Model Output Discussion - 23rd Jan - 12z onwards

[Mucka]

Yeah its day 10 but that low to the NW that was supposed to bring the "beakdown" disrupts through the UK with a reload.

 

 

Fantastic run.

[J10]

EC is just stunning all the way though tbh, however if we stick to T144, a Steve says there is a front moving down, IMO there are a couple of surface features (i.e upto around 8000ft) coming down the country, as we get closer, history (and far too much model watching), tells us that the warmer sector and colder sector in these features amplifies down to around T48-72 region. With the amplification comes rain and sleet for areas west of the features centre and heavy snow just to the east. These features also tend to move west a bit as well imo.

With that in mind a forecasting would be very concerned with *snow potential* atm, particularly for areas east of devon and west wales and west of say the M1.

A wide area atm, which will get narrowed down, but dry this aint.

 

As such tend to prefer no areas of precipitation and would rather showers.

However thereafter there are many opportunities for western areas in terms of wishbone snow showers IF this run verifies.

 

Not getting carried away, there will be model ups and downs, and still T+168.

[TSNWK]

I agree best run for cold uppers and duration since 2010.. Yes I know! But and of course it is a big if! Thar run verifies then it will be 2010

[Ice Day]

Forgive me for a little imby post, but the uppers over the south east don't get above -5 from 120 through to 240.  This at 240, super stuff!  

 

Edit - mind you, that goes for pretty much the whole country!

 

Edited January 24, 2015 by Ice Day

[Daniel*]

Those complaining by poor 850s should be relieved as I expected an upgrade on the uppers, ECM 12Z is very nice for all, as others have said very unstable flow, as good as any for widespread snow showers. I think this cold spell should be given more "respect" and shouldn't be underplayed.

[TEITS]

Nice band of snow developing on the ECM at +216 which tracks SE across the UK. Probably more in the way of rain for the W but snow for the E.

 

http://www.meteociel.fr/modeles/ecmwf/runs/2015012412/ECM1-216.GIF?24-0

[nick sussex]

Yeah its day 10 but that low to the NW that was supposed to bring the "beakdown" disrupts through the UK with a reload.

 

 

Fantastic run.

I think I'd give it 7/10, it doesn't split the PV this time and the depth of cold is okay but nothing great. There is room for improvement especially upstream.

 

Some snow chances but at this range detail is likely to change, overall not a bad run but I'd hope there would be better ensemble members.

[Cheshire Freeze]

The most pleasing aspect of the ECM 12z is the shrinking of the deep low heights around Canada and Greenland- something which we have been completely devoid of so far this winter. Combine this with a displacement of the vortex core to the eastern side of the hemisphere and you have a recipe for a fairly stable pattern of large scale troughing to our east and heights repeatedly attempting to ridge N to our west.

The reason I couldn't get excited over the last colder spell (as many will remember) is because the profile just didn't look 'right' i.e too much energy over the top due to the dominant western N hemispheric vortex. As soon as you see low heights drain or displace from that locale, you'll see that the jet relents (and can become more meridional) due to an easing of relative temperature differentials across the area.

Edited January 24, 2015 by CreweCold

[winterof79]

Reviewing the ECM 144 it has

* A trough moving south over the uk ( look at the kink )

* low heights - circa 500mb thickness ~ 524 dam

* low uppers over england - as low as -8c in the SE

Thats certainly has wintry potential!!

s[/

Steve you must admit the weather gets the better of the best of us.You were conceding defeat yesterday.

[nick sussex]

As I said earlier it's more a 14 day cold spell...things are changing for UK for Feb....cold is coming

I admire your optimism but if you take the ECM at face value the upstream pattern flattens out too much and the PV will just run east, that deep low leaving the ne USA needs to be more amplified to at least build more ridging ne ahead of it, that way you might get the ridge toppling favourably and a ne flow, this would extend the cold by a few days.

 

Of course things might change and of course I'd love to see an extended cold spell but I think we have to be realistic and not get expectations that are impossible to meet.

 

In the UK 7 days of cold is very good going anyway, lets see what happens in the next few days.

[Jason H]

GEFS are a further downgrade IMHO. Others will no doubt see thing differently (which is perfectly fine)

By 252 hours the Atlantic has broken things down on all but a couple of ptrbs. In terms of the depth of cold a few are better than the opp, but overall the opp is representative of the 12Z suite.

 

Phew, so we're looking at a charts 11 days away to confirm the cold spell that hasn't started has finished. LOL.

