Model Output Discussion 13/11/13 >

[Barry12]

The Met Office see some heavy snow on Wednesday I think

[A.J]

Or, maybe we can just steer a little of topic for absent friends,(TEITS)and wish him the best?

I'm sure Dave will appreciate the sentiments and best wishes from all members and we all no doubt wish him a speedy recovery

 

 

In the short/medium term, some interest still on the 18z GFS run this coming tuesday and into wednesday for weather with a wintry flavour in Scotland and Northern Ireland then sliding down the western flanks of the UK, as a nose of high pressure ridging in from the west is quickly eroded by a small disturbance that runs down the Irish Sea and into the near continent. GFS modelling (for what it's worth, has been quite consistent with this

[Panayiotis]

That's because UKMO aren't buying their 12z GM run into midweek. Major modifications to the version being used operationally. A long story beyond repeating here, but currently looking a wet picture into Weds.

Thanks for this Ian, it was why I found it interesting. I did comment earlier discussing if the UKMO were going to modify the fax, as the general evolution shown on the 12z wasnt supported by the other models. 

Fergie why don't you input more on here!! A LOT more interested/fascinated and adapted than a lot of those on twitter!According to bbc website the models in txt seem to show sunny conditions up here in leeds mid week.

He does but only when issues need to be addressed, it was a great help last year especially during the January cold spell having his input into this thread!

Edited November 16, 2013 by Panayiotis

[Richie V]

My concern is the sheer weight of cold heavy air around and to the north of Greenland. Hpa 850's approaching -40c have the power to flattern ridges in themselves. Think of it mechanically if you will coupled with an at times extremely intense pool of low 500 thickness. The risk of the high been squeezed toward been a euro high are immense imo. You will need much lower height (500) over europe to allow the forcing north and eastward of this mid Atlantic hp.

[stratty]

GFS 00z - sums up roughly the bbc/met outlook, cold 'blip' beginning of next week, then staying below average with an easterly/south easterly feed/dry

ECM - cold/very cold potential with more in the way of wintry showers for eastern counties as it goes on,Steve's sausage again evident!

Edited November 16, 2013 by stratty

[ICETAB]

The BOM and ECM looking cold all the way through!

 

I love the look of the last frame of the BOM. I think it could go on to show another easterly, except when it evolves this time it will drag down very cold air. Winter could be interesting.

 

 

 

 

 

 

ECM brings more cold at T216 as that low out west goes under the block.

 

 

 

850s stay low enough for snow to lower levels at T240

 

 

Edited November 16, 2013 by ICETAB

[Severe Siberian icy blast]

Somethings brewing in the water folks . I think what we will see is a cold week next week, raw but not snowy. But I have a feeling the following week we may see a lot more cold coming down into Central Europe into the uk. Once we get an outlet in the Arctic to feed cold into Europe we will see things develop . See the stray ensembles going very cold , this to me tells me something's aloft.

[SMU]

http://www.meteociel.fr/modeles/ecmwf/runs/2013111600/ECH1-240.GIF?16-12

 

Morning a more solid run from the ECM today & backs up lasts nights higher confidence levels of an Easterly flow around day 7/8

 

Another opportunity on the ECM day 9 / Day 10 ^^^ to get some vertical advection going west of greenland, although on the operational its not quite North enough-

 

much to be optimistic about today- more so in the synoptics & general pattern as opposed to bucket loads of snow-

 

S

[West is Best]

Great upgrade overnight runs picking up on the signs yesterday. There's still some unusual variation at relatively short range. Compare, for instance, UKMO at T120 with the GFS. UKMO is chart of the day at that range:

 

http://www.netweather.tv/index.cgi?action=meto;sess=

 

The development of the easterly is starting to look odds-on with the ECM pulling it through more progressively than GFS. Although the latter is the gold standard it has been said many times on here that in blocking patterns it can be slow to react compared to the European models. Either way the ECM type set up would start to allow bitterly cold conditions to begin setting in.

 

Also worth mentioning that the Alpine ski resorts are going to get a covering of early season snow from this.

 

Edit. Wrote all that before I saw Steve's post. Nice to see my amateur effort tallies with his thoughts.

