Winter 2011/12 - General Discussion

[Cheshire Freeze]

The Positive weather solutions winter forecast is out, it's bad news for snow fans with no extended spells of snow likely, drier than normal in the south,

Winter 2011-12: Occasional Wintry Weather, Often Dry in South

December – often cold, chance of snow in places

There is also strong evidence during the month for some chilly but mainly settled weather, with possibly severe overnight frost, along with persistent fog in low-lying localities. It is furthermore likely that a definite wintry episode will become established, with the potential for snow especially over areas of the North and East. Within this general circulation, some parts of northern and north-eastern Britain retain the best chance of experiencing a White Christmas.

January – some cold, dry South developing

The first month of 2012 looks like being characterised by a sometimes mild North, and developing dry, at times colder conditions in the South. The prospect of prolonged wintry activity looks however unlikely, although occasional colder cells embedded within the overall flow will provide the North, especially upland districts, with temporary snow cover. January’s temperatures will approach the norm or exceed it in some northern and western parts. Southern and eastern areas may be drier than the average.

February – generally milder

There are indications that February over the British Isles may initially offer some of the most unsettled weather of the entire season. There is however no strong signal for any widespread period of sustained cold. The month will also feature some drier and pleasantly sunny passages, these most likely as the month progresses and across southern regions and the South-West in particular. Temperatures overall for the month are likely to be on or above the norm, perhaps notably so for parts of the South; rainfall also looks set to reflect on or above average values.

All looks good to me so James Maddens forecast seems to be in fantasy land.

http://www.positivew...ge-Forecast.php

The same PWS that no-one seems to have taken seriously in the past on this forum?

At the end of the day I'm pretty sure that no-one knows with any degree of certainty how this winter will pan out whether it be akin to a mini ice age or a break on the Spanish Riviera.

Though of the article, what I would say is if I was a paying customer for that forecast I would be very disappointed- 'colder cells embedded within the overall flow will provide the North, especially upland districts, with temporary snow cover'...... who'd have thought it, upland areas may see more snow than lowland districts- I would have thought that was a no brainer regardless of the synoptics we encounter over the winter period

[Snowmadsam]

Erm...i somehow don't think that PWS is right.....what ever happened to waiting to november

[summer blizzard]

Was just reading the talk in the model discussion thread about the statistical links between one month and another (repeating patterns etc..). Looking at this from a teleconnection based point of view i decided that as probably the 3rd/4th most important teleconnection for winter but one that is very important for the UK in particular i decided to look at the Arctic Oscillation for potential guidance.

For the record, something like 70%+ of -AO months see below average temperatures, visa verse for +AO months.

Thinking of October because we are in it.. There are 9 Octobers which recorded an AO value in excess of -1, only 1 October (1974) did not see at least 1 winter month with an AO value of -1 or more. For the record, 2009 saw the most -AO October on record and we all know that this pattern well and truly repeated itself. Irrelevant to this year however as the AO value is likely to be near neutral. So a 85+% success rate for pattern repetition.

Looking ahead to November, we see 13 Novembers which recorded AO values in excess of -1 but only 2 which did not see a winter month with an AO value in excess of -1. This indicates an 84% chance of pattern repetition.

Looking at 2011 and the months since June onward with high amplitude AO values, we only have August (-1). Looking at Augusts with an AO value of -0.5 or more negative (only 3 others had -1 or greater), we see 15 Augusts with AO values of -0.5 or more negative, just 1 of these did not see a winter month with an AO value in excess of -1. A stunning 90+% success rate here. It should be noted that the 3 Augusts with AO values deeper than -1 all produced at least one winter AO value in excess of -1.

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/monthly.ao.index.b50.current.ascii.table

While not guaranteeing a cold winter, the August figure does at least point to at least one winter month with a highly negative AO value which statistically at least points to at least one cold month.

