Autumn And Winter

[BLAST FROM THE PAST]

Damien

I think where you are going wrong when you have a tendency to keep going on about a freeze with the Thames freezing over etc. A cold/very cold winter may well happen and I certainly believe that a below 1c month can be achieved as you quite rightly point out near record/record cold events have occurred recently to our east. With the correct draw and for long enough it 'can' still happen but unlikely, but I think synoptic pattern has had the major influence over that. Examples being July was hot because just look at where the lengthy draw came from and we have had our weather coming from the west recently and temps are perfectly normal. However, if the continued longterm synoptics favour then we can get sub 1c, the odds have been utterly against it but to me the odds have lessened a tad.

BFTP

Edited August 26, 2006 by BLAST FROM THE PAST

[Stratos Ferric]

Steve, John,

Re the falling trend. You're absolutely right, but I'll still offer a little "however".

The four previous occasions on which CET fell for four consecutive years ended in the years, and with a cumulative fall in CET, are as follows:

1675: 1.21C - this value needs treating with caution because at this time temperatures were recorded only to intervals of 0.5C. This value, therefore, is +/- 1.0C, the others are +/- 0.2C

1740: 3.46C

1765: 1.50C

1838: 2.42C

In the three years to date since 2003 we have fallen 0.16C

1740 was one of the coldest years on record, so the dip here was unusual in that it was out of a short phase above the mean at the time and then dramatically down.

1765 is a reflex from a short warm spike, occuring during an otherwise cool run.

1838 was another reflex, this time from the hottest CET for around 100 years either side into quite a cold CET, but again, most of the movement here was from a warm excess.

(to date in the current run we remain at almost unprecedented heights re CET).

What we have in the current run is, for sure, three cooler years, but whether or not this is significant is unclear given that the cooling has been very slight, and, I hasten to add, is still within the mathematical error of +/- 0.2C.

To reach a cooling of, say, 1.5C by the end of this year the following would have to happen:

1 - the year on year cooling required this year (1.3C) would surpass anything bar the 16 biggest year-year drops, putting it at the 1:20 or so; very unusual but not exceptional; 1996 and 1962 both had drops about this large.

2 - the outturn for the year would be 9.2, a level not seen since 1987 - this would, whilst not blowing a fatal hole in GW, certainly be cause for abrupt reassessment;

3 - assuming 16.2C for August, we would have 85.6 cumulative average degrees to date this year: last year had 125.3. The 1.3C fall across the year would mean 15.6 (1.3 x 12) less than this, say around 110 cumulative average degrees by the year end. The last four months of the year thus would have around 25 degrees to "play with" from where we are now. This has occurred four times, three times in the 17th century (bear in mind what I said above about margin for error back then), and most recently in 1740, mmm, 1740 - that exceptionally cold year again! IN most recent years September and October alone would account for all of these 25 degrees.

So, is continual cooling at the moment of interest? My assessment is that it's worth watching, but then I've been saying that for the past couple of years, not so much of itself, but because the CET is so unprecedentedly high that we're in the last chance saloon for arguments against the forward trend. If it doesn't correct back down now, then it's hard to argue against continued increases, given the scientific arguments for warming in the system anyway. But, and here's the answer to your question John, the fact that we've had 3/4 years of consecutive cooling actually matter less than the amount of cooling. The overall trend is a function of absolute temperature, not year to year trends. Therefore, not only should we wish for another cooler year if we want to hang on to realistic prospects for wintry weather, but we should wish for a significantly cooler one. The analysis above suggests we're unlikely to get it, but what's gone before is no definite determinant of what's yet to come.

Edited August 26, 2006 by Stratos Ferric

[Stu_London]

Autumn:

Wetter than average

Temps about normal

Sometimes stormy

Winter:

Average rainfall (or snowfall) - but will seem much wetter after last year

Temps slightly above average but with some dramatic swings and I fully expect 1 cold snap from the North for about a week and maybe another easterly but less confident about this.

Nothing too scientific has gone into this - just my view on how things might pan out after what was a significant pattern change at the end of last month.

1675: 1.21C - this value needs treating with caution because at this time temperatures were recorded only to intervals of 0.5C. This value, therefore, is +/- 1.0C, the others are +/- 0.2C

1740: 3.46C

1765: 1.50C

1838: 2.42C

I think at least one of the above events may have been influenced by major volcanic activity

Saw a program recently - might be the 1830s event I think.

