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chionomaniac

Stratosphere Temperature Watch 2015/2016

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We are very close to a SSW now. The warming is impressive. 

56ac6649cae33_SSWbijna.thumb.PNG.978c72a56ac6656c95d8_SSWbijna2.thumb.PNG.a5f822

Is there anyone who can tell me what kind of wave breaking we are seeing? 

56ac697657203_SSWgolf.thumb.PNG.86736a5d

https://www.jstage.jst.go.jp/article/jmsj/86/5/86_5_613/_pdf

I would say a sheared wave breaking in poleward direction, but  is it cyclonically or anti-cyclonically?

 

 

Edited by Paul123

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Well, the split idea has vanished from GFS and now it can't even manage a decent displacement. Hilarious, in an irritating sort of way.

ECM is capturing the expected tropical forcing (MJO => amplification) better and I wonder how that might affect the wave breaking expected? Does it influence the probability of seeing some wave 2 activity join in during the 2nd week of Feb? TIA for responses.

 

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The warming modelled on the Berlin site this morning is quite remarkable. Will it happen and will its impact be equally remarkable

temps.gif

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50 minutes ago, fergieweather said:

Latest UKMO assessment as follows:

- Current warming episode still expected to be minor

- Mixed model signals re SFC story early-mid Feb, but current preferred outcome is for (at least passing) colder phases from later next week and more especially during 2nd week Feb (longevity uncertain) with pattern amplified behind lows and ridging in Atlantic (as per EC Monthly & GloSea5)

- Stratospheric diagnostics indicate resumption of stronger zonal flow for a time from mid into 2nd half Feb

- A more mobile/unsettled outcome then returning for UK (EC Monthly also suggests W'ly return later Feb)

- GloSea5 continues - as before - to signal any more definite/major stratospheric warming is most likely late Feb-early March

The above postings suggests the affects from current strat warming most likely to downwell later in Feb rather than earlier - the mention of westerlies returning later in Feb - we've been locked in a more mobile/unsettled outcome since late October - so it won't be anything of a change, not sure the reasons why this is being suggested. This must be turning into the most sustained unsettled period of weather for well I don't know how long, I thought Dec 13-Feb 14 wouldn't be bettered for a long while, well we are beating it now, how many dry days have there been in the northern half of the country since late October, barely any.. dry weather here now classed as a day of showers or just a shortlived light spell of precipitation.

In the shorter term, some potent PM air shots look likely first half of Feb hitting as you would expect the NW most significantly.. plenty of snow for Scottish Ski resorts in time for Feb half term holidays, so they will be happy.

 

 

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7 minutes ago, damianslaw said:

The above postings suggests the affects from current strat warming most likely to downwell later in Feb rather than earlier - the mention of westerlies returning later in Feb - etc

NB Note further edits to my post

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1 hour ago, fergieweather said:

Latest UKMO assessment as follows:

- Current warming episode still expected to be minor

- Mixed model signals re SFC story early-mid Feb, but current preferred outcome is for (at least passing) colder phases from later next week and more especially during 2nd week Feb (longevity uncertain) with pattern amplified behind lows and ridging in Atlantic (as per EC Monthly & GloSea5)

- Phases of colder Am episodes expected. Given potential passage of low-latitude systems towards S'rn UK in 00z EPS, snow risk may not be confined just to N'rn UK

- Stratospheric diagnostics indicate resumption of stronger zonal flow *for a time* from mid into 2nd half Feb

- A more mobile/unsettled outcome *may* then return for UK (EC Monthly also suggests W'ly return later Feb)

- However, 00z data is also suggestive of generally colder, more anticyclonic conditions later Feb: JURY OUT

- GloSea5 continues - as before - to signal any more definite/major stratospheric warming is most likely late Feb-early March

I think you highlight the difficulty here in translating how a possible vortex displacement event high up in the stratosphere may affect the troposphere at a later point. Especially if the displacement nudges the vortex off the pole leaving a temporary technical SSW, but the vortex recovers positionally wise - without ever losing enough intensity for long enough to have long lasting and propagating effects tropospherically. And that to me is the big question mark regarding the upcoming warming event. This can be demonstrated using the GFS as it shows what could potentially happen after day 10.

So day 10 we see a strong warming with considerable displacement placed on the vortex and the vortex is in some distress

viewimage-1.thumb.png.cfd3b011f4ffd799ea

However, the warming is not strong enough, and without the back up of a Karate chop wave 2 we see the vortex recover, not totally unscathed, but strong enough probably to still have an impact on the tropospheric vortex especially in the Atlantic sector.

viewimage-3.thumb.png.281f536cb056b7fdb1

Those situated under the stratospheric Aleutian high are probably more likely to see tropospheric blocking with the favoured areas always towards the Pacific sector - the best we can hope for is probably a west based -Ve NAO but probably a pattern more like this as MV highlights from the ECM week 4 ensembles

 

The East coast of the US wins again.....

