Model Output Discussion 1st Nov.2013

[shedhead]

It's the gfs so you must expect anything from sublime to ridiculous and everything in between, however, I'm sure there will be lots of cold potential within the GEFS 12z perturbations and we must remember the timeframe of interest is still beyond T+240 hours.

 

Therein lies the age old donkey and carrot winter model watching problem and tbh I wouldn't mind a tenner for everytime it or something very similar has been said in here.  If 90% of the winter charts between T+240-384hrs verified, it would be 62/63 every winter....

[MR EXTREMES]

Good to see unrealistic charts into fi perhaps we need the straws to clutch.

After a period of higher heights it does look like a 're run of the zonal train.

As Greenland block very unrealistic considering the vortex has yet to increase in strength.

Although colder snaps rather than cold spells are showin on most model outputs very flat and weak blocking still lots of the winter wonderland jigsaw still missing so realistically looking at the charts settling down for southern areas of the UK for awhile frost and fog.

More unsettled the more north you go then return to a more typical west nw flow at times arctic.

[Captain Shortwave]

Actually, I take back the whole flattening pattern thing, look at these two charts

This mornings ECM

This afternoons UKMO, 12 hours earlier but the difference between the two is noticeable

GFS same time

 

 

I know this is a long shot but look what happens on the GFS (slightly less amplified than the UKMO at this time), This is 24 hours later on the GFS

 

I wonder what the UKMO for the same time would look like, I would think there would be a deeper low over Europe and heights further north than the GFS is showing. A long shot but something to look at, but this amplification has developed pretty much since this morning on the output.

If the ECM backs the UKMO at T144, I wonder if it would pull a Scandi high.

Or I could be completely wrong and straw clutching 

Edited November 8, 2013 by Captain shortwave

[The PIT]

Therein lies the age old donkey and carrot winter model watching problem and tbh I wouldn't mind a tenner for everytime it or something very similar has been said in here.  If 90% of the winter charts between T+240-384hrs verified, it would be 62/63 every winter....

And vice versa for summer. Looks like we'll be mainly topping up the rain totals although hints of the south turning drier.

[MR EXTREMES]

Actually, I take back the whole flattening pattern thing, look at these two charts

This mornings ECM

This afternoons UKMO, 12 hours earlier but the difference between the two is noticeable

GFS same time

I know this is a long shot but look what happens on the GFS (slightly less amplified than the UKMO at this time), This is 24 hours later on the GFS

I wonder what the UKMO for the same time would look like, I would think there would be a deeper low over Europe and heights further north than the GFS is showing. A long shot but something to look at, but this amplification has developed pretty much since this morning on the output.

If the ECM backs the UKMO at T144, I wonder if it would pull a Scandi high.

Or I could be completely wrong and straw clutching

And look at the deep lows to the north right to left awfully bad charts if cold spell is what your looking for.

Swift flattening of heights back to zonal for the rest of November perhaps into December.

[shotski]

And look at the deep lows to the north right to left awfully bad charts if cold spell is what your looking for.

Swift flattening of heights back to zonal for the rest of November perhaps into December.

Deep lows ????? Oh yeh must be that 1015 mb one to the left  

[bluearmy]

despite what some are seeing, the GEFS in week 2 continue to play with a vortex split/disruption. also, mid lat highs are fine for a cold outlook if you have some amplification headed from the west - after all, you cant retrogress something you dont have !!  from a coldie perspective, i wouldnt be worried about the pattern flattening next week or the ecm day 10 amplification never getting much closer - the ens take has always been for this to become relevant as we approach the 20th.

[BlueHedgehog074]

It will be interesting to see how the various models continue to model the possible (although not entirely definite) cold spell in the near future if it's wintry weather, frosty weather, and/or cold weather you are after.

 

This top secret chart from the NOAA between days 8 and 14 continues to show some higher than average heights to the South of the UK (with areas of lower heights to the North of us), but still with possibility of some amplification to the West of us, which could help promote further cool/cold Polar Maritime airflow's - maybe the chance of these squeezing even colder air towards the UK should those possible amplified heights out West help turn the Westerly or North-Westerly airflow to something more Northerly over the UK.

