Model output discussion - proper cold spell inbound?

[Duane S.]

An improvement mid term on the 06z at least...

12z...

 

06z...

Edited February 11, 2018 by s4lancia

[SMU]

GFS much more in tune with what we would expect to see in any transitional phase around Day 7

Edited February 11, 2018 by Steve Murr

[Great Plum]

Improvements from the 6z...

 

[inghams85]

1 minute ago, Steve Murr said:

GFS much more in tune with what we would expect to see in any transitional phase around Day 7

What I've noticed is slowly the Block to the East has started to back further West after a few runs in decline. Interesting 

[tight isobar]

•back in the madhouse●

Iv'e used my noggle and refrained posting- due to model miss-management, and the daggers in here!!!?..

12z gfs offering up better variation of heights...and also some gain from the mother canadian lobe being syphoned across the eastern qud lobe....@last output seems to be sniffing out the ssw...

Ecm 'should gain in evolvement on its 12z...more to this angle.

Lets see how we play out!!??

Edited February 11, 2018 by tight isobar

[Dunlop Dave]

Another flip flop from the gfs. Coming back in 4 days. This rollercoaster is driving me nuts !

[Snowy L]

This may be the first run to already have the wind reversal taken into account at the start of the run.

[ZK099]

This doesn't make any sense. How on earth is the PV still present in Greenland after such a massive strat warming and reversal? It's that which is preventing heights building north towards Greenland. Something isn't right here. 

[Ice Day]

4 minutes ago, Snowy L said:

This may be the first run to already have the wind reversal taken into account at the start of the run.

That's a very good point Snowy, I think the GEFS may be quite revealing a bit later to see if the Op is smelling something.

[ICE COLD]

Ok I lied ? I'm not taking a break nice point to that high pressure and angle of attack . 

[Captain Shortwave]

Day 6 charts

UKMO/GFS/GEM

      

Pretty similar, the UKMO probably the flattest but all three tend to build a solid high over the UK, both the GEM and GFS do introduce a cold feed from the east or north east though wintriness would be limited. That said a UK high isn't the worst place to be going forwards towards the end of the month as we would likely see the high drift further north to allow proper cold to aim towards the UK.

[Radiating Dendrite]

2 minutes ago, ZK099 said:

This doesn't make any sense. How on earth is the PV still present in Greenland after such a massive strat warming and reversal? It's that which is preventing heights building north towards Greenland. Something isn't right here. 

I think there is a little bit of confusion around the SSW. The split is straight through the middle of the vortex which has left a daughter vortex over Canada and another over Siberia. The stratospheric vortex has not been smashed to smithereens but split into two.

Thinking a displacement event might have actually been better rather than a straight split. 

[That ECM]

5 minutes ago, Dunlop Dave said:

Another flip flop from the gfs. Coming back in 4 days. This rollercoaster is driving me nuts !

Flip flopping and driving me nuts

[Man With Beard]

2 minutes ago, Captain Shortwave said:

Day 6 charts

UKMO/GFS/GEM

      

Pretty similar, the UKMO probably the flattest but all three tend to build a solid high over the UK, both the GEM and GFS do introduce a cold feed from the east or north east though wintriness would be limited. That said a UK high isn't the worst place to be going forwards towards the end of the month as we would likely see the high drift further north to allow proper cold to aim towards the UK.

Close enough!!

And what's the GFS doing now? T192, high pressure moving east to west across Finland - could be headed for a big NEly in FI...

[Banbury]

2 hours ago, - 40*C said:

You wont get much cold out of any blocking in March as the sun will be too strong  .

Sorry but that is utter rubbish 

 

Ermmmm March 2013

[tight isobar]

Thie evolving synoptics you want to see as we gain!!!.

Jet carved...big time...heights 'sound'...

Sister lobe leaking cold as heights align- and block goes steady....then boom, ya-cold door is firmly open....and a totaly feasible progress...given atmospheric developments!!!!

Ecm 'should' also now begin resolve!!!

[bobbydog]

so, winter's over. the teleconnections are a load of old rubbish, the "told you so"ers were right.

oh hang on, it's back on again...

