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Stratosphere and Polar Vortex Watch


Paul

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Posted
  • Location: North East
  • Weather Preferences: Thunder , Lightning , Snow , Blizzards
  • Location: North East
13 minutes ago, Glacier Point said:

Based on where we're at...

748884558_zonalpropagation.thumb.png.465fc72b8175ea846fad751bf92c4c1f.png

Impacts look to be sustained and long duration - February into March

Oh noooo , hope we don’t have the same conversation as last year regarding the interruption of the ‘festival’ second week of March  

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Posted
  • Location: Worcestershire
  • Weather Preferences: Forecaster Centaurea Weather
  • Location: Worcestershire

 

Hmmm, I remember watching the snow shower at school very well....

Edited by Glacier Point
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Posted
  • Location: Cwmbran. South East Wales 300ft ASL
  • Location: Cwmbran. South East Wales 300ft ASL
1 hour ago, Glacier Point said:

Based on where we're at...

748884558_zonalpropagation.thumb.png.465fc72b8175ea846fad751bf92c4c1f.png

Impacts look to be sustained and long duration - February into March

Hi Stu

Sounds great.....the million dollar question now being how big is the impact (I:e cold and snowy  )

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Posted
  • Location: North East
  • Weather Preferences: Thunder , Lightning , Snow , Blizzards
  • Location: North East
1 hour ago, Glacier Point said:

 

Hmmm, I remember watching the snow shower at school very well....

And is if by magic the 12z GFS given an 87’ ...I knew you were good , but not this good  

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Posted
  • Location: Stoke Gifford, nr Bristol, SGlos
  • Location: Stoke Gifford, nr Bristol, SGlos
2 hours ago, Glacier Point said:

 

Hmmm, I remember watching the snow shower at school very well....

Watched it in the bookies after work (delay due to weather meant i could watch it). Had £20 on at 8s. Jumping up and down wearing my 'Motson' sheepskin coat as The Thinker bolted up!

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Posted
  • Location: @scotlandwx
  • Weather Preferences: Crystal Clear High Pressure & Blue Skies
  • Location: @scotlandwx
11 hours ago, Interitus said:

The GFS parallel has attracted some attention in recent runs with increased meridionality towards the end which can be seen with reversed tropospheric zonal flow at 60°N. However the interesting thing is that this is led from the troposphere to the strat as can be seen in this plot of zonal wind at various pressure levels -

894670882_zonalwindseriesfv319011000.thumb.png.8e8b621770ceb2149a74ccbb7c371496.png

There is a marked dip around Jan 22nd which propagates from the lower trop with a minimum at 30mb 51 hours later. This is not to say that the SSW hasn't potentially caused this in the first place, but concluding that these events are the result of SSW is fraught with uncertainty.

70hPa caught my eye on this plot too, vs the callout on the trop led activity.

Per above 87 redux - neat slicer work with GP - the Glosea sneak preview via you tube live stream mirrors protracted impacts, some trop fortuity could lead to something special and lasting.

Just now the killer question appears to be just how much energy remains on the Canadian segment, and subsequent to that given the wave breaking activity in the Atlantic, just how much this pulls the plug out of the sink and helps energy drain from that daughter vortice. The wave guide creates a neat path for dissipation with a filament from the Siberian vortex acting as a magnet dragging the jet on that classic NW-Se trajectory.

Looking at NWP and in close up mode - CMC looks to be progressive with u re-establishing at 60N 10hPa vs the other models and perhaps is a little quick with the 'best in class solutions' given they support a quicker 'flush down' analogy. GEFS and ergo GFS in a very different tropical position too vs rest of suite for what lies ahead, perhaps demonstrating the predication to push eastward - plus bias, although FV3 seems to have plenty of attention in correcting this classic deficit. Looking at the MJO plots in the order of CMC > EC > JMA and then comparing to GEFS / GEFSBC shows the difference in the exit from the -1SD COD. 

Given all that commentary, it's really difficult to roadmap right now i think in all honesty, the only certainty I see is the elongated 'dripping paint' as evidence in Polar Cap anoms etc. When this comes to trop fruition precisely v difficult to plot other than a mean starter pistol c 20-22 Jan. It's a case of watch and enjoy I think !

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Posted
  • Location: Longden, Shropshire
  • Location: Longden, Shropshire
5 hours ago, Glacier Point said:

Based on where we're at...

748884558_zonalpropagation.thumb.png.465fc72b8175ea846fad751bf92c4c1f.png

Impacts look to be sustained and long duration - February into March

Hi GP.  Do you have any thoughts regarding the descending westerly QBO having any potential impacts on February and March?

