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Depends on how quickly the westerly winds downwell, and also to a certain extent how early/late the final warming of the PV is. For example the Jan 2013 SSW didn't really mix down until late Feb and the effects lasted through March and early April. This one may not hold as long but its certainly a possibility that we keep this wonky mix for a while yet.

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3 hours ago, mushymanrob said:

so, if things have returned to normal in the stratosphere, does that suggest that by spring, (march 1st) . 'normal' conditions are most likely at surface levels?

I believe the modelling is mixed on that at the moment rob and the current mindset is to wait for the ec seasonal run at the end of the month.....i would have thought march 1st will be too soon though  

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Edited by knocker

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Well, it seems like this SSW has not downwelled sufficiently through the lower layers of the strat to give us a HLB in the troposphere.

Some posters have now given up hope of HLB in February because the EC46, whick knocker, kindly answered my question about the other day, shows no HLB during this month. So it seems this SSW  not dealt us a kind hand.  I don't agree with the idea that the split was too good- last year was a major warming and it delivered the goods, but this year it just seems to have been a split with the remants of the main vortex landing in the wrong place.

Edited by Bricriu
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Even Carol K called it a polar vortex without specifying stratosphere on the BBC this morn. I almost lost consciousness.

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One for the experts here. I've spotted a small area that's anomalously (relatively) warm - 31 c instead of - 40's to - 60's C. 

Is this the start of a new warming event, is it just a regular anomaly or is a little knowledge a dangerous thing? 

Screenshot_20190131-224542.png

Edited by JeffC

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14 hours ago, JeffC said:

One for the experts here. I've spotted a small area that's anomalously (relatively) warm - 31 c instead of - 40's to - 60's C. 

Is this the start of a new warming event, is it just a regular anomaly or is a little knowledge a dangerous thing? 

Screenshot_20190131-224542.png

the anomaly still there but not quite so marked...

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8 minutes ago, Summer Sun said:

 

GFS not covered itself in glory has It??

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3 minutes ago, winterof79 said:

GFS not covered itself in glory has It??

Nor has the EC monthly tbh

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I'm wondering if the only action we have to come , in reality, is the form the 'Final Warming' takes and any anoms it might drive?

Edited by Gray-Wolf

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4 minutes ago, Gray-Wolf said:

I'm wondering if the only action we have to come , in reality, is the form the 'Final Warming' takes and any anoms it might drive?

Final Warming?

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28 minutes ago, Rambo said:

Final Warming?

Yes the end of Winter when the polar night ends and the sun returns over the pole which gradually warms the top of the Stratosphere.Sometime in March but the date of final demise of the pv can vary time wise.

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2 hours ago, Gray-Wolf said:

I'm wondering if the only action we have to come , in reality, is the form the 'Final Warming' takes and any anoms it might drive?

Possibly. It has certainly been a season of the non event. Virtually no frost, little wind, very little rain and next to no accurate medium or long range forecasting. When the likes of Amy Butler have a wtf moment with a forecast AO flip you just know something about this winter has not sat right. A few theories out there, but in general nothing convincing. A badly busted forecast ought to provide us with many more lessons than a forecast that comes to pass. Let’s hope so, because if Feb now pans out westerly and average then we’ll need something positive to come out of this grim season!!

Still a chance mid to late month, but I’m not holding my breath. The expected long lasting euro trough is disappearing and back comes the strong sub tropical high. For a bit of fun I’m going to investigate winters when the AH got a pasting and departed the scene, and see if there is anything in the pattern to suggest a precursor. Certainly the Canadian shard has sat tight, but so too as the AH. Ying and Yang for a poor winter.

Edited by Catacol
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36 minutes ago, Catacol said:

Possibly. It has certainly been a season of the non event. Virtually no frost, little wind, very little rain and next to no accurate medium or long range forecasting. When the likes of Amy Butler have a wtf moment with a forecast AO flip you just know something about this winter has not sat right. A few theories out there, but in general nothing convincing. A badly busted forecast ought to provide us with many more lessons than a forecast that comes to pass. Let’s hope so, because if Feb now pans out westerly and average then we’ll need something positive to come out of this grim season!!