[summer blizzard]

http://www.cpc.ncep....ent.ascii.table

I have decided to do the same for winter months with AO values of -2 or deeper (a regression this time).

The months with AO values in excess of -2 then are..

December 1976

December 1995

December 2000

December 2005

December 2009

December 2010

January 1959

January 1960

January 1963

January 1966

January 1969

January 1970

January 1977

January 1979

January 1980

January 1985

January 1998

January 2010

February

1956

1958

1960

1965

1968

1969

1977

1978

1986

2010

Regressing this then, we want to look at the June-November period of..

1955

1957

1958

1959

1962

1964

1965

1967

1968

1969

1976

1977

1978

1979

1984

1985

1995

1997

2000

2005

2009

2009

2010

So if we look for AO values of +1 or more and -1 or more from the list above we see...

+ June: 0

- June: 2

+ July: 0

- July: 1

+ August: 0

- August: 2

+ September: 0

- September: 1

+ October: 2

- October: 3

+ November: 1

- November: 8

I conclusion to this data, there is no clear link between a high amplitude AO value either way preceding a -2 or deeper AO value during winter.

That said, a link clearly exists between the August-November period and winter months of -1 or deeper.

[Cloud 10]

Here are the monthly values for the NAO if anyone wants to analyse them!

www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/norm.nao.monthly.b5001.current.ascii.table

Its also nice to look at the charts from previous years which tie in with your favourite

-nao winter!

UK Weather Forecasts - Radar, Alerts, News and More - Netweather.tv

[AWD]

The Positive weather solutions winter forecast is out, it's bad news for snow fans with no extended spells of snow likely, drier than normal in the south,

Winter 2011-12: Occasional Wintry Weather, Often Dry in South

December – often cold, chance of snow in places

There is also strong evidence during the month for some chilly but mainly settled weather, with possibly severe overnight frost, along with persistent fog in low-lying localities. It is furthermore likely that a definite wintry episode will become established, with the potential for snow especially over areas of the North and East. Within this general circulation, some parts of northern and north-eastern Britain retain the best chance of experiencing a White Christmas.

January – some cold, dry South developing

The first month of 2012 looks like being characterised by a sometimes mild North, and developing dry, at times colder conditions in the South. The prospect of prolonged wintry activity looks however unlikely, although occasional colder cells embedded within the overall flow will provide the North, especially upland districts, with temporary snow cover. January’s temperatures will approach the norm or exceed it in some northern and western parts. Southern and eastern areas may be drier than the average.

February – generally milder

There are indications that February over the British Isles may initially offer some of the most unsettled weather of the entire season. There is however no strong signal for any widespread period of sustained cold. The month will also feature some drier and pleasantly sunny passages, these most likely as the month progresses and across southern regions and the South-West in particular. Temperatures overall for the month are likely to be on or above the norm, perhaps notably so for parts of the South; rainfall also looks set to reflect on or above average values.

All looks good to me so James Maddens forecast seems to be in fantasy land.

http://www.positiveweathersolutions.co.uk/UK-Eire---Long-Range-Forecast.php

it's not THAT bad for coldies like myself, yes it may not be great but it's far from suggesting a mild and wet winter! I like cold crisp dry days just as much as snow, and that forecast as a bit of both in it!

I can think of a lot more worse than that!

[mcweather]

I wouldn't go slitting my wrists over any PWS winter forecast .

Here is last winters one from them just so you know why I won't be losing any sleep about this years.

December 2010: Chilly some wintry weather around.

January 2011: Dry start Wintry weather developing. ( the detail forecast was for possibly disruptive snow after mid-month. No I didn't see it either.

and the best for last

February 2011: Bitter cold month Wintry weather ( again the detail forecast even more disruptive snowfall then they expected for January.

So you can see that the only month they got even close to was December and even that is a very generous interpretation.

[HammerJack]

Well PWS are changing again. In my personnel oppinion lets wait until the second week of November, before we can make real judgements. Hopefully buy that time we may have a clearer picture?