[blizzard81]

Great ECM tonight. Can't see a breakdown coming any time soon on the 240 chart. What also strikes me is the strength of the Siberian high on that chart and the positioning of it - looks primed to head west to me

[Jason M]

Good Ecm. That would be plenty cold enough across much of the UK.

Be interesting to see the ensemble means later on.

[offerman]

Yeah its day 10 but that low to the NW that was supposed to bring the "beakdown" disrupts through the UK with a reload.

 

 

Fantastic run.[/quote

What time did you get? :-)

[Geordiesnow]

No disputing the weather could turn colder next week but I really would like too see a better amplified ridge in the Atlantic to sustain any TRUE Northerly(isobars coming all the way from Svalbard/Arctic) and allow the colder uppers to come down within the flow... again, the -10hpa does not really make an appearance into mainland Britain but with some adjustments then surely this is possible, especially with that huge solid lump of PV that is forecast to come out of the Arctic. 

 

The detail will no doubt vary and we will see some good and some not so good runs but the theme as we head into the latter part of January does seem to be one of turning colder with an increased risk of snowfall starting from midweek with what could be a fairly potent WNW'ly. 

[Jason M]

Phew, so we're looking at a charts 11 days away to confirm the cold spell that hasn't started has finished. LOL.

Why not post something which contributes to the thread?

My post was based on what the model was showing. Posting about the models in the model thread? Whatever next :-)

Please do try harder!

[SMU]

Looks Nice tonight - ECM Reminds me of jan 2004 IIRC- thundersnow lol

 

In terms of the ECM, it manages a fine balance ( very rare in the UK ) of established Northerly winds & a jet that stays attenuated enough to keep us in the cold air for more than 2 days.

 

It does still feel a little 'optimistic' especially after 168 with 2 reloads & no eastward progression from the Atlantic however a couple of amazing charts...

 

one for the UK-

http://www.meteociel.fr/modeles/ecmwf/runs/2015012412/ECU1-144.GIF?24-0 possible frontal snow- rare as turkey teeth

 

http://www.meteociel.fr/modeles/ecmwf/runs/2015012412/ECU1-216.GIF?24-0 More frontal snow for the NE

 

however this all superseded by the bowling ball cold cover the Whole eastern seaboard of America... day after tomorrow stuff!!!!

 

http://www.meteociel.fr/modeles/ecmwf/runs/2015012412/ECH0-240.GIF?24-0

 

Certainly an uptick in optimism tonight- although still 'noise' around longevity -- however all models have hinted that a reload of some sorts is likely with the first atlantic attack taken away to the SW of the UK
S
 

Reviewing the ECM 144 it has
* A trough moving south over the uk ( look at the kink )
* low heights - circa 500mb thickness ~ 524 dam
* low uppers over england - as low as -8c in the SE
Thats certainly has wintry potential!!
s[/

Steve you must admit the weather gets the better of the best of us.You were conceding defeat yesterday.

 

 

Not quite conceding defeat, however the angle of the low & shape was preventing any true cold air coming south- luckily the ECMs view today has certainly sharpened up the flow to suitable levels- IE sub -6c

S

[nick sussex]

Nick the T144 to 216 I feel will be cold..it's the signal out the MO I like for after that re a first negative NAO for mid Feb...models poss not seeing it yet...I'm optimistic this cold snap could become a 14 day spell...we shall see

To extend the cold you need the type of set up shown below:

 

The deepish low exiting the ne USA needs to be more oval elongated, this will drive better WAA ne, this will in turn amplify the Azores high, even if the PV then edges east this could topple towards Scandi with a cut back of ne'rlies as this happens.

 

If the ECM had delivered that on its T240hrs it would have got a 7.5/10 from me! lol

 

[West is Best]

I have concerns about this because the models seem ripe for the whole set up to get shunted further east nearer the time. That's my fear. It's the absence of upstream blocking, and specifically the absence of a Greenland high, and the continued cyclogenesis off the eastern seaboard, which are my concerns. Take this chart, for instance, and drag your drooling eyes from the east to west. Have a look at the low developing off the US/Canadian coast. Without blocking I can just see this northerly on our shores getting pushed away, first 50 miles, then 100 miles, then 200 miles and, before we know it, we're in toppler territory with barely a whisper of the current promise. I want to see upstream blocking.

 

Edited January 24, 2015 by West is Best

[IDO]

The 12z runs are OK IMBY with some chances of snow, maybe settling. However I am looking for a true wintry spell where there are no marginal uppers with big opportunities for snow. Something like this:

 

  RaleighWx
Raw 12z ECMWF numbers showing around 35 inches at Boston over next 9 days.
24/01/2015 18:53

 

That is what I would like to see! The US are seeing another memorable winter. I suppose unlike last year we are getting more scraps. Fingers crossed there are upgrades from the GFS as I have no confidence in the ECM.

