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Posted
  • Location: Nuneaton,Warks. 128m asl
  • Weather Preferences: Snow then clear and frosty.
  • Location: Nuneaton,Warks. 128m asl

If you are correct about the startosphere then it could be a long wait before the chance of a Greenland high Chino.

Thats a depressing thought

:sorry:

All is not lost.

It`s still feasable to get decent cold from a Scandi/Siberian block provided there`s enough meridonality in the jet and sufficient energy underneath such a block.

I must say though these have been rare beasts in recent times and it does require the strongest part of the Vortex towards the other side of the pole and the jet to play ball.(not much to ask for!).

post-2026-0-28234200-1320775822_thumb.gi

A recent example above.

Apart from that we have few options without Northern blocking, outside the infamous Northerly topplers.

I think we all remember them too well over the last 20 odd years--those of us who have been around long enough that is.

post-2026-0-16787200-1320776134_thumb.gi

Probably not the best example but you get my drift.

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Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

Since you mentioned the word depressing? Check this: http://www.cpc.ncep....s3/euT2mMon.gif

The CFS must be expecting a winter free of stratospheric warming events! lol

Karyo

and how many times has it changed in the past month-is there any pattern to it if you look closely. I ask as I don't follow that particular output much.

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Posted
  • Location: Brighton (currently)
  • Location: Brighton (currently)

and how many times has it changed in the past month-is there any pattern to it if you look closely. I ask as I don't follow that particular output much.

It has been very consistent for November and December! The only change is that the positive anomaly has intensified and spread to a larger area. Also, January has gone from neutral to mild so there is a strengthening signal for a mild winter!

Karyo

Yes i really enjoyed the regional snow threads last 2 winters Karyo but do you think this year it might not be as fun for us? :sorry:

edit although there is no singal for the uk but very warm for scandy maybe they expect a big euro high pressure belt affecting europe

Yes, we had so much excitement but I think we have to be prepared for the worst this time!

Karyo

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Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

It has been very consistent for November and December! The only change is that the positive anomaly has intensified and spread to a larger area. Also, January has gone from neutral to mild so there is a strengthening signal for a mild winter!

Karyo

Yes, we had so much excitement but I think we have to be prepared for the worst this time!

Karyo

thanks for that

John

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Posted
  • Location: Strathblane/Killearn nr Glasgow
  • Location: Strathblane/Killearn nr Glasgow

One thing to note today is the positive zonal mean winds indicated on the following chart.

post-4523-0-08507900-1319614794_thumb.gi

These wind anomalies are found around 100-200 hPa height and 40-50 Degrees north. This is the jet stream when averaged out across the northern hemisphere. Now look at the mean zonal wind chart forecast and watch the jet stream trend north. The further south we see this the better.

http://wekuw.met.fu-...l&var=u&lng=eng

Please, explain how to read this chart?

How do you interpret what is shown on the diagram?

What do the wavy lines indicate?

What do the colours mean?

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Posted
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.
  • Weather Preferences: Snow and storms
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.

Please, explain how to read this chart?

How do you interpret what is shown on the diagram?

What do the wavy lines indicate?

What do the colours mean?

Happy to do this.

But first do you understand what I mean by the term mean zonal mean winds?

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Posted
  • Location: Strathblane/Killearn nr Glasgow
  • Location: Strathblane/Killearn nr Glasgow

Happy to do this.

But first do you understand what I mean by the term mean zonal mean winds?

Westerly winds inhibit blocking; easterly winds favour blocking.

Strong zonal winds are indicative of a strong vortex and vice versa?

A warming or something has to happen in the stratosphere to reverse the zonal winds to make them weaker to encourage a weaker vortex?

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Posted
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.
  • Weather Preferences: Snow and storms
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.

Westerly winds inhibit blocking; easterly winds favour blocking.

Strong zonal winds are indicative of a strong vortex and vice versa?

