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A Winter's Tale

The Seasonal Forecast Thread

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So, broad continuity continues with overall themes (milder start to season; potential switch to colder/blocked 2nd half), but do bear in mind - as I was at pains to stress this evening when discussing this stuff on-air - that it's only 13 October; still much water to run under the bridge; plus the Seasonal Team at Exeter are yet to summarise the current output into public domain for D-J-F probabilistic purposes. The difficulty into 2nd half of winter is compounded, of course, by the fact that even a strong SSW signal yields only circa 2 weeks reliable lead time in GS5 - something no seasonal forecast can adequately accommodate at this range and still profess to be 'reliable' (not that D Express et al care). This, plus a variety of key, combining imponderables this winter in terms of global drivers, means waiting until nearer the start of December before pinning hats on where GS5, or for that matter EC Seasonal model, is presently taking us. Either way, it's an interesting and challenging period unfolding for the good folk at Hadley Centre.

 

 

I concur.

 

I really do think 2 weeks forward is all we can hope to forecast out to, with any degree of confidence. This will never change (At least for the moment :) )

 

What does excite us is the potential for the coming winter. There is the strong El Nino, the cooling of the North Atlantic. It is a long time , if I remember correctly, of High pressure being so dominant in October, and  a very cold and snowy eastern Europen continent.

 

So fingers crossed for a colder than normal winter.

Edited by John Cox
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What does excite us is the potential for the coming winter. There is the strong El Nino, the cooling of the North Atlantic. It is a long time , if I remember correctly, of High pressure being so dominant in October, and  a very cold and snowy eastern Europen continent.

 

 

This is a very interesting quote, and has me pondering big style.  The blocking is somewhat very interesting 

 

 

BFTP

Edited by BLAST FROM THE PAST
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This is a very interesting quote, and has me pondering big style.  The blocking is somewhat very interesting 

 

 

BFTP

 

This is a very interesting quote, and has me pondering big style.  The blocking is somewhat very interesting 

 

 

BFTP

Hi BFTP,

 

A big fan of mine you are :)

 

What ponders you about my quote?

 

From what I have read, the strong El Nino threatens a colder Westerner European winter and the colder pool in the western Atlantic also might indicate a slowing down of the North Atlantic drift which could , at least, in the longer term give us colder winters.

 

Perhaps, I have interpreted things incorrectly or just wishful thinking on my part :)

Edited by John Cox
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ACCU have released their winter forecast for 2015/16. To be honest, it isn't really what I was hoping for but not as bad as it could be. Anyway, here is the forecast:

post-17472-0-66099100-1444777240_thumb.j

England should expect seasonal conditions throughout, whilst Scotland should expected cold spells.

A measly five days of snow/ice is forecasted for London:

post-17472-0-96236300-1444777741_thumb.p

I can pretty much guarantee this will be more accurate than Nathan Rao's forecast on the Express (which is most likely from Exacta Weather).

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So, broad continuity continues with overall themes (milder start to season; potential switch to colder/blocked 2nd half), but do bear in mind - as I was at pains to stress this evening when discussing this stuff on-air - that it's only 13 October; still much water to run under the bridge; plus the Seasonal Team at Exeter are yet to summarise the current output into public domain for D-J-F probabilistic purposes. The difficulty into 2nd half of winter is compounded, of course, by the fact that even a strong SSW signal yields only circa 2 weeks reliable lead time in GS5 - something no seasonal forecast can adequately accommodate at this range and still profess to be 'reliable' (not that D Express et al care). This, plus a variety of key, combining imponderables this winter in terms of global drivers, means waiting until nearer the start of December before pinning hats on where GS5, or for that matter EC Seasonal model, is presently taking us. Either way, it's an interesting and challenging period unfolding for the good folk at Hadley Centre.

 

Cheers for that Ian. So to extrapolate what you said and to read between the lines somewhat, the Glosea has expressed continuity in the expected winter pattern, albeit too early to make any firm judgements, and I'm guessing the output (more especially the strength of that Jan-Mar anomaly) has raised a few eyebrows?

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fergieweather, on 13 Oct 2015 - 21:39, said

 

Either way, it's an interesting and challenging period unfolding

I feel that this late autumn/ winters one of the the most interesting to study, more likely then not i feel also one of the top 10 most interesting winters to come

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I concur.

 

I really do think 2 weeks forward is all we can hope to forecast out to, with any degree of confidence. This will never change (At least for the moment :) )

 

What does excite us is the potential for the coming winter. There is the strong El Nino, the cooling of the North Atlantic. It is a long time , if I remember correctly, of High pressure being so dominant in October, and  a very cold and snowy eastern Europen continent.

