month.

Central Canada has finally gone cold (ie Winnipeg). Ottawa is forecast to be 23c on Friday. Moscow max temps stay well into high single figures right into early Nov based on current output. None of this of itself is proof but it now happens year after year. Anyway, lets leave there as don't want to derail the thread. 

Current output looks like typical fare in our part of the world. In truth anything synoptically good is an utter waste until we get into the middle of Nov anyway.

If your still going for a cold winter, I (genuinely) wish you well with that 😀

 

I'm not looking at synoptics around our shores at present...it's relatively inconsequential at this point. What is of more importance is the general NH profile- in particular that of the area around Russia.

If the ECM is anywhere near the mark this evening, we'll be seeing stress on the fledgling vortex already.

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26 minutes ago, CreweCold said:

I'm not looking at synoptics around our shores at present...it's relatively inconsequential at this point. What is of more importance is the general NH profile- in particular that of the area around Russia.

If the ECM is anywhere near the mark this evening, we'll be seeing stress on the fledgling vortex already.

just checked 12EPS and few more colder clusters appearing for my location by 03.12.mean down to  about 0C at 850hPa

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Winter 96 is not a good analogue in my opinion.  The Nina was too weak and the PDO was positive.

99 and 11 broadly match the ONI, PDO and QBO to a pretty good degree. They also both had a cool November, mild February and a March close to average. December and January are up in the air.

The only other factor in our favour is that 2020 will likely be a top 10 spotless year.

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I’m not concerned as yet re our chances of a disastrous winter.   It isn’t really the weather that affects us per se that is important in October or early November either.  It probably will be off the Atlantic and wet.  ECM T168 and T240:

D2BD6F85-4F4F-4EB2-B3AE-9E65F3ACC9E9.thumb.png.f763a38426282897183832c2bf3c4ef5.png3029C616-2B7E-4F75-854F-E9BA647410E0.thumb.png.1a55597795b32cdfba19733fbee240f2.png

It is where the blocking is that is more important at this stage, E Scandi and Russia good for putting pressure on the vortex early doors, if it comes good, flip to cold last week November, i reckon, not earlier.  Which is the earliest we want it anyway!

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