A warming or something has to happen in the stratosphere to reverse the zonal winds to make them weaker to encourage a weaker vortex?

Yes.

So now to the following chart:

post-4523-0-87886300-1320789026_thumb.gi

This chart is a cross section of the mean zonal mean winds from the troposphere to the top of the stratosphere from the equator to the North Pole. The orange areas signify where mean westerlies prevail and the blue areas signify where mean easterlies prevail. We can see the areas where westerlies or easterlies are prevalent in the troposphere and stratosphere by looking at the pressures and latitudes.

So if we look at the equatorial mean zonal winds we can see an area of blue easterly winds between the pressure levels 40-5 hPa - the easterly QBO.

After a SSW occurs we observe an area of easterly blue mean zonal winds flood down from the top of the stratosphere in an area from the pole - 60ºN towards the troposphere. It is this that causes Northern blocking depending on how far down it propagates.

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Posted
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.
  • Weather Preferences: Snow and storms
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.

First sign of something?

post-4523-0-73875900-1320827924_thumb.gi

Too early to make too much of it yet.

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Posted
  • Location: Barnet/south Herts border 130m asl
  • Weather Preferences: snow, thunderstorms & all extreme weather
  • Location: Barnet/south Herts border 130m asl

It has been very consistent for November and December! The only change is that the positive anomaly has intensified and spread to a larger area. Also, January has gone from neutral to mild so there is a strengthening signal for a mild winter!

i see those cfs charts slightly differently. despite not having much faith in them at all, i do check them quite regularly (i should get out more!).

its roughly one and a half months til january, so if we go back one and a half months and look at what cfs was showing for november, it was showing cold/average. i therefore dont pay much attention to cfs beyond one month.

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Posted
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.
  • Weather Preferences: Snow and storms
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.

At last something to monitor.

The warm patch is there on the GFS forecast at 30 hPa as well.

post-4523-0-23049200-1320836423_thumb.gi

Right, game on!

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Posted
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.
  • Weather Preferences: Snow and storms
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.

The stratospheric temperature forecast on the Berlin site doesn't look good though!

http://wekuw.met.fu-...ww/wdiag/ts.php

Karyo

This won't be picked up there yet!

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Posted
  • Location: Live Haddenham (Bucks). Work Heathrow Airport
  • Location: Live Haddenham (Bucks). Work Heathrow Airport

At last something to monitor.

The warm patch is there on the GFS forecast at 30 hPa as well.

post-4523-0-23049200-1320836423_thumb.gi

Right, game on!

So this would mean the the PV maybe weakening?

do you have a link to where i can view this chart please on a regular basis. I was trying to find a link to 30hpa charts yesterday without no joy.

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Posted
  • Location: Netherlands
  • Location: Netherlands

At last something to monitor.

The warm patch is there on the GFS forecast at 30 hPa as well.

Right, game on!

For me, it's a little bit to far, to be excited (goosebumps) , but indeed finally something to look forward. Thanks for sharing this information with us.

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Posted
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.
  • Weather Preferences: Snow and storms
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.

So this would mean the the PV maybe weakening?

do you have a link to where i can view this chart please on a regular basis. I was trying to find a link to 30hpa charts yesterday without no joy.

It means nothing yet. But it is the first step on a long road that could lead to stratospheric disturbances. I am just glad that we have stepped onto the road!

Charts found below:

http://wekuw.met.fu-berlin.de/~Aktuell/strat-www/wdiag/diag.php

http://www.cpc.ncep.noaa.gov/products/stratosphere/strat_a_f/

(All links are on the first post with most info)

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Posted
  • Location: Orleton, 6 miles south of Ludlow
  • Location: Orleton, 6 miles south of Ludlow

At last something to monitor.

The warm patch is there on the GFS forecast at 30 hPa as well.

post-4523-0-23049200-1320836423_thumb.gi

Right, game on!