[ukpaul]

PWS Winter 2010/11 Forecast -

"A chilly but dry start to December with some dry and bright weather around, but also some rain - amounts of which are not expected to give cause for concern. Through mid-month, high pressure consolidates, so expect a run of dry weather"

Didn't exactly cover themselves with glory on that one!

Then they said that the worst of winter last year would be in February!

EDIT: Sorry McWeather, hadn't seen that you'd posted something similar.....

Edited October 18, 2011 by ukpaul

[summer blizzard]

Here are the monthly values for the NAO if anyone wants to analyse them!

www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/norm.nao.monthly.b5001.current.ascii.table

Its also nice to look at the charts from previous years which tie in with your favourite

-nao winter!

UK Weather Forecasts - Radar, Alerts, News and More - Netweather.tv

To be honest, there is a far bigger statistical link between UK weather and the AO than there is the NAO (the NAO is essentialy dictated by the AO anyway) because the NAO simply measures pressure at 2 points while the AO measures pressure over a large area.

Given that the October AO will likely be neutral, let us hope for a -AO during November although the August link is clearly very impressive.

Edited October 18, 2011 by summer blizzard

[NorthernRab]

It's started in the Scottish Highlands:

http://www.flickr.com/photos/32323463@N03/6257753003/

[swipe]

At least the PWS forecast will shut the likes of the Daily Mail up. Any mild winter forecast is great news for me. Mild winters = less money wasted on heating bills.

[johnholmes]

thanks for the NAO data and also about the AO link folks

[Ladyofthestorm]

Lol, winter has arrived here in the Highlands, blowing a NLy gale, -8C windchill, heavy sleet showers and snow level down to 600m..... brrrrr.

As for PWS, didnt they forecast an iceage winter a few months back? lol changed there mind have we?

I get an inkling that this winter will be similar to 1998-1999.... why? Summer up here wasnt great, May was awful, that was after a great early spring... just like 1998.... its got the same kind of atlantic activeness to it as well.

What does that mean for snow lovers? Well mixed news unsettled, Polar Maritime weather, potentially very stormy, with occassional Nly bursts, but not the long standing cold. A slightly cooler than average typical British winter.... but then again I said that months ago didnt I! lol

I cant see the cold building up like last year, Im sure by now it was already very cold over eastern Europe, also last year I remember looking at the GFS charts in awe as weather systems seemed to be going against the laws of physics and headed the other way deflected back towards the atlantic.... that was weird.... but that isnt happening this year. NAO is now positive and looks like it shall stay that way for a little while anyway. Pressure over Greenland builds but then quickly disperses again..... that didnt happen last year either. I remember the watching the Greenie High forecast building it 10 1050mb+ and thinking cold plunge here we come.

Mind you winter might come much later this year.

[Coast]

October started with some of the warmest temperatures for decades but transport chiefs are planning ahead as some forecasters warn of a ‘Siberian’ winter. The Department of Transport said it has a 2million ton stockpile of salt and grit – its biggest ever. The Highways Agency has 500 salt-spreading trucks ready and Network Rail has spent £40million on heating and de-icing units.

Met Office forecaster Tom Morgan said yesterday: ‘This is the first cold snap of autumn and today is the changeover day. He said: ‘All parts will be much colder, with wintry showers of hail, sleet and possible snow on the Pennines and North Yorkshire Moors, and hail and sleet in the Peak District. ‘Wednesday afternoon will see sharp showers in those areas, and we could see snow to lower levels in northern and north-eastern Scotland.’ Mr Morgan said that once the gale force winds subside, temperatures will fall further. Forecasts of Arctic weather have raised fears of a major spike in oil prices for home heating.

http://www.dailymail...l#ixzz1bD7ikWpN

So who's forecasting Arctic weather then?

[johnholmes]

.

hi SB

thanks for the posts you have made regarding -ve AO and -NAO in October and subsequent winters.

