Netweather Winter Forecast 2014/15 - A Cold Hearted Winter

[Dancerwithwings]

I can only respond to this with my psychologist's hat on. Have you considered that the authors got enjoyment and satisfaction from writing this forecast. Are you considering that the readers are similarly enjoying the read. Most people realise that long range forecasts are going to be difficult in the detail and allow for such.

 

We are a weather community, let's applaud the effort on our behalf - the exchange of knowledge between individuals and professions is a wonderful aspect of this and other forums.

With complete agreement and verbal applause    ....hear hear

[Midlands Ice Age]

 

With complete agreement and verbal applause    ....hear hear

[/quote)

And so say all of us....

For he's a ......

MIA

[Mark Bayley]

This one?

 

Robust Arctic sea-ice influence on the frequent Eurasian cold winters in past decades

 

 

http://www.nature.co...s/ngeo2277.html

 

Yes, that is an example and one im hoping to read

Edited November 29, 2014 by Mark Bayley

[Nouska]

I knew it. An agent provocateur in out midst.

 

With a provenance from TWO's climate forum and that avatar......this old gal cannot resist.

[TobyT]

Another belated "thanks guys" a good read, very easy to follow and well presented,I really hope it pans out for you, most of us would be very happy if it did, it can only be a step in the right direction in helping to improve LRF in general. Once again thanks for all the hard work. 

Edited November 30, 2014 by TobyT

[lorenzo]

This is November 2014 as of 28 November and the build from the Winter Forecast composite, happy to see that the key anomalies are matched quite well.

 

 

 

[chionomaniac]

This is November 2014 as of 28 November and the build from the Winter Forecast composite, happy to see that the key anomalies are matched quite well.

 

November NH 500mb.gifcompday.JswcZUutkJ.gif

Can we cash out now, Tony? 

[lorenzo]

Can we cash out now, Tony? 

Winter forecasts sponsored by Bet 365 - good call !

 

Nah, am happy to stick til at least January 8th..

[marksiwnc]

What's the next step then boys?? Lol

[syed2878]

Manage to get a look at the nw w14-15 forecast and I must say it's interesting lets hope the forecast bares fruit quite an exciting forecast.  One question to you Edd or tony. What do you boys see different to the other forecast centres like the ukmo? surely the met take the strat into acount and yet they going for an avrage winter.  Well any way it's here at last first day of winter and the waight is over let us sit back and see what it brings. Keep up the good work Tony and Edd a forecast well put.

[lorenzo]

@syed - you would need to ask the Met Office for a winter LRF then compare. Sorry, I can't answer the question fully, it would require one of their professionals to explain the weightings and variables considered. It is worth remembering that LRF are inherently different to the mid range guidance provided in their extended outlooks.

 

Early in the build of the winter forecast, we saw a period in December analogs not unlike present, which we also guessed would lead to some discontent and a period of particularly woeful / uninspiring model output. Everyone seems to have had their fill of NAO positive regimes following 2013-14, thankfully we are not back there again and it could be easy to think we are given the modelling of a strong atlantic depression for mid week.

 

In order to look at this more closely here are a couple of more charts derived from the December analog, basically it is December chopped down the middle, and much like the football cliche we see a game of two halves.

 

December 01-15

 

December 16-31

 

The charts above speak for themselves - significant pattern shift and highly different, thankfully not without some tentative support in the longer range ensemble predictions.

 

ECM / NAEFS

 

A lot to look out for until we get to mid month to keep things ticking along - 

 

AO downward trend from peak

Inhibiting Eurasian Low Pressure dissipating

Siberian High re-establishes, hemispheric tendency showing it's hand re: Cohen mapping

Renewed Wave Activity Flux

MJO Event - eventual resolution of will it won't it Phase 7-8-1 / recycle

ENSO and stratospheric pathway

Vortex on it's travels. 

 

 

 

 

 

 

 

[Severe Siberian icy blast]

@syed - you would need to ask the Met Office for a winter LRF then compare. Sorry, I can't answer the question fully, it would require one of their professionals to explain the weightings and variables considered. It is worth remembering that LRF are inherently different to the mid range guidance provided in their extended outlooks.

Early in the build of the winter forecast, we saw a period in December analogs not unlike present, which we also guessed would lead to some discontent and a period of particularly woeful / uninspiring model output. Everyone seems to have had their fill of NAO positive regimes following 2013-14, thankfully we are not back there again and it could be easy to think we are given the modelling of a strong atlantic depression for mid week.

