Stratosphere Temperature Watch

[weatherjunkie]

Initial warming is occuring over Siberia as the vortex stretches to almost breaking point, but how long will it remain there is a key question?

If we look at stratospheric ozone concentrations, we can see that the core build up is towards the Canadian Arctic and western Greenland, as it has been all winter largely:

http://www.cpc.ncep....7_nh_latest.gif

upper tropospheric and stratospheric temperatures largely tie in with ozone concs., so perhaps we should see the warmth now being generated tranfer readily across Greenland towards Canada. Interestingly, blocking in this locale has the support of tropical forcing centred east of the Dateline.

Strong west based -NAO?

Looks like the eastern US will be fair game starting around the third and lasting for quite a while.

GL to you guys in Europe. I hope the second half of winter provides snow for all.

[chionomaniac]

No change in the ECM output this morning.

Extreme easterly momentum suggested in 9 days time. Great propagation of negative mean zonal winds.

[chionomaniac]

Third round of warming showing up now.

The timeframe of these repeated warmings could possibly lead to a prolonged spell of blocking right through to March.

The GFS 100 hPa chart forecasts show very little change still suggesting reducing Scandi trough whilst forming Atlantic trough drifts west towards Canada.

[weatherjunkie]

Third round of warming showing up now.

The timeframe of these repeated warmings could possibly lead to a prolonged spell of blocking right through to March.

The GFS 100 hPa chart forecasts show very little change still suggesting reducing Scandi trough whilst forming Atlantic trough drifts west towards Canada.

Wouldn't that signal a +NAO in the future? Or is this still one of those elephant trunk tornado scenarios?

[Weather-history]

Here is a snippet from today's Weather Eye from the Times newspaper. What do the pundits make of it because at face value it looks a load of bumpkin to me.

"The story begins with El Nino the big warming of tropical seas happening in the Pacific. So much hot air is rising up fromt eh ocean that it has punctured the stratosphere and caused turmoil, as fast winds that sweep westwards around the arctic suddenly reverse and flow eastwards"

Edited February 1, 2010 by Mr_Data

[Guest North Sea Snow Convection]

Technically no MMW it seems as the 10mb and 30mb contours barely scrape the bottom

However, within the context of the cold winter pattern, this doesn't seem to be too crucial, and providing the vortex disrupts favourably in terms of situ, as seems to be now suggested, then an easterly should still be on.

Edited February 1, 2010 by North Sea Snow Convection

[chionomaniac]

Here is a snippet from today's Weather Eye from the Times newspaper. What do the pundits make of it because at face value it looks a load of bumpkin to me.

"The story begins with El Nino the big warming of tropical seas happening in the Pacific. So much hot air is rising up fromt eh ocean that it has punctured the stratosphere and caused turmoil, as fast winds that sweep westwards around the arctic suddenly reverse and flow eastwards"

I don't necessarily think it is bumpkin Mr, D and I have seen links between the Nino state and stratosphere previously. There would have to be a mechanism to transfer the warm energy from El Nino into the stratosphere and then a deflection polewards. And perhaps this is where strong mountain torque events perhaps under the influence of enhanced blocking created by increased NH snow cover come into play?

Technically no MMW it seems as the 10mb and 30mb contours barely scrape the bottom

However, within the context of the cold winter pattern, this doesn't seem to be too crucial, and providing the vortex disrupts favourably in terms of situ, as seems to be now suggested, then an easterly should still be on.

Yes, the stratospheric vortex and energy profiles since the warming ( and I don't think that it matters that we have just missed out on a MMW) are now looking slightly more favourable. The door that was shut with the linkage of the Atlantic trough to the Scandi trough is opening up again. If this continues watch that support for the easterly grow again before the ridging is likely then to transfer to be more Greenland based.

c

ps snooz I tried to pm you to explain what a MMW is (read the first post in this thread) but your pm wasn't accepting messages.

[Guest North Sea Snow Convection]

Todays update suggests an MMW may finally occur with negative zonal winds predicted (just!) at 10 and 30mb levels. Associated I guess with the third pulse of warming

Edited February 2, 2010 by North Sea Snow Convection

[chionomaniac]

A very confusing pattern with the stratosphere presently with regards to vortex shape, vortex positioning, areas of warming and propagation of negative zonal wind anomalies.

The only theme that I can get across the board is a split vortex with one area of vortex over Siberia but trending to head towards Scandinavia, with the other area over Greenland with the trend to send this westward too. Separating these vortices is an area of weak ridging. This could trend to weak ridging to our north but with such inconsistent lower stratospheric vortex modeling it will be difficult to have any confidence in this outcome.

c

[johnholmes]

that fits in with the NOAA 500mb anomaly charts, or should I say they fit in with that comment ch.

Thus there is a degree of agreement between Strat and Trop interactions and the various model outputs used in each atmosphere.