Is the predicted warming in the right place? Or maybe, it can be anywhere in the NH?

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Posted
  • Location: Nuneaton,Warks. 128m asl
  • Weather Preferences: Snow then clear and frosty.
  • Location: Nuneaton,Warks. 128m asl

At last something to monitor.

The warm patch is there on the GFS forecast at 30 hPa as well.

post-4523-0-23049200-1320836423_thumb.gi

Right, game on!

The first positive for cold lovers for a while Chiono?

I wondered,as i am new to this part of meteorology,is this an upwelling wave from the Tropics,maybe caused by a Mountain torque?

The reason i am thinking this way is the forecast warming seems to start at 100hpa as early as T120 here,

http://wekuw.met.fu-...st=f120&lng=eng

and then the warm area seems to show it`s hand higher up as the timeframe goes on to T240hrs. at 30hpa --as you have shown.

Maybe i have got this wrong and what i am looking at are isolated patches of warmer air circulating around at lower levels.

Be glad of your imput,

Regards,Phil

Edited by phil n.warks.
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Posted
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.
  • Weather Preferences: Snow and storms
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.

Is the predicted warming in the right place? Or maybe, it can be anywhere in the NH?

I am a believer that any warming doesn't have to be in a set place. What I would say it is where I would have expected it be following the Asian mountain torque event - just perhaps a little later than I would have anticipated.

Interesting that if this warming grows then we may get a Canadian type early season warming, which does not reverse then mean zonal mean winds at 30 hPa, but does cause a distortion of the vortex away from the Canadian segment.

The first positive for cold lovers for a while Chiono?

I wondered,as i am new to this part of meteorology,is this an upwelling wave from the Tropics,maybe caused by a Mountain torque?

The reason i am thinking this way is the forecast warming seems to start at 100hpa as early as T120 here,

http://wekuw.met.fu-...st=f120&lng=eng

and then the warm area seems to show it`s hand higher up as the timeframe goes on to T240hrs. at 30hpa --as you have shown.

Maybe i have got this wrong and what i am looking at are isolated patches of warmer air circulating around at lower levels.

Be glad of your imput,

Regards,Phil

That sounds very reasonable Phil. I would need to re read the literature on the mechanisms involved to be sure though.

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Posted
  • Location: Nuneaton,Warks. 128m asl
  • Weather Preferences: Snow then clear and frosty.
  • Location: Nuneaton,Warks. 128m asl

I am a believer that any warming doesn't have to be in a set place. What I would say it is where I would have expected it be following the Asian mountain torque event - just perhaps a little later than I would have anticipated.

Interesting that if this warming grows then we may get a Canadian type early season warming, which does not reverse then mean zonal mean winds at 30 hPa, but does cause a distortion of the vortex away from the Canadian segment.

That sounds very reasonable Phil. I would need to re read the literature on the mechanisms involved to be sure though.

Thanks for your reply Chion.

It`s a fascinating subject and i will follow this with great interest.

Meanwhile i will keep reading up myself.

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Posted
  • Location: Camborne
  • Location: Camborne

I have been reading a paper regarding Alaska, An Analysis of the Classic Arctic Outbreak Event of Late December 2008-Early January 2009, that contains a section on The Role of the Stratosphere in Classic Arctic Outbreaks in southern Alaska. I wondered if it might be of interest.

http://pafc.arh.noaa...extn=php&page=3

The whole of the paper here. It sure got a bit nippy.

http://pafc.arh.noaa...extn=php&page=1

Edited by weather ship
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Posted
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.
  • Weather Preferences: Snow and storms
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.

Re the 'warm patch' could there be any connection with the event in this link - see also much comment in the worldwide weather thread 'Alaska Storm' http://www.livescien...-explained.html

That is very much a tropospheric event which doesn't normally affect the stratosphere.

Does ECM agree tonight?

The stratospheric charts only update once daily so we will have to wait until tomorrow.

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