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Stratosphere Temperature Watch 2012/2013


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Ian has mentioned in model thread and regional thread that some information on the Meto discussions may be forthcoming shortly, will be an interesting read, perhaps they will pin up another blog article on the news pages.

Am sure that this event will have them buzzing with anticipation as it is another good workout /validation for the high top Glosea4 model.

Maybe relevant to dig this paper out published 13 Sept 2012.

Seasonal forecasts of northern hemisphere winter.pdf

Couple of extracts.

Intro

Here we investigate winter 2009/10 with the Met Ofï¬ce seasonal forecast system GloSea4 [15] in both the operational

conï¬guration then being used (low top) and the subsequent operational conï¬guration using a model with an extended

vertical domain and more levels (high top). First we examine the low top model results, and investigate whether they

can be explained by existing hypotheses. The high top model better resolves the stratosphere and simulates SSWs,

so may be expected to give better results

Data

The low top (L38) and high top (L85) model conï¬gurations have 38 and 85 vertical levels, with top-level heights of 40 km and 85 km respectively. The operational GloSea4 system in use during the 2009/10 winter produced regular forecasts before and throughout the winter.

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Some one mentioned three warmings on the model thread earlier and I had noticed that myself.

Here they are:

No 1 displacement induced current:

post-4523-0-21306400-1357166902_thumb.pn

No 2 split induced T+ 240

post-4523-0-84029600-1357166950_thumb.pn

No 3 re split induced T+384

post-4523-0-58957900-1357167018_thumb.pn

Nos 2 and 3 are in great positions to destroy the vortex that is unfavourable for us - over Greenland.

Look how the blue colder strat reduces from 1 to 3 as well. The strat will take a long time to recover from this.

I just tweeted Matt Hugo pointing out the above 3rd warming, and good to see the 18z continuing that trend

It couldn't really be better positioned in terms of destroying the W Greenland/Canadian vortice, with one warming attacking it from the east and then the following from the west.

The 100mb plot explains what we see down in the troposphere - as we start to remove any remaining influence to our NW of the aforementioned Canadian segment, the Siberian/Scandi segment becomes a bit flabby and prevents too much ridging to our locale. But that is slightly out of kilter with previous runs, which have tended to keep this aligned more meridonally.

With this number of warmings you would feel sorry for the PV were it not such a nuisance to us. Anyway, thanks for popping by to check up on us again Mr. Vortex, see you next year?...

SK

Edited by snowking
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Im just wondering if these warmings do downwell and put pay to the tropospheric vortex over greenland, is there anything happening that the experts on here see that is likely to put pay to stubborn troughs setting up to the West of the UK which has been a recurring theme of this winter, and the reason that in my opinion the MO are saying later in Jan rather than mid jan before any deep cold likely, it seems to me as though a smashed PV and getting HLB are likely now but there is this recurring theme showing on GFS op runs and more worryingly on NAEFS anomolies charts, even the GEFS H500 anom that GP posted with a stonking massive mean ridge all the way across the Northern lattitudes also had a mean trough to the West of us.

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Stuck record post from me.

ecm not showing the second warming at day 10.

i continue to be of the opinion that ecm is playing catch up with gfs in the strat. The heights on ecm from yesterdays run now reflecting what gfs has been showing for many days now. Of course we only see strat data from the 12z run but its been barking up the same tree and now shifts to gfs's solution. I wonder if todays 12z data will show the east american warming days 9 and 10?

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EC shows a SSW at day 4, day 9 the zonal winds are positive again.

As the canadian vortice expands across the pole. Gfs wasnt too different at that timescale but the new warming on gfs at that time helps push that segment away from the pole again and encourages the ridge to expand across the pole. Ecm run ends so we dont see what comes thereafter.

Just noticed the second gfs warming showing further up on ecm. Maybe its just downwelling a bit more slowly than on the ncep model.

Not particularly concerned from a negative perspective.

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Apologies if these questions have already been answered but can anyone enlighten me on the following::

1. Does Stratospheric warming occur every winter but in varying degrees of intensity.

2. Is the warming greater when the wind flow is at its stongest and at right angles to the mountain ranges.

3. Is the current warming and predicted evolution of the warming significantly different from other years.

4. Does the shape of the stratospheric temperature signal e.g. the vortex and the shape of the warm area represent low and high pressure in the stratosphere

5. Can the shape of this temperature/pressure signal in the stratosphere result in a eventual similar distribution of pressure at the surface.

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2009 10 days before...

2009 is an interesting case and quite well studied with numerous papers such as http://www.staff.science.uu.nl/~delde102/TroposphericResponseSSW.pdf linking winter cold to the SSW, which was one of the biggest on record.

The winter in the UK was cold prior to this, particularly in early January, with a 60 day CET anomaly of -1.23°C (compared to mean 1940-2012) and 30 anomaly of -1.53°C.

Initially, there appeared to be a cooling temperature response with the period 9-16 days after warming having a CET anomaly of -4.27°C.

However....

as far as cet temperatures are concerned

following a stratosphere warming one should look at the + 15 to 45 day time

frame for effects.

days 15-45 were 1.23°C above the long term average and 2.76°C higher than the month before SSW.

The cold first half of February was cancelled out by mild weather and ended up about average.

Did the SSW actually knacker the cold winter?

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Does anyone know if the southwest will be getting snow this winter? Will there be severe cold in the next 2 - 3 weeks or so as we always seem to luck out even when it's cold the rain comes in from the west which brings the mid air in to us in the winter then tends to turn to snow in east devon or Somerset onwards....

I'm still learning the technical aspect of the weather but I'm really interested in 'interesting' weather!