In order to look at this more closely here are a couple of more charts derived from the December analog, basically it is December chopped down the middle, and much like the football cliche we see a game of two halves.

December 01-15

December 01-15 Composite.gif

December 16-31

December 16-31 Composite.gif

The charts above speak for themselves - significant pattern shift and highly different, thankfully not without some tentative support in the longer range ensemble predictions.

ECM / NAEFS

Capture ECM.JPGCapture.JPG

A lot to look out for until we get to mid month to keep things ticking along -

AO downward trend from peak

Inhibiting Eurasian Low Pressure dissipating

Siberian High re-establishes, hemispheric tendency showing it's hand re: Cohen mapping

Renewed Wave Activity Flux

MJO Event - eventual resolution of will it won't it Phase 7-8-1 / recycle

ENSO and stratospheric pathway

Vortex on it's travels.

Yes some very good matches there to see where we are at present , all very interesting , and like you say some very tentative but early signs of the change toward mid month , maybe this time next week things will start very different In the models ? Edited December 4, 2014 by Severe Siberian icy blast

[bluearmy]

ian linked to Hadley's winter outlook on the MOD tues early am which took all teleconnecive drivers into account (OPI apart).  basically it said that most indicators apart from its computer modelling show a likely -AO/poss - NAO, especialy further into the season. however, they are going with their model.

Edited December 4, 2014 by bluearmy

[johnholmes]

ian linked to Hadley's winter outlook on the MOD tues early am which took all teleconnecive drivers into account (OPI apart).  basically it said that most indicators apart from its computer modelling show a likely -AO/poss - NAO, especialy further into the season. however, they are going with their model.

 

Yes their press release really is worth reading and perhaps speculating beyond the reasons they give as to why they ended up with the result they did.

easy to find on their web site and as someone else posted great to be able to have some inside knowledge into their thinking, what they use etc.

 

oh and here is the latest NOAA output, or rather one para that may be of interest to the long term tel'c folk

Similar to last month, most models predict SST anomalies to be at weak El Niño levels during November-January 2014-15 and to continue above the El Niño threshold into early 2015 (Fig. 6). Assuming that El Niño fully emerges, the forecaster consensus favors a weak event. In summary, there is an approximately 65% chance of El Niño conditions during the Northern Hemisphere winter, which are expected to last into the Northern Hemisphere spring 2015 (click CPC/IRI consensus forecast for the chance of each outcome).

 

and the full link below

http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.pdf

Edited December 4, 2014 by johnholmes

[Nouska]

I don't want to take the thread of topic but it is worth comparing the December forecast from the CFS V2. The first chart was run around tenth November, the second is their up to date forecast for this month. From being very few negative NH land anomalies, there are now large areas with some deeply negative anomalies. No Z500 height charts provided, sorry.

 

 

 

Just posted to highlight that maybe some of these colder indicators are now feeding through and also to say it shows a three month ahead forecast means nothing other than what the starting conditions infer.

[lorenzo]

Evening All,

 

Well am not going to hide behind anything and as we put the forecast out there based on the best knowledge ( academic papers) and best re-analysis for correlation ( monster set of data) we could gather, I will admit that this Winter so far has been challenging/ frustrating. Above all it is still a learning curve and although frustrating to many, we are still peeling back the layers of understanding, being a whole lot more invested this season having written a forecast, trust me I have not stopped dissecting it from run to run across each model from 500hPa to the top of the strat.

 

As a foreword for looking at December, I want to say that I know we are all sick to the back teeth of a positive NAO and this particular profile pulling through on modelling makes hearts very heavy, I think that the backdrop of the strong solar minimum winters we have just evolved out of amplifies this in a manner of 'I do not want what I have not seen'. i.e if we had not seen such fierce synoptics over recent years our expectations may have been set more in reality, whereas a 1 in 100 year winter is actually so memorable it changes that expectation dramatically.  As a counter to that the recency effect of 2013 I think may make folks automatically assume it is just the jet or just like our normal zonal affair, truth told it is more complicated than this, 2013-14 is completely different atmospheric profile, it has just delivered 'some' similar patterns - so far.

 

Still, December..