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Posted
  • Location: East Ham, London
  • Location: East Ham, London

That's very interesting from Todd Crawford. The 10HPA charts show the strat regaining size and some strength but still well above normal temperatures with -72c on offer rather than the -88c or lower you would expect in mid January which is the peak of mid winter.

Signs at the very end of GFS of a new warming starting and I wonder what the impact of a renewed phase of Wave 1 warming at the very end of January/beginning of February would be. Possibly not what we want overall if it knocks the PV back over Canada but could it lead to another split in say mid February which might lead to an interesting start to spring.

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4 hours ago, Glacier Point said:

I posted similarity with 1986 event to illustrate likely timescales but this one occurring a month earlier, so not a total match up. 1984/5 also running close to a top analogue..

The closest 30-day analogues of 10mb 60°N zonal wind to 11/01/19 (MERRA2 data) are 20/02/01, 15/01/04 and 20/01/13 -

425655476_2019u1060.thumb.png.7e856072ac8a1b3ad899c2370f576b1f.png

This chart includes the GEOS forecast period to 19/01/19 during which 2004 deviates somewhat, but 2001 and 2013 remain closest analogues.

From these dates, the AO chart to 11/01/19 shows closest similarity to 2013 but this then undergoes a couple of weeks in +ve territory for the forecast period while 2001 and 2004 have some fairly negative AO -

933476305_2019ao.thumb.png.e56367a8a4267a0cb90902b472525507.png

Similar to the AO, the lower strat 150mb wind is closest to 2013 whereas 2001 and 2004 weakened from stronger values but notable in the near term forecast period is that these analogues all display more marked weakening than 2019. At this pressure level it is not always clear if the effects are working downwards or up, but if downwelling is suspected, it is quite poor at the moment and in the short term.

56290408_2019u150.thumb.png.8dbb273a5e5204c0e877839c03d6683b.png

 

Edited by Interitus
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Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

I am not sure if this has been posted before, by Peter Gibb, and a very good and simple explanation of SSW. It also makes it clear that it only affects surface weather 2 out of 3 times it occurs. A point to be remembered perhaps in the frenzied model thread.

https://twitter.com/fergieweather?ref_src=twsrc^google|twcamp^serp|twgr^author

 

scroll down to post from Ian F January 1 st for the link to the explanation from Peter Gibb, qualified Met Ofice forecaster.

Edited by johnholmes
wrong letter!
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Posted
  • Location: Carmarthenshire
  • Location: Carmarthenshire
11 hours ago, johnholmes said:

I am not sure if this has been posted before, by Peter Gibb, and a very good and simple explanation of SST. It also makes it clear that it only affects surface weather 2 out of 3 times it occurs. A point to be remembered perhaps in the frenzied model thread.

https://twitter.com/fergieweather?ref_src=twsrc^google|twcamp^serp|twgr^author

 

scroll down to post from Ian F January 1 st for the link to the explanation from Peter Gibb, qualified Met Ofice forecaster.

Minor typo there John, I believe that should be SSW.

Thanks for the links.

Edited by Buzz
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Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks
1 hour ago, Buzz said:

Minor typo there John, I believe that should be SSW.

Thanks for the links.

thanks for spotting that-cheers

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Posted
  • Location: North West of Ireland
  • Location: North West of Ireland

For blocking towards the end of the month and into February we need to be seeing signs of reversals first at 100 hPa, then at 200, 300 and finally 500 hPa levels, but they are absent.

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Posted
  • Location: Methil, Fife
  • Weather Preferences: Baltic
  • Location: Methil, Fife
19 minutes ago, Bricriu said:

For blocking towards the end of the month and into February we need to be seeing signs of reversals first at 100 hPa, then at 200, 300 and finally 500 hPa levels, but they are absent.

Slowely getting there at 100hpa, its been a drag this one

Screenshot_20190112-233011.thumb.jpg.5198e0b810a6311e13f4da7d357e57cb.jpg

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Posted
  • Location: Lincolnshire - 15m asl
  • Weather Preferences: Frost and snow. A quiet autumn day is also good.
  • Location: Lincolnshire - 15m asl
14 hours ago, Bricriu said:

For blocking towards the end of the month and into February we need to be seeing signs of reversals first at 100 hPa, then at 200, 300 and finally 500 hPa levels, but they are absent.

Not really. Those figures are averaged and don't take into account local variation. It is important to get that average down - but it doesn't need to reverse all the way down to provide conditions for height rises. We have a retreat of the Euro shard back east...and this does enough to allow height rises in the north atlantic alongside pressure from the pacific pattern and general weakening of average circulation.

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