Model Output Discussion - 23rd Jan - 12z onwards

[Mucka]

Mucka, is your comment re 'lacking data' based on something concrete or is it just a 'too good to be true' feeling?  Fantastic chart by the way!

 

A bit tongue in cheek but also genuine curiosity. 

It is just that it is unusual for something to change and get cross model support for that change in the 3/4 day range (Shortwave not drop SE and develop) and then suddenly reappear which it has here with the Op and control and several ensemble members.

My upgrade comment was slightly premature though because although there are some very nice looking runs out to say 144 it also goes crazy with flattening the pattern thereafter with only a few members surviving to show any form of blocking by 192. That is probably the ensembles being far too progressive though.

All a bit odd but then ECM shifted its morning pattern a thousand miles or more West so anything could happen I guess. 

 

ECM London ensembles. No support for a deep freeze but some support for a little lengthening of the cold.

 

Edited January 27, 2015 by Mucka

[Ice Day]

A bit tongue in cheek but also genuine curiosity. 

It is just that it is unusual for something to change and get cross model support for that change in the 3/4 day range (Shortwave drop SE and develop) and then suddenly reappear which it has here with the Op and control and several ensemble members.

My upgrade comment was slightly premature though because although there are some very nice looking runs out to say 144 it also goes crazy with flattening the pattern thereafter with only a few members surviving to show any form of blocking by 192. That is probably the ensembles being far too progressive though.

All a bit odd but then ECM shifted its morning pattern a thousand miles or more West so anything could happen I guess. 

 

OK, many thanks.  You're spot on though, there's some very volatile output on show currently.  The optimist in me believes that chaos reigns before decent UK snow events, so this should be a good one.  Simples!

Edited January 27, 2015 by Ice Day

[pages]

This would be fun London at a stand still

Edited January 27, 2015 by pages

[Mucka]

This would be fun London at a stand still

 

It would cause chaos no doubt but the 2 inches of snow it would bring would probably get more coverage than the Boston blizzard.   

[pages]

OK, many thanks.  You're spot on though, there's some very volatile output on show currently.  The optimist in me believes that chaos reigns before decent UK snow events, so this should be a good one.  Simples!

Chaos is reining because the models keep trying to rebuild the trop vortex in the medium- long term. but the lower strat is starting a large warming from t54 onwards. look at the last 4 days of GFS 18z for the same time. (31/01 at7pm)

 

As modeled Saturday

As modeled Sunday

As Modeled Yesterday

as modeled tonight

 

Its quite clear to see that the energy coming out of Canada has decreased each run. only now are we seeing energy go under.

Watch the models do the same with next lot of energy over the next couple of days. The vortex is not as strong as the models are currently modelling. this trend won't continue indefinitely but i think as long as the low strat is warming, we may continue to see the models over play the strength of the trop vortex

[Mucka]

Good morning.

 

Met Office talking of mainly rain to low levels through Friday and snow showers turning to sleet and rain later Thursday so it would seem the warm sectors will make it a slushy start to the cold spell for those lucky enough to see any lying snow in the first instance. Let's hope ppn is limited as the warm sectors pass through.

 

00z runs rolling out. GFS is so far quite similar to yesterdays 18z run with the shortwave running SE down the Eastern flank of the ridge so it will be interesting to see if the Euros go back to that as well. 

 

Edited January 28, 2015 by Mucka

[JoeShmoe]

Mucka, do you sleep !

Yes, GFS encouraging so far with a continuation of what it showed on the pub run last night ....

[MR EXTREMES]

notice the lil feature running through the alantic then dives to our southwest and possibly better heights heading towards greenland.

not to worry just a channel low that i will say has been popping up a bit lately

could this be the trigger point for a more prolonged setup........

yummy

ukmo does not have the channel low but very much showing the strong mlb which is good and consistent

ukmo t144 now says how about we go for a north easterly flow great fantastic continuation from recent runs there getting better and better.

 

looking likely a very cold start to feb slack cold northerly north easterly towards the end of the gfs with cold embedded air anything falling from the sky would be wintry.

absolutely nothing mild at all absolutely the best charts all winter although the alantic heights look like they could topple down but from the runs so far there no change to mobile westerly through out the run.