 

I posted up some anomaly charts breaking down December into 2 and mid month, I had hoped we were about to turn a corner, what has been massively interesting this year is the addition of Dr Cohen's AER blog and extra insight to the Wave Activity Flux (WAFz) and Polar Cap Heights (PCH) forecasts in real time.  With such a strong analog for SCE - Snow Cover Extent and SAI - Snow Advance Index, we knew this winter would put the theory fully to the test, at the same time providing a stringent examination of the new OPI - October Pattern Index which extended the work of Cohen and Jones.

 

We didn't turn the corner as the images attached show, Dr Cohen identifying the lack of WAFz or wave driving due to the inhibitive effects of the Barents and Kara Sea LP anomaly ( visible on the second fortnight of December). I do not think with such SCE / SAI / OPI this explanation is the magic bullet for why things have not developed as hoped.

 

Images attached, to me, indicate some other ideas, particularly over the Indian Ocean and typhoon spawning, the Pacific and non-translation of Nino to atmosphere particularly with respect to the pattern in existence over the West Pacific.

 

The second half of December is of interest as anomaly wise things are not as disconnected and we have a reasonable assumption for where the analog failed.

 

I hope that the charts attached give some more insight, closer than one would expect I think in the face of close up model output.

 

Onwards and Upwards folks here is to a lot of Winter left.

 

 

 

 

As far as stratospheric events go, I am proud that we have new information and displays of information available via weatherbell and wsi, it shows that this area of forecasting is being recognised more widely in the community. We have a strong change evident in the strat. just now with W1 and W2 events really caring the vortex up across different levels, with various impacts of Wave 1 and Wave 2, simply put it is the most dynamic strat evolution I have come across.

 

For January, this was the strongest month for analogs so given SIPS / CPC guidance I would expect changes, the reality being HLB and particularly Greenland blocking a la 2010 seems to be the holy grail for many readers.

 

Let's all acknowledge that we are doing the best we can, we already have a massively varied winter and this is not the zonal fest of last year. Enjoy the rest of the season !

 

 

 

 

 

 

[summer blizzard]

You mentioned elsewhere that you got the warming forecast but did not forecast its effect.

Do you still believe the stratosphere will cool into February.

..

I recall the winter of 2012 saw a warming which failed to reverse and while we did get a very cold spell from it, we then saw a near record cold stratosphere headed into spring heralding March 2012.

[lorenzo]

Here are the 30mb charts from the original forecast analogs, the February charts indicative of vortex recovery.

 

January

 

February

 

Ed, is better placed to answer the question for you SB but will throw in my thoughts, right now I would not like to pitch either way as I think you could argue the toss for both vortex continuing to remain perturbed, and evidence of the vortex intensification continues.

 

Also with another MJO cycle emerging, phase 2 once this one crashes through COD meaning round we go again into further mountain torque events and more forcing.

 

For the remainder of Jan the last Cohen update pointed out the Polar Cap temps remaining high inhibiting vortex recovery.

 

However we still have the issue of lack of wave activity, which really is the main question this year and will feature in any autopsy.

 

It's almost as if we are getting 25% the expected impacts with the net effect an overall vortex dilution without the spectacular.

 

It's been a frustrating yet fascinating watch. Signals in favour not delivering as required, and illustrative of the precision timing and exact nature of events required to deliver for our part of the world, or to deliver a major SSW as opposed to minor.

 

The other angle being -  at points during Nov/Dec it appeared that no SSW would be required. I will take being 6 or 7 ms-1 off a technical SSW at a range of 38 days, not a bad guess, just a pity it didn't go the whole way.

 

SCE / SAI / eQBO all at record or near record positions, yet we had solar flux peaking and MJO / GWO not assisting. The combined effects of ENSO and Solar Max not working constructively on the vortex, which itself has perhaps been too perturbed this season continuing its elasticity. Those early November hits I thought were leaving it wide open, appear to have just conditioned it and toughened it up with that all important 30hPa core just not yielding or giving the EP Flux that final assist. Nina esque Vortex intensification period dampening the so called wave driving that would have tipped things to Major SSW. 

 

 

 

 

[BLAST FROM THE PAST]

So we still need to find out hat the 'driver' is as everything anticipated seems to have been overridden?  I didn't anticipate a cold Jan, but I expected a lot better from Dec so that was blasted out of the water for me.  That PV has 'ridden' the blows well, like Ali riding the punches on the ropes to just come back and knock his oponents out

 

BFTP