[Stu_London]

As for the debate to getting a CET for 1C thats very tricky- & if we assume the globe has risen by at least 1c then thats the same as asking for a freezing month which has a return of ~ 1 in 20 years-

Its possible, however I think the goalposts have moved as such that the new freezing month is a 2C CET.....

I would be VERY Surprised that by the end of Winter 2008/9 we hadnt had one of those Months & if thats the case we can kiss goodbye to anyhope of a significantly below average Winter Month again....

S

Interesting that you have lowered the bar to 2C

As I am sure you know, the last month below this level was Feb 1991.

Most of the 90s thereafter were a complete write off winter wise however I think a subtle pattern change took place after 1999. Since then we have basically been unlucky - cold spells have missed us by a whisker or gone t*ts up at sometimes less than 72 hours notice.

Another more significant pattern change in Feb 2005 leaves in a situation where I believe 2C could be acheived in the next couple of years if a spell of weather falls neatly into one month - a la July 2006.

[Lincs Observation]

Good afternoon

well i would like to throw in my tupence to, everyone is going on about august but would i be correct in saying that there has not been many days this month that tempretures have fallen below 20oC, and in my book thats a plesant August in my book, However it has been wet and would like to think that rainfall averages have been up for August.

with regard to Winter and looking at the last two years general trends as an onlooker and with (no science behind my thinking) i would plump for a coldish winter something along the lines of the early 80's with more frost than snow but when snow is falling it may be widespread.

with the past 20months of dryish weather (hence the water ban) nature has a way of addressing the balance. and i believe that will start in late october early November through to feb 2007 after an indian summer late september.

thats my thoughts and its only gut feelings that got me to this conclusion so shoot away

LO

Edited August 26, 2006 by Luton Observation

[Rollo]

My problem in issuing any sort of forecast is that as I dearly would like to see a 62-63 type winter that tends to colour my thinking.In all honesty that winter followed a fairly consistant run of cold type winters and as has been said the last decent cold one was 10 years ago. I think it is best not to commit in any way at this stage as in my case it would only be hopecasting.

[Snowyowl9]

As far as autumn goes I say september will be cool unsettled, october may start of cool then it`ll settle down to bring a warmer period later in the month then I think november will start mild then we`ll get a very cold northerly with a strong greenland high and hopefully it will be better than last years november northerly, as we got hardly any snow from that, west wales and cornwall got the brunt of that.

I`ve seen much better november`s for snow than that.

That`s as far as I`m going to go at the moment.

S9.

Edited August 26, 2006 by Snowyowl9

[Thundery wintry showers]

If we were to get a significant northerly this November, it would be the first time we'd had northerly incursions in three successive Novembers since 1978/79/80.

Certainly not impossible, but it would be interesting if it did happen.

[Steady Easterly]

Its a bit early isnt it?

[Hiya]

now i'm not even gonna pretend i have the knowledge of SF and people who post in here but i thought i'd point something out.

No one has mentioned the period of 1997-2001 for cooling, now i know the year in the middle was a buck to the trend, but if you knock it into excel u get a gradient of -0.124 or for those who like pictures:

for 2002-05 the gradient is -0.05:

But the cooling resets itself 2002 and if we take the trend over the whole period- 1997 to 2005 - is only 0.0017, virtually nothing:

heres a nice wavy graph to illustate that:

Anyway, by the end of this year i would expect that if we added it on to the above graph we'd be into a -ve gradient over the last 9 years.

I really like using the numbers to all sorts of statistical ends and at the end of the winter this year it'll be really interestingcause then there will be enough data to start analysing the post-feb 2005 change to the weather.

PS don't pan for only using 9 years, i'm only pointing out short term trends

Scotaidh

Edited August 26, 2006 by Hiya

[Snowyowl9]

If we were to get a significant northerly this November, it would be the first time we'd had northerly incursions in three successive Novembers since 1978/79/80.

Certainly not impossible, but it would be interesting if it did happen.

We`re overdue then

S9.

[tugmistress]

now i'm not even gonna pretend i have the knowledge of SF and people who post in here but i thought i'd point something out.

