The hunt for cold - Model discussion (late November)

[Met4Cast]

5 minutes ago, feb1991blizzard said:

They're dyer by 360 though, Euro high significantly represented.

Yeah.. 

Major, major change at day 7-10 on the EPS from zonal to heights to the North/more blocked, but lets instead focus on the day 15 clusters which have about a 1% chance of verifying..

PS. Latest Met 16-30dayer talking of snow showers in the East.. 

Edited November 28, 2018 by Daniel Smith

[booferking]

Control consistency??

[tight isobar]

8 minutes ago, feb1991blizzard said:

That's buggared us then as that +PDO signal will just mean troughs exploding off the Eastern seaboard.

The eastern seaboard..

Pac-ridge...is a very influencial..

Breader..

With pv-trop ..latter strat destruct!!

Edit-..Talking of signals..

And data will likely be of juice squeeze.

The spag plots- (upto date).are of good construct for nw/uk "cold...ALSO..

Edited November 28, 2018 by tight isobar

[feb1991blizzard]

2 minutes ago, Daniel Smith said:

Yeah.. 

Major, major change at day 7-10 on the EPS from zonal to heights to the North/more blocked, but lets instead focus on the day 15 clusters which have about a 1% chance of verifying..

Mean for your neck of the woods doesnt go anywhere near to zero for nightime minimum temps and hardly anything significantly below that in terms of individual members throughout the whole run. If this is more of your evidence for a mid December freeze then its pretty flimsy as far as i can see.

[Met4Cast]

1 minute ago, feb1991blizzard said:

Mean for your neck of the woods doesnt go anywhere near to zero for nightime minimum temps and hardly anything significantly below that in terms of individual members throughout the whole run. If this is more of your evidence for a mid December freeze then its pretty flimsy as far as i can see.

I'm not too worried about the mean at this stage. 

The clusters are an improvement. There are more cold clusters in the extended compared with previous runs, the mean is on a downward trend in any case. Baby steps.. but the model outputs/ensembles today have increased my confidence a little.

[tight isobar]

Lets take some mass spead ensembles..

With 'raw' data..and backing syncs..

And divulge- into sync- prog- territory!!..

 

Thers amp-and flux..twinned- with upper att- strucure!!..

The mess decipher...

Unwinds...too.......

..got the other geo- graphs..in case of exactions/probs!!!

 

 

On a gain..goin forwards method....

Edited November 28, 2018 by tight isobar

[lorenzo]

On 27/11/2018 at 11:31, Glacier Point said:

One further observation. Both EPS and GEFS very keen to dislodge the Siberian lobe of PV into the Pacific sector and nudge the Canadian lobe further west. Net result - the hemispheric wave number becomes much reduced and aggregated. That's a massive signal for high pressure development in the high latitudes across the eastern side of the hemisphere. Not a lot of change is going to happen to that wave pattern so we are lining ourselves up for the winter pattern here. Slowly slowly catchy monkey.

Stewart, the GLAAM 5-6-7-6 analogs to me look sound - no question there - you are more than the guru for those, the technical thread of old is sheer weather mysticism! What I would like to see - is another post qualifying the credence of this.

I have concerns around the anomalous GLAAM position - IIRC have not advertised what I would class as a Super Nino ( a la 83 87 or the modern age 2016 event), yet... we have AAM at massive peaks synonymous with Super Ninos? Spikes via EAMT even have note juiced this recent run - the Asian region a usual catalyst - this time it was the Andes !

 Acknowledge we have had bits of strong Modoki Nino, strong EPAC nino and much slosh with MJO - I just cannot connect the AAM cycle to this. 

If it is true and we have a genuine AAM connect then magic for UK winter prospects, however given the SSTA's across the Pacific I fear the AAM analogs are fast here and up against the traditional constraints of the Vortex intensifying -  'progressive'. The Vortex is entering a strong VI period ( Vortex Intensification) via a strong wQBO. As an aside how effective is trop action in over -riding natural variation - I would suggest limited given only 4 ssw since sat obs in 79.

I genuinely defer to your knowledge here and this is not a challenge - this is simply a question around base states, and ergo possibly difficult to answer until the progression unfolds.

My gut tells me we will have the GWP progression as demarcated - however the atmosphere may not be adequately harnessed due to other elements.

By other elements I mean traditional GWO analogs as gone this season, we have no adequate baselines since the unexplained QBO blip 2 yrs ago.

I hope your call verifies, it's good for blocking - it's good for this thread. Either way would be great for u to dissect the mechanics of it however it turns out.

For those thinking all teleconnections or non- NWP ,methods are out the window, sorely mistaken, sadly we do not have the models resolving stuff to the level we need to see 'more' and 'longer lead' patterns.