Edited November 16, 2013 by West is Best

[shaky]

http://www.meteociel.fr/modeles/ecmwf/runs/2013111600/ECH1-240.GIF?16-12Morning a more solid run from the ECM today & backs up lasts nights higher confidence levels of an Easterly flow around day 7/8Another opportunity on the ECM day 9 / Day 10 ^^^ to get some vertical advection going west of greenland, although on the operational its not quite North enough-much to be optimistic about today- more so in the synoptics & general pattern as opposed to bucket loads of snow-S

yup and the models look a look better earlier on compared to yesterdays 12zs!!I defo think something is stirring and within the next day or so we gona see some BOOM charts!!what do you think steve?

[bluearmy]

Gfs is the 'gold standard' ?? you can't get away with that west!

ECM and uknto differ with their handling of the Atlantic depression at a reasonably short range. That should tell us what we need to know for the time being. All roads do appear to lead to cold surface conditions but whether we can subsequently hit the 'jackpot' of a stray left over cold pool is rather a lottery.

[Purga]

Yes a much more encouraging run from ECM with the chart at 240hrs continuing the N blocking theme and showing a split vortex

 

I think the best chances of proper cold can occur in a few weeks time IF the northern blocking continues.

 

I'm hoping we're in the 'set up' phase at the moment.

[MPG]

Yes a much more encouraging run from ECM with the chart at 240hrs continuing the N blocking theme and showing a split vortex

 

I think the best chances of proper cold can occur in a few weeks time IF the northern blocking continues.

 

I'm hoping we're in the 'set up' phase at the moment.

Think you hit the nail on the head there, the pattern is evolving, and this could be just the set up stage as you describe. Massive amounts of Northern Blocking being modelled by the long rangers, interesting times. We could end up stuck under cold air, with the surface temps getting colder and colder everyday.

[shaky]

According to matt hugo on twitter latest ecm seasonal update shows a mild winter with a +nao!!just thought I would let everyone in on that!!!

[bluearmy]

ECM mean at day 10 is sold on taking the core of the vortex to Siberia. At the same time, the stretching that precedes this leaves a lobe over Canada which works its way east by the end of the run. What will this create? An east coast trough to throw WAA and force another ridge to our west? An increased jet profile to drive the Atlantic through ? as much as the Siberian master will dictate a colder pattern for areas to our ne, so this detached lobe will probably cause us headaches.

[ICETAB]

According to matt hugo on twitter latest ecm seasonal update shows a mild winter with a +nao!!just thought I would let everyone in on that!!!

I thought he posted something about the ECM32 dayer yesterday that suggested december showed Northern blocking. Does that not mean the first month of winter will have a -NAO?

[Cecil Hogmanay Melchett]

Personally i couldn't care less what the EC seasonal suggests,and thats not because its gone mild,i saw the 32 dayer get it wrong so many times last winter im not going to worry myself with a 3 month forecast.

Anyway,still some divergence on model guidance for Tues/wed.

UKMO seems keen to bring some precipitation to the UK while GFS/ECM look less keen.

FAX charts will reveal more this morning.

Longer term,ECM looks more appealing with solid blocking to the NE and a southerly jetstream.

For many of us its midweek thats attracting attention.

[Frosty.]

I think this is going to be another FANTASTIC day of model watching, already we have these charts which caught my eye on the GEFS 00z perturbations, following the initial plunge of arctic air, there could be a rapid reload from the north as another trigger low sweeps south...and then we have P 7..now P 7 is very special... it turns into a cobra run, there would be so much white stuff we would all need a snow plough..Epic potential again, and a good chance of a scandi high developing, and strong greenland high with retrogression, so many possibilities.  

Edited November 16, 2013 by Frosty.

[Polar Front]

Or, maybe we can just steer a little of topic for absent friends,(TEITS)and wish him the best?

What has happened to TEITS? Noticed he has not posted since August! Loved his optimism every winter for an 80's style Scandinavian high described as "The Beast from the East"!

[Cloud 10]

CFS ensemble mean for the first week of winter looks enticing with an uber-block to 

our NW and what looks like a cross polar flow.

 

 

 

Maybe a northerly-easterly-northerly combo in the next 3 weeks. 

 

 

just to add a rather chilly looking set of ensembles from the 00z ECM.

 

Edited November 16, 2013 by Cloud 10

[BLAST FROM THE PAST]

 

That snapshot at t144 from ECM....if it consolidates in future runs it is a very good position to get to.  My overnight chart of the day

 

 

BFTP

[Catacol]

I'm dashing out... but a quick look at the models today and very happy indeed. Running both GFS and ECM and it is clear that the westerly circulation in our part of the world is grinding to a halt; LP systems stalling and sliding south with pressure high to our north in some shape or form. Cant ask for much better really - apart from the obvious point : WHY are we getting these synoptics in November! Aaaarghhhhh - to get them in January would be SO much more productive. For most of us I still think cold rain is the likely outcome unless at elevation at this time of year.