No one has mentioned the period of 1997-2001 for cooling, now i know the year in the middle was a buck to the trend, but if you knock it into excel u get a gradient of -0.124 or for those who like pictures:

for 2002-05 the gradient is -0.05:

But the cooling resets itself 2002 and if we take the trend over the whole period- 1997 to 2005 - is only 0.0017, virtually nothing:

heres a nice wavy graph to illustate that:

Anyway, by the end of this year i would expect that if we added it on to the above graph we'd be into a -ve gradient over the last 9 years.

I really like using the numbers to all sorts of statistical ends and at the end of the winter this year it'll be really interestingcause then there will be enough data to start analysing the post-feb 2005 change to the weather.

PS don't pan for only using 9 years, i'm only pointing out short term trends

Scotaidh

hehe youi and i both ... i have absoltuely no knowledge as most of this lot will tell you

just a request really, i can understand graphs etc so your post was really easy to follow, would you be able to do something similar to the last graph you did but for the last say 20 years? it would be within my age of remembering (yes i have abad memory for an old person ).

[Nick F]

If we were to get a significant northerly this November, it would be the first time we'd had northerly incursions in three successive Novembers since 1978/79/80.

Certainly not impossible, but it would be interesting if it did happen.

On the subject of November N'erlies, I was quite impressed how potent the N'erly was at the end of last November here, on the 25th the temp got no higher than 2.5C with snow showers with a min overnight of -5.5C, something we haven't seen in Jan or Feb in some of the warmer winters more recently. Though the Easterly of 1993 was even colder around here, with 3 or 4 days with maxes of just 2C.

Edited August 26, 2006 by Nick F

[Hiya]

hehe youi and i both ... i have absoltuely no knowledge as most of this lot will tell you

just a request really, i can understand graphs etc so your post was really easy to follow, would you be able to do something similar to the last graph you did but for the last say 20 years? it would be within my age of remembering (yes i have abad memory for an old person ).

as requested and a little bit more

last 20 years expressed as a 4th degree polynomial:

i like that one - things are on the way down...

last 20 years as a rolling 3 year average:

last 20 years with a lineof best fit:

that last one is a bit skewed due to the data limits but its still valid to say "in the last 20 years there has been an average increase in CET by over 1 degree"

I love graphs

btw using the numbers i generated according to the 20 year stats this year should have a CET of 10.67 but according to the data from the last 4 years 10.38, which sounds more realistic.

Scotaidh

Edited August 26, 2006 by Hiya

[reef]

On the subject of November N'erlies, I was quite impressed how potent the N'erly was at the end of last November here, on the 25th the temp got no higher than 2.5C with snow showers with a min overnight of -8.5C, something we haven't seen in Jan or Feb in some of the warmer winters more recently. Though the Easterly of 1993 was even colder around here, with 3 or 4 days with maxes of just 2C.

The November 25th 2005 northerly was pretty impressive here too, a maxima of 5.1°C so close to the coast was rather low, and the morning brought a heavy snow shower which gave around a 1cm covering.

What was annoying however, was that the more "potent" 28th snowfall in the west, was just rain and sleet here, this despite a maximum temperature of a 4.2°C, nearly a degree lower! It was very reminiscent of the Feb 2005 easterly, where dewpoints were just marginally to high so what fell that day was over half an inch of rain/sleet!

[Thundery wintry showers]

I have weather record archives for November 2005 in Cleadon (Tyne & Wear).

On the 25th the temperature fell to -0.8C overnight, and then there was a wet snow flurry at around 8am. The temperature hovered around the 3C mark for most of the day, but soared to 6-7C that evening as a strong north-east wind picked up off the sea, associated with a warmer airmass.

The 28th had a max of just 2.6C- the lowest in November since 1993- but showers were mainly of sleet or wet snow with little or no accumulation during the morning, and none during the afternoon (anything that did settle melted immediately afterwards). I wasn't there at the time, but the Tyne Tunnel webcam and my parents confirmed the above. Dewpoints may well have been a major factor- I've known snow settle quite readily at 0.5-1.0C before, which is the temperature range at which much of it fell.

Lancaster had its first accumulation of snow in November since 1996, despite the fact that they had an accumulation of snow on October 30th 2000 (!)

In Leeds there were some snow flurries on the 28th, but nothing settled.

