Sudden Stratospheric Warming 2016/2017 ?

This chart is absolutely beautiful .

pedigree 6 wrote: »

Could you tell where blocking could occur in the northern hemisphere by that chart?

Not a guarantee of a location but you can still estimate by where the stratospheric warming goes.

nacho libre wrote: »

Well, from what i've been reading this is more likely to be a displacement, rather than a split vortex, so there is the danger a lobe of the vortex will stay over Greenland. Although if that did transpire it's not much different to what we have now - a weakish vortex which still has enough oomph to inhibit blocking near Greenland. Still it does seem to be our best shot of a sustained cold outbreak in the weeks ahead. I wonder will the effects of it show up quicker in the troposphere, given there is not a very powerful vortex this winter

I'd still be up to that, I love this bland weather. Winter 2005/06 was very similar and then we had the extremely good Summer of 2006! Here's hoping it will be like that.

Yep, very disappointing today. The Stratospheric warming is still consistent on the GFS with the same warming expected BUT the AO is trending very positive .

ArKl0w wrote: »

https://twitter.com/hannahattard/status/822456820191072256

The ECMWF shows some warming to take place on the 29th at 30 hPa i.e. the Troposphere but it's not up to the standard of the warming at 10 hPa.

The GFS and ECMWF still show some significant stratospheric warming at the end of this week at the same strength as the past few days. Not much signs of it elongating into the Troposphere though which is very unfortunate.

The AO is trending positive but then the trend goes towards neutral at the very end of the period (4th/5th February). I think it will stay positive at least until mid-February.

pedigree 6 wrote: »

What the hell?? Sorry.:eek:
I didn't realise I did anything wrong.

Say what you want then. I won't say anything again.

I've never been called a troll before.

Yeah, I don't see how you trolled him. Arkl0w, that was really uncalled for like what the hell?

I think it's most certainly safe to say that it's definitely not a SUDDEN stratospheric warming but it is a very significant stratospheric warming.

So according to the experts over on netweather a technical SSW has occurred.

Hopefully this leads to a sustained cold spell, rather than something brief as M.T. seems to think so.
He seems to be siding with the GFS view of things. Although that model in the past has been known to be too progressive in shunting away blocking highs in the past.

sryanbruen wrote: »

A technical BUT an extremely weak SSW. The zonal winds at 10hPa are -0.1 m/s which is very weak and could potentially be the weakest SSW on record unless they go more negative over the next few days but I don't expect any further drops, I expect the zonal winds to go back into positive territory.

Meanwhile, the AO is trending very negative up to 16 February. Very interesting but unfortunately, the NAO is still trending rather positive and for a better chance of a sustained cold spell, you need the NAO to go negative.

That's true.
It's a weak warming because of the westerly QBO state- that is why the NAO is likely staying positive too. The one thing on our side is the size of the block, although with a positive NAO and the vortex forecasted to quickly recover due to the weak reversal, the odds of the Atlantic getting back in over us is high. England, as always, has a greater chance of holding on to a continental feed. Still i wont complain at all if only we get a 2- 3 day cold spell with heavy snow showers

This winter will go down as the winter that promised so much but gave F all

UK people could be in for a February 1991 situation as the Polar Vortex looks like being properly split despite the SSW being extremely weak unlike in 2013. I'd like to thank the guys at Netweather for sharing this chart from January 1991.

This chart in the attachment below shows some very significant warming at the end of January 1991 much like what happened in January 2017 but unlike this year, the 1991 warming wasn't considered a SSW. Nevertheless, due to how weak the SSW is in 2017, it is very similar to 1991's warming.

For anybody that doesn't know, February 1991 started off exceptionally cold across the UK in particular with the cold far less intense over Ireland but it was still colder than normal. Around the end of the first week, snow started to show its hand across the east of Ireland and there were some heavy falls. After around 2 weeks of bitterly cold conditions, however, the Polar Vortex reformed and we got a much milder and wetter end to February 1991 with 13c on the 23rd. Read more about it here:

https://drive.google.com/file/d/0BwAX53FX4EFMVEdtbTRFTDRCdjQ/view?usp=sharing

Before January & December 2010, February 1991 was the last month in England to record a mean temperature of less than 2c.

February 1991 was not the most severe cold or snowy month by any means but I'd take it if I were offered it .

GFS is now showing another significant warming to take place through the 3rd to last week of February. This one looking like disrupting the Polar Vortex more abruptly.

I'll leave this for greater minds than mine to interpret.

Could this mid-March cold spell that's being shown by the models be the response to the Stratospheric Warming?

nacho libre wrote: »

The guys over on the Netweather Stratosphere thread believe there is usually a two- three week lag period before the effects begin to show up in the troposphere.
As i mentioned in the other thread, the uk met office must, to commit to a cold spell at this stage, be picking up a strong signal from their own model.

Of course it will all go pear shaped in the end:pac: At this time of year it does not bother me if that happens, as without the perfect set up it will be cold rain or sleet, rather than snow that gives accumulations at lower levels.

So there was no response to the January SSW (which was extremely weak)?

nacho libre wrote: »

I think there was, remember that brief weak south easterly flow we had due to the scandi high, which quickly sunk.

You thought that was the response? I thought that was way too fast for a response to the SSW.

It looks as though the response to the late February stratospheric warming is taking place now except in the USA where the eastern seaboard is much colder than normal and a nor'easter will take place in the coming days bringing blizzards. This is a contrast to the warm Winter they recorded. Meanwhile, temperatures at home are expected to go back down to average or stay slightly above for the next 7-10 days after a warm weekend.