Jump to content

Stratosphere Temperature Watch 2012/2013


Recommended Posts

Apologies if this has been covered already, but I'm keen to know if whats happening in the Stratosphere is taken into account with the model output runs? I was of the understanding that the information received from all the data points provide an accurate current situation and this info is fed into the computer and the programm run to provide a likely outcome over the following days ....Even if the Stratosphere data is inputted then surely the limited historical data must make the model outputs very volatile to say the least?

on the UK Met research area-this of any help?

http://www.metoffice...her-forecasting

or this?

http://www.metoffice.../climate-models

and to repeat there is no historical data fed in just what the actual weather is at the levels given.

Edited by johnholmes
  • Like 3
Link to post
Share on other sites
  • Replies 2.5k
  • Created
  • Last Reply

Top Posters In This Topic

We still on course for the 6th Jan? It was the 4th, any further delays?

Regards

Technical SSW is just a touch off being achieved by 12Z on the 6th, very clearly achieved on the 7th.

Posted Image

Posted Image

Look for 'blue' (negative zonal winds) at 60N and 10hpa. The 4th did look a bit early and it did initially look like being sometime around the 6th-8th so I wouldn't say we've seen much of a delay.

Edited by LomondSnowstorm
  • Like 1
Link to post
Share on other sites

Technical SSW is just a touch off being achieved by 12Z on the 6th, very clearly achieved on the 7th.

Look for 'blue' (negative zonal winds) at 60N and 10hpa. The 4th did look a bit early and it did initially look like being sometime around the 6th-8th so I wouldn't say we've seen much of a delay.

note that GFS strat forecast SSW was always post 6th jan so ecm is again, not for the first time, not verfiying as well as gfs high up with the big calls. chio mentioned this in the past. given we dont have agreement with the split locales of the vortices, maybe we should be following ncep ahead of ecm (as opposed to generally accepted trop thinking) ????

Link to post
Share on other sites

note that GFS strat forecast SSW was always post 6th jan so ecm is again, not for the first time, not verfiying as well as gfs high up with the big calls. chio mentioned this in the past. given we dont have agreement with the split locales of the vortices, maybe we should be following ncep ahead of ecm (as opposed to generally accepted trop thinking) ????

I'm a tad confused by that, BA: If said SSW has always been forecast to occur 'post 6th Jan' how can any of the models have verified?

Link to post
Share on other sites

I'm a tad confused by that, BA: If said SSW has always been forecast to occur 'post 6th Jan' how can any of the models have verified?

well GFS has always forecast the SSW to occur post 6th jan. 7th/8th consistently over the past few days. once ecm came within range, it began by forecasting it 4th jan, then 5th jan and now 6th/7th jan. therefore, i consider gfs to be more consistent on the timing.

i'm waiting for reading to answer my query on the height of the ecm ens model top. if it is 5hpa, then i'll be asking the obvious question re model reliability in top down SSW scenarios. i guess it maybe that they dont consider a trop response to activity above 5hpa within 2 weeks to be feasible ????

Edited by bluearmy
  • Like 1
Link to post
Share on other sites

Not a bad chart;

post-12721-0-88612600-1357127481_thumb.j

Just need these sort of positions to filter down into the 500mb heights.

Edited by AWD
Link to post
Share on other sites

Few obervartions - still no agreement post day 8 with the split vortice locations ecm/gfs. No sign of a second warming near ne canada/greenland on ecm. Crazy place for our part of the split vortex to end up at 1hpa on ecm day 10 (biscay)

Fnally, the uptick in zonal flow right through the strat above 60N in the next few days is noticeable and the sudden drop off to negative that follows may well be posing the trop modelling some issues. I do recall stewart mentionng something in nov about a surge of zonal flow just before a SSW.

As I posted yesterday in this instance I believe the zonal flow and change in extended range outlook that happened at the end of the first third of December was down to the Strat warming that initiated from the tropical pacific working its way north and eastward around the globe then exploded over Asia due to the Cohen effect.

You can see this in the animation.

post-10506-0-72763700-1357131610_thumb.g

Edited by cooling climate
Link to post
Share on other sites

Forgive me for being a little dim but what does this chart show and why are 'getting there'? Many thanks GSL

Hi GSL

If you take a look at the two charts myself and AWD posted:

The first one from AWD shows the expected geopotential heights (essentially consider this as identifying where the pieces of the polar vortex - low pressure - lies, and where any corresponding ridges - high pressure - lie) up at a height of 10mb - considered part of the middle, bordering upper, stratosphere. What we see there is the two main pieces of the split polar vortex lying over Siberia/East Scandinavia, and another across Canada. This then leaves a ridge in between, across the pole and down towards Iceland/Greenland.

