Model Output Discussion - early October

[bluearmy]

Last Ec46 was strong on a griceland high anom week 2 .... tonight’s ecm op is on that page ..... a few hours away from seeing how the 46 sees the balance of November 

[feb1991blizzard]

1 minute ago, bluearmy said:

Last Ec46 was strong on a griceland high anom week 2 .... tonight’s ecm op is on that page ..... a few hours away from seeing how the 46 sees the balance of November 

Only problem is, the EC46 will be derived from the 0z EPS, so will the 12z EPS actually be more instructive?

[Allseasons-Si]

Hummm!!!

the gfs is toying with something upstairs.

[Mike Poole]

4 minutes ago, Allseasons-si said:

Hummm!!!

the gfs is toying with something upstairs.

Tiny signs, yes, looks like a push on both sides to me, wave 2?

[feb1991blizzard]

Its going to take something a lot stronger than that now to stop a strong strat-trop coupling at some point in November / December.

[knocker]

22 minutes ago, feb1991blizzard said:

Only problem is, the EC46 will be derived from the 0z EPS, so will the 12z EPS actually be more instructive?

Well one things for sure this type of analysis is not necessarily good news for those of a peculiar persuasion

 

[Mike Poole]

9 minutes ago, feb1991blizzard said:

Its going to take something a lot stronger than that now to stop a strong strat-trop coupling at some point in November / December.

Genuine question - we have a very meridional jet at the moment, models forecast to continue (maybe solar minimum implicated in this) and a faster spinning vortex above.  Would not a faster spinning strat vortex take longer to couple with a messy trop vortex, the two seem poles apart at the moment?

[feb1991blizzard]

1 minute ago, knocker said:

Well one things for sure this type of analysis is not necessarily good news for those of a peculiar persuasion

 

Its not terrible though, as soon as i read your assessment i expected a huge low anomaly over Greenland, obviously though i admit that chart  would rule out any serious early cold in the next 2 weeks, deep negative anomaly over the continent to the East still keeps interest going though for a while, before the inevitable strat-trop coupling and VI and period of zonality.

[MATTWOLVES 3]

Great posts on the strat folks.... But I'm lost so let's keep it simple, that's was quite a tempting finale from the 12z, very cold uppers tantalisingly close to our shores....just another few weeks on, and this would most definitely be a.... Let the battle commence situation... Fun and games are gerrin close to playing out. 

Edited October 24, 2019 by Mattwolves

[feb1991blizzard]

3 minutes ago, Mike Poole said:

Genuine question - we have a very meridional jet at the moment, models forecast to continue (maybe solar minimum implicated in this) and a faster spinning vortex above.  Would not a faster spinning strat vortex take longer to couple with a messy trop vortex, the two seem poles apart at the moment?

Might be worth asking this in the Strat thread but from my limited un-scientific knowledge of watching these charts the last 10 years, if this serious meridionality continued (it has to be very strong though with a strong -NAO / -AO setup not some half baked transient 60N ridges), it would almost intuitively have some effect in slowing or stopping the upper Westerlies from downwelling from the Strat, not all years without early top down SSW's (far from it) were zonal from the start, so by definition you can have strong enough tropspheric waves that cause an extensive period of cold UK weather - i don't think Dec 2010 had any serious early upper strat warming although stand corrected and that was some serious -AO --NAO persistent setup, it can be self perpetuating if you keep on getting these repetitive patterns.

[Frosty.]

Nice post Matt, sorry I'm out of reactions mate, most annoying!!!...anyhoo, tonight's Ecm 12z ensemble mean looks more cold than mild to me, especially the further north one is. I can't help feeling we are going to get an early taste of winter in the next 2 or 3 weeks!!

Edited October 24, 2019 by JON SNOW

[Mike Poole]

30 minutes ago, feb1991blizzard said:

Might be worth asking this in the Strat thread but from my limited un-scientific knowledge of watching these charts the last 10 years, if this serious meridionality continued (it has to be very strong though with a strong -NAO / -AO setup not some half baked transient 60N ridges), it would almost intuitively have some effect in slowing or stopping the upper Westerlies from downwelling from the Strat, not all years without early top down SSW's (far from it) were zonal from the start, so by definition you can have strong enough tropspheric waves that cause an extensive period of cold UK weather - i don't think Dec 2010 had any serious early upper strat warming although stand corrected and that was some serious -AO --NAO persistent setup, it can be self perpetuating if you keep on getting these repetitive patterns.

Thanks, feb, that kind of reinforces my thinking re this year, the problem I have is that  the last time this sort of issue arose was ten years ago, well before I was watching the models so I have no kind of scientific memory of it to fall back on, but the cold Decembers of 09 and 10 do intuitively seem relevant here.

Edited October 24, 2019 by Mike Poole

[MATTWOLVES 3]

Likewise Karl... Aka Jon Snow.... Fab posts has always on here, the winter time really brings out the class on here... I agree with your thinking regarding some colder Conditions, sooner, rather than later. The ens show the op was going pretty cold by the end, and tbh, the mean ain't that shabby either. That's me over and out for now.... Heads up for a big EC46. 

