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

[mb018538]

At the moment, Thursday to Sunday is looking especially cold! Where will the snow end up though.....the million dollar question. Looks like a milder interlude before literally anything could happen after mid month. Lots of cold GFS ensemble members again after the 17th though.

http://www.theweatheroutlook.com/twodata/chart.aspx?chart=/charts/gefs/gefsens850London0.png
 

[Seasonality]

6 minutes ago, That ECM said:

Pv is interesting at this time. Less forcing on the high. Might not sink on this run and join the party?

Hopefully. So hard to predict past a few days that anything is possible. And even on Tuesday morning I wouldn't dare to call Sunday nailed in such a set up and such a winter.

[East_England_Stormchaser91]

Although it's fantasy land, GFS seems to be trending more towards that Greenland high theme! 252hrs had some monstrously cold uppers flooding out!! Who knows what may happen after this initial cold and likely snowy theme! One thing is for sure, is that it does not look like warming up at all in the foreseeable. 

[Man With Beard]

As much as it looks cold until D6, it increasingly looks less cold after that.

I think the ECM is actually getting back on top of things, as it has been consistent for 3 runs now in removing Euro troughing after Sunday - and now the other models have largely followed at D7-D8.

I doubt there'll be any snow falling next week, now.

[mb018538]

ECM seems quite bullish in building this Euro high and delivering some southerly winds of sorts. Either way - not zonal!

[Wayneywoo]

I can't remember, this winter, the last time ECM predicted anything with confidence, correctly beyond +72...

Only when UKMO/GFS agree for a few consecutive runs would I bother with ECM.

[East_England_Stormchaser91]

5 minutes ago, mb018538 said:

ECM seems quite bullish in building this Euro high and delivering some southerly winds of sorts. Either way - not zonal!

Even with a southerly, it will be cold at the surface. Looks very stagnant and slack. Notice how those super cold uppers and trough on the