Model Output Discussions 18z 31/01/2016

[Paul]

32 minutes ago, winterof79 said:

More garden path scenarios and we still believe it is gospel. Great fun model watching but not this winter as they have no idea.

Maybe it's time to drop this line. No-one that I can see is believing anything as gospel, they're commenting on what they see the models showing this evening, nothing more or less. Yes, obviously some are enjoying the colder outputs, and there's some interest/excitement around it, but that's a bit different to people claiming it's nailed on to be the next ice age soon.

You're equally welcome to comment on what you're seeing in the models of course, but if you just want to have a moan up about let downs and how it's all not going to happen because it hasn't so far this winter, then maybe head over to the chat and moans thread for that.

 

[northwestsnow]

TREMENDOUS ECM ens- trended MUCH colder this evening.

RAMP-METER going into overdrive-

edit - think we will be a tad colder than Debilt

 

Edited February 19, 2016 by northwestsnow

[Ice Day]

Some fantastic output from the ECM tonight and at least it's not in deepest darkest FI.  Beautiful 144 chart with *proper* uppers over us so marginality shouldn't be a problem

.

Yes, everyone on here knows we could be being led up the garden path, yada yada yada, but let us have one evening of dreaming of the white stuff!

All aboard

[Frosty.]

The Ecm 12z ensemble mean has got me dreaming of a cold spell with increasing snow potential next week which could last beyond...Arctic air digging south as next week progresses and a cold pool establishing and look how far south the polar front jet goes!..BANK

[Weather Observer]

Woke up this morning to a sparkling hoar frost after overnight low of -6c. Spring in my step, but I still want my winter fix. The latest ensembles flatlining cold look good enough for that to me. At the last knockings of winter, with higher lapse rates and instability, snow could pop up at any time. And it could trend colder.

If I can borrow a phrase to describe this winter, we have spent so long with our feet in the gutter that we have forgotten where to look for the stars.

[Mair Snaw]

Well i went to the village pub at 5pm and its under new management so they are selling old stock off at £2 a pint.... ive come home home to over 60 posts in here to get thru and it also looks as tho the ECM has gone on a Cobra run with best charts of the winter being churned out.... either that or ive been on the pub run and im seeing things.... stunning charts tonight from the ECM and if they are repeated tomorrow then i think i may get my hopes up....will we get cross model agreement on this one??

[Paul]

And another request - posts about hoping to see cold/mild/whatever weather, or about frosty (or any other member) deserving to get their favourite weather type really aren't model discussion. 

You may call me a kill joy or whatever else, but we get complaints about this stuff from those who want to read actual model related discussion in here (ie the majority of users!) 

So I've moved the last couple to the chat thread, and ask anyone else wanting to make a similar one to head over there too please.

 

[Long haul to mild]

Seems to be pretty good model agreement to drop LP to the SW of the U.K. next weekend. How it transpires after that it crucial to snow chances. I'm not usually fussed about the pub run but tonight's will be very interesting in what solution it offers.

Same goes for the overnight runs, some consistency would be nice, especially as Nick Sussex's laptop (not to mention many other members' electronic devices) may not survive the throw from the window if this all goes pear shaped again!

[phil nw.]

Looking at the mean ecm/gfs charts this evening and the ecm suite are looking the colder of the 2,although both outputs are showing below average for the next 10 days.

Day 5 and 10 uppers for both

GFS 

 

ECM

Quite a cold ECM set with -8C uppers getting right down the country through the period.Although the axis of Arctic air across the pole is not the most favourably aligned for the Atlantic sector we see enough amplification to achieve a more direct Northerly from this model.A more direct Arctic feed would see lower dew points reducing the marginality of snow instead of rain further south resulting from any lows diving se into Europe.

It will be interesting to see which model has the better handling of the vortex breakup and the consequent release of the Arctic air to mid-latitudes.

Even the less bullish gfs ens shows a cold period as we change months.Temp anomalies for nw Europe for 2 x 3 day periods from a week ahead

so looking below average countrywide after the weekend ,and If the ecm is anywhere near then Winter looks like ending on quite a cold note with this trend continuing into March.

