Winter 2012/13 - Chat

[Paul]

Please discuss the upcoming winter here - as a guide this thread is for talking about seasonal forecasts, data for the upcoming winter, speculating how it may be and general winter related chat.

For those who are riding an extreme rollercoaster of emotions every day as to whether the winter may be cold or not, please take a look at the Winter Emotions thread - http://forum.netweat...inter-emotions/

[Paul]

To get the ball rolling again - here's Stewarts preliminary winter thoughts as released this week (full forecast on the way mid-month).

Full page with the presentation along with the video:

http://www.netweather.tv/index.cgi?action=winter-thoughts-2012;sess=

[BornFromTheVoid]

Please discuss the upcoming winter here - as a guide this thread is for talking about seasonal forecasts, data for the upcoming winter, speculating how it may be and general winter related chat.

For those who are riding an extreme rollercoaster of emotions every day as to whether the winter may be cold or not, please take a look at the Winter Emotions thread - http://forum.netweat...inter-emotions/

Good evening Paul. Just wondering if ye might be able to put together a video, like the preliminary winter thoughts, but with a more technical slant to it?

I know for myself, I've gotten to the point where I'm aware of the different teleconnections and how they work, but still find myself struggling with how they all link together and the finer detail with incorporating them into a regional specific LRF, as Glacier Point does so well.

While I'd love to pick at Stewart's brain for a while, I doubt I'll ever have that opportunity. So, I think an "extra technical forecast video" would be the next best thing, if that's at all possible?

EDIT: "Stewart", not "Stuart"!

Edited November 10, 2012 by BornFromTheVoid

[Paul]

We're doing another video for the full forecast mid-month so hopefully that may add another layer, there are also some other ideas which I'm planning to put to Stewart / the others here which may also work along those lines so watch this space so to speak

[UV-RAY]

Matt Hugo's latest tweet doesn't bode well for the first part of winter. Strat reaching record cold levels and if we miss out on a cold spell come the end of November it could be a long wait from thereon. Oh dear not another winter like the last one I hopes!

Edited November 10, 2012 by Seven of Nine

[Great Plum]

I'm certainly no expert but isn't there a lag with the strat of at least 4 weeks? It also appears that other factors are counteracting that...

[UV-RAY]

I'm certainly no expert but isn't there a lag with the strat of at least 4 weeks? It also appears that other factors are counteracting that...

I hope so GP, but a strong PV doesn't bode well for winter as you know. Lets hope the other factors can override this, personally I can't see this.

[Great Plum]

It's an interesting one 7/9... Had there ever been a case when a strong vortex has been overridden by other factors?

[bluearmy]

It's an interesting one 7/9... Had there ever been a case when a strong vortex has been overridden by other factors?

There must be but we don't have enough historical data on the strat to show it. (Assuming you mean a strat vortex as opposed to a trop one)

[UV-RAY]

It's an interesting one 7/9... Had there ever been a case when a strong vortex has been overridden by other factors?

As far as I'm aware there hasn't been.

There must be but we don't have enough historical data on the strat to show it. (Assuming you mean a strat vortex as opposed to a trop one)

Are there no historical charts we could look back on BA, in order to gauge whether such events can take place? Edited November 10, 2012 by Seven of Nine

[I remember Atlantic 252]

00Z ecmwf model looks fairly decent for mid Nov, mainly dry, could be even frost and fog, with high dominating

I had an ice day on 19th Nov 05, with rime and freezing fog

[Coast]

I won't be put out if we don't see much (or anything) wintery in this part of the World before Xmas. I'm hoping it might all come together early in the New Year though. No science or knowledge in that by the way, just hope-casting!!!!

[bluearmy]

Are there no historical charts we could back on BA, in order to gauge whether such events can take place?

Ncep data goes back to 1979 and Berlin (ECM) to 1964 although the info is restricted. I'm sure ed has stated that afahk, an anomalously cold mid/upper strat means no HLB can occur. however, I think that there are other variables that may have existed which we cannot know about. Remember that our knowlege of the physics of the strat is in its infancy compared with the trop.

[phil nw.]

No doubt that those low heights are strengthening over the pole and it is a concern if we are looking at NB.

An interesting conflict developing between the ever cooling upper levels of the Stratosphere and the forecast trophospheric wavebreaking event and how much impact this will have.

[UV-RAY]

I'm not sure if this is relevant or not and to be honest it's a wee bit over my head.

http://www.ann-geophys.net/28/2133/2010/angeo-28-2133-2010.pdf

Edited November 10, 2012 by Seven of Nine

[Liam J]

I'm not sure if this is relevant or not and to be honest it's a wee bit over my head.

http://www.ann-geoph...8-2133-2010.pdf

I haven't read through it all but imo this more evidence that the srat temp plays a siginficant role in NB & the disruption of the polar vortex and effects it can have in terms of winter weather patterns for the northern hemipshere. We really need to see SSW if it's cold weather you want.

Currently near record low levels.

Edited November 10, 2012 by Liam J

[bluearmy]

I haven't read through it all but imo this more evidence that the srat temp plays a siginficant role in NB & the disruption of the polar vortex and effects it can have in terms of winter weather patterns for the northern hemipshere. We really need to see SSW if it's cold weather you want.