From my view - I see no SSW at present - I see an anomalous W2 followed by a 'traditional' W1 followed by a trop led W2 courtesy of MJO - which is heavily caveated by Nino development. This occurs across the classic VI period - leading to a late Jan Window for any kind of SSW.

In contrast - I also see - MJO activity creating W2 which will again weaken the vortex subsequent to a W2 and W1 assaulty, followed by the MJO P3 play through creating wave driving circa Dec.

So, take your pick. Sum up - genuinely impossible to call I feel - and Copernicus Seasonal date says the same Glosea truly at odds with ECM

Let's just keep on looking  and enjoy the thrill of the chase

[Kirkcaldy Weather]

a few from the 18z GEFS 

 

 

P10  

 

 

 

 decent ensemble graphs for here too 

[tight isobar]

15 minutes ago, lorenzo said:

Stewart, the GLAAM 5-6-7-6 analogs to me look sound - no question there - you are more than the guru for those, the technical thread of old is sheer weather mysticism! What I would like to see - is another post qualifying the credence of this.

I have concerns around the anomalous GLAAM position - IIRC have not advertised what I would class as a Super Nino ( a la 83 87 or the modern age 2016 event), yet... we have AAM at massive peaks synonymous with Super Ninos? Spikes via EAMT even have note juiced this recent run - the Asian region a usual catalyst - this time it was the Andes !

 Acknowledge we have had bits of strong Modoki Nino, strong EPAC nino and much slosh with MJO - I just cannot connect the AAM cycle to this. 

If it is true and we have a genuine AAM connect then magic for UK winter prospects, however given the SSTA's across the Pacific I fear the AAM analogs are fast here and up against the traditional constraints of the Vortex intensifying -  'progressive'. The Vortex is entering a strong VI period ( Vortex Intensification) via a strong wQBO. As an aside how effective is trop action in over -riding natural variation - I would suggest limited given only 4 ssw since sat obs in 79.

I genuinely defer to your knowledge here and this is not a challenge - this is simply a question around base states, and ergo possibly difficult to answer until the progression unfolds.

My gut tells me we will have the GWP progression as demarcated - however the atmosphere may not be adequately harnessed due to other elements.

By other elements I mean traditional GWO analogs as gone this season, we have no adequate baselines since the unexplained QBO blip 2 yrs ago.

I hope your call verifies, it's good for blocking - it's good for this thread. Either way would be great for u to dissect the mechanics of it however it turns out.

For those thinking all teleconnections or non- NWP ,methods are out the window, sorely mistaken, sadly we do not have the models resolving stuff to the level we need to see 'more' and 'longer lead' patterns.

From my view - I see no SSW at present - I see an anomalous W2 followed by a 'traditional' W1 followed by a trop led W2 courtesy of MJO - which is heavily caveated by Nino development. This occurs across the classic VI period - leading to a late Jan Window for any kind of SSW.

In contrast - I also see - MJO activity creating W2 which will again weaken the vortex subsequent to a W2 and W1 assaulty, followed by the MJO P3 play through creating wave driving circa Dec.

So, take your pick. Sum up - genuinely impossible to call I feel - and Copernicus Seasonal date says the same Glosea truly at odds with ECM

Let's just keep on looking  and enjoy the thrill of the chase

@stale data..

 

Wave sst's are involved...

And of contribute...via mjo/rossby waving.

And the accomplishment of pv- destruct/..and-or major displace!!!

Edit..great post..

And balanced

Edited November 29, 2018 by tight isobar

[SMU]

On the night shift tonight as only 1030 in NYC -

Icon 180 shows pressure building towards Greenland - at that point it would be weak wedge type - more of a steering high rather than a real one of meaningful depth but its a start !

 

[Mucka]

Still an outside chance of some snow for the North from the potential Southerly low around 4th/5th.

It is all about timing and whether we can enough cold air down from the initial trough. If it delays it blows up and tracks further North(Just rain) 

 

If it pushes through quicker and stays further South it could give snow Northern edge (more especially high ground) but the wrap around cold as it passes through on its Western flank would turn any ppn more to snow. Still a long shot for now.

 

UKMO/GFS 144 quite different ideas about blocking to the E

Edited November 29, 2018 by Mucka

[Mucka]

GFS quite different how it handles the Atlantic this run with lows more prone to disrupt and slide than barrel through.

Atlantic running out of puff?

 

Out to 192 now and look interesting.

 

Turns out a chilly run but of course the Atlantic is on steroids as soon as we hit low res.

So much difference in the models by day 7 and run to run hard to know what we will get but nice to see some cold air be modelled to get across the UK within 10 days.

Edited November 29, 2018 by Mucka

[BLAST FROM THE PAST]

2 hours ago, Steve Murr said:

On the night shift tonight as only 1030 in NYC -

Icon 180 shows pressure building towards Greenland - at that point it would be weak wedge type - more of a steering high rather than a real one of meaningful depth but its a start !

