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Model output discussion 25th Jan - The final third of winter beckons..


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27 minutes ago, Weathizard said:

Depends if you're happy with a dry, chilly easterly. It's like settling for a 5/10 when you could have had a 10/10.

Its not one op run, no sustained cold enough for snow is showing... there is a 48/72 hour window when snow flurries are possible but high pressure is too close by for most its a non event in the near term and we are left chasing clean evolutions to cold in FI again.

To me it's not reactionary to say this, the ensembles and models are in agreement on a 'warm' up in the medium term, although it will be cold at the surface.

 

 

I don't know what 10/10 means to you though I can guess (as for most on here) it means copious amounts of lying snow.

Was that ever on offer ? I don't recall many runs showing widespread heavy lowland snow.

I'm a fan of cold - snow less so - so perhaps my perspective is somewhat different  but I see plenty to like in the OP charts.

We are certainly at a spell of below average and indeed well below average temperatures over the next 10 days - the possibility (and that's all it is for now) of retrogression and a reload from the north is there. London should be at 8-9c by day but I don't see that in the near future.

A couple of charts before the Mods get annoyed:

UW144-21.GIF?07-06

This morning's UKMO T+144. That's a solid chart for cold and some wintry possibilities for the SW. IMHO, the UKMO has done extremely well this winter and its consistent support for this colder evolution has been a strong support.

Here's your "jam tomorrow" chart:

gfsnh-0-372.png?6

The PV gone - a lobe over Scandinavia and solid heights to the N or NW and a family of channel LPs in a cold NW'ly airflow and it's still February. Excellent.

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Knee-jerk, a joke!?...if that is what you believe then simply don't follow. I was simply highlighting what the EC ENS are showing and to be honest certain people need to read before commentating, perh

Yes, I recognise these sage pieces of sentiment so well. The signals are always wrong, and the professionals (and others) who try to present and explain them, when an operational appears to take away

This is an unusual set up for the UK, hence the model variations. The bigger picture according to seriously knowledgeable people like @Tamara tends to suggest that the hemispheric factors that actuall

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32 minutes ago, stodge said:

I don't know what 10/10 means to you though I can guess (as for most on here) it means copious amounts of lying snow.

Was that ever on offer ? I don't recall many runs showing widespread heavy lowland snow.

I'm a fan of cold - snow less so - so perhaps my perspective is somewhat different  but I see plenty to like in the OP charts.

We are certainly at a spell of below average and indeed well below average temperatures over the next 10 days - the possibility (and that's all it is for now) of retrogression and a reload from the north is there. London should be at 8-9c by day but I don't see that in the near future.

A couple of charts before the Mods get annoyed:

UW144-21.GIF?07-06

This morning's UKMO T+144. That's a solid chart for cold and some wintry possibilities for the SW. IMHO, the UKMO has done extremely well this winter and its consistent support for this colder evolution has been a strong support.

Here's your "jam tomorrow" chart:

gfsnh-0-372.png?6

gfsnh-0-372.png?6

The PV gone - a lobe over Scandinavia and solid heights to the N or NW and a family of channel LPs in a cold NW'ly airflow and it's still February. Excellent.

 

The PV gone - a lobe over Scandinavia and solid heights to the N or NW and a family of channel LPs in a cold NW'ly airflow and it's still February. Excellent.

Is that my imagination or is there a significant chunk of polar vortex over Scandinavia.

If this does materialise I do believe that's the closest I have ever seen a lobe this close to us.

If I am wrong apologies

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Very much agree with above posts let's concentrate on the next few days. The charts for next week will change a lot between now and Monday the block / cold is always hard to shift once it's in place. 

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GFS is depending on a circumstantial alignment of the flow that brings air our way that has passed over the Alps and undergone adiabatic warming. As far as I can see, a direct import from the Med. still doesn't make it east of western France. 

One thing I have found a bit odd, though, is that while the upper flow is as described above hence the warm air import aloft, the surface flow is much more toward easterly so you'd think we'd stay chilly given the feed from out east where the colder air remains in place. Could there be mixing down of the less cold air from above?

In any case it remains a highly unusual situation and perhaps an unprecedented way to interrupt a mid-February cold spell. I remain suspicious of the idea that the Iberian low will lift slowly NW, as this is the ideal path we often see in summer plume scenarios, only for the low to actually break down with a secondary feature heading NE and cutting off the flow. Given the blocking in the way I guess such a feature would try to move east early next week... or just get stuck in place. Either way, the long-draw SE'rly upper flow could be disrupted.

We can only wait and see, and even with a notable milder interlude the odds remain stacked in favour of a wedge of higher heights moving to our NW and ushering in an E to NE or even N flow before long - regardless of what some of the supercomputers are outputting.