[Catacol]

CFS ensemble mean for the first week of winter looks enticing with an uber-block to 

our NW and what looks like a cross polar flow.

 

wk3.wk4_20131114.z500.gif

 

 

 

 

That second chart isnt good at all. North Westerly flow with HP extending to our south. Yuck. Unless you're up a mountain. Hoping for much better based on the op runs this morning.

Edited November 16, 2013 by Catacol_Highlander

[Summer Sun]

Latest from Gibby on the models

 

All models show agreement now on the pattern of events up to the middle of next week. A slack airflow over the UK will persist today with cloud invading the still cold and frosty SE later today. Some light rain in the NW intensifies later as a cold front sinks slowly South over the next 24-48hrs. A band of rain will accompany it before colder clearer weather follows slowly behind reaching Southern England later on Monday. With a cold NW airflow then showers will be driven into Northern and Western areas and will turn to snow on all high ground and some lower ground too at times. Southern and Eastern England will see relatively few showers and will see some cold sunshine through these days.

 

GFS then shows the post midweek period as becoming dry and frosty over the UK with mist and fog problems night and morning as High pressure builds across from the West. Later in the run Southern and Western areas are shown to turn more unsettled as a chilly SE flow develops with pressure falling to the SW sending rain bearing troughs NE into Southern and Western Britain. Northern and Eastern areas look like staying predominently dry and rather chilly throughout the run with this weather type extending back over the South too at the end of the run.

 

UKMO closes it's run with High pressure sliding SE across the UK with settled and dry weather but pretty cold conditions at the surface and overnight frost and freezing fog could become a big problem for commuters towards the end of next week and may fail to clear by day in places.

 

GEM this morning shows a progression towards mostly dry and fine weather following the cold weather early in the week with wintry showers. With High pressure just to the West a lot of rather cloudy and benign coditions look likely with temperatures just below average but with some frost at night behind weak cold fronts passing South at times when skies clear.

 

NAVGEM shows High pressure building across more Northern locations later next week but the South maintains a very cold and blustery ENE flow with rain and sleet at times and snow on the hills. Some frost and freezing fog patches will develop over the cold and less windy North late on in the run.

 

ECM brings high pressure across from the West midweek snubbing out the Northerly flow and frost and fog in calm conditions look likely for a day or two. Pressure falls to the West and later the South with a chilly SE then NE wind across the South with rain at times later with even a little sleet over the hills while Northern areas stay largely dry and rather cold.

 

The GFS Ensembles show a short cold snap before conditions slowly recover to very much average conditions for late November. A period of stagnant High pressure seems likely with frost and fog at the surface issues late next week before the mean for the pack suggests the Atlantic cranking up later with rain and strong winds crossing East over the Uk on occasions late in the run.

 

The Jet Stream shows the flow way North of the UK currently before it turns sharply South early next week. This northern arm then detaches from a weaker Southern arm and continues to blow strongly East at high latitudes later next week suggesting UK High pressure. It does break down later and resets closer to the UK later in the run.

 

In Summary the Northerly of next week still looks like there is an opportunity of a day or two when snowfall could be seen by some parts of the UK chiefly in the North and West and over the hills. Thereafter High pressure looks likely to build in from the West or NW with a chilly and raw day or two possible in the South on a ENE flow around midweek. It looks likely the High will migrate East then into Europe and maintain a ridge West or NW over Northern Britain.

 

This sets up a SE flow over the South and with falling pressure down to the SW rain would make progress into these parts with time to give dull and uninspiring late November conditions down here with some rain at times while Northern locations stay largely dry and bright if on the chilly side. most output does suggest High pressure in the Scandinavian region later in the run and this could be the catalyst for more blocking conditions for the UK which could in time result in further cold outbreaks developing as we drift deeper towards Winter official from December 1st. For now though all of the above suggests typical November weather for the UK.

 

http://www.norton-radstockweather.co.uk/Model-Analysis(2859336).htm

Edited November 16, 2013 by Summer Sun

[bluearmy]

That second chart isnt good at all. North Westerly flow with HP extending to our south. Yuck. Unless you're up a mountain. Hoping for much better based on the op runs this morning.

 

thats a bit fussy CH. after all, we would have decent surface cold after week 3 (if it verified).