Stratosphere and Polar Vortex Watch

[Mike Poole]

55 minutes ago, Met4Cast said:

Worth noting the -VE bias on the GEFS though, this isn’t the first time they’ve shown this only to revert to less extreme of a deceleration as the time approaches. 

GFS/ECM are a much better guide & have been far more accurate so far this season.

 
Wouldn’t get excited until we see some notable weakening showing from the GFS. 

The way the trop modelling is going, I'm almost inclined to think that what we want for a cold outlook for the UK from the strat at the moments just a slowing of the zonal winds, nothing disruptive so the output suits me fine at the moment. As winter progresses and things change (sooner or later) we may be looking for more...

[Met4Cast]

2 hours ago, Mike Poole said:

The way the trop modelling is going, I'm almost inclined to think that what we want for a cold outlook for the UK from the strat at the moments just a slowing of the zonal winds, nothing disruptive so the output suits me fine at the moment. As winter progresses and things change (sooner or later) we may be looking for more...

I agree - The displacement to the Asian/Siberian side is a good thing for us, especially as there are signs the trop vortex will be following suit, this should encourage height rises to our NE mid December onwards

[Mike Poole]

Almost forgot to post this!  I was musing yesterday in the MOD about whether the pressure on the strat vortex at 10mb was from the top or bottom, here the Berlin charts from yesterday's ECM 12z, at T240, levels 1, 3, 10, 50, 150 mb:

Seems the pressure on the strat vortex is coming from below, bottom two charts have reversed temperature profiles over the pole, my view from a winter coldie perspective that we want this to continue not be potentially blown away by a SSW at this early point -1 day into winter...opinions welcome.  I am still very much on a learning curve re the strat - it is fascinating, but I know there are real experts out there....

[ArHu3]

37 minutes ago, Mike Poole said:

Almost forgot to post this!  I was musing yesterday in the MOD about whether the pressure on the strat vortex at 10mb was from the top or bottom, here the Berlin charts from yesterday's ECM 12z, at T240, levels 1, 3, 10, 50, 150 mb:

Seems the pressure on the strat vortex is coming from below, bottom two charts have reversed temperature profiles over the pole, my view from a winter coldie perspective that we want this to continue not be potentially blown away by a SSW at this early point -1 day into winter...opinions welcome.  I am still very much on a learning curve re the strat - it is fascinating, but I know there are real experts out there....

Check out the animations on https://stratobserve.com/misc_vort3d to easily understands what happens (too bad we can't see the animations from last year's split) 

[Mike Poole]

17 minutes ago, ArHu3 said:

Check out the animations on https://stratobserve.com/misc_vort3d to easily understands what happens (too bad we can't see the animations from last year's split) 

Thanks, that's  the animation that famously recently produced a pair of pants, I think!  (I have a particular fascination in weather models that look just like something else, people on here will probably be fed up with it!) Stratobseve is great, but it is only GFS ensembles and friends. Yes, to unravel last years fiasco would be a welcome learning curve indeed!  

Edited November 30, 2019 by Mike Poole

[ArHu3]

8 hours ago, Mike Poole said:

Thanks, that's  the animation that famously recently produced a pair of pants, I think!  (I have a particular fascination in weather models that look just like something else, people on here will probably be fed up with it!) Stratobseve is great, but it is only GFS ensembles and friends. Yes, to unravel last years fiasco would be a welcome learning curve indeed!  

Last year the split began as a tear from bottom to top but a 3rd mini vortex was created too exactly located over Greenland which stopped the downwelling for us again. It was quite obvious from the animation downwelling would fail unless that mini daughter vortex would fade away. 

[Duane S.]

Best yet?

I think there has to remain a suspicion that the recent record breaking wave1 event may be confusing the forecast.

Either way, after the forthcoming uptick to zonal winds, a drop back down again looks fairly assured. It’s to what degree that is far from established.

[feb1991blizzard]

1 hour ago, s4lancia said:

Best yet?

I think there has to remain a suspicion that the recent record breaking wave1 event may be confusing the forecast.

Either way, after the forthcoming uptick to zonal winds, a drop back down again looks fairly assured. It’s to what degree that is far from established.

Wonder what GLOSEA5 is showing right now.

[northwestsnow]

13 minutes ago, feb1991blizzard said:

Wonder what GLOSEA5 is showing right now.

