Model Output Discussion 01/09/17

[bluearmy]

AO landing currently looks to be trending a bit lower than mentioned earlier and would be a strongish correction at this stage for it not to land sub -4.  

12z suites and ops around -4.2/4.3

[Man With Beard]

EC ensembles continued - funnily, there's more agreement later in the runs - the low pressure areas after the initial shortwave all seem to get developed, don't disrupt, and eventually cross the Atlantic by D8, generally centred through Scotland. Only about 10% of runs keep anywhere cold by this time apart from the far north, and instead rain (and maybe strong winds) is more of a concern. Will these follow-up lows really behave in such an orderly way??

Edited November 16, 2017 by Man With Beard

[bluearmy]

3 minutes ago, Man With Beard said:

EC ensembles continued - funnily, there's more agreement later in the runs - the low pressure areas after the initial shortwave all seem to get developed, don't disrupt, and eventually cross the Atlantic by D8, generally centred through Scotland. Only about 10% of runs keep anywhere cold by this time apart from the far north, and instead rain (and maybe strong winds) is more of a concern. Will these follow-up lows really behave in such an orderly way??

Often happens like that - obviously the hope for coldies is that the blocking forces the jet south and the run of systems across the Atlantic runs into the base of a cold nw European trough. currently a fairy forlorn hope but not yet impossible. 

[bobbydog]

have i just landed in a parallel universe? i can't believe the despondency on here! the last time a hemispheric profile even remotely like this- 

appeared at or around the same date, was in 2010 

now that gave us snow- but that was just the starter before the main course. maybe not to be on this particular occasion but talk of last chances and forlorn hopes are slightly bewildering to me. anyone would think we were approaching the end of february. its still only november!!

[summer blizzard]

Looking at the Euro and GFS there are common themes but they handle the vortex quite differently. 

So basically after the shortwave drama both models attack the vortex from Russia through days 5 and 10 and both models essentially create a three wave pattern however while both models agree on the core of the vortex energy being over eastern Siberia they have completely different angles at our end. The GFS is essentially a classic west based NAO with a flat southern jet being flung back towards by a trough to our south west. The Euro on the other hand has a jet aimed NE but at day 9 the low is negatively tilted and headed east. 

 

[stewfox]

3 hours ago, nick sussex said:

Shortwave chaos!

All big 3 disagree with these and this looks like its got a bit more mileage to go. No resolution tonight regardless of what the ECM does in its later output.

Every year we get those pesky short waves in FI !

Supporting chart attached

[damianslaw]

Another day - and still more flip flopping from the models well within the reliable timeframes - end result, we are still non-the wiser how things may ultimately play out next week. There are very fine margins being played with, as others have said all depends on the position of the shortwave feature out west, and how this engages with the trough, will it disrupt, will it be absorbed into the trough.

GFS is yo-yoing all over the place, ECM has reverted back to something colder, UKMO siding more with ECM, won't be surprised to see GFS 18Z show something similiar to last nights again.

And the answer is we won't know for certain until well probably Sunday at this rate - can we wait another 3 days of this.. It is nowcasting and short-term development time, history has shown how sudden changes within 24 hrs can make a major difference to prospects thereafter,and I think this is one of those cases.

Might be best to refrain from looking at the models for 3 days and then just accept what will be will be i.e something milder and wetter, something a bit in the middle, something colder and wintry. Could be some interesting marked differences from north to south next week. Remember high pressure in winter is much denser than moist tropical air, and significant blocks wherever they sit, have a habit of being greater force.

[Duane S.]

I know this phrase is over used on here, but it really is on a knife edge here.

Maybe not the most likely outcome, OK pretty definitely not the most likely outcome! but we seriously cannot discount this working out in our favour with that big old block forming above us. It wouldn't take much, at all, for a different fork in the road to be taken at around D5 and then, very quickly, its game on. It's still on the table.

Edited November 16, 2017 by s4lancia

[Allseasons-Si]

That shortwave is a lot further south in Scotland at t90 compared to 12z t96,small incremental steps could have big differences later in the run,also more of a NE dig of cold in the NE.

nope,not quiet there but it is slightly better than the 12z.

Edited November 16, 2017 by Allseasons-si

[Cheshire Freeze]

Just look at those heights throughout the Mediterranean into central Europe

Stuck like a limpet. We won't see anything of note until they disappear.

[blizzard81]

4 minutes ago, CreweCold said:

Just look at those heights throughout the Mediterranean into central Europe

Stuck like a limpet. We won't see anything of note until they disappear.

Things must be parched down there. Do they ever get any rain? 

[feb1991blizzard]

7 minutes ago, CreweCold said:

Just look at those heights throughout the Mediterranean into central Europe

Stuck like a limpet. We won't see anything of note until they disappear.

And they wont disappear until a powerhouse Northerly in that locale happens so its chicken and egg. We are buggared.

Edited November 16, 2017 by feb1991blizzard

[bluearmy]

5 minutes ago, CreweCold said:

Just look at those heights throughout the Mediterranean into central Europe

Stuck like a limpet. We won't see anything of note until they disappear.

If the upstream pattern played ball then I think you see those heights pushed east Crewe. 