[Jason H]

Why not post something which contributes to the thread?

My post was based on what the model was showing. Posting about the models in the model thread? Whatever next :-)

Please do try harder!

Touchy. I was merely pointing out that any breakdown on the GFS was over 11 days away, so shouldn't be taken as gospel. And, not to worry too much. Yesterday I was sceptical of the up and coming cold spell. I think it's been upgraded today with colder uppers now being introduced, so mu bullishness is increasing. I'll wait for the Met Office or Ian F to comment further.

[Mark Neal.]

The 12z runs are OK IMBY with some chances of snow, maybe settling. However I am looking for a true wintry spell where there are no marginal uppers with big opportunities for snow. Something like this:

 

  RaleighWx

Raw 12z ECMWF numbers showing around 35 inches at Boston over next 9 days.

24/01/2015 18:53

 

That is what I would like to see! The US are seeing another memorable winter. I suppose unlike last year we are getting more scraps. Fingers crossed there are upgrades from the GFS as I have no confidence in the ECM.

 

I think for us down south we would settle for 2-3 inches tbh. really hoping something like the ECM comes off, with cold uppers and a low pressure moving down the country, would be fantastic to have a situation like you also mention, where marginality isn't needed, it seems like overtime for us down South. Encouraging output today with a 2-5 day cold spell at least, potentially longer if the ball is rolling.

[damianslaw]

Models continue to paint a cold unsettled theme as we move through next week, with a deep trough digging into Europe enabling a very unstable cold NW flow to develop by weeks end. ECM suggesting a locked in cold polar/arctic maritime airflow into the start of Feb with embedded troughs from the NW as heights over mid atlantic stay well out to the west.

 

Jetstream profile backs up what the models are showing i.e. a deep longwave trough digging into central Europe with the uk on the cold side of the polar front, however, it also shows the return of the jet on a west-east axis by around the 4th Feb.

 

Met Office update hinting at the chance of a more blocked outlook as we approach mid Feb, for the first time all winter.. nothing unusual in this, as traditionally blocking tends to become more likely by middle of Feb as the atlantic eases - we don't know what the signals are for such suggestion but it could well be a sign of a strengthening Siberian block edging into scandi behind the projected euro troughing and a generally more amplified pattern with weakened PV displaced away from Baffin Island region.

 

I think things will go one of two ways as follows, but we will eventually end up with a drier colder pattern by middle of Feb:

 

1. A cold NW/N blast from next Wednesday lasting roughly a week before we see a westerly flow around the 4th Feb, lasting about a week becoming weaker against increasing heights to our east.

2. A locked in cold NW/N blast with the euro trough in place, eventually heights sinking down over scandi behind the trough to set up a more easterly airflow.

 

From a long term perspective chances of a more sustained colder pattern are at there highest they have been so far all winter.. with a much better northern hemisphere profile + time of year.

[nick sussex]

The 12z runs are OK IMBY with some chances of snow, maybe settling. However I am looking for a true wintry spell where there are no marginal uppers with big opportunities for snow. Something like this:

 

  RaleighWx

Raw 12z ECMWF numbers showing around 35 inches at Boston over next 9 days.

24/01/2015 18:53

 

That is what I would like to see! The US are seeing another memorable winter. I suppose unlike last year we are getting more scraps. Fingers crossed there are upgrades from the GFS as I have no confidence in the ECM.

Yes its amazing when you look at the USA with the depth of cold so far south and here in Europe its true we've been feeding off scraps and are supposed to be thankful for small mercies!

 

Its for that reason that I hope the models can deliver some decent depth of cold and dry snow, I'd like to put the term marginal into the swear filter!

[Froze were the Days]

I have concerns about this because the models seem ripe for the whole set up to get shunted further east nearer the time. That's my fear. It's the absence of upstream blocking, and specifically the absence of a Greenland high, and the continued cyclogenesis off the eastern seaboard, which are my concerns. Take this chart, for instance, and drag your drooling eyes from the east to west. Have a look at the low developing off the US/Canadian coast. Without blocking I can just see this northerly on our shores getting pushed away, first 50 miles, then 100 miles, then 200 miles and, before we know it, we're in toppler territory with barely a whisper of the current promise. I want to see upstream blocking.

 

My concerns as well - I feel we will get low heights to the E/NE but how long it stays there and the depth of cold it pulls in is certainly up to discussion, I feel the GFS 12z is closer to the mark (unfortunately).