Edited February 3, 2010 by johnholmes

[cooling climate]

Very encouraging signs from the ECM stratosphere forcasts this morning which ties in with the

blocking to the north being shown on the ECM synoptics charts.

http://strat-www.met.fu-berlin.de/cgi-bin/ecmwf?alert=1&level=10&forecast=f192

Below is the chart for the 400K isentropic chart (roughly 50,000 feet) and you can see a

very favorably split vortex.

http://strat-www.met.fu-berlin.de/cgi-bin/ecmwfpv?alert=1&level=400&forecast=f192

Also various levels of the stratosphere showing negative (easterly) wind anomalies.

Below is the forcast chart for the 10hpa level at day 8.

http://strat-www.met.fu-berlin.de/cgi-bin/ecmwf?alert=1&level=100&forecast=f192

[jethro]

Stumbled across this, thought some of you may find it interesting:

http://www.congrex.nl/09c24/S5/S5_06_Foerster_paper.pdf

[picog]

The duration of the temperature rise seems long to me. I'm not sure if that's correct, or what it might mean, if anything.

http://strat-www.met...t=temps&alert=1

[johnholmes]

Stumbled across this, thought some of you may find it interesting:

http://www.congrex.n...rster_paper.pdf

I don't even understand the conclusions so hopefully someone will explain it all in plain English for the likes of me!

[Rollo]

I don't even understand the conclusions so hopefully someone will explain it all in plain English for the likes of me!

If you cannot understand it John-what chance have I? Hope you enjoyed your skiing holiday by the way.

[chionomaniac]

Very encouraging signs from the ECM stratosphere forcasts this morning which ties in with the

blocking to the north being shown on the ECM synoptics charts.

http://strat-www.met.fu-berlin.de/cgi-bin/ecmwf?alert=1&level=10&forecast=f192

Below is the chart for the 400K isentropic chart (roughly 50,000 feet) and you can see a

very favorably split vortex.

http://strat-www.met.fu-berlin.de/cgi-bin/ecmwfpv?alert=1&level=400&forecast=f192

Also various levels of the stratosphere showing negative (easterly) wind anomalies.

Below is the forcast chart for the 10hpa level at day 8.

http://strat-www.met.fu-berlin.de/cgi-bin/ecmwf?alert=1&level=100&forecast=f192

I would agree with your thoughts here, cc. If we can eliminate the uncertainty then the stratospheric profile is becoming more favourable by the minute. There are now suggestions that an MMW is back on the cards. Originally the stratospheric warming has displaced the stratospheric vortex away from the pole but not quite enough to reach MMW status.

However the latest warming looks to split the displaced vortex and is enough to cross the line as a MMW within 6 days.

The vortex splitting at the 10 hPa level is agreed with by the GFS and looks very significant by T+240

Now will this be classified as a split or displacement MMW?

The splitting is nevertheless carried down to the 100 hpa level and again the profile looks increasingly better for northern height rises around Iceland and fits in nicely with the link that cc provided to the 400K chart:

My feelings are that this could help lengthen any cold spell perhaps delaying the onset of the west based -NAO. We shall see.

The duration of the temperature rise seems long to me. I'm not sure if that's correct, or what it might mean, if anything.

http://strat-www.met...t=temps&alert=1

The duration of the current warming is linked to the prolonged increase in wave 1 activity seen in January.

http://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/gif_files/time_pres_WAVE1_MEAN_JFM_NH_2010.gif

This is now coming to an end but has left a legacy that could last well into March.

c

Stumbled across this, thought some of you may find it interesting:

http://www.congrex.nl/09c24/S5/S5_06_Foerster_paper.pdf

Blimey Jethro, that's certainly an insomniac's paper if I ever saw one!

Edited February 4, 2010 by chionomaniac

[chionomaniac]

Stratospheric signals are still improving day by day to support a cold spell. it has to be said that they are a lot better than this time last week when there was uncertainty about Atlantic and Scandi trough linkage.

The next phase of vortex disruption looks set to occur within five days. So far with this warming event we have seen the vortex severely displaced from the pole which has weakened it considerably. This has not been quite enough to create a MMW, however the next phase of disruption looks set to qualify. This involves the displaced vortex splitting into two. This forecast split is set to progress right through the stratosphere and troposphere unlike the partial splits seen earlier this winter. The initial effects from this split are likely to be felt as ridging around Iceland with the residual vortices remaining as troughs either side. Both the GFS and ECM are suggesting this (as BF has demonstrated with the ECM charts in the technical thread). Here is the GFS 100 hPa chart for T+240:

This all looks promising and it will be interesting to see what is modeled from that point onwards and how severe any mean zonal negative winds may be.

c

[chionomaniac]

Really interesting forecast today. This year the way the stratosphere is behaving is totally different to last years. Last year we had a record breaking MMW that after the initial impact failed to give any sustained tropospheric response. This winter we have seen a warmer than average stratosphere to start the winter and now a prolonged stratospheric warming episode that is about to lead us into a MMW. The troposphere has responded to this all winter.

The Forecast MMW is set to occur on the 9th of February. Remember the mean zonal mean winds need to reverse at 10 hPa and 60ºN for this to occur.