The much maligned ec 46 isn't without interest as we head through December.  Not seen the NH plots as yet. 

[bobbydog]

3 minutes ago, CreweCold said:

Just look at those heights throughout the Mediterranean into central Europe

Stuck like a limpet. We won't see anything of note until they disappear.

[Allseasons-Si]

4 minutes ago, CreweCold said:

Just look at those heights throughout the Mediterranean into central Europe

Stuck like a limpet. We won't see anything of note until they disappear.

Yes,rather worrying the 500mb 6-10 and the 8-14 day outlooks look dreadfull too.

i wish i could say something positive about the models today but there isn't any unless you wan't Daffadils to come up before Christmas

oh!,there is one positive!!!,it's still only November

[Allseasons-Si]

5 minutes ago, bobbydog said:

I find looking at that disturbing

anyway,nothing will be resolved tonight obviously,lets see what tomorrow brings,will it be resolved tomorrow?

[lorenzo]

1 hour ago, bluearmy said:

AO landing currently looks to be trending a bit lower than mentioned earlier and would be a strongish correction at this stage for it not to land sub -4.  

12z suites and ops around -4.2/4.3

Have you got this plugged in a table anywhere, would be good to see the trend shift over the last week.

This may help us determine a model bias when reading blocking...

I.e we get a read on which model jumps first, then when which model follows, then which is likely to be correct

 

[knocker]

A pretty fair agreement between the GEFS and EPS anomalies this evening although they do not really tell us anything we didn't already know

Leaving aside the Pacific end of the pattern for the moment the key areas in the Atlantic arena are the trough down the east of N. America which is a subsidiary of the Canadian vortex, a trough in mid Atlantic that runs a fair way south and third lobe/trough Scandinavia down to eastern Europe with an extension south into the Atlantic.

Thus quite a strong westerly upper flow leaving the eastern seaboard that goes via the mid Atlantic trough over the UK en route to the trough in the east. This would portend some quite unsettled weather over the UK but this is complicated by the cold pool of the Icelandic trough and a subsidiary energy flow running south over eastern Greenland

Thus the two energy flows meet in the eastern Atlantic with a marked delineation between the warm/cold airmases and a strong thermal gradient. This evening the ecm had 80kt 500mb winds in places as quite intense cyclogenesis took place.

The percentage play is for systems to track east or north east, the HP to the south remaining resilient, with temps around average but any incursions of the colder air could well complicate matters. It certainly will be no surprise if the det runs take a couple days grappling with the details of the evolution. I suspect the main worry with all of this is the risk of severe gales.

Edited November 16, 2017 by knocker

[blizzard81]

16 minutes ago, bluearmy said:

If the upstream pattern played ball then I think you see those heights pushed east Crewe. 

The much maligned ec 46 isn't without interest as we head through December.  Not seen the NH plots as yet. 

May I ask what you have seen of the ec46 and what is so interesting? 

[nick sussex]

If I'm being charitable slightly better early on then the dreaded blue wave from the ne engaged the shortwave and then it was game over.

Any se momentum of the shortwave is finished off as the engagement causes a deepening of that which then will try and move ne.

If both tonights Euros had dumped any hope then I would be chucking the towel in, given its the GFS and has been known to be wrong well within T96hrs then I'd view tomorrows 00hrs runs as the jury coming back in after much bickering to deliver a majority decision.

 

 

 

[Frosty.]

8 minutes ago, Allseasons-si said:

Yes,rather worrying the 500mb 6-10 and the 8-14 day outlooks look dreadfull too.

i wish i could say something positive about the models today but there isn't any unless you wan't Daffadils to come up before Christmas

oh!,there is one positive!!!,it's still only November

Another positive is the ensembles are apparently clueless so anything could happen next week onwards..I don't think anyone could say right now what's going to happen next week with any degree of confidence which just shows how potentially complex the situation currently is..I found another positive..today's MO update mentions blocky patterns, cold weather and snow with frosty nights in the north which with a bit of tinkering could become more widespread...chin up fellow coldies

 

[Eskimo]

Lack of posts sums it all up. I appreciate things can suddenly change, but I feel the Game is over.

[swfc]

Not a lot of positives to take from the 18z tonight. Im generally a positve person but if any decent cold spell can be salvaged over the 2-3 days il ride a penny farthing naked threw sheff town centre singing "show me the way to amarillo"!!!.so with that roll on the oz 

[bluearmy]

2 minutes ago, lorenzo said:

Have you got this plugged in a table anywhere, would be good to see the trend shift over the last week.

This may help us determine a model bias when reading blocking...

I.e we get a read on which model jumps first, then when which model follows, then which is likely to be correct

 

Wish I had tony!

anecdotally, gens have done worst on this followed by eps with the GEFS being the best guide. I would say that the ops have probably been the best guidance re the likely depth of the drop. 

 

[bluearmy]

4 minutes ago, blizzard81 said:

May I ask what you have seen of the ec46 and what is so interesting? 

only the Atlantic sector - the euro high heights seem to drop away after week 2 (seen that before but eventually it has to be right). Atlantic ridging and scandi troughing and eventually high anomoly to our north. So nothing that screams deep mid winter but output that allows for cold scenarios to play out.