Stratosphere and Polar Vortex Watch

[knocker]

The ecm this morning has the vortex at 10mb and down to 50mb realigned and under pressure from the double whammy over the ten days

Which is not out of kilter with the tpv popping back to it's old stamping ground, regression of the Atlantic trough accompanied by some amplification of the European subtropical high

 

 

Edited January 25, 2020 by knocker

[Nick F]

Gaining momentum by the day on GEFS. May not see effects until end of Feb to early March if a SSW were to transpire.

 

[knocker]

PSC's ?

[summer blizzard]

That might be the first forecast of an SSW by the ensemble mean.

[bluearmy]

Reversal down to about 7 hpa on the latest gfs op by day 14...... 

 

[mushymanrob]

2 hours ago, knocker said:

The ecm this morning has the vortex at 10mb and down to 50mb realigned and under pressure from the double whammy over the ten days

 

Which is not out of kilter with the tpv popping back to it's old stamping ground, regression of the Atlantic trough accompanied by some amplification of the European subtropical high

 

 

Thats completely in line with the NOAA 500mb 8-14 day chart.  (not got time to post it).

 

[knocker]

29 minutes ago, mushymanrob said:

Thats completely in line with the NOAA 500mb 8-14 day chart.  (not got time to post it).

 

[Mike Poole]

6z GFS follows the 0z with the split, gathering momentum now, here T348, T384:

If the split occurs it will be important how big the two daughter vortexes are and where they go, 6z is a rather uneven split with one piece much bigger than the other.

[damianslaw]

55 minutes ago, mushymanrob said:

Thats completely in line with the NOAA 500mb 8-14 day chart.  (not got time to post it).

 

Read somewhere that this kind of synoptic is often a precursor to when a SSW occurs, high pressure building through the UK sometimes brings a milder surge then bang.. this happened in Feb 2018 from memory..

[Mike Poole]

22 minutes ago, damianslaw said:

Read somewhere that this kind of synoptic is often a precursor to when a SSW occurs, high pressure building through the UK sometimes brings a milder surge then bang.. this happened in Feb 2018 from memory..

Yes, and certainly, the 8-14 day range is well before any effects of the potential SSW, even split SSW, would make themselves felt on the weather patterns down here.  But with a split SSW, a quick tropospheric response could be on the cards, putting the last half of Feb the timeframe of interest for coldies, if something is to develop as a result of things in the strat, I guess.

Edited January 25, 2020 by Mike Poole

[SMU]

Lets hope for a QTR to save Winter !!

[Don]

7 minutes ago, Steve Murr said:

Lets hope for a QTR to save Winter !!

Our last chance?!

[sundog]

Last chance saloon time.

[Interitus]

1 hour ago, Mike Poole said:

6z GFS follows the 0z with the split, gathering momentum now, here T348, T384:

If the split occurs it will be important how big the two daughter vortexes are and where they go, 6z is a rather uneven split with one piece much bigger than the other.

Trying to split on 00z -

Not split on 06z -

Maybe tries to nip the end off, despite perhaps a better split at the higher levels, the 30 mb temperature gradient is not conducive to a 10 mb reversal on the 06z but reversal likely on the 00z. Perhaps most significantly, whilst 1mb reversals are still at the end of the forecast periods, the last three runs start to bring reductions in 1mb zonal wind closer to the reliable at 9 days rather than stuck beyond 10 days +

edit: Note the strongest 1mb reversal forecast was still that from the 18th 00z (not shown)

Edited January 25, 2020 by Interitus

[sundog]

If nothing else at least it will provide some interest/ the possibility of something happening.  There has been zero chance of any cold spell so far this winter. At least something to keep an eye on.

[Singularity]

For a QTR response, we need to see the dual-warming (wave-2) peak at good strength. Probably won’t cut it if the first bout eases more than a little by the time the 2nd becomes strong.

06z GFS is almost there. Paying this potential event more attention than the Dec one as GFS with the FV3 core is making much more of it this time around - and we saw how the improved strat resolution helped it relative to GEFS in Dec.

Then there’s the EPS support which is now non-negligible, but still low for the ‘proper split’ we need (don’t want a displacement with secondary splits like last year). 

[Kirkcaldy Weather]

Some charts from stratobserve showing quite a few splits and reversals   < check out CMC / GEM ensemble member 4!   certainly looks like an interesting time coming up. 

Edited January 25, 2020 by Kirkcaldy Weather

[Mike Poole]

17 minutes ago, Kirkcaldy Weather said:

Some charts from stratobserve showing quite a few splits and reversals   < check out CMC / GEM ensemble member 4!   certainly looks like an interesting time coming up. 

Yes interesting indeed @Kirkcaldy Weather and this is definitely different to the interest in a SSW in December.  Then the op didn't want to know, and there was discussion about the FV3 GFS vs the ensembles, and it didn't look right, and didn't happen!  This looks right, the way it is showing up on the models, but what form will it take? I think the split is gathering momentum, we will see...

Edited January 25, 2020 by Mike Poole

[Mike Poole]

Trying to get there on the 12z, T 384:

Not exactly the same as the 0z or 6.  All within the envelope of what exactly?  Well I think it has all the hallmarks of a SSW that isn't too far away being picked up slowly by all models...so that's all good.

Edited January 25, 2020 by Mike Poole

[Interitus]

4 hours ago, Mike Poole said:

Trying to get there on the 12z, T 384:

Not exactly the same as the 0z or 6.  All within the envelope of what exactly?  Well I think it has all the hallmarks of a SSW that isn't too far away being picked up slowly by all models...so that's all good.

 Actually the 12z backed away from an SSW, 1mb minimum wind of 11.7 ms at T261 recovering to 29.8 ms at the end.  10mb ends on 16.5 ms which is higher than the previous 3 runs.

[Dennis]

10Hpa zonal winds forecast/reversal at 2Hpa

 

Edited January 25, 2020 by Dennis

[Interitus]

18 minutes ago, Dennis said:

These are interesting charts, but look at the verification scores on the right hand side.

[Don]

30 minutes ago, Interitus said:

 Actually the 12z backed away from an SSW, 1mb minimum wind of 11.7 ms at T261 recovering to 29.8 ms at the end.  10mb ends on 16.5 ms which is higher than the previous 3 runs.

Come on, don't let us down GFS....... 

[feb1991blizzard]

6 minutes ago, Don said:

Come on, don't let us down GFS....... 

Little change stratospherically from 12z to 18z up to 276.

[Don]

1 minute ago, feb1991blizzard said:

Little change stratospherically from 12z to 18z up to 276.

Not great news, then?  However, plenty more twists and turns to come yet?