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Early run up to Winter 2020/2021 discussion


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Mild in november doesnt mean anything regarding Winter ahead.Some of the coldest spells of winter weather in history have had  very mild spells in November,obviously if it was end of December now and this pattern was setting up then it would be a concern again,but its not so stop writing winter off,looking at you jules216 😁

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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

Hi. Just briefly dipping into this thread, as a one off, to perhaps provide some further insight here... The spike in AAM in Oct was, of course, directly related to the eastward movement of the M

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8 minutes ago, Broadmayne blizzard said:

With respect. Yes Jules I have seen the 12z which doesn't even go out to the final week of November let alone early December that the Meto update refers to.  I appreciate that the big high parked over central Europe is not great for you at that point but things can and do change.

I certainly wouldn't be writing off winter on November 5th for the uk or central Europe.

I hope you get a good winter and some decent snow.

Iam refering to moderate/strong La Nina November analogs which all pointed to cold November under striong mid Atlantic high and Euro trough.I have seen a lot of snow in November 1988,1998,1999 and 2007.So for me an oportunity wasted

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8 minutes ago, jules216 said:

Iam refering to moderate/strong La Nina November analogs which all pointed to cold November under striong mid Atlantic high and Euro trough.I have seen a lot of snow in November 1988,1998,1999 and 2007.So for me an oportunity wasted

This is why analogs (along with any other form of pattern matching etc) are never a great idea to pin your hopes on! The weather will do what it likes. MJO has overridden the Nina pattern in a big way and messed everything up. No Atlantic ridge.

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Don't put too much faith in the seasonal models either,unless  they are showing very mild for DJF😒Remember EC46 showing blocking over the Arctic regions over recent winters ,not happened.Big FAILURE.

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Oh dear . Another winter down the pan before it’s even started . So depressing chasing cold and snow every year that never turns up 🙁. It’s slowly sinking in that are winters are not really gonna be winters anymore in the UK . 

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3 minutes ago, ICE COLD said:

Oh dear . Another winter down the pan before it’s even started . So depressing chasing cold and snow every year that never turns up 🙁. It’s slowly sinking in that are winters are not really gonna be winters anymore in the UK . 

I fear you may be right.  Things seem different climate-wise, and many of the things we could hope would give us an improved chance of cold in winter no longer seem to apply.

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2 hours ago, sebastiaan1973 said:

EmEkQyjW0AEhAvb.jpg

ps2png-gorax-green-008-6fe5cac1a363ec1525f54343b6cc9fd8-Vklkzp.png

+NAO signal albeit not too strong.  Most of the signals and seasonal models are pointing to a milder than average winter.  A milder than average winter can still have a cold/snowy interludes so let's not lose hope yet.  And above all, it's only early November and things can (and have) changed significantly with regards the upcoming winter.

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As we had into winter things only get more abnormal.

Tried to match the 500mb Geopotential height anomaly of Septembers and Octobers to 2020.

Got double match for 2003 and 2012. I squeezed October 2012+1952 because they seem to be more far away from Oct 2020.

Could have tried to match November 2020, since it is pretty much a done deal with the persistent high pressure and mild conditions.

 

september_matches.png

october_matches.png

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1 hour ago, noname_weather said:

As we had into winter things only get more abnormal.

Tried to match the 500mb Geopotential height anomaly of Septembers and Octobers to 2020.

Got double match for 2003 and 2012. I squeezed October 2012+1952 because they seem to be more far away from Oct 2020.

Could have tried to match November 2020, since it is pretty much a done deal with the persistent high pressure and mild conditions.

 

It’s the 7th of the month ..............nothing is a done deal for the November upper pattern .....

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16 hours ago, Broadmayne blizzard said:

Just carrying on from the models suggesting a warm November. 

According to the CET index

The winters following the 20 warmest November's on record. Produced 10 December's with a CET mean temp below 5c

7 January's with a CET mean below 3c

And 12 February's with a mean CET below 4c

Certainly not indicative of writing off winter.

How many of those are say the last 15 years?...I bet the figures will look less impressive, some good research there but analogues from many winters ago are futile with GW overriding many factors. 

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1 hour ago, Froze were the Days said:

How many of those are say the last 15 years?...I bet the figures will look less impressive, some good research there but analogues from many winters ago are futile with GW overriding many factors. 

Five of the top twenty warmest Novembers are from the last 15 years. Of the remaining 15 warmest November's 8 were from the 20th century. Of The remaining7 there were 5 from 19th C and 2 from 18th.

The most recent warmest November to produce a cold winter as a whole was 2009.  And at least one of the twentieth century one produced a white Xmas whilst another was followed by a sub zero CET month during the winter.