 

 

Not really much signs from this for High Pressure to make a big influence over the UK, or at least make a long lasting visit over the island. However, considering some models, such as the GFS, does attempt to build High Pressure over us, that solution perhaps shouldn't be discarded completely. Especially since it's not that deep in FI either:

 

(Edit: from the old 06Z run, but the 12Z run does follow a similar trend)

 

It could be true that the GFS could start dropping its High Pressure idea (even though the High Pressure doesn't dominate the UK for the whole of that old 06Z run) and start following ECMWF's more unsettled outlook with Lows tracking mostly across our North with High Pressure generally staying put to the South. ECMWF's run does also seem more akin to what that NOAA 8 to 14 day anomaly chart shows, particularly at 240 hours where it seems to amplify High pressure to the West of us.

 

 

The ECMWF ensemble mean does also show something fairly similar, although perhaps with the pattern looking seemingly flatter (although, to be fair, the ECMWF ensemble mean chart does become less and less detailed the further into the outlook it's viewed. So it's hard to be entirely sure).

 

As such, I would probably say a pattern dominated generally by a Westerly flow looks likely to continue, but probably with a fair amount of amplification at times out West to make the pattern become 'bumpier' and help deliver some potent/fairly potent Polar Maritime airflow's, which could eventually lead to chilly Northerly setups. The chances for High Pressure to build or track over us (even it it was temporarily to our South) could happen too. But I'm not too sure this will become a big feature in our weather with the ECMWF operational chart and the NOAA anomaly chart not being on the GFS's side in regards to this. Having said that, the 12Z UKMO does look as though it may head in the GFS's direction with that amplified High to the West of the UK looking as though it would track over us:

 

From both the 12Z UKMO and 12Z GFS at 144 hours:

 

I think even if we do get High Pressure making an influence over the UK, it probably would still be a brief affair, with Lows out West flattening out our ridges or knocking them East. But it could be possible that even if High Pressure does pay a visit over the UK, we could see troughs/Lows drop down to our East (something that I think a few people mentioned earlier on), and help squeeze High Pressure back Westwards or North-Westwards towards the Greenland or Iceland area. Something alike what that NOAA 8 - 14 day chart showed could still arise from this, with the possible amplified heights out West, and areas of Low heights either over us, or to our East. Getting an area of the Polar Vortex to hang about near the Scandinavia/Northern Scandinavia area will probably help to promote Lows or troughs to drop down over us and/or to the East.

 

Understandably, outlooks 8 or so days away will likely to keep changing a lot. Whether or not the models will provide tickets for the cold and snow fans to get on board that Polar Express train is still not certain. (I would love to go on that train one day and visit the North Pole, he he hee). I guess the best that could be hoped for regarding a mid/late November cold spell for those of you that want one is to see High Pressure become amplified enough to our West to give the Polar Vortex a good enough slamming to turn the amplified High into a blocking Greenland High. (Personally, though, periods of Polar Maritime air along with possible Northerly topples is still probably the most likeliest scenario, especially if the NOAA anomaly chart has nailed the general pattern accurately).

 

Before then, rain, showers, combined with periods of brighter weather between, is likely to invade the UK for the next few days or so. The weekend looks as though it will be quite cold with those cool Westerly or North-Westerly winds and some of the precipitation will probably fall as sleet or snow over Higher ground, most especially over Northern areas. Some days looks as though they will be more milder, such as Monday as the winds back more South-Westerly...

 

 

This will be accompanied by a spell of rainy weather too.

 

There could be a chance for areas to start settling down, particularly in the South, if High Pressure does make attempts to visit the UK (perhaps also depending if the Jetstream can be forced to go far enough North for a while and/or with an arc of it going across the North of the UK).

 

But should the worst come to the worse, the fans of cold and snow could always use this to take out the Polar Vortex...

 

 

Edited November 8, 2013 by DiagonalRedLine

[Barry12]

ECM at 144:

 

 

ECM at 168:

 

 

ECM at 192:

 

 

ECM at 216

 

 

ECM at 240:

 

Edited November 8, 2013 by Barry95

[phil nw.]

Agood post DRL and well reasoned.

A chance of some short cold spells if we get that ridging in the Atlantic but as we can see the daily Op runs are changing the amount of amplification run to run and this is not unusual when looking so many days ahead in a mobile setup.