192hrs still cold excellent winter has finally arrived.

id be inclined to say its very december 09 like

Edited January 28, 2015 by emotional rollercoaster

[Mucka]

I am sleeping now

 

 

That is getting pretty close to giving the Southern contingent happy days. It is further North than last nights run so by this evening it may be the channel low of that p20 run 

Also the embedded trough in the Northerly flow would bring a band of snow South. Very wintry,

 

UKMO does move the shortwave SE but it has virtually disappeared by the time it is NW of Ireland, nice chart though.

 

 

And 144 very nice indeed.

 

 

So I would say excellent output out to the midterm so far this morning

 

Continuing the updates.

I can't say I had high hopes of last nights pub run being repeated this morning but the 00z does just that and upgrades the cold into the bargain.

 

 

Starting to get quite exciting for coldies but it is just two Op runs thus far with little to no ensemble support and ECM has shown something quite different so too early to get too excited just yet.

GFS FI being what it is the Atlantic races in later but the general pattern is actually better than the 18z if you want an Easterly.

Edited January 28, 2015 by Mucka

[Penrith Snow]

Great charts, the UKMO is peach, note the mid Atlantic Ridge joining with a pronounced Arctic High +144, potential is an understatement.

Ramping not required, the computers have done that for us.

Up early to drive to Glasgow on M74 which rises to 850 feet at Beattock Summit, the drive home will be interesting!

Andy

[Captain Shortwave]

Good morning, another good set of runs so far, the GFS again draws in a slack easterly later on in its high resolution run and the UKMO looks better than the GFS at day 6.

ECM starting to put that shallow low back into the fray as well now

Will be interesting to see the track. Nice northerly flow too with a kink in the isobars moving south to potentially enhance the snow showers down eastern coasts and possibly drive them inland too.

ECM tracks that low further north before sinking the system down the western side of the UK.

Snow from this away from the south west. But the details up for debate at the moment. Especially as the ECM disagrees with the GFS and UKMO which both have a faster and more southerly track (though the UKMO has a much weaker system).

Edited January 28, 2015 by Captain shortwave

[Man With Beard]

ECM follows GFS to some extent with a slider low tracking SE across the country between T120 and T144. If it verified, a snow-fest will be on order for those on the eastern flank ... and a nervous wait for those in the west to see how far the mild zone penetrates in land. The GFS version, as mentioned already, misses us completely to the south - by a fraction (similar to March 2013)

Still quite far out for a small feature, so just 'one to watch' for now.

[Duane S.]

I think the 00z was out on the town with the 18z last night, the diving low pressure system is there this morning, upgraded if anything as it is slightly deeper and a touch further North. Euros doing the same albeit not as such a well defined trough, maybe more realistic.

Anyway, it's another GFS op run that has Dorset averaging around -5 850s for 10 days, the control goes further and does it for all 16 days! This is no cold snap...

Essentially then short - medium term is looking great. Thereafter potential remains rife. I'll take that!

[Ice Day]

Fantastic overnight runs from both GFS and UKMO,  ECM looking OK as well, toying with an easterly at 192! 

 

 

[Ali1977]

The high is strong near newfoundland so might aid getting rid of the PV over Greenland and help enhance northern blocking.

[shaky]

Crazy output this morning! ! We are approaching the first day of this cold spell and the cold is getting extended further day by day!! Normally its the other way around! ! Anyway gfs was onto something last night with that shortwave diving south east again!! Gota hand it to the gfs for leading the way with that low!!

[Severe Siberian icy blast]

Fantastic overnight runs from both GFS and UKMO,  ECM looking OK as well, toying with an easterly at 192! 

 

 

yes excellent charts . The shallow trough picked up by gfs is there on all 3 models this morning . The UKMO having it as a much weaker affair . But great to see this being thrown into the mix.

The ECMWF_0Z at t192 is the flattest out the 3 . To much troughing north and north east of the high for it to ridge East . So I suspect It'l sink . But non the less what a great start to the day .

[chris55]

Excellent runs from the big three this morning. To note is the little diver low out in the Atlantic IF we could get very lucky with it then that could produce a proper snow event, though way to far out at the moment. All in all though it could be a very cold first week of Feb

[Timmytour]

Mid Atlantic blocking

Sliding Lows

This is no ordinary cold spell

This is an M&S cold spell!