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I've not seen the weather forecast since 1am, last night...and unless there's been a MASSIVE DOWNGRADE!! Tomasz on BBC week ahead, said the coming easterly was here well into next wks at least...yet because the ECM, isn't playing the same tune!! It's correct?? I've read what bb62/63, steam murr and tamaras XCELLENT posts say and they look spot on...even bb62/63 thinks only a blip if that!! All 3, ecm, gfs n ukmo...seem at odds with each other...this coming weekend should provide a better understanding...it still looks good for coldies, been said time after time don't look more than 3days ahead, if that!!...unless your one of the more knowledgeable like the above :hi:

Ps... I wonder what GP, thinks...not seen any of his posts for sometime ( unless I've missed then?? ) he's another poster whose up there with above 3 :) 

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4 minutes ago, Singularity said:

GFS is depending on a circumstantial alignment of the flow that brings air our way that has passed over the Alps and undergone adiabatic warming. As far as I can see, a direct import from the Med. still doesn't make it east of western France. 

One thing I have found a bit odd, though, is that while the upper flow is as described above hence the warm air import aloft, the surface flow is much more toward easterly so you'd think we'd stay chilly given the feed from out east where the colder air remains in place. Could there be mixing down of the less cold air from above?

In any case it remains a highly unusual situation and perhaps an unprecedented way to interrupt a mid-February cold spell. I remain suspicious of the idea that the Iberian low will lift slowly NW, as this is the ideal path we often see in summer plume scenarios, only for the low to actually break down with a secondary feature heading NE and cutting off the flow. Given the blocking in the way I guess such a feature would try to move east early next week... or just get stuck in place. Either way, the long-draw SE'rly upper flow could be disrupted.

We can only wait and see, and even with a notable milder interlude the odds remain stacked in favour of a wedge of higher heights moving to our NW and ushering in an E to NE or even N flow before long - regardless of what some of the supercomputers are outputting.

So I understand what you mean, are you suggesting that the low over Iberia could track somewhat more easterly than is currently being shown?

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Just now, Racing Green said:

So I understand what you mean, are you suggesting that the low over Iberia could track somewhat more easterly than is currently being shown?

Either the whole thing (lower probability) or a secondary low developing and splitting away from it. A very uncertain situation though! Sort of hopecasting I must admit :ninja:

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1 minute ago, Singularity said:

Either the whole thing (lower probability) or a secondary low developing and splitting away from it. A very uncertain situation though! Sort of hopecasting I must admit :ninja:

Thanks. As opposed to the current situation of sliding down the coast of Portugal, whats to stop the models sending it more-so through Spain and into the western Med? I can't help but think this can't be ruled out.

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Just a quick one from me for a change as I do need to run my full-time business as well!

I simply do not understand the dire mood from many posters this morning.  I was very busy writing my two posts and didn’t check the 0z (and 6z) runs properly until just now.  I do not see anything “mild” in any of the outputs – this week, next week or beyond! The models are really struggling with the transition from phase 1 of the forthcoming cold spell with the easterly to phase 2 with a broad northerly (and possible further easterly after that). There are the usual timing issues. Several models, like ECM and the GFS 6z, are very progressive in sinking the Scandi HP from around D5, several others do this after D7 and several hardly show this at all – see the NAVGEM, GEM and JMA. We cannot exactly say how the UKMO will go after D6 as its main output stops there (those tropical T+168 charts do not show the key areas to our north and east) but the latest MetO update suggests that it might be somewhere in between. Sorry, no time for my full cross model analysis.

Let’s go with the flow (not quite literally!) and assume a transition from around D7 to D10.  These models sink the HP somewhat but NOT completely. A south-easterly sets up for quite a few days. Forget about the uppers – this period will be all about surface cold which I am almost convinced will, yet again, be hugely under estimated. Much of Europe will be at least partially snow covered by then – we may even have had some ourselves. The cold will be entrenched. Even with the supply of the intense cold feed from the north-east being cut off for a while, there will be plenty of deep surface cold around. I’ll stick my neck and say that any south-easterly will see temps close to 0c for much of the time across most of the UK! If that LP to the south-west shown on models like the 0z ECM around D6 materialises, it could actually bump into the cold and produce a significant snowfall. It might even go on eastwards to undercut the HP and strengthen the easterly.

Remember, this evolution may not happen at all. I have suggested in my two reports this morning that the HP may well hang on stubbornly close to its current position. This would maintain a cold easterly for much longer and with access to top ups of further deep cold from the north-east.

After this, everything points to our north and north-west and HLB building around Greenland. Whether that’s the Azores HP ridging northwards or the Scandi HP ridging west-north-westwards is yet to be decided.