 

On another note 1 recent post has been removed as it was a dig at someone.

 

I know many of us are eagerly seeking the first real cold shot but please keep it friendly and respect others who are only trying to give a realistic view of current models.

 

Thanks all .

[Captain Shortwave]

The ECM like the GFS has pushed the Atlantic train clear of the UK

 

The pattern across the Atlantic and Europe seems to have ground to a halt

Edited November 8, 2013 by Captain shortwave

[Cheshire Freeze]

Progressing nicely at 240 hrs

 

[Summer Sun]

ECM ends with a northerly lining up if it went beyond t240 it would probably show one

 

Edited November 8, 2013 by Summer Sun

[Cheshire Freeze]

ECM ends with a northerly lining up if it went beyond t240 it would probably show one

 

 

Yep it would. Would love to see the following frames and ties in very nicely with the post Bluearmy made about interest around the 20th.

[SMU]

http://www.meteociel.fr/modeles/ecmwf/runs/2013110812/ECH1-240.GIF?08-0

 

Chart of the season by the ECM-

 

the vortex being shunted over back towards Siberia - & a big rise in pressure to Greenland-

 

S

If you notice as well- out with the negative PNA pattern- Hello + PNA ridge & Low teleconnector off the eastern seaboard stuck in situ...

 

S

[Cheshire Freeze]

http://www.meteociel.fr/modeles/ecmwf/runs/2013110812/ECH1-240.GIF?08-0

 

Chart of the season by the ECM-

 

the vortex being shunted over back towards Siberia - & a big rise in pressure to Greenland-

 

S

If you notice as well- out with the negative PNA pattern- Hello + PNA ridge & Low teleconnector off the eastern seaboard stuck in situ...

 

S

 

Sure looks like a nice pattern emerging there Steve with support from the GEFS too.

[Captain Shortwave]

Sure looks like a nice pattern emerging there Steve with support from the GEFS too.

Certainly a nice chart, would look good for a significant cold spell there. Just hope we can pull this closer to reality. Given how things are shaping up. It looks like a battle of the mid-latitude highs to see which one can move towards the pole and deliver the northerly as the polar vortex shrivels up and weakens. At least the zonal train looks like being derailed and even a spell of quite weather with frosts is better than some of this wet and windy malarkey 

Edited November 8, 2013 by Captain shortwave

[SMU]

^^ Yes CS- I may do a post later around what stops the PV in its tracks- one sure fire way is to have low pressure moving Northwards into the pole as opposed to eastwards-

 

Northwards will always ruin the vortex & displace cold air south & east ( or south & west sometimes)

 

S

[cooling climate]

The ECM t240 chart would indeed indeed herald a much colder and potentially wintry

pattern setting up for the UK and Europe if it varifies. The chart looks like the onset of

a possible CW (Canadian warming) to me.Also if the amount of amplification that t240

and onwards show then this would also be seen in the lower stratosphere at least.

All of this is a knock on effect from the ridging in the Pacific and E-P fluxing in the

troposphere and lower stratosphere.

This still has to verify of course but one thing is certain if the signified pattern change

that the ECM run hints at does come to fruition then this would only be possible by a

troposphere, stratosphere interaction. Apart from say slight amplification over the Arctic

any real height anomalies and blocking along with any prolonged and significant cold

for the mid latitudes only comes about when their is  troposphere and stratosphere  

interaction.

[Midlands Ice Age]

dont normally post in here...

 

Has anyone else noticed the ghostly apparition in the ECM 500 at 240hrs?

Is this a potent of winter to come?

 

Seriously though  it is getting very interesting.

Has anyone ever noticed this structure before?

 

MIA.

[Summer Sun]

Latest from Gibby

 

All models seem to be singing from the same hymn sheet now with regard to the pattern and sequence of events between now and the middle of the next week. An unstable Westerly flow is blowing across the UK and it has steadily become rather colder of late. This trend continues tonight and tomorrow with showers at times, mostly in the West with a longer spell of rain in the South tomorrow as a trough passes. This is then followed by a strong rise in pressure through Saturday night and Sunday allowing light winds and a frost to develop. Sunday will then be a cold and crisp Remembrance Day with long sunny spells only giving way to cloudier skies later from the West as an active warm front approaches. This crosses the UK Sunday night with a spell of wet and breezy weather for all. Conditions then improve slowly from the NW on Monday as a cold front slips SE but the South will remain cloudy and mild till very late in the day. Tuesday will be a bright and fresh day with some sunshine but it will feel chilly before strong winds, milder and duller weather with rain returns across many parts midweek heaviest over the North and West.