Thankyou

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Does anyone know if the southwest will be getting snow this winter? Will there be severe cold in the next 2 - 3 weeks or so as we always seem to luck out even when it's cold the rain comes in from the west which brings the mid air in to us in the winter then tends to turn to snow in east devon or Somerset onwards....

I'm still learning the technical aspect of the weather but I'm really interested in 'interesting' weather!

Thankyou

That is a very good question and one I wish I could answer for you. The truth is that no one will know exact weather conditions etc for many days if not weeks yet. Our chances of cold and snow should improve though following a SSW.

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I'm still learning the technical aspect of the weather but I'm really interested in 'interesting' weather!

Thankyou

Best start over here TG81:

http://www.netweathe...-tutorial;sess=

Then a bit more specifically on the SSW here:

http://en.wikipedia....spheric_warming

After that, consider a scenario from a couple of years ago:

http://www.patricktm...t-polar-vortex/

It's too early to give you any specifics on any snow fall in any location, but keep looking in here for hints, also the model discussion thread here:

http://forum.netweat...ting-12z-301212

and ultimately here!

http://www.netweathe...l-it-snow;sess=

We are also discussing your region and the possibilities here:

http://forum.netweat...-december-2012/

Posted Image

Edited by Coast
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The weather Outlook's update today:

http://www.theweatheroutlook.com/

There is currently a lot of speculation about the potential for a Sudden Stratospheric Warming (SSW) event to bring much colder weather during the second half of January, and Buzz will be keeping an eye on this with regular updates. The TWO January weather forecast suggests a mixed month, with the coldest weather probably avoiding the UK.

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2009 is an interesting case and quite well studied with numerous papers such as http://www.staff.sci...ResponseSSW.pdf linking winter cold to the SSW, which was one of the biggest on record.

The winter in the UK was cold prior to this, particularly in early January, with a 60 day CET anomaly of -1.23°C (compared to mean 1940-2012) and 30 anomaly of -1.53°C.

Initially, there appeared to be a cooling temperature response with the period 9-16 days after warming having a CET anomaly of -4.27°C.

However....

days 15-45 were 1.23°C above the long term average and 2.76°C higher than the month before SSW.

The cold first half of February was cancelled out by mild weather and ended up about average.

Did the SSW actually knacker the cold winter?

I've never known a SSW to give us a great winter, only a massive snowfall event or something rather cold. I don't know of any Winter since 2008 to really be big following a SSW. I am sure there are examples in the past, after all this is a Stratosphere thread.

  • April 2008 was following a minor warming?
  • January/February 2009 was following a SSW - and didn't last very long for the UK.
  • December 2009/January 2010 was synoptically great.
  • November/December 2010 was synoptically great.
  • February 2012 was following a SSW?
Correct me if I am wrong.

What does this mean for the whole of the uk, including the southwest? Are we to expect severe cold and heavy snowfalls? Sorry I'm very interested in the weather but still learning the technical aspect of it Posted Image

This is a past winter :) Jan/February 2009.

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Does anyone know if the southwest will be getting snow this winter? Will there be severe cold in the next 2 - 3 weeks or so as we always seem to luck out even when it's cold the rain comes in from the west which brings the mid air in to us in the winter then tends to turn to snow in east devon or Somerset onwards....

I'm still learning the technical aspect of the weather but I'm really interested in 'interesting' weather!

Thankyou

I suspect you will get snow, however, with blocking set ups and attacks from the SW you are always more likely to see snow turn to rain and be influenced quiker by milder temps. However, if we get a robust block then you could do a lot better than most too as the fronts advance no further than SW or S Wales. I lived in Swansea from birth until March '87 and snow wise....I couldn't complain but also had to accept we had cold break down earlier than most. Similar set up to winters back then looks plausible

BFTP

Edited by BLAST FROM THE PAST
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Ah thankyou guys! So it's looking hopeful even for us in waterlogged Devon! Posted Image

I'll be keeping an eye on the weather updates in the next couple weeks...I hope I start to understand all the technical talk soon, I guess I need to research more!

Thankyou for taking the time to post your replies, it was really helpful

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what was intresting about winter 09/10 was the sun had gone through a major spotless streak and the nao ao and jet stream were all very much onside.

but there is some good points raised here about the negitive effect of a strat warming event on a colder setup.

although what i am finding intresting is the models are starting to trend colder already although is this just a standard setup with models when factoring ssw event.

and so far how would some explain is this ssw event all that special compaired to other ssw events?

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well it wouldnt as the cold started last week of november and you'd struggle to get a SSW in november !! there are bound to have been cold spells with no SSW cause. not really for this thread though.

Sorry, I was just answering the question ?

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One slight concern of mine and i hope i am reading this wrong but the 384 GFS 12z 100mb height chart looks to be a concern, whilst it does not look terrible and still maintains a split, the 288hr chart looks miles better with a massive Greenland ridge, but it looks like the PV could be phasing into one again if it went out another 100hrs, i know there is another warming at 10hpa which will take its time to probagate so maybe its not a worry at all, i cannot post the charts because they are from instant weather maps and we are'nt allowed are we?

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GP touched on 1979, 1982 and 1987, a lot to note, but also a tad on the extensive warmings, and the relevance in the polar high dynamics for the year below

the relevance in the current tropospheric modelling also lies to a certain extent with 1985, an extensive polar high with cold in the UK mid-month.. and the polar vortex goes off on one, record breaker-

post-12276-0-09789600-1357237743_thumb.p

Sub 492dm in NE US, sub -30c 850s over much of the NE US.. a polar vortex displacement to an incredible extent

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