[Snowyowl9]

On the subject of November N'erlies, I was quite impressed how potent the N'erly was at the end of last November here, on the 25th the temp got no higher than 2.5C with snow showers with a min overnight of -8.5C, something we haven't seen in Jan or Feb in some of the warmer winters more recently. Though the Easterly of 1993 was even colder around here, with 3 or 4 days with maxes of just 2C.

We had the same temperature as you that day also at 2.5c with a few light snow/hail showers which only brought a dusting, because the next day 26th it thawed.

Max that day was 5c.

The lowest temperature during the actual northerly got down to -3.1c.

We had colder nights before the northerly set in must of been when we had high pressure.

S9

[J10]

Very snowy on 25 November last year with 4 inches of snow on the grass (properly measured) and closer to 2 inches on other surfaces.

The heaviest snow fell between 6-8am in the morning, a good time for snow sticking.

Very unusually the snow stuck around to give a snow day for 3 days before gradually thawing away.

Some photos on the BBC website

http://www.bbc.co.uk/wales/southwest/sites...ow05_2.shtml?13

[Nick F]

Last November didn't give any lying snow here unfortunately, the snow was just not heavy enough. I can only remember two Novembers in the past which I've seen snow lie in the SE, and that was during the Easterly in late Nov 1993 and more especially in Nov 1988 where there were several cms of snow when I was in Kent and an unusually early, for the time of year, day off school due to snow - i vividly remember for some reason!

[tugmistress]

hiya hiya :lol:

thanks for that it makes interesting viewing.

if you fancy curing a little more of my curiosity, how long ago, using the format for the first graph in your answer to my first request, did the graph start rising? ie do you have to go back 30 yrs,40yrs, 50yrs or whatever for that graph to have a trough at the lowest point recently?

did that make sense?

[Hiya]

u only have to go back 2 years.

I don't even need toput any lines in this graph, u can clearly see a pattern.

[The Enforcer]

These yearly CET stats are all well and good, but they don't really help much in delivering snow on the ground. What use is a 'cooling CET trend' (significant or otherwise) or marginal cold snaps in November when every January, when it really matters, turns up the same south-westerly dominated gunk?

[The Enforcer]

There is a quite a high chance that this winter could well be one of the most coldest ones in history. Possibly as cold as the worst ones of the last century or even as cold as some of the 16th and 17th centurys. The reason behind this forcast is the due to a cool August this year following a very hot July.

An absolutely classic example of "current conditions = cold winter ahead".

[HellyHanson]

Last November didn't give any lying snow here unfortunately, the snow was just not heavy enough. I can only remember two Novembers in the past which I've seen snow lie in the SE, and that was during the Easterly in late Nov 1993 and more especially in Nov 1988 where there were several cms of snow when I was in Kent and an unusually early, for the time of year, day off school due to snow - i vividly remember for some reason!

Here we have had lying snow for two Novembers in a row.

November 2004

http://www.wetterzentrale.de/archive/ra/20...00120041119.gif

http://www.wetterzentrale.de/archive/ra/20...00220041119.gif

We were forcasted to have rain with mabey a little snow on the hills of N England. It started raining heavily early afternoon and this soon turned to snow after 6 'o'clock. It lasted for about 2 hours or so then stopped. All surfaces were covered by about 2 inches of snow with mabey 3/4 inches on the grass. This was a shock as it wasn't forcasted. The snow hung around for 2 days or so then melted.

November 2005

http://www.wetterzentrale.de/archive/ra/20...00120051125.gif

http://www.wetterzentrale.de/archive/ra/20...00220051125.gif

These were probably the best november charts i had seen in a while. We had snow all afternoon but none of it settled. Then around 5 o clock there was a burst of very heavy snow. The snowflakes measured about 2.5/3" in diametre. It was probaly the biggest flakes of snow i've seen in my life. But this only lasted for about 40 minutes and left about 2.5/3" of snow on the pavement. But some of it melted and by morning there was only about an inch or so.

[tugmistress]

thanks again hiya

it depends on how you interpret the data, to my simple mind *if* that pattern is going to repeat then the next dot will be down, other people will have different ideas other people will rubbish me. i don't mind i look at that and counted the dots from peak to trough, it's not by any means regular but then again, the weather isn't either lol.

i'll go and hide in my corner again now :lol: