Autumn And Winter Lrfs

[SMU]

I thought that of all the winter forecasts around last year, Ian's winter forecast was a good second in accuracy, after that of the Met Office, so it'll definitely be worth watching.

Sorry to pour cold water over this thread- but it still amazes me how the Winter forecast was written with specific dates put into the equation....

After looking through the archives it just seems a pointless exercise in every way shape or form-

The MET office used 2 simple parameters- Temp rainfall- they didnt pad the forecast out with more than was neccasary-

Sorry if people think Im being overly critical- but putting specific dates into a winter forecast is not to desimilar to playing pin the tail on the donkey-

It always has & always will be-

Its also a pity (Ian/Melanies-one of the same) posts over on TWO never reflected the observations presented in the Winter forecast- There should at least be some consistency....

It will be interesting this year to see the scientific rational behind a forecast that is made up of firm 'events' occuring.......

S

December

As I said in the Autumn forecast, I expect to see a chilly end to November and this could extend into the first few days of December. However it will become briefly milder during the first week, before a major northerly plunge, associated with pressure rise over Greenland, takes hold around the 10th. I would expect this spell to be of the ‘cold zonality’ type, with snow especially affecting Northern and Western areas, but it will be cold or very cold everywhere.

Less cold air will move in from the West around the 15th or 16th and it will become unsettled in the days leading up to Christmas with, Xmas day itself mainly dry with above average temperatures across most areas, although there maybe some rain in Scotland and N Ireland.

The period between Xmas and New Year will herald a major change. Complex Low pressure maybe sitting across the UK, but as pressure rises to the North and North East, these systems will be forced back South and West, with the obvious possibility of snowfall before the cold air arrives from the East.

An average month in terms of rainfall generally, with a below average CET of around 4C.

January

An end to the run of mild Januarys, and probably the coldest since 1987, depending on the timing of the cold spells.

The month begins with a continuation of the cold easterly spell, with snow likely across many parts but with sheltered Western areas probably remaining mainly dry and cold. Gradually, High pressure will move across the UK and wintry precipitation will become confined to Eastern coasts. With clear skies and snow cover, some very low minima will be possible almost anywhere.

By around the 9th or 10th, the block will begin to weaken as winds turn South Easterly and then southerly as milder air moves in from the South. But with pressure remaining high over Greenland, Low pressure systems will be taking a fairly Southerly track, and this could see snowfall across higher ground in the North and Scotland particularly, with rain likely further South in between settled spells.

As we enter the final third of the month, pressure will once again be rising over Scandinavia and mainland Europe will be very cold. Eventually we should see this cold air extending across Britain and another easterly outbreak, with snow particularly affecting the South and East.

A drier than average month, possibly exceptionally so in some Northern and Western areas. A CET return of between 2 and 2.5C, depending on the timing of the second easterly spell.

February

A cold start to the month, with the possibility of Atlantic systems running into the cold air to give snowfall across the Southern half of the UK. The Atlantic should finally break through to bring milder air to all around the 9th or 10th.

With the Northern block collapsing into Europe, this may well lead to a mild or very mild spell with some high rainfall totals in the West mid-month.

The latter part of the month may see High pressure building across the UK to bring a settled although not especially cold end to February.

Drier than average in all areas, and a tentative estimate of a CET around 4.5C, as this will be dependent on the length of the cold spell and High pressure positioning thereafter.

Edited August 22, 2006 by Steve Murr

[TEITS]

Sorry to pour cold water over this thread- but it still amazes me how the Winter forecast was written with specific dates put into the equation....

After looking through the archives it just seems a pointless exercise in every way shape or form-

The MET office used 2 simple parameters- Temp rainfall- they didnt pad the forecast out with more than was neccasary-

Sorry if people think Im being overly critical- but putting specific dates into a winter forecast is not to desimilar to playing pin the tail on the donkey-

It always has & always will be-

Its also a pity (Ian/Melanies-one of the same) posts over on TWO never reflected the observations presented in the Winter forecast- There should at least be some consistency....

It will be interesting this year to see the scientific rational behind a forecast that is made up of firm 'events' occuring.......

S

I agree with every word Steve.

The problem that I see with putting exact dates in an LRF is what OON said to me last winter. If for example the forecast goes pear shaped during the first week of Dec then the rest of the forecast may aswell be thrown in the bin because you cannot take credit for weather event's happening after this period because then it would be coincidental because of the failure of the forecast at the beginning.