I’m running out of time now – so I’ll post just one chart from the JMA which actually has one of the more continuously colder runs. Just for fun this is yesterday’s 12z T+204:

J204-21.GIF?06-0

Spot the world record Greenland HP of 1085 mb! The JMA model has a serious problem with overstating the pressure over the high Greenland plateau – probably over 25 mb lower when adjusted to mean sea level pressure. The serious part of the run (with the first part updated with today’s 6z output) is that it shows cold throughout.

Overall, I remain totally optimistic that this will be a prolonged and memorable cold spell, with perhaps, phase 2 delivering more snow than the initial easterly. Loads to watch out for.  So please enjoy it all and do not get hung up with just a few temporarily downgraded runs – which may or may not verify.  

EDIT (1):

 @Chris.R  Your excellent link to the Euro pressure and temps etc is very useful but only tells half the story. There are many locations in that region where there are only small towns and villages . We hit 1050 mb about an hour ago (in line with my predictions in my update this morning) and our Scandi HP is still slowly intensifying. I still predict around 1055 mb some time tomorrow - so the models are still playing catch up with the strength of the HP, the intensity and extent of the surface cold and also (contrary to popular belief) the 850s as well. I'll provide a full update around 0730 tomorrow but here are 2 very current pressure and temperature charts to go on with and for those still saying "what cold?" the deep cold has continued its progression westwards during today. The 1650 chart was not far off the "maximums" for today + the live chart. Note not just the purple but also the blues:

European Surface Pressure Charts:                                                                                   European Surface Temperatures Charts:

                   Current "live”                                            Feb 7th 1650                                        Current "live”                                         Feb 7th 1550                            

   pression2_eur2.png          pression2_eur2-15.png       temp_eur2.png       temp_eur2-15.png

Before some you guys post some gloomy one liners and the most negative chart that you can find, I suggest you always quickly check the current and very short term charts and you will be far more upbeat (or at least you "should" be) !

EDIT (2):  

I will add the two latest updated Met Office fax charts below as soon aon as they come out (due around 1500 to 1600 but seriously delayed today). They will give a good indication of the UKMO position for D4 and D5. The MetO written update does mention a brief "less cold" south-easterly followed by a renewed easterly with some very cold conditions. This would be a "middle of the road" solution. So come back and check shortly.

MET OFFICE 12z T+96 SAT FEB 11TH                             MET OFFICE 12z T+120 SUN FEB 12TH

 

                                                           TO FOLLOW SHORTLY

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Edited by Guest
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2 hours ago, Man With Beard said:

GEFS calls a prolonged milder "blip" into serious question. Most members cut off the Mediterranean influence by T216 and a majority of member have east or north-easterly influence once again. 8 out of 22 members even have a cold pool back over the UK.

The milder T144-T240 on some of the ops is rather like a summer plume - now how many forecasted plumes actually make it to the UK? 

I may have suggested no snow possible next week, but if I may, I'd like to go back on that please - I rate chances of another cold blast by the end of next week at 30%.

Roll on further to next weekend and lots of northerlies starting to appear...

on balance I'd say the "plume" has more chance of verifying than any northerlies next weekend at this stage.

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9 minutes ago, Certain kind of fool said:

on balance I'd say the "plume" has more chance of verifying than any northerlies next weekend at this stage.

Really a plume? Some models are expressing some change of air mass to come from a SE quadrant over a fairly cold continent, surface cold would see be very viable under these circumstances, the ensembles see a less cold period but no plume, do you have any charts to back this up please?  

Edited by connorlad1974
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Here is the GEFS spread at just +120, 5 days

gensnh-22-1-120.png

So how anyone can have any confidence on anything past that, except for using background signals as drivers, is shooting in the dark...

Edited by Wayneywoo
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The easterly spell back in October had less energy going over the top helping build some heights over Greenland. Also the Low to the SE in October helping angle the Scandinavian block better rather than a Low to the SW forecast at 96h this morning.  Let's hope the game of chance favours us later this month.

IMG_0952.PNG

IMG_0953.PNG

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24 minutes ago, Certain kind of fool said:

on balance I'd say the "plume" has more chance of verifying than any northerlies next weekend at this stage.

I strongly oppose that.

D10 GEFS mean is fantastic a very strong signal for our Scandinavia heights to retrogress to our NW it certainly fits within MJO progression to 'holy grail' phase 8.

Fun times ahead. :) 

image.thumb.png.89748352ba0f5f6a4d7b2c6662a1aa93.png

 

Edited by Daniel*
must proof read!..
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2 minutes ago, fulham snow said:

Getting very confused.Is the easterly on or off,seems to change ever run

All models are showing an Easterly from Thursday through the weekend.

Edited by FreezingFog
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