What we want to see is this pressure pattern move down (downwell) to the surface. The chart I show is the above, but at a height of 100mb, the bottom of the stratosphere, and this shows that pattern emerging there too.

This tells us that the pattern from up in the stratosphere is beginning to move down towards the surface.

Obviously if it did, it would likely leave height rises to our north, with the potential for LP just to our east - which essentially opens up the chance of a more northerly flow, and therefore anomalous cold to flood out of the polar regions and into the mid-latitudes around our locale.

Its also worth bearing in mind that at present this is a forecast, and it will take some days to see whether we can get this pattern from 100mb down to 500mb

SK

Edited by snowking
  • Like 7
Link to post
Share on other sites

Tropospheric response by mid jan looks to be an extensive polar high with the hotspots being North Pole and Iceland - and the polar vortex energy split between eastern Scandinavia and Hudson Bay - the EC forecasts seem to extend the stratospheric ridge into Baffin which will cause fluctuations in their 500mb modelling. Northerly extending into north easterly ?

  • Like 4
Link to post
Share on other sites

Just a quick question, does anyone have any data for all the SSW that failed to bring cold to the UK and also when we have had cold spells without any SSW.. I've tried researching this but I'm struggling to find anything conclusive.

Link to post
Share on other sites

Just a quick question, does anyone have any data for all the SSW that failed to bring cold to the UK and also when we have had cold spells without any SSW.. I've tried researching this but I'm struggling to find anything conclusive.

Thats a huge ask SE. look at page 1 of the thread for links to historical strat data. looking at patterns post warmings is workable but to do the cold spells with no SSW, you will need a fantastic memory or to trawl through the archive ncep charts on meteociel

Link to post
Share on other sites

Thats a huge ask SE. look at page 1 of the thread for links to historical strat data. looking at patterns post warmings is workable but to do the cold spells with no SSW, you will need a fantastic memory or to trawl through the archive ncep charts on meteociel

Thanks BA, I think. When I get the time I'll try and trawl through the archives and see what I come up with, the only cold spell I can remember without a SSW is February 1991.
Link to post
Share on other sites

GFS showing a 3rd warming over Canada in deep FI, at this rate the North Pole will be staying relatively warm for 3-4 weeks. Also showing the colder air going to the North Pacific, if the vortex can end up there and we get a deep low in that area we could set off another round of wave 1 activity.

Just a concern about tropospheric impact of the SSW, the GFS continues to show low pressures running the show in that gap between scandinavia in Greenland, despite the split in the vortex down welling very smoothly from 10mb to 100mb. Kind of frustrating seeing very little on offer in terms of cold in FI GFS. Surely that's the last place we would expect to see low pressures in a couple of weeks time?

Edited by Snowy Liverpool
Link to post
Share on other sites

Thanks BA, I think. When I get the time I'll try and trawl through the archives and see what I come up with, the only cold spell I can remember without a SSW is February 1991.

The famous Dec of 2010 with its CET of -0.7C didn't have SSW.

Link to post
Share on other sites

The famous Dec of 2010 with its CET of -0.7C didn't have SSW.

well it wouldnt as the cold started last week of november and you'd struggle to get a SSW in november !! there are bound to have been cold spells with no SSW cause. not really for this thread though.

  • Like 1
Link to post
Share on other sites

Am awaiting Hadley Centre's wisdom on how the SSW evolution and subsequent translation to us (or not) fares in their own modelling. Interesting times.

awaited with great expectation ian. have you any idea what level in the strat mogreps-15 goes up to ?

  • Like 1
Link to post
Share on other sites

awaited with great expectation ian. have you any idea what level in the strat mogreps-15 goes up to ?

from UK Met site

MOGREPS Global ensemble 60 km 432 x 325 70

(lid ~80 km) 72 hrs 00, 12

Global analysis + 24 member ETKF perturbations

MOGREPS medium-range ensemble 60 km 432 x 325 70

(lid ~80 km) 15 days 00, 12

Global analysis + 24 member ETKF perturbations

Link to post
Share on other sites

from UK Met site

MOGREPS Global ensemble 60 km 432 x 325 70

(lid ~80 km) 72 hrs 00, 12

Global analysis + 24 member ETKF perturbations

MOGREPS medium-range ensemble 60 km 432 x 325 70

(lid ~80 km) 15 days 00, 12

Global analysis + 24 member ETKF perturbations

thats to the top of the mesosphere !! MOGREPS isnt going to miss anything in the strat then !

Link to post
Share on other sites

thats to the top of the mesosphere !! MOGREPS isnt going to miss anything in the strat then !

best you ask Ian if he can ask them about any warmings and how they assess the prob of any effect down here?

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...