[Nick L]

The ECM low on Monday night brings a lot of precip into Wales, western England, West Midlands and parts of the southwest, with decent cold air too. That would make a good snow event and finally bring something widespread for central and southern areas!

Edited January 28, 2015 by Nick L

[Man With Beard]

www.meteociel.fr/modeles/ecmwf/runs/2015012800/ECM1-240.GIF?28-12

Northerly reload looks possible at the end of the ECM run with 850s never getting above 0C. Still, anything beyond T144 is a long way out in a UK cold spell.

[bluearmy]

Upstream beginning to look more conducive to prolonging the cold.

The NH profile at day 10 broadly in line with the ens mean but with far more ridging evident which is natural on an op in comparison with a mean. So no outlier pattern although the detail for large areas can still vary significantly.

[West is Best]

Good morning all,

 

I've spent a few days watching the medium term patterns, in other words from the critical point of 3rd Feb onwards. The 2-3 day colder spell Thurs-Sat is fairly nailed on, although there remain issues about the uppers, it's what comes after that has been of interest to me. The GFS op has consistently been progging a northerly reload, but it is also consistently lacking in support. At times the scatter has been tighter, but in the last two runs the op has been very much on the colder side: the 18z was an outlier altogether.

 

My point here is that once the arctic sourced westerly, then eventually northerly sets in, beyond that (Sunday onwards) remains unclear and far from certain. We watch with all due caution. The operational has been below the ensemble mean in every single run for the past 48 hours. So I would temper understandable medium term enthusiasm and make the most of the next 2-3 days. Beyond that still looks precarious from these ensembles and the toppler scenario is likely to emerge at some stage in an operational if this much scatter persists for much longer:

 

https://forum.netweather.tv/gallery/image/20785-/

https://forum.netweather.tv/gallery/image/20786-/

https://forum.netweather.tv/gallery/image/20787-/

https://forum.netweather.tv/gallery/image/20788-/

https://forum.netweather.tv/gallery/image/20789-/

https://forum.netweather.tv/gallery/image/20790-/

https://forum.netweather.tv/gallery/image/20791-/

https://forum.netweather.tv/gallery/image/20792-/

 

In the meantime this colder blast should be fairly interesting.

Edited January 28, 2015 by West is Best

[nick sussex]

Morning all, Happy Christmas! lol

 

Some belated Christmas presents from the outputs today, the pick of the bunch for the medium term is the UKMO which has the most pronounced ridge to the ne.

 

It's been a strange few days with the shortwave ahead of the upstream low now shown to separate earlier after going through some separation anxiety for a few days, this was complicating the issue so we do need the models to stick to this renewed trend.

 

The models deal differently in terms of track of that shortwave, the GFS deepens this  more, you'd preferably want this to stay a shallowish feature incase its track is more through the UK and from my own perspective I don't really want to see this blow up in the Bay of Biscay, so by all means if its going to develop, a favourable track to deliver some northern flank snow to favoured areas of the UK would be most welcome!

 

After this shortwave possibilities of an east/ne flow but detail still unclear there, overall a good start today for cold and snow potential but I'll be happier once that shortwave is modelled within the T96hrs timeframe.

[bluearmy]

Morning all, Happy Christmas! lol

 

Some belated Christmas presents from the outputs today, the pick of the bunch for the medium term is the UKMO which has the most pronounced ridge to the ne.

 

It's been a strange few days with the shortwave ahead of the upstream low now shown to separate earlier after going through some separation anxiety for a few days, this was complicating the issue so we do need the models to stick to this renewed trend.

 

The models deal differently in terms of track of that shortwave, the GFS deepens this  more, you'd preferably want this to stay a shallowish feature incase its track is more through the UK and from my own perspective I don't really want to see this blow up in the Bay of Biscay, so by all means if its going to develop, a favourable track to deliver some northern flank snow to favoured areas of the UK would be most welcome!

 

After this shortwave possibilities of an east/ne flow but detail still unclear there, overall a good start today for cold and snow potential but I'll be happier once that shortwave is modelled within the T96hrs timeframe.

Come on nick - you can sacrifice a biscay low for a part of the uk to get a proper dumping! (As long as it 'blows up' closer to Spain than the uk!)

as nick L has said, that ECM run delivers a proper fall to the sw quadrant (inc wales)