 

[Nouska]

1 hour ago, chris55 said:

ECM op shows why deblit ens are not all that useful in this potential scenario!

The ECM 12Z ensembles for Reading.

[winterof79]

I cannot see anything snowy before the middle of next week at least. This being the reliable time frame.

Wednesday

So that is by next Thursday and I can see no snow or cold.

 

 

Edited February 19, 2016 by Paul

[Banbury]

On 17/02/2016 at 9:43 PM, Lukesluckybunch said:

According to GFS that is , this is one model. Dont hang your hat on one model, so much uncertainty as T Schaffffaghanoheuhnacker just said

Blocking to the NE on Monday????

Really?

 

[Ice Day]

Heights heading up to Greenland at 162, but quite different from the ECM before then?  On the face of it, should be a good run, but who knows with the Pub Run?

 

[snowice]

1045Hp out of greenland on pun run high pressure in mid atlantic could be an omega block in the days to come?

[Froze were the Days]

1 hour ago, swilliam said:

Tonight's for WEERplaza - looks pretty good to me.

 

and mean 850 for 1 week away - -6 across middle of England - also pretty good

I don't mean to be pedantic but weren't the models projecting around -6 uppers in this supposed cooler/colder period we've just had and here in the south east we've seen nothing colder than just below 6c during the day and with a projected area of low heights close to the country by then surely that good ol' word marginal will once again be in force - we really need to tap into a 'cold' source, and yet again maybe the further north and east you live the better (how many times has that been said). All looking a good week away so much can change but just food for thought.

[stodge]

Evening all

Some overall thoughts on tonight's 12Z output and where we might be going toward the end of the month and beyond:

1) The UKMO is a step back from last night's run which I think fell into the outlier category. Tonight ECM has come to the rescue of fans of cold with a very strong run backed by its Ensembles (a big plus).

2) As for GFS, it once again plays with amplification and trough disruption but restores the status quo at the beginning of March as the PV re-constitutes (the usual reaction to the wave attack). The problem though for cold fans is or remains the position and orientation of the Azores HP. Those members which offer the coldest solutions are those having the Azores HP displaced furthest SW or oriented away from Europe. This allows the trough to dig south (rather than SE) into France and pulls in a colder airflow from the North Sea.

3) In order for the trough disruption to work, we need to see those heights rising to the NE but it's still very tentative and transient but it wouldn't take long for an in-situ cold pool to develop over Scandinavia  IF heights get established.

4) The Parallel shows what COULD happen and would be the nightmare for coldies as the low heights drain out of Europe and the Azores HP migrates eastwards. I actually think this is a possibility as part of the "false spring" scenario I mentioned before.

It's one to watch.

[Singularity]

I turn away to watch a movie and that ECM run rolls out!

Good to see it making sense again in that the Candian vortex doesn't come roaring back into Greenland. A breakaway of low heights heading SE across the Atlantic is far more logical given the stratospheric and MJO setup. It is curious though how even this ECM run has low 500 mb heights over Canada and relatively high 500 mb heights over Eurasia at a time when the lower stratosphere is expected to be in entirely the opposite arrangement!

I expect it's no coincidence that the best run of the day has come from the model which takes the MJO into decent amplitude phase 8 soonest. Convective activity reaching the dateline has a remarkably strong connection with a protracted negative NAO taking hold shortly afterward so I'd expect to see the Canadian vortex being interfered with well into the first half of March. In fact it should really be taken apart entirely before too long. 

 

Interesting that ECM has southern snow early Tuesday; the 850 hPa values barely seem adequate. Though I suspect 'southern' isn't actually including the coastal counties? Happens often, much to my despair 

Got to keep it realistic though - even with the ECM 12z it would be tricky sustaining any snow cover during the daytime down south. Further north it is a more exciting theme, I know.

[fergieweather]

56 minutes ago, Nouska said:

The ECM 12Z ensembles for Reading.

The new parallel (HRes) EC is repeatedly verifying best of all suites lately and albeit running the trend at base of clusters (plume below, 12z, Reading), it nonetheless matches well the colder transition in the sister EC Op. The EC snow signal (by T+210 across much of UK away from the SE, S coast and SW peninsula) is, of course, highly unreliable at this range anyway so not worth posting here. And thus by definition, anything shown by GFS at that range is even *more* unreliable, but that's an old and now wearying story.

