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Stratosphere and Polar Vortex Watch


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Some useful tropospheric developments upcoming which are likely to have stratospheric impacts towards the end of November and more particularly into December. A strong convectively coupled tropic

so after many days the GFS & FNMOC & canadian finally now follow the Euro with 44 out 64 Members with a split at day 9- The ECM is day 8. We will call it - SSW & Split for 1st Ja

For all that watch the zonal winds. Let me urge you to look at the geopotential heights more. At least as far as weakening/strengthening trends go. Because as the polar vortex cries for help, you migh

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16 hours ago, Recretos said:

My new animation sequence, showing the nice wave2 pressure from GFS in late terms, which are strongly tropospheric forced, by the Alaskan and Atlantic ridges

Interesting and cool animation - it nicely shows how the troposphere in this case is forcing the polar vortex aloft to be 'squeezed' by effects induced by two tropospheric ridges.

The animation also made me wonder - would it be insightful to create a similar animation of the polar vortex in terms of temperature? I would expect that if you visualize the edges of the polar vortex via temperature, you should be able to see the ascent and descent of warmings that propagate from the troposphere/upper stratosphere to the mid-stratosphere or vice-versa. In other words - it could give more insight in both the horizontal and vertical development of warmings that may or may not affect the polar vortex, including its sources.

Just to show some examples of what I am imagining - below are maps of the polar vortex at 10 hPa forecasted for 20 nov 2018 (left; with an intact vortex) and 14 feb 2018 (right; just after the SSW of 12 feb 2018). The blue line roughly delineates the line bordering the -45 degree isotherm. Arrows point towards the colder air.

In this case I imagine that the blue line below represents one 'slice' of the edge of the polar vortex in 3D. Of course the temperature threshold could be set to any value ?.

 

Afbeelding2.thumb.png.7b014e24657e3afca640bfa80b532252.pngAfbeelding1.thumb.png.90608d3a09a937d95fd33b4e8ab367ce.png

GPH (black lines) at 10 hPa at 20-11 (left - normal polar vortex) and 14-2 (right - SSW) and temperature (colors). The blue line indicates the border of the 45-degree isotherm; the arrows point towards colder air. Charts obtained via FU Berlin.

Any thoughts whether this would be something useful to do or not?

 

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5 hours ago, Dennis said:

There is some nice progress in pv ...

ecmwf1f240 (1).gif

ecmwfzm_ha2_f168.gif

ecmwfzm_vt_f240 (1).gif

For the past 3 years we have seen the same, early weakening polar vortex during November only to suddenly come back with a vengeance mid December and by the time the next wave hits and the effects downwell it's already spring ?

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Have at it folks - long week at work so these were made late on Thursday when data released onto Copernicus, if there are any corrections needed then please let me know... so busy this week it's been a blur. 

Within the doc are the ECM and UKMO strat progressions for winter, you will see that we have very different stories ahead.

@Recretos - incorporated your advice around the plot scaling by determining the original Min / Max and equalising.

@Interitus - thanks again for guiding me through my first steps into using Panoply, the ability to re-render the ESRL data into Panoply is great, I like the ESRL suite, but let's face it - Panoply makes it a whole lot cooler - like jumping from 80's graphics to the now immediately, a new perspective..

Plus - the added bonus is we rarely see UK Met stuff on twitter etc that details the strat outlook, save the under the counter musings from live glosea - it's neat to see the raw seasonal data rendered.

PS - I am mindful that this data although produced from information available on Thursday, may have been initiated earlier, thereby not incorporating in initiation the anomalous Scandi block creating the waves in the strat...

 

Copernicus November Seasonal.pdf

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1 hour ago, lorenzo said:

Have at it folks - long week at work so these were made late on Thursday when data released onto Copernicus, if there are any corrections needed then please let me know... so busy this week it's been a blur. 

Within the doc are the ECM and UKMO strat progressions for winter, you will see that we have very different stories ahead.

@Recretos - incorporated your advice around the plot scaling by determining the original Min / Max and equalising.

@Interitus - thanks again for guiding me through my first steps into using Panoply, the ability to re-render the ESRL data into Panoply is great, I like the ESRL suite, but let's face it - Panoply makes it a whole lot cooler - like jumping from 80's graphics to the now immediately, a new perspective..

Plus - the added bonus is we rarely see UK Met stuff on twitter etc that details the strat outlook, save the under the counter musings from live glosea - it's neat to see the raw seasonal data rendered.

PS - I am mindful that this data although produced from information available on Thursday, may have been initiated earlier, thereby not incorporating in initiation the anomalous Scandi block creating the waves in the strat...

 

Copernicus November Seasonal.pdf

That's an interesting late winter pattern. Front loaded winter? Maybe not....

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I dusted off the polar vortex model given the favorable pattern for activating the vertical energy transfer from the troposphere to the stratosphere and perturbing the stratospheric PV.  The model correctly predicted a weakening of the stratospheric PV for this week followed by a strengthening of the stratospheric PV in early December and then an even greater weakening of the stratospheric PV starting the third week of December.  My interpretation of the SLP anomalies coupled with the polar vortex model is that the second half of December is one period to watch for a possible significant PV disruption and that period could extend into early January.  If a significant stratospheric PV disruption does occur in late December or early January, I would be more confident in a relatively cold winter across large stretches of the NH mid-latitudes especially northern Eurasia and the Eastern US. https://www.aer.com/science-research/climate-weather/arctic-oscillation/

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