This is caused by the previously displaced vortex, that came very close to a MMW last month, splitting into two daughter vortices. By day 10 these daughter vortices are positioned in the middle stratosphere as thus:

I can't remember ever seeing a stratospheric split vortex profile following other MMW's such as this and is probably down to the fact that the vortex displaced prior to splitting so this could be a bit of uncharted territory here for computer models.

This translates closer to the troposphere as a pattern such as this at 100 hPa by day 7:

Again a very unusual pattern that probably hasn't been seen for years. Note that this could lead to the UK being in a potentially very cold NE airstream at this time with ridging splitting the main vortex components. Also the mean zonal winds are negative!

These negative mean zonal winds have been repeatedly suggested at the tropospheric surface between 50-60ºN. That to me suggests that we are likely to have a trend of higher pressure wedged slightly north of us but not necessarily dropping. Furthermore there are indications that these negative zonal wind anomalies will extend further north as the month progresses. A colder than average February is extremely likely imo.

c

[picog]

Great update Chio, thanks for keeping us all so well informed with your mountain of knowledge.

[SteveB]

Yeah thanks Chio,

My main interest for this Winter & coming year is for low CET's. We have already bagged a low December & very low January, now for the chance for a low Feb also. How low is the next question.

It would be good to see a below average Spring with an average Summer and the lead into a below average Autumn to give us a chance of a sub 9.5 annal CET.

keep up the fantastic work you and GP bring to this forum.

[lorenzo]

Really interesting forecast today. This year the way the stratosphere is behaving is totally different to last years. Last year we had a record breaking MMW that after the initial impact failed to give any sustained tropospheric response. This winter we have seen a warmer than average stratosphere to start the winter and now a prolonged stratospheric warming episode that is about to lead us into a MMW. The troposphere has responded to this all winter.

The Forecast MMW is set to occur on the 9th of February. Remember the mean zonal mean winds need to reverse at 10 hPa and 60ºN for this to occur.

This is caused by the previously displaced vortex, that came very close to a MMW last month, splitting into two daughter vortices. By day 10 these daughter vortices are positioned in the middle stratosphere as thus:

I can't remember ever seeing a stratospheric split vortex profile following other MMW's such as this and is probably down to the fact that the vortex displaced prior to splitting so this could be a bit of uncharted territory here for computer models.

This translates closer to the troposphere as a pattern such as this at 100 hPa by day 7:

Again a very unusual pattern that probably hasn't been seen for years. Note that this could lead to the UK being in a potentially very cold NE airstream at this time with ridging splitting the main vortex components. Also the mean zonal winds are negative!

These negative mean zonal winds have been repeatedly suggested at the tropospheric surface between 50-60ºN. That to me suggests that we are likely to have a trend of higher pressure wedged slightly north of us but not necessarily dropping. Furthermore there are indications that these negative zonal wind anomalies will extend further north as the month progresses. A colder than average February is extremely likely imo.

c

Great update Chiono, TY. Regarding bold above... Winter into March?

[chionomaniac]

Great update Chiono, TY. Regarding bold above... Winter into March?

I would say that Northern blocking is highly likely to continue well into March considering the length of the current stratospheric warming and the extent of the disruption of the polar vortex already seen this winter.

We can see the extent of the current warming between 65-90ºN this winter at 10 hPa. The mean stratospheric temperature is presently around -40ºC.

Now look at this. The mean temperature of the tropical stratosphere at this time. Remembering that the greater the differential the greater the potential for a stronger stratospheric vortex, we see that the tropical stratosphere at the same level is currently lower than the polar stratosphere!

No wonder the vortex is in such a disrupted state and we are about to see a MMW!

[Guest mycroft]

I would say that Northern blocking is highly likely to continue well into March considering the length of the current stratospheric warming and the extent of the disruption of the polar vortex already seen this winter.

We can see the extent of the current warming between 65-90ºN this winter at 10 hPa. The mean stratospheric temperature is presently around -40ºC.

Now look at this. The mean temperature of the tropical stratosphere at this time. Remembering that the greater the differential the greater the potential for a stronger stratospheric vortex, we see that the tropical stratosphere at the same level is currently lower than the polar stratosphere!

No wonder the vortex is in such a disrupted state and we are about to see a MMW!

could you tell me what MMW stands for again.thanks

[Typhoon John]

MMW = Major Mid-Winter Warming

SSW = Sudden Stratospheric Warming

FW = Final Warming

[chionomaniac]

The complex pattern persists with the split and displaced vortex from the top of the stratosphere right through down to the troposphere. There are two main segments of split vortices which will have some control on the weather we receive after the initial easterly. These are situated over Eastern Canada and Scandinavia. The amount of eastwards momentum carried down from the stratosphere will probably determine the tropospheric positioning of the likely tropospheric troughs associated with these. There are hints that there will be an increase in negative mean wind propagation by day 10 which could position everything a little too far west but we will see.

The MMW is still set for tommorrow.