 

That’s the initial way forward. Cold theme re-asserting with LPs steered south and colder air shunting south with it.  Excellent GFS 00z to kick off today, UKMO pretty darn good too. We don’t need mega blocks initially for cold to bleed south, GEM nice too.  

Just add, the south may have to wait, but for me there is growing chances of quite wintry weather spreading down from the north as the LP track lowers and lowers as we go through early December  

 

BFTP

Edited November 29, 2018 by BLAST FROM THE PAST

[northwestsnow]

TBH my interest at the moment is focused on the strtat-

GFS00z is interesting in the strat,there are small warmings  way to our NNE, but then by the end of the run the core cold in the strat has completely shifted towards NW Russia..

Edited November 29, 2018 by northwestsnow

[Seasonality]

ECM seems to be buying into more euro troughing this morning compared to yesterday's 12z.

[Radiating Dendrite]

26 minutes ago, northwestsnow said:

TBH my interest at the moment is focused on the strtat-

GFS00z is interesting in the strat,there are small warmings  way to our NNE, but then by the end of the run the core cold in the strat has completely shifted towards NW Russia..

PV over Siberia and height rises to our west?

Only worry is a west based negative NAO.

[Seasonality]

I'm still convinced the general direction of travel is towards colder conditions in the second week of December. Even if the exact destination isn't yet settled. 

[danthetan]

On this morning GFS and ECM there seems to be an appetite for a wedge of high pressure in the N Atlantic to steer the jet and those shallow low pressure systems further south of the UK. one to watch as cold air is lurking to the North and could get wrapped around the low giving snowfall events. 

[Chesil View]

GEM picking up the ECM idea and then some. A cracking run

[Met4Cast]

Hows this for an ECM & ensemble mean

The switch to cold is happening & it’s happening fast! 

[mulzy]

A slight change in the NWP with a more southerly tracking jet been shown.  Northern areas *could* get some transient wintriness as Atlantic systems brush against any entrenched cold air.  However the mild and unsettled theme is still the form horse, especially in the medium term.

Day 10 EPS mean suggests an Atlantic influence in the 10-15 day period and this is confirmed by the extended EPS.  A classic winter tale of Atlantic troughing and ridging from southern Iberia into Eastern Europe.

 

[Tom Montalbano]

Morning all,

Just want to return to my "spat" with Cheeky Monkey, last night. I see like myself, C.M has been a member since January 2005. Like myself he should, by now, understand the "machinations" of the Model thread at this time of year. 

I'm way too long in the tooth to suggest that no snow before Christmas, can lead to a "Nirvana" style Winter for cold weather fans, a la 1962/63!!

I was merely pointing out that my calendar tells me it's still November and amazingly, still does this morning!! And that the "Winter's Over" type posts, are way too premature.

I stand by what I stated last night. I'm 63 now and havn't witnessed that much snow, this side of Xmas. I'm sure that is the case for many of you that live in southern areas of the U.K. But that certainly doesn't mean were on the cusp of something special!!

I also would like to apologise for my flippant remark, about my Father. Dad was indeed a West Ham fan and was born in Poplar, East London. That's within the sound of Bow Bells and made him a true Cockney!! Although he moved to Bromley, Kent (NOT By-Bow) a little later.

I hope that clears things up a little.

Regards,

Tom.  

[Met4Cast]

Extended EPS replaces the Scandi trough which has a strong signal days 7-13 with a signal for high pressure across Scandi by day 15, though it has to be said it looks fairly mobile with a signal for low pressure to be quite close to the UK..

GFS not quite as interested in earlier cold as per ECM/GEM and instead waits until the end of the run to throw up high pressure across the UK towards Scandi.. ECM/GFS actually quite similar for a change out to T240

[jules216]

2 minutes ago, mulzy said:

A slight change in the NWP with a more southerly tracking jet been shown.  Northern areas *could* get some transient wintriness as Atlantic systems brush against any entrenched cold air.  However the mild and unsettled theme is still the form horse, especially in the medium term.

Day 10 EPS mean suggests an Atlantic influence in the 10-15 day period and this is confirmed by the extended EPS.  A classic winter tale of Atlantic troughing and ridging from southern Iberia into Eastern Europe.

 

yes, dreaded Euro high, yet few day ago it was showing a central EU through, this is what I was commenting on yesterday. plenty of blocking to around Scandi and Arctic, but lacking the trigger low

[Met4Cast]

2 minutes ago, jules216 said:

yes, dreaded Euro high, yet few day ago it was showing a central EU through, this is what I was commenting on yesterday. plenty of blocking to around Scandi and Arctic, but lacking the trigger low

Don’t be too surprised to see the models now begin to downplay the Atlantic once that ridge of heights to the North sets up..