A raging vortex with little interference at a rough guess.

[Griff]

Can anyone enlighten me? There's a chap on twitter constantly posting PV related tweets (@PvForecast), accompanied by cryptic comments but no real analysis or explanation. It's all a little confusing...

 

[ALL ABOARD]

10 minutes ago, northwestsnow said:

A raging vortex with little interference at a rough guess.

If that was the case doubt they'd have worded the end of the extended forecast like that 

[ALL ABOARD]

7 minutes ago, Griff said:

Can anyone enlighten me? There's a chap on twitter constantly posting PV related tweets (@PvForecast), accompanied by cryptic comments but no real analysis or explanation. It's all a little confusing...

 

Shows easterly winds right from the trop into the strat as dipicted by the blue colours 

[feb1991blizzard]

^

Would be helpful if a colour  legend was shown on the bottom of the graph.

[northwestsnow]

7 minutes ago, ALL ABOARD said:

If that was the case doubt they'd have worded the end of the extended forecast like that 

True enough

im just sceptical of GFS..

[Griff]

13 minutes ago, ALL ABOARD said:

Shows easterly winds right from the trop into the strat as dipicted by the blue colours 

Awesome, thanks

[Interitus]

28 minutes ago, ALL ABOARD said:

Shows easterly winds right from the trop into the strat as dipicted by the blue colours 

It doesn't show easterly winds - as described at the top of the main webpage - https://acd-ext.gsfc.nasa.gov/Data_services/Current/seasonal_strat/seasonal_strat.html

"The plots are all 2-panel. The RHS plot shows the 60-day time-mean profile of the quantity, while the LHS shows the deviations from this 60-day mean."

So the blue colours in the forecast show winds below the previous two month average.

 

[Griff]

6 minutes ago, Interitus said:

It doesn't show easterly winds - as described at the top of the main webpage - https://acd-ext.gsfc.nasa.gov/Data_services/Current/seasonal_strat/seasonal_strat.html

"The plots are all 2-panel. The RHS plot shows the 60-day time-mean profile of the quantity, while the LHS shows the deviations from this 60-day mean."

So the blue colours in the forecast show winds below the previous two month average.

 

I said it was confusing, thanks for the heads up, much appreciated

[Mike Poole]

Today's stratobserve plots are out, based on 0z runs:

The GEFS mean is heading towards a reversal, interesting to see if this continues, but some significant members, P13 for displacement, P14 for split are good examples.

[tight isobar]

3 minutes ago, Mike Poole said:

Today's stratobserve plots are out, based on 0z runs:

The GEFS mean is heading towards a reversal, interesting to see if this continues, but some significant members, P13 for displacement, P14 for split are good examples.

On these alone @00z plots..there is room for optimism..

[Met4Cast]

3 hours ago, Griff said:

Can anyone enlighten me? There's a chap on twitter constantly posting PV related tweets (@PvForecast), accompanied by cryptic comments but no real analysis or explanation. It's all a little confusing...

 

I believe he's from the Netherlands and doesn't speak English all that well, I suspect that's mainly the reason for the lack of explanation. 

[bluearmy]

Recovery in zonal speeds at 10hpa 60N now fairly clear .....(contrary to what gefs were seeing).  Gefs continue to show a drop off thereafter and the spv stays displaced on the op even under an averageish flow at 10hpa/60N.    The ec late on continues to show reversals in the polar field to a reasonable strat height .

[Allseasons-Si]

The jma showing an uptick at 30hpa,just waiting to see if there will be an uptick on the 10hpa over the coming days.

 

[Yarmy]

19 minutes ago, Allseasons-si said:

The jma showing an uptick at 30hpa,just waiting to see if there will be an uptick on the 10hpa over the coming days.

 

 

I don't know about the GEM ens, but anyone still giving any credence to the GEFS is deluding themselves. The only reason they get such prominence is that the data is freely available.

Edited December 2, 2019 by Yarmy
Typo

[Allseasons-Si]

2 minutes ago, Yarmy said:

 

I don't know about the GEM ens, buy anyone still giving any credence to the GEFS is deluding themselves. The only reason they get such prominence is that the data is freely available.

Hey!!!,don't shoot the messenger

[feb1991blizzard]

The difference between the EPS and GEFS remains stark.

Unfortunately though i get the feeling Micheal Ventrice's question is a rhetorical one.