 

GFS then shows a change later in the week as another cold front moving SE over Britain delivers a spell of rain before clearer and colder conditions take hold under developing anticyclonic conditions by the weekend. From then on with slack pressure over the UK for some considerable time the path is set for cold or rather cold and foggy conditions to develop with frost in places too and fog lingering all day too in places. Late in the run things turn colder still has High pressure develops on the Northern flank of a Southward sinking depression over Iberia with an East flow developing across the South with occasional rain giving way to cold and misty conditions which will also be experienced over the North in the interim days.

 

UKMO closes it's run tonight with a cold Northerly flow, especially over the East as High pressure rests close to the SW of Ireland at 1040mbs. Some cold showers would be likely in the East for a time before the most likely scenario of rather cloudy benign conditions from off the North Atlantic developing over the days that follow with average temperatures.

 

GEM illustrates the UKMO pattern well tonight moving indeed forward to bring milder Atlantic winds to end next week prior to a cold front bringing a rinse and repeat pattern of alternating milder and colder weather with a little rain, chiefly over the North and East.

 

NAVGEM topples a ridge down over the UK from the NW and develops it into an elongated High pressure area lying West to East across Central England and on into Europe. Dry weather would develop for many and if clearances in cloud permit a good deal of mist and fog would likely form across central and Southern Britain by next weekend, stubborn to clear in the daytime and making it feel rather cold away from the milder far North.

 

ECM tonight shows High pressure held down to the SW in it's extended run because of too much energy in the Atlantic train to the North forcing any ridging back South and maintaining an overall mild feed of air across he British Isles with stronger winds in the North with rain bearing fronts crossing East here too on occasion. 

 

The GFS Ensembles are trending downwards in temperature over the coming two weeks. we must take into account the natural seasonal fall off in average temperature is quite marked at this time of year so overall temperatures remain never far from the seasonal normal. With High pressure around on some of the members outputs including the operational run described here conditions at the surface don't always reflect the uppers above so there could be some cold and foggy weather to be found in among these ensembles.

 

The Jet Stream forecast is that the flow currently blowing across the UK is destined to pull Northward next week to run ENE well to the NW of Scotland and then down over Europe at least for a time.

 

In Summary tonight it's more of the same from the models with alternating milder and colder phases of weather when rain at times on fronts affect all areas at times but more frequently and meaningful over Northern Britain. There seems no way out of the current Atlantic bandwagon with High pressure at least moving in closer to SW Britain damping down the rain in the South next week but at the same time keeping any really cold weather bottled harmlessly well away from British shores for the time being.

 

http://www.norton-radstockweather.co.uk/Model-Analysis%282859336%29.htm

[Frosty.]

I managed to find something for all the coldies to wish for among tonight's GEFS 12z perturbations, there are some epic charts here (P9)  especially which would bring snow and sharp frosts to many parts of the uk if they verified. There are a lot more anticyclonic options compared to the 00z-06z but i'm not going to bore you with those.   

[TootyFruity]

As a newbie I'm totally confused some say maybe a cold shot mid November some argue no such thing , it's very confusing , some of the charts posted look ok for a cold spell then some don't I suppose it's just different people different opinions but It is very confusing . The only way that I definitely know if there's a true hint of a cold spell is when Mr Steve puts a post on ... Then I take notice !!

[Frosty.]

T+264 would have been sensational on tonight's ECM 12z op run but T+240 is setting us up for a potent blast from the Arctic with snow and frosts sweeping south across the uk. just look at those thicknesses to the northwest of the BI ...528 dam then 522 dam then..510 dam incoming.what a tease that last frame is, it almost pulls the trigger and would on the next frame...BOOM       

Edited November 8, 2013 by Frosty.

[Scorcher]

Some rather mild air over us in those charts though Frosty, I would take those charts for sure! In fact some of the mildest air in the whole of Europe.