This coming winter I shall be looking for two things in an LRF, temp/rainfall and like yourself I would like to see the scientific reasoning for this forecast and which method's were used. I believe we are a long way away from producing successful LRF's and this is why I think anyone who tries to produce a LRF should stick with the basic's i.e temp/rainfall and then build from there.

[VillagePlank]

Naieve as I am, I still think that it's possible to describe expected events, and perhaps, bifurcation of events. You do not need to specify actual dates, but you could certainly extend a forecast to include the series of events.

[TEITS]

We have moved away from the specific detail type of LRFs, although I would still be prepared to estimate specific periods for pattern changes if people requested that.

One thing I will say IB please don't think I was having a go because I enjoy reading your forecast's and have great respect for you.

[Anti-Mild]

Of all the winter forecasts issues last year I have to say that the NetWeather one was second only to the Met Office's. Too many forecasters allow 'hopecasting' to cloud there judgement but, thankfully, the team were sensible and realistic in there forecast. Hopefully this winters forecast will be the same.

AM

[BLAST FROM THE PAST]

We have moved away from the specific detail type of LRFs, although I would still be prepared to estimate specific periods for pattern changes if people requested that.

The period between Xmas and New Year will herald a major change. Complex Low pressure maybe sitting across the UK, but as pressure rises to the North and North East, these systems will be forced back South and West, with the obvious possibility of snowfall before the cold air arrives from the East.

An average month in terms of rainfall generally, with a below average CET of around 4C.

January

An end to the run of mild Januarys, and probably the coldest since 1987, depending on the timing of the cold spells.

The month begins with a continuation of the cold easterly spell, with snow likely across many parts but with sheltered Western areas probably remaining mainly dry and cold. Gradually, High pressure will move across the UK and wintry precipitation will become confined to Eastern coasts. With clear skies and snow cover, some very low minima will be possible almost anywhere.

IB

I thought that was a good call. I understand what Steve says but I think there is also a 'fun' factor as well as genuine interest in specific dates so I would ask you kept them in.

Steve

You called 23 Aug as final nail in summer coffin...specific date? I know what you are on about and are correct btu there is room for specific dates and events?

TEITS

If the events follow on in correct timing then I think a success can still be claimed because the set up/pattern prognosis is right IE if you call everythting a week early but the pattern follows your forecast but a week late then there is a degree of success there.

BFTP

Edited August 22, 2006 by BLAST FROM THE PAST

[SMU]

Steve

You called 23 Aug as final nail in summer coffin...specific date? I know what you are on about and are correct btu there is room for specific dates and events?

BFTP

Lol/.....

7 Days..... 2/3 Months......

Steve

[Turnedoutniceagain]

Of all the winter forecasts issues last year I have to say that the NetWeather one was second only to the Met Office's. Too many forecasters allow 'hopecasting' to cloud there judgement but, thankfully, the team were sensible and realistic in there forecast. Hopefully this winters forecast will be the same.

AM

When's it due out ??? Oct/Nov' ??

[Anti-Mild]

When's it due out ??? Oct/Nov' ??

If I remember rightly last year's came out around mid November.

If Steve Murr is doing an Ode this year, if it comes out the same time as last year then that'll be out in October.

AM

[Damien]

Personally I hope this forecast will be right, even though I don't trust it one bit:

http://www.cpc.ncep.noaa.gov/products/peop...bT2mSeaNorm.gif

February is especially staggering - even though the Atlantic is still a little too close for comfort for me - in all months.

Edited August 22, 2006 by Damien

[moses]

A strong pacific jet correlates with low heights (pressure) over Greenland. We saw last winter how the jet careered on a flat trajectory across the mainland of the US.

Only when the jet became more amplified later in the winter did pressure rise over Greenland to allow for colder synoptics over the UK.

Not that this tells the whole story, a strong pacific jet also correlates with blocking over Eastern Europe as the jet runs out of steam further West. We saw this blocking extend far enough West in late December 2005 to bring colder weather to our shores but it was only ever likely to be temporary with no blocking over Greenland.

Similarly, we can't say that a weak Pacific jet will mean a cold winter in Western Europe, as there will always be Low pressure activity off the Eastern Seaboard of the US and the question is where that energy goes. In the worst case scenario for cold fans, it piles across the GIN Sea area and all the way into Scandinavia and Western Russia. Then you have problems when the pattern switches because the milder air has 'invaded' the cold sources.

Yes, mid November will see the release of the winter forecast. I think it is too early to form any concrete views of the winter months at this stage.

Cheers mate

I'm not sure I understand this ha well -