Not trying to prove anything with these statistics just pointing out that even in relatively recent times Warm November's do not preclude a cold winter or cold winter months 

 

Edited by Broadmayne blizzard
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Just been musing over this 3 month smoothed average glosea chart from October for 500hpa. I’m on record as saying these 3 month smoothed projections are poor output to give the public - they give nothing of much use because 3 months is too long to be useful.

image.thumb.png.bcbb3a7ae4bde52de7d97b965b0665b7.png

But I think, as we wait for the November update in a few days, absorb the evolving shape of Niña and chew over what impacts (if any) all this autumnal open water over the Siberian arctic might have - there are grounds for optimism....at least until we see a November glosea comparison. 3 things strike me - the North Pacific high would appear to be displaced slightly further south than we might expect in a Niña season and low pressure near alaska may dominate. Wave 2 precursor?  The Azores high signal to the SW is weak to average. And generally there is a signal for higher than average pressure across much of the North Atlantic. There is also a signal for high pressure in Eastern Europe - another possible wave 2 precursor. 
 

Might we be in for a winter of extremes? At times extreme warmth as we tap into a southerly draw, but at times also proper cold as high pressure gains traction to the NW in December and at times over Scandy later in the season. 
 

Looking forward to the final pre winter glosea run. Will it set tongues wagging, or have us crying in our milk?!

 

Edited by Catacol
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1 hour ago, Froze were the Days said:

and of the other 4 warmest Novembers in the last 15 years?...and I take it you're talking about 1970 for the white Xmas?

Not a fan of analogues myself, Froze... But, having said that, I'm no more qualified than anyone else is, for predicting what the upcoming winter will be like -- I haven't seen a single, solitary hedgehog yet!🙈

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3 hours ago, Froze were the Days said:

and of the other 4 warmest Novembers in the last 15 years?...and I take it you're talking about 1970 for the white Xmas?

Hi Froze of the other 4 warmest in the last 18 years three of them produced at least one settling snowfall during the winter that followed at my lowland location here a few miles from the channel coast.

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I'll try not to sound overly negative:

It seems winters in the UK are becoming the 'worst' season for those who like proper seasonal weather. I've come to the conclusion that in a warming world it's better to look out for heat in the summer as this is getting better and more reliable. (Okay that is coming from someone in SE England!)

The best summers will be bettered, but the best winters will never be bettered.

Cold (even dry or cool) is something which, yes we WILL see again, is ultimately on it's way out long term.

Personally I can't see this winter delivering, if anything it'll be a day of wet snow end of Jan. 

Make sure you're wellbeing isn't too connected to the weather during winter! Some of the happiest spells of my life have actually occured during wet and mild winters!

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I gave a prediction earlier (mid-Oct) that was essentially mild and unsettled first half, cooler and more settled with potential for cold second half.

But what do the closest CET analogues say? (I am not a huge proponent of analogues but I looked them up out of curiosity). 

The following list shows the twelve closest analogue years to past 12 months (assuming this Nov finishes very mild at 9.0), so the period of analogy is Dec of previous year to this month. Then the table shows the NOV to MAR CET values of those winter seasons that followed (in general the Jan to Mar of the winters will be the following calendar year, the NOV and DEC will complete the analogue's calendar year. 

The bias statistic should be read as that year's tendency relative to 2020. A positive number indicates the average departure was higher (a warmer year than 2020) and a negative shows it was colder. The bias differs numerically from the mean absolute only if it contains a mixture of signs -- a close analogue that has all positive or negative differentials will have the same bias statistic (diff sign if all neg). The bias should in most cases be smaller than the average absolute differential because it contains a mixture of positive and negative departures.

A year like 1761 with a negative bias almost the same as the total and average differential is basically showing the same variations around a lower base line which one might expect from similar trending years well back into the past. Since this current year would be tied warmest on record with a 9.1, 7.1 (or any other totalling 16.2) CET finish, and using the 9.0 CET for November, only 2014 would likely show a positive bias relative to 2020.

The column titles in the table are skewed to the right of the numbers so a mix of type styles helps with orientation to them. 

TOP TEN CET ANALOGUES _ 12 MONTHS ENDING NOV 2020

Rank __ Year* __ Total absolute differential (CET) __ Avg abs monthly diff _ bias _ _ _  Nov Dec Jan Feb Mar CET _ winter

_ 01 ___ 2004 _________ 7.1 ______________ 0.59 _______ -4.9 (avg -0.41) ___ 7.7  5.4  6.0  4.3  7.2 _ 2004-05

_ 02 ___ 2007 _________ 8.8 ______________ 0.73 _______ -2.8 (avg -0.23) ___ 7.3  4.9  6.6  5.4  6.1 _ 2007-08

_ 03 ___ 2002 _________ 9.7 ______________ 0.81 _______ -4.9 (avg -0.41) ___ 8.5  5.7  4.5  3.9  7.5 _ 2002-03

_ 04 ___ 1761 ________ 10.0 ______________ 0.83 _______ -8.4 (avg -0.70) ___ 6.2  4.4  4.7  4.0  3.7 _ 1761-62

_ 05 ___ 1943 ________ 10.1 ______________ 0.84 _______ -6.5 (avg -0.54) ___ 6.3  3.5  5.8  3.6  5.2 _ 1943-44

