Morning all,

Well the past few days have seen increasing discussion on stratospheric temperatures, and the potential for a SSW event.

I guess the big question is the extent to which these variables have an effect on blocking, and consequently our winter weather patterns.

Is the link overstated?

If anyone has any interesting thoughts/analysis on the current stratospheric profile then please post them here.

Could be looking at a cold spell come mid January due to the current activity?

Discussion here please.

Edited by user 27 December 2011 12:00:13(UTC)  | Reason: Not specified

Here is the current Strat Temps, we can see that it is cold at present, if we do get any warmings or a SSW event you'll see it here. (not a forecast but a tool for analysis)

http://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/gif_files/time_pres_TEMP_MEAN_OND_NH_2011.gif

Also if we look back at the yearly chart there were a few warmings at the 1hpa level back in Jan and Feb that did not propagate down through to 30hpa, and in turn did not have much of an effect on our weather. So a warming that propagates down through the atmosphere is what we need to see.

http://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/gif_files/time_pres_TEMP_MEAN_ALL_NH_2011.gif

GFS forecast this morning showing a warming at 30hpa at 240h, over Alaska , potentially encouraging high pressure to build there, in turn helping to trigger another warming (I think). As well as squeezing the PV east a bit. 

http://www.cpc.ncep.noaa.gov/products/stratosphere/strat_a_f/gif_files/gfs_t30_nh_f240.gif

Edited by user 23 December 2011 10:19:01(UTC)  | Reason: Not specified

Originally Posted by: Maunder Minimum

Originally Posted by: Chris

GFS forecast this morning showing a warming at 30hpa at 240h, over Alaska , potentially encouraging high pressure to build there, in turn helping to trigger another warming (I think). As well as squeezing the PV east a bit. 

http://www.cpc.ncep.noaa.gov/products/stratosphere/strat_a_f/gif_files/gfs_t30_nh_f240.gif

As I put above, previous history appears to show one uptick following another during an SSW.

To be positive about current forecasts - they have come earlier this season than in previous seasons when we have been hoping for cold.

A couple of years back, we got a major SSW event in mid-Jan, following a remorselessly zonal winter period, which was followed by cold weather in the UK starting the second week in Feb. If we get a similar process this time, we can look forward to a pattern change by about the end of the first week of January.

This warming was a major one, as you say, and you can see it here

http://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/gif_files/time_pres_TEMP_MEAN_ALL_NH_2009.gif

But it had a rapid effect on our weather and by the 1st of Feb blocking was already in place,

http://www.wetterzentrale.de/pics/archive/ra/2009/Rrea00120090201.gif

Is the link proven? Not sure, but I do remember the Met Office talking about the SSW and relating it to the cold that followed.

EDIT, although there was another warming in 2010 that did take longer to trigger some blocking, second week in Feb

http://www.wetterzentrale.de/pics/archive/ra/2010/Rrea00120100209.gif

Edited by user 23 December 2011 10:37:01(UTC)  | Reason: Not specified

This link gives the temperature anomoly for the Northern Hemisphere...

http://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/gif_files/time_pres_TEMP_ANOM_ALL_NH_2011.gif

I like this format is it shows the propogation through the atmospere (should it happen)..

More out of curiosity than my faith in 384 charts.

http://images.meteociel.fr/im/228/gfsnh-10-384_uhx7.png

Originally Posted by: Steam Fog

More out of curiosity than my faith in 384 charts.

http://images.meteociel.fr/im/228/gfsnh-10-384_uhx7.png

Stratosphere charts are generally more reliable at 240 than the surface charts are, or rather there's less variation between runs. Doubtless that applies at 384 too.

What's interesting going by those Meteociel charts is that the warming at 384 is actually the second bout of warming; there's an initial warming which takes place in the next couple of days but that fizzles out. Another round then starts up and it's that which is shown at 384.

Reading the NW thread it seems this SSW wont be striong enough to break apart the PV and it may well be a second wave that evetually does.

Given the lag between these events and any possible blocking you'd be looking late Jan for height rises to the North. And thats even IF this next SSW is strong enough

Merry xmas

Remember also that you dont need a SSW to get Northern Blocking although it can help.

Note the 2009 Chart and there was no warming in November/December 2009 prior to the UK going into the freezer.

SSW's seem to trigger a Scandy High where as a Greenland High seems independant of these events (at least thats my take on it but could be totally wrong)

Either way we need something dramatic to break us out of this 1,000metre deep weather rut

Andy

Originally Posted by: nsrobins

Originally Posted by: Retron

Originally Posted by: Steam Fog

More out of curiosity than my faith in 384 charts.

http://images.meteociel.fr/im/228/gfsnh-10-384_uhx7.png

Stratosphere charts are generally more reliable at 240 than the surface charts are, or rather there's less variation between runs. Doubtless that applies at 384 too.

What's interesting going by those Meteociel charts is that the warming at 384 is actually the second bout of warming; there's an initial warming which takes place in the next couple of days but that fizzles out. Another round then starts up and it's that which is shown at 384.

Now that chart has certainly interested me. The dip being modeled on the berlin charts is before this period as you say. If that proves correct, that's a 10HPa of above 0deg which definitely falls in the significant category. Not to sure if the Alaskan/Barents Arctic is the best place vis a vis blocking that will benefit us here thoough.

It is as I was putting earlier - SSWs are seldom single events but for some reason the first appears to trigger a second, often stronger event.

As for whether it is the best place for us or not - any height rises in Artic cause buckling of the jet and can lead to better weather prospects here. Let's get the SSWs nailed on first and then see what transpires from them.