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A bit of jumping the gun in here. To be fair Ian, and the Met at the moment don't have a straightforward outcome right now as to how the rest of winter and early spring could play out. It seems to me from Ian's latest update and the models regarding the Strat that there is just as much uncertainty over the possibility of a full split/displacement and colder, drier blocked conditions continuing into February and March as there is of a temporary displacement of the vortex with a short cold period and westerlies/Atlantic dominated weather returning (which is pretty much what happened recently this month) Not one outcome is more likely or certain at the moment, but I suppose we have to hope the dice rolls in our favour to finally get the sustained, drier and perhaps colder weather from a SSW to finally end this prolonged period of generally unsettled weather. But that update just confirms to me that nothing is set in stone at the moment.

Edited by wishingforsnow

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Just looked at the 12z ECM strat at 10hpa and tomorrow mornings Berlin data could well show a tech SSW forecast at day 10. 

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1 hour ago, bluearmy said:

Just looked at the 12z ECM strat at 10hpa and tomorrow mornings Berlin data could well show a tech SSW forecast at day 10. 

We need all the good news we can get :)

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1 hour ago, bluearmy said:

Just looked at the 12z ECM strat at 10hpa and tomorrow mornings Berlin data could well show a tech SSW forecast at day 10. 

It'll be close. I'm going for +3.5m/s!

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7 minutes ago, Minus 10 said:

We need all the good news we can get :)

I think it's purely academic at this stage. Without a split to follow the displacement, I'm not overly encouraged at what would follow any SSW.  And the difference between -3.5 m/s and +3.5 m/s is purely for the record books and wouldn't make any difference to what transpires as a result. 

I would say that glosea-5 seems to have doe a pretty good job thus far this season.

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Shouldn't the core temperature in the stratosphere naturally warm through February anyway and more so into March - thus weakening the Polar Vortex.. March typically sees a much weaker PV, so if we do unfortunately end up with power of the PV winning out.. it shouldn't be a return to what we have endured between Nov -Jan.

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22 minutes ago, damianslaw said:

Shouldn't the core temperature in the stratosphere naturally warm through February anyway and more so into March - thus weakening the Polar Vortex.. March typically sees a much weaker PV, so if we do unfortunately end up with power of the PV winning out.. it shouldn't be a return to what we have endured between Nov -Jan.

Sadly, you are correct, and that's exactly the form horse for the run up to spring!

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I got a niggling feeling that we may be seeing the final throws of a final warming prior to the destruction of the pv until spring / summer only a gut feel

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20 hours ago, chionomaniac said:

 

The East coast of the US wins again.....

Seems to be a difference of opinion here because Joe Bastardi has the cold further west. 

He has a major cold outbreak between the Rockies and the Appalachians between 5th and 20th Feb on one of his tweets.

 

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The final warming is the last stratospheric warming of the season. After this warming, the stratosphere never recovers to its previous state and the vortex breaks up and dissipates. The final warming often occurs in March or April. Sometimes the stratosphere never recovers from what would otherwise be a mid-winter major warming in January or February, and that warming becomes the final warming. Unfortunately  I don't have a crystal ball that can see the model runs for the stratosphere past the end of the gfs, thus the gut feeling.

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3 hours ago, Interitus said:

+16.1 m/s

Poor estimate of the strength of the flow by me!

the zonal winds on that ECM run are strange indeed. Pretty quiet a early on and then ramping up somewhat days 6/7 before falling back quiet again by day 10. Presumably this is due to the vortex attempting to stay close to the pole as it feels the pressure from the higher heights pushing it off.  Will it recover and bring the zonal flow back up again or is it beaten into being displaced this side of the NH? 

 

Edited by bluearmy

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44 minutes ago, Weather-history said:

Seems to be a difference of opinion here because Joe Bastardi has the cold further west. 

He has a major cold outbreak between the Rockies and the Appalachians between 5th and 20th Feb on one of his tweets.

 

I think the tweet I posted is for the week after that.

 

And @Interitus and @bluearmy that 10hPa is a lot larger value than I thought. 

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30 minutes ago, chionomaniac said:

I think the tweet I posted is for the week after that.

 

And @Interitus and @bluearmy that 10hPa is a lot larger value than I thought. 

fluxes.thumb.gif.801acb564141a39f23f6150

It would appear as if this is the rise before the fall. 1 hpa winds have gone negative at the end of the forcast.

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