Still a chance mid to late month, but I’m not holding my breath. The expected long lasting euro trough is disappearing and back comes the strong sub tropical high. For a bit of fun I’m going to investigate winters when the AH got a pasting and departed the scene, and see if there is anything in the pattern to suggest a precursor. Certainly the Canadian shard has sat tight, but so too as the AH. Ying and Yang for a poor winter.

I don't know if this is the right time or place but I think the 'backdrop' to all of this is the shift in 'average position' of the polar jet since the 2012 ( ish) seasonal opening of the Pacific side of the Arctic basin?

The opening of the Atlantic side ( Barentsz/Kara) had been slowly impacting the 'average position' of the polar jet in our neck of the woods  throughout the noughties with 07's record Arctic drop seeming to be a convenient place to pick up the 'washout summers' positioning of the jet. 

Since 2012 I think we have begun shifting to a drier, more H.P. dominated 'average position' of the jet with the old trough now in the far easterns edge of Europe ( see the recent flooding in Bosnia?).

Without the polar night jet throwing a spanner in the works we were ( IMHO) always going to see things settle back to H.P. dominating our patterns?

If we are now in some 'post 2012 polar jet configuration' then the summer to come will be even better than last year ( to the point of having issues with heat and lack of rain?) as High Pressure again favours keeping close to ,or dominating, our weather?

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9 minutes ago, Gray-Wolf said:

I don't know if this is the right time or place but I think the 'backdrop' to all of this is the shift in 'average position' of the polar jet since the 2012 ( ish) seasonal opening of the Pacific side of the Arctic basin?

The opening of the Atlantic side ( Barentsz/Kara) had been slowly impacting the 'average position' of the polar jet in our neck of the woods  throughout the noughties with 07's record Arctic drop seeming to be a convenient place to pick up the 'washout summers' positioning of the jet. 

Since 2012 I think we have begun shifting to a drier, more H.P. dominated 'average position' of the jet with the old trough now in the far easterns edge of Europe ( see the recent flooding in Bosnia?).

Without the polar night jet throwing a spanner in the works we were ( IMHO) always going to see things settle back to H.P. dominating our patterns?

If we are now in some 'post 2012 polar jet configuration' then the summer to come will be even better than last year ( to the point of having issues with heat and lack of rain?) as High Pressure again favours keeping close to ,or dominating, our weather?

Yes up to this last week the oustanding fact of this winter has been the lack of rain on this side of the Moray Firth and as a farmer i have been saying to others that this coming summer if it turns out to be a dry one could be really difficult for growing crops and grass following on from last years  very dry summer. Stocks of hay and silage will be exhausted on stock farms this spring with nothing to carry forward so we are looking for a damper summer than last year. Looks like your thoughts will turn out correct.

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The polar jet shift with climate is a very interesting theory that’s related to an expansion of the Hadley cell driven by increased vertical lift over the tropics and greater available overall energy for the circulation.

Potentially, this imprints a La Niña-like tendency during the first half of each year, with the Azores High stronger than usual and taking a greater amount of Nino-driven forcing to quash.

I’n not sure whether this relates much to the stratospheric downwell issues though - that may be more to do with having had an unusual tri-vortex pattern that proved too messy in the vertical to allow the usual amount of vertical propagation of anomalies. 

The model projections of a rapid AO recovery positive might be more connected though - Nina-like forcing helps consolidate low heights over the polar region. With such an incoherent downwell pattern there’s not enough coming down to counter it - assuming the models had the right idea that is. The expanded Hadley cell may be misleading them a bit and causing the Nino forcing from the current MJO Pacific crossing to be incorrectly washed out or derailed.

The Hadley cell may have been especially strong this Jan due to the Arctic managing to be the coldest overall since 2008; this also increased the Ferrel and Polar cells, enhancing the zonal flow across the mid-lats. Question then becomes - how did the Arctic manage to achieve that colder state relative to the recent tendency for otherwise?