 

[Singularity]

 

Amazing isn't it? Now we see a second kick of amplification in the Atlantic and a small low cutting south through Scandinavia with the Siberian high reaching west behind it.

 

The saga continues. Odd that the 12z has been the most wintry run of the day from GFS for a number of days running.

I do see that the vortex segment over Scandinavia takes a little longer to head to the Canadian one on this run but it's a very small change so seems unlikely to explain such a large swing from one run to the next. It just seems to be a chaotic combination of variables at play although I do still believe the MJO is among the most influential in terms of whether the ridge building Thu-Sun can gain enough latitude to set up a cold feed across the south ahead of the stratospheric impacts.

 

What can you do but laugh (manically?).

[Ice Day]

Out to 240 and that's one beautiful chart, looks cold and possibly snowy for much of England (just for fun at this range of course!) .  This is how it's going to be for a while, upgrade..downgrade...and so on.  

 

 

[Winter Hill]

11 minutes ago, bobbydog said:

so, winter's over. the teleconnections are a load of old rubbish, the "told you so"ers were right.

oh hang on, it's back on again...

 

Oh so winter is back on again because you've posted a chart for the 21st of Feb..

Get that down to T+48 and I might just believe you.

 

Edited February 11, 2018 by Winter Hill

[Snowy L]

10 minutes ago, Singularity said:

 

Amazing isn't it? Now we see a second kick of amplification in the Atlantic and a small low cutting south through Scandinavia with the Siberian high reaching west behind it.

 

The saga continues. Odd that the 12z has been the most wintry run of the day from GFS for a number of days running.

I do see that the vortex segment over Scandinavia takes a little longer to head to the Canadian one on this run but it's a very small change so seems unlikely to explain such a large swing from one run to the next. It just seems to be a chaotic combination of variables at play although I do still believe the MJO is among the most influential in terms of whether the ridge building Thu-Sun can gain enough latitude to set up a cold feed across the south ahead of the stratospheric impacts.

 

What can you do but laugh (manically?).

Singularity I don't think the Scandinavian daughter vortex moving west to the Canadian one is causing the problems seen on the morning runs. If anything you would expect east to west movement of the Scandinavian lobe to help, especially as on the strat charts the Scandinavian vortex is moving under the high pressure.

ECM just shows raging westerlies through the entire Atlantic and into Norway almost to day 10, which is why I think it's wrong

 

Edited February 11, 2018 by Snowy L

[tight isobar]

Could almost begin to feel compassion(polar vortex).....

Edited February 11, 2018 by tight isobar

[Thundery wintry showers]

I think we probably will see an easterly flow develop at some point after the 20th February, with the SSW, the MJO and the large Siberian/Scandinavian high being well set up for one, but before that we will probably see a relatively mild anticyclonic interlude- we saw this following the sudden stratospheric warming event in January 2013 for example.  The GFS was probably being too progressive in bringing an easterly flow into the British Isles from around the 20th, with today's GFS 12Z run perhaps more realistic regarding the timing.

Here's the MJO forecast for example, showing it continuing to hover around phase 7:

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/foregfs.shtml

However, I'm not anything like as confident that we'll actually get a significant snowy spell from it.  We're getting quite late in the season now and a watered down version with moderately cold air coming in from the SE (which I think is as plausible an outcome as an input of arctic continental air from the E/NE) would most likely result in dry cloudy weather with the odd flurry near the east coast.

Edited February 11, 2018 by Thundery wintry showers

[Met4Cast]

So all the people that were saying winter is over, the SSW isn't going to have any effect blah blah blah are suddenly shouting of cold, snow and Scandinavian highs? Some peoples temperaments on here are as bad as the GFS', bewildering. 

GFS an improvement bringing back in heights to our North after the last couple of runs, I wonder where the ECM will go with this one now.

Edited February 11, 2018 by Daniel Smith

[bobbydog]

1 minute ago, Winter Hill said:

Oh so winter is back on again because you've posted a chart for the 21st of Feb..

 

last time i checked, the 21st of feb was still winter. i could post the earlier charts which lead to this if you like?

in fact, here you go- 

the 144 chart with the ridging underway which leads to HLB.

Edited February 11, 2018 by bobbydog