[Thundery wintry showers]

My main concern regarding "snow potential" is the record warmth of the Arctic so far this year, which doesn't look like changing prior to this projected cold spell.  In previous years, when we've had cold spells coming from a long way north, we've had some mixing with airmasses that saw surface and 850hPa temperatures of -15C or below, and often around -25C.  The cold air of course gets modified near the surface as it heads south to the British Isles and gets mixed out by less cold pools of air, but stays cold in the upper atmosphere and comes accompanied by low dewpoints- hence deep cold.

But, for example, take a look at how unusually high the 850hPa temperatures are projected to be in the high Arctic on the ECMWF at T+120:

Although the ECMWF still has the 850hPa temperatures getting down to around -8C over the British Isles, this is not the sort of deep cold that we would normally expect to get from those source regions.  I would expect a spell similar to the cold snap that we had last weekend, with maximum temperatures between 5 and 7C, and marginality being a significant issue everywhere, though with snow for some.

Edited February 19, 2016 by Thundery wintry showers

[fergieweather]

8 minutes ago, Singularity said:

Interesting that ECM has southern snow early Tuesday; the 850 hPa values barely seem adequate. Though I suspect 'southern' isn't actually including the coastal counties? Happens often, much to my despair 

Who said it had snow by then? Wales aside, a very minor signal by end Tues, eg Cotswolds/Mendips (and bear in mind EC offers solid PPN too readily anyway). 

[Man With Beard]

NOAA tonight - baby steps towards an Omega block?

[northwestsnow]

GFS again not interested in any meaningful cold - hopefully ecm keeps the faith this morning.

Dont think ecm is going to look much like the 12z yesterday either, looks very cold but dry.

 

Edited February 20, 2016 by northwestsnow

[Severe Siberian icy blast]

3 minutes ago, northwestsnow said:

GFS again not interested in any meaningful cold - hopefully ecm keeps the faith this morning.

 

The GFS is totally ridiculous in the way it blows up a shallow flat low south of the UK into a monstrous dart board low with severe gales.  It's absolutely ridiculous and not even worth looking at after t144 at the very latest . Even the way it delayes the cold air Sunday now until Monday evening getting south of the Midlands is suspect . It's been Sunday evening all week but now it's Monday afternoon.  

Il be very wary of this model . Not because it's not showing what I want but because it's over complicating matters in typical fashion it's really annoying ! Anyway rant over lol

[Captain Shortwave]

15 minutes ago, Severe Siberian icy blast said:

The GFS is totally ridiculous in the way it blows up a shallow flat low south of the UK into a monstrous dart board low with severe gales.  It's absolutely ridiculous and not even worth looking at after t144 at the very latest . Even the way it delayes the cold air Sunday now until Monday evening getting south of the Midlands is suspect . It's been Sunday evening all week but now it's Monday afternoon.  

Il be very wary of this model . Not because it's not showing what I want but because it's over complicating matters in typical fashion it's really annoying ! Anyway rant over lol

Unbelievably the ECM is very close to the GFS solution this morning, we don't see any trough disruption with low pressure sinking southwards to our west which turns conditions milder as we pick up a flow from southern Europe.

                              ECM                                                                                 GFS

                     

The main issue across the output is a west based -NAO developing meaning the trough sets up too far west to get another cold spell going beyond the one during the first half of the week, in line with the longer term guidance but with a fair correction westwards of the pattern. It is worth adding that we have a complication for the south of the UK during the beginning of the coming week as the front pushing south this weekend stalls and develops further waves in response to the shallow lows moving east across the Atlantic and into France, this is why the cold air struggles to affect the south initially.

      

Edited February 20, 2016 by Captain Shortwave

[Man With Beard]

For me, the ECM op is not really worth following after T144 at the moment - the last two ops have probably been outliers at the both ends of its ensemble suite. GFS, not such wild swings but also doesn't fill you with confidence in that sinking trough. The only trend is some sort of easterly after D8 - but could as easily be Mediterranean sourced as Scandinavian sourced.

Edited February 20, 2016 by Man With Beard