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Observed and Simulated Teleconnections Between the Stratospheric Quasi‐Biennial Oscillation and Northern Hemisphere Winter Atmospheric Circulation

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Abstract

The Quasi‐Biennial Oscillation (QBO) is the dominant mode of interannual variability in the tropical stratosphere, with easterly and westerly zonal wind regimes alternating over a period of about 28 months. It appears to influence the Northern Hemisphere winter stratospheric polar vortex and atmospheric circulation near the Earth's surface. However, the short observational record makes unequivocal identification of these surface connections challenging. To overcome this, we use a multicentury control simulation of a climate model with a realistic, spontaneously generated QBO to examine teleconnections with extratropical winter surface pressure patterns. Using a 30‐hPa index of the QBO, we demonstrate that the observed teleconnection with the Arctic Oscillation (AO) is likely to be real, and a teleconnection with the North Atlantic Oscillation (NAO) is probable, but not certain. Simulated QBOAO teleconnections are robust, but appear weaker than in observations. Despite this, inconsistency with the observational record cannot be formally demonstrated. To assess the robustness of our results, we use an alternative measure of the QBO, which selects QBO phases with westerly or easterly winds extending over a wider range of altitudes than phases selected by the single‐level index. We find increased strength and significance for both the AO and NAO responses, and better reproduction of the observed surface teleconnection patterns. Further, this QBO metric reveals that the simulated AO response is indeed likely to be weaker than observed. We conclude that the QBO can potentially provide another source of skill for Northern Hemisphere winter prediction, if its surface teleconnections can be accurately simulated.

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JD029368     Open access

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The Corresponding Tropospheric Environments during Downward-extending and Non-downward-extending Events of Stratospheric Northern Annular Mode Anomalies

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Abstract

Using the NCEP/NCAR reanalysis dataset, this study classifies stratospheric Northern Annular Mode (NAM) anomalies during negative/positive phase into two categories—anomalies extending into the troposphere (referred as negative/positive TEs) and those not extending into the troposphere (referred as negative/positive NTEs), and the corresponding tropospheric environments during the TEs and NTEs are identified. Compared with that for the negative NTEs, the upward wave fluxes entering the stratosphere are stronger and more persistent during the negative TEs. Furthermore, the stronger and more persistent upward wave fluxes during the negative TEs are due to more favorable conditions for upward wave propagation, which is manifested by fewer occurrences of negative refractive index squared in the mid-high latitude troposphere and stronger wave intensity in the mid-high latitude troposphere. However, the tropospheric wave intensity plays a more important role than the tropospheric conditions of planetary wave-propagation in modulating the upward wave fluxes into the stratosphere. Stronger and more persistent upward wave fluxes in the negative TEs, particularly wave-1 fluxes, are closely related to the negative geopotential height anomalies over the North Pacific and positive geopotential height anomalies over the Euro-Atlantic sectors. These negative/positive geopotential height anomalies over the North Pacific/Euro-Atlantic are related to the positive/negative diabatic heating anomalies and the decreased/increased blocking activities in the mid-high latitudes. The subtropical diabatic heating could also impact on the strength of the mid-high latitude geopotential height anomalies through modulating horizontal wave fluxes. For positive NAM events, the results are roughly similar to those for negative NAM events, but with opposite signal.

https://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-18-0574.1 Open Access

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Meanwhile back at the ranch signs that the downwelling effects at ground level,for what they were,are forecasted to weaken 

umedel60.thumb.png.2a392b14004e4a93734daa54612ea4c8.png

Weak positive mean zonal winds anomalies are set to return in a few days along with an increase at the top filtering down towards mid-level. 

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1 hour ago, phil nw. said:

Meanwhile back at the ranch signs that the downwelling effects at ground level,for what they were,are forecasted to weaken 

umedel60.thumb.png.2a392b14004e4a93734daa54612ea4c8.png

Weak positive mean zonal winds anomalies are set to return in a few days along with an increase at the top filtering down towards mid-level. 

talk about a damp squib - if you can stomach it try reading the posts from December , its like watching a slow motion car crash - you will find your self screaming at the screen slightly demented going " no it won't ... its not going to be a quick response !!"

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