Currently near record low levels.

liam, very doubtful you will see a SSW this side of jan. hopefully there will be some warming to take the mid strat back towards average or even above but a reversal of zonal winds at 30hpa looks an awfully long way off. as far as the strat is concerned, i would advise being an observer until we see what is showing on the extended ens in the trop late november and into the first part of december.

[Liam J]

liam, very doubtful you will see a SSW this side of jan. hopefully there will be some warming to take the mid strat back towards average or even above but a reversal of zonal winds at 30hpa looks an awfully long way off. as far as the strat is concerned, i would advise being an observer until we see what is showing on the extended ens in the trop late november and into the first part of december.

Yes, i'd stick my neck out and predict no significant SSW until the new year perhaps even the second half of January, then you have to take into consideration the lag time effect - so on that basis alone things do not look good imo, however, many other factors also will have bearing on what synoptic patterns develop over the coming months so on lookers don't despair. Also SSW may well occur sooner so I'd be cautious with anyone making predictions in the extended range.

Edited November 10, 2012 by Liam J

[Eskimo]

Can i stick my neck out and say that this record cooling may contribute to a record warming sometime in the next 4 weeks based on no scientific evidence on those thoughts?

Edited November 10, 2012 by PerfectStorm

[Liam J]

Can i stick my neck out and say that this record cooling may contribute to a record warming sometime in the next 4 weeks based on no scientific evidence on those thoughts?

Based on no scientific explanation then I wouldn't say that is completely out of the question however, looking at the strat behavior and the trend shown on the graph posted I'd say we were now into a cooling/cold period of strat temps which could last into 2013? Then again I admit i'm now out of my depth regarding the stratosphere......

[bobbydog]

now i'm not suggesting there will be an SSW, however, correct me if i'm wrong, but isn't an SSW- just that?- a sudden and unexpected stratospheric warming?

apparently, SSW's are associated with an easterly QBO phase, which i believe we are in. (again, correct me if i'm wrong)

"On average, sudden stratospheric warmings occur in every second winter, and they are very unevenly distributed over the observation period. Only a single stratospheric warming occurred between the winters of 1988/1989 and 1997/1998, while nine have been registered since the beginning of this millennium. So far there has been no explanation. With their new research, the meteorologists at Freie Universität have shown that the intermittent sudden stratospheric warmings are a consequence of the interaction between the North Atlantic, the troposphere, and the stratosphere. They found that an increased number of sudden stratospheric warmings occur when the heat flux from the North Atlantic into the atmosphere is increased."

my point being, if they are unpredictable, how do we know it won't happen?

http://www.scienceda...10121081051.htm

just to add a bit more-

" They observed that there is an increased number of stratospheric warmings, when the heat flow from the North Atlantic into the atmosphere is increased"

i believe SSTs are high in the north atlantic, therefore with an easterly QBO, are conditions not favourable for an SSW?

Edited November 10, 2012 by bobbydog

[CanadaAl]

now i'm not suggesting there will be an SSW, however, correct me if i'm wrong, but isn't an SSW- just that?- a sudden and unexpected stratospheric warming?

apparently, SSW's are associated with an easterly QBO phase, which i believe we are in. (again, correct me if i'm wrong)

"On average, sudden stratospheric warmings occur in every second winter, and they are very unevenly distributed over the observation period. Only a single stratospheric warming occurred between the winters of 1988/1989 and 1997/1998, while nine have been registered since the beginning of this millennium. So far there has been no explanation. With their new research, the meteorologists at Freie Universität have shown that the intermittent sudden stratospheric warmings are a consequence of the interaction between the North Atlantic, the troposphere, and the stratosphere. They found that an increased number of sudden stratospheric warmings occur when the heat flux from the North Atlantic into the atmosphere is increased."

my point being, if they are unpredictable, how do we know it won't happen?

http://www.scienceda...10121081051.htm

just to add a bit more-

" They observed that there is an increased number of stratospheric warmings, when the heat flow from the North Atlantic into the atmosphere is increased"

i believe SSTs are high in the north atlantic, therefore with an easterly QBO, are conditions not favourable for an SSW?

I agree with this completely, I do also think (yes the strat is cooling to record low levels apparently) but we should consider other factors in our favour. Plus the strat is very complex and for we all we know the cooling could stop abruptly. I still think it's all to play for. Even the met who haven't had a great track record but are the most widely known forecast in the uk, are going for a cold end to november. So who knows really

[I remember Atlantic 252]

Fantasy slider on the 12Z, but surely trend developing for a weekend northerly toppler of some kind, 23-25th Nov

[bluearmy]

Can i stick my neck out and say that this record cooling may contribute to a record warming sometime in the next 4 weeks based on no scientific evidence on those thoughts?

Well that's sort of what happened last year. It was so cold that when when the warming came, it was very marked indeed. Technically, there wasn't an SSW though as no reversal of mean zonal winds occurred at 30hpa (just)

[SnowObsessor90]

Well that's sort of what happened last year. It was so cold that when when the warming came, it was very marked indeed. Technically, there wasn't an SSW though as no reversal of mean zonal winds occurred at 30hpa (just)

Did that contribute towards the NAO failing to go properly negative in any way during Feb or was that down to other factors?