_ 06 ___ 2000 ________ 10.6 ______________ 0.88 _______ -7.2 (avg -0.60) ___ 7.0  5.8  3.2  4.4  5.2 _ 2000-01

_ 07 ___ 1828 ________ 10.8 ______________ 0.90 _______ -7.0 (avg -0.58) ___ 7.4  7.4  0.3  4.3  4.3 _ 1828-29

_ 08 ___ 2014 ________ 11.2 ______________ 0.93 _______ +2.0 (avg +0.17)___ 8.6  5.2  4.4  4.0  6.4 _ 2014-15

_ 09 ___ 1834 ________ 11.3 ______________ 0.94 _______ -3.1 (avg -0.26) ___ 6.7  5.6  2.9  5.7  5.8 _ 1834-35

_ 10 ___ 1736 ________ 11.5 ______________ 0.96 _______ -7.5 (avg -0.63) ___ 6.9  6.4  6.2  4.2  6.1 _ 1736-37

_ 11 ___ 1730 ________ 12.0 ______________ 1.00 _______ -8.0 (avg -0.67) ___ 9.2  3.4  1.9  2.2  6.0 _ 1730-31

_t12 ___ 1999 ________ 12.2 ______________ 1.02 _______ -2.2 (avg -0.18) ___ 7.9  5.0  4.9  6.3  7.6 _ 1999-2000

_t12 ___ 1914 ________ 12.2 ______________ 1.02 _______-11.0 (avg -0.92) ___ 6.8  4.6  4.1  4.3  5.2 _ 1914-1915

----------------------------------------------------------------------------------------------

Some notes on this analogue set. 

The total differential could improve in each case but 1730 if Nov CET is lower than 9.0 ... 2014 then 2002 have the least to lose before they max out in their analogue potential, then any actual outcomes in the 7s will boost most of the others. 1761 and 1943 are already high ranked and can only improve with almost any lower values of Nov CET. However, with the models showing a week of very mild weather to come, it seems likely that the Nov CET will be well in excess of 8 C. 

This is good in one way. It seems like a safe bet nowadays that one month out of five will be 1 deg above recent normals, so if November falls in that range, it may remove one obstacle to a cold winter spell. 

The averages of these twelve years for Dec to Mar CET values are 5.2, 4.2, 4.2, 5.8. This gives the appearance of a statistical trend towards near normal values slumping a bit below normal near the end. So it reinforces my own forecast methodology (which has some analogue techniques built in) that points to a better chance of wintry conditions in Feb and Mar, but it's only a weak indication. At least the analogues don't shout out "mild" although the first few of them are milder than the set as a whole. 

Other than Jan-Feb 1731 and 1829, there are few months in these top analogues that one could describe as cold. 

The best ranking analogues that includes a subzero CET month in the following winter are 14th place 1822 (Jan 1823 -0.1) and 19th place 1939 (Jan 1940 -1.4).  

The next best analogue winters indicated, after the 14 listed above (two t12 and 14th 1822-23) are 15 (1686-87), 16 (2003-04), 17 (2008-09), 18 (2009-10). 19 (1939-40), 20 (1949-50), 21 (1846-47) and 22 (1732-33, 1990-91, 1998-99 tied). There begin to show a few colder (recent too) winters in this set (1686-87 by Maunder standards was quite mild, not quite as mild as 1685-86 which got that year into the running). However, t25th place includes 2015, say no more. 

The lowest ranked analogues since 1971 are 1979-80, 1985-86 and 2013-14. These three winters were nothing like each other, but their signals were not buried in the analogue set anyway. That may be a bit of good news as there are a lot of recent years in the analogues and we don't want another 2013-14.

The worst analogue all-time was 1740-41, but 1740 was such a cold and unusual year in general that it probably says nothing about the chances of this winter being like 1740-41, which was rather cold but not exceptionally so. 

The bottom line with this analogue analysis is, if you believe there is anything at all valid about analogues, some cold weather is indicated as being quite likely and a very cold month is by no means ruled out. This brings us back to about where we were in the larger discussion. So there's nothing to worry about from this analogue set although I would expect a good amount of mild weather in the mix. 

 

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My research also includes investigations of storm potential and I would say that intervals around late December, mid January and late January have high storm potential especially if we are in zonal flow at those times. The mid-December period may see the storminess further north (Scotland in particular).

In my forecasting I combine three index values, temperature, storminess, and blocking or retrograde potential. That combination attempts to forecast the general circulation features for the winter. 

Would say then that the flows will be strong zonal most of December and early to mid-January, temperatures generally mild, several peaks of stormy conditions. Flow will begin to relax towards late January, may split around Euro high and some retrograde potential then. I am not wildly optimistic this will do much more than reduce temperature anomalies to near normal but there could be a colder spell. These tendencies get stronger by early March which is why I think late Feb or early Mar will be coldest of the winter. In the top analogue indicated (2004-05) I recall it was turning quite cold at times in late Feb 2005 (that's when I first joined Net-weather). This was by no means a memorable cold spell but there was a bit of frost and snow with it. 

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