 

So fingers crossed for a colder than normal winter.

 

There were decent chunks of high pressure dominated weather in October 2013 I think.

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An interesting analog from weather bell for the upcoming winter. Has this been posted elsewhere

post-6981-0-23952900-1445112413_thumb.jp

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An interesting analog from weather bell for the upcoming winter. Has this been posted elsewhere

attachicon.gifimage.jpg

I think there's aproblem with 1958 Blue-it shows up 3 times on that chart.

I also used that year as one of the years on mine and that showed up twice.I wonder what years they actually used,my betting is one of those 1958's should be 1988.

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Good spot Phil. No matter - it's a corking cold winter chart.

It is- but would love to know what years they did use. :)

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It is- but would love to know what years they did use. :)

They have probably just given 1957/58 extra weighting - 3 times as much!

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Thank you Roger. On a selfish level I hope your forecast is wrong as it looks to be suggesting an Eastelry flow which these parts invariably do well out of. A quick question on the cold blob which when compared back to the early 80s looks quite small in comparison, so how would this partially override the strong Nino event?

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Thank you Roger. On a selfish level I hope your forecast is wrong as it looks to be suggesting an Eastelry flow which these parts invariably do well out of. A quick question on the cold blob which when compared back to the early 80s looks quite small in comparison, so how would this partially override the strong Nino event?

HP, the cold pool has been and I think still is significant and could be a longterm change in cycle.  Lets see what happens with it over the next month

 

 

BFTP

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HP, the cold pool has been and I think still is significant and could be a longterm change in cycle.  Lets see what happens with it over the next month

 

 

BFTP

Yes and I think it's the precursor of a flip in the AMO Blast, but when compared to the 80s it's very small in comparison. Of course this cold pool will expand when we see the AMO flip to its negative phase, but for now I'm interested in whether it will counter effect the strong Nino event?

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I think there's aproblem with 1958 Blue-it shows up 3 times on that chart.

I also used that year as one of the years on mine and that showed up twice.I wonder what years they actually used,my betting is one of those 1958's should be 1988.

 

I know JB is a believer in a return to the fifties analogues where tropical forecasting is concerned - he's obviously giving 57/58 triple weighting in this analogue.

 

I'm not sure I would even use it once, given it was the absolute maximum of the strongest solar cycle in our records. RZln64h.png

Edited by Nouska
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Hi Roger

Far more indepth than the 'test' I ran myself a couple of years ago but the end result very similar.  What I saw through the 20th century was that there was no weighting for any winter type. It broke even for cold, mild and average over the 100 years so for me it wasn't a predictor for UK winter

 

 

BFTP

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Many thanks for that, Brick. Very informative! :D

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Just a brief update -- Fred and I are generally satisfied with how the pattern seems to be evolving and have no revisions to make to the winter forecast presented a few posts above (#790) ... we expect the winter to be a slow developer in general with considerable promise for a good spell of cold and possible snowfall events towards end of January and into parts of February. I continue to think there is better than average potential for a major windstorm event given the SST pattern, and the most likely time window for that is late December and early January.

 

Fred may have some more specific thoughts to add, I will just say that while November has turned out very mild, the pattern from now to 30th as shown on GFS is quite similar to what was envisaged for the setup for the main winter period, so we are not concerned about that very mild weather and in fact we both predicted it in the monthly CET forecast thread.

 

My personal forecasts for the three CET values ahead (and Fred is off the hook on these) would be something like 6, 4 and 3, so a gradual transition from above to below normal. The frequency of colder than normal conditions would be something like 30%, 50% and 70%. The best period for snow in the scenario foreseen is late January and early February, but this matches climatology, the more significant prediction might be that we think there's a chance of this snow being somewhat heavier than normal amounts when it does arrive.

 

As I've said on the Irish weather forums where I post, I am not as optimistic of either the cold or the snow reaching Ireland in much force but it could do so in modified amounts.

 

North American summary -- mild coast to coast JAN-FEB, mild west and cold or very cold east by FEB and part of MAR, best chances of east coast snowstorms FEB 8-20.

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Thought I would pop this in here from Matt:

@MattHugo81: Final EC seasonal update before winter starts (Dec) onwards supports the idea of a gradual change to a more blocked regime Jan/Feb time.

So following the theme of just about every (credible) forecast you've probably all read already. Big test ahead this year of many 'positive' variables. Can that monster wQBO really be overcome? My suggestion would be...eventually...

SK

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