Maybe its my old eyes but I did not see which Octobers with AO of -1 had at least one winter month with a -1 AO.

Can you point me to that please?

thanks

[sebastiaan1973]

Winter 2011/12 Weather Forecast

Method;

- ENSO

- Solar Activity

- QBO

- Sea Surface Patterns

Winter as a whole: Below Average temperatures, drier than average.

I've pasted and copied the main part of my forecast above, but I do go into more detail about the drivers behind the forecast with charts to illustrate on my blog.

http://ukweather.wor...inter-20112012/

(I don't know if its okay to post the link to it or not, I assume because its weather related and because I've posted my forecast here, that it'll be okay, if not, please feel free to remove the link mods)

Nice to read your forecast (at your website). Please note that La Nina is predicted in the new CFS forecast to become -2 in the period december-januar-februar. What are the results of this new prediction for your forecast?

[Downburst]

thanks for the NAO data and also about the AO link folks

Yes, many thanks for that, interesting. I tried to export the 60 year table to Excel but is crashes, I was looking for the average for each month over that period. Would also be nice to grapsh the 60 year trend for lets say the winter months to see if we can spot a patteren?

[greybing]

It's started in the Scottish Highlands:

http://www.flickr.co...N03/6257753003/

That looked cool.I assume it was for you guys.

thanks for the NAO data and also about the AO link folks

Yes ,thanks also.

[Met4Cast]

Nice to read your forecast (at your website). Please note that La Nina is predicted in the new CFS forecast to become -2 in the period december-januar-februar. What are the results of this new prediction for your forecast?

Thanks

If anything, the now progged stronger La Nina only reinforces the risk if a milder, more mobile second half to winter.

[johnholmes]

I took the data for AO values from 1950 up to the present and used the suggestion made by SB that if either October or November showed a value of -1.0 or more then on 85% of occasions at least 1 winter month showed a value of -1.0 or more.

For this to be tested fully, in my view, you also have to test those instances where there are no -1.0 AO values in October or November and see what those years give-the null test is it?

Summing up

Between 1950 and 2011 there were 19 Oct/Nov months with the AO at or below -1.0

The number of winters with at least 1 month showing an AO of -1.0 or greater was 15 or 79% with 2 having 2 months=10.5%

Testing the null case, that is when neither Oct nor Nov showed a value of -1.0 or more and seeing what that result gave showed the following.

There were 37 years that satisfied this criteria. In 21 of these years at least 1 winter month had an AO of -1.0 or more=57%, of these 7 had 2 winter months=19%

In neither instance was there ever a 3 month winter period showing the AO of -1.0 or more for each month.

Quite what one makes of those statistics I am unsure. To me, and I may be wrong as I am no statistician, I do not think the case can be made that there is a sufficiently strong set of results to justify being able to use either the initial case nor the null case. Indeed that may be why no meteorological centre appears to use this data.

I know some say it’s the AO that governs what the NAO shows but I will try and do a similar test for the NAO data and see what that comes up with. I have no idea what it will show.

[Summer Sun]

Anyone noticed how quiet James Madden has suddenly gone, it has been him who has been the lead Amature forecaster in saying this winter was going to be very cold and snowy now it's almost a month since his website has been updated, i wonder why?

[Aaron]

Maybe there's no reason to update, he's probably sticking to his guns with his original forecast.

[weatherobsuk]

I wonder if we'll get round to beating this again this October..I think the likelyhood is slim however

http://www.telegraph.co.uk/topics/weather/8085946/Frozen-Britain-braves-coldest-October-night-for-17-years.html

[penicuikblizz]

My winter forecast is for a mild to average winter!! Forecast based on a hunch, all the hype over a mini ice age, big freeze winter is over the top all from amatuer forecasters and the media hyping it up!!! Don't see the Met Office on board with the cold forecast and long range CFS models don't forecast a big freeze so why all the hype???