Edited October 24, 2019 by Mattwolves

[damianslaw]

In the shorter time frame - consistency between ECM and GFS, high pressure to the NW, and a cold northerly flow Sunday-Monday, thereafter a difference with the ECM blowing up a low to the west crossing the UK, before a northerly comes back, GFS having none of this.. usually its the GFS that does this kind of thing.. either the ECM will remove such feature in future runs, or the GFS begins to show it..

The evolution though is to further chilly northerly sourced airflow as we enter November.

[Allseasons-Si]

I have just borrowed Nick Sussex's fine set of pens to elaborate(try to) what is going on,well foretasted to go on

the latest from the cpc 500mb outlook for 6-10 and 8-14 days shows signs of the HP cell in the Atlantic and into Greenland migrate further NW,this allows the floodgates to come from the N/NE veering NE poss ENE with time

this is an upgrade from the ones i posted last night when the hp cell was more over the uk

these are the ecm expert ens for Holland from this morning

temps,dew points and wind direction,if i have read the wind direction right then i have circled the letters N=northerly and E=easterly 

so we go into a northerly in a few days time,then an easterly then poss another reload from the north later but unclear due to the scatter

they have just updated recently and little change from this morning.

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Bekijk de 15 daagse trend Europees weermodel voor regio Midden. Weergave van de ECMWF-EXPERT pluim met de lange termijn verwachting van Weerplaza.

 

the NAO/AO are better than last nights in terms of going neg again,that is why i didn't post them last night

last night NAO.

so some upgrades again today/tonight,the rollercoaster is fun and games isn't it.

 

 

[knocker]

But this blowing up a low is in fact quite interesting imo. All down to the quite unusual intense upper low in the Atlantic from which a trough breaks away. Of course probably will not happen this way.

[feb1991blizzard]

8 minutes ago, Allseasons-si said:

I have just borrowed Nick Sussex's fine set of pens to elaborate(try to) what is going on,well foretasted to go on

the latest from the cpc 500mb outlook for 6-10 and 8-14 days shows signs of the HP cell in the Atlantic and into Greenland migrate further NW,this allows the floodgates to come from the N/NE veering NE poss ENE with time

 

 

 

Remember though, the red is the anomaly, the Green is the 500mb flow, mean NW flow or WNW on the second chart, its is of course over a period of 6 days so of course may allow for some brief genuine cold shots, so below average but not frigid overall, of course as you say, it could evolve into something colder thereafter.

Edited October 24, 2019 by feb1991blizzard

[damianslaw]

10 minutes ago, knocker said:

But this blowing up a low is in fact quite interesting imo. All down to the quite unusual intense upper low in the Atlantic from which a trough breaks away. Of course probably will not happen this way.

Yes the models did this to a degree with tomorrows frontal/low pressure feature only to back away and show a much shallower feature. It seems odd and not backed by the Ensembles.

[Allseasons-Si]

1 minute ago, feb1991blizzard said:

Remember though, the red is the anomaly, the Green is the 500mb flow, mean NW flow or WNW on the second chart, its is of course over a period of 6 days so of course would allow for some brief genuine cold shots, so below average but not frigid overall, of course as you say, it could evolve into something colder thereafter.

Yes i know that the reds and the blues are  -/+ height anomalies and the green lines are the upper mean flow,just looking at the general pattern.

[knocker]

20 minutes ago, feb1991blizzard said:

Remember though, the red is the anomaly, the Green is the 500mb flow, mean NW flow or WNW on the second chart, its is of course over a period of 6 days so of course would allow for some brief genuine cold shots, so below average but not frigid overall, of course as you say, it could evolve into something colder thereafter.

The surface analysis is very tricky from that and this chart but with a westerly upper flow, albeit fairly weak flooding from the NE would not be the percentage play. You could even get something popping NE from the trough to the south west. Much like the ecm is showing this evening  In my limited experience you have to be wary of trying to elucidate too  much detail from anomaly charts

Edited October 24, 2019 by knocker

[feb1991blizzard]

3 minutes ago, knocker said:

The surface analysis is very tricky from that and this chart but with a westerly upper flow, albeit fairly weak flooding from the NE would not be the percentage play. You could even get something popping NE from the trough to the south west. Much like the ecm is showing this evening  In my limited experience you have to be wary of trying to elucidate too m much detail from anomaly charts

Thanks for the reply.

[knocker]

30 minutes ago, damianslaw said:

Yes the models did this to a degree with tomorrows frontal/low pressure feature only to back away and show a much shallower feature. It seems odd and not backed by the Ensembles.

Yes with a baroclinic zone to the south west and a shallow wave forming on the front. As you say it doesn't look like it will deepen as much as earlier expected Illustrated quite well here Note the WAA into Greenland and Europe

 

Edited October 24, 2019 by knocker

[shaky]

Gfs 18z not backing ecm at 120 hours!!cool easterly flow into england instead!shortwave no where to be seen!!

[feb1991blizzard]

85 or 2010 anyone??

[feb1991blizzard]

Nice start to the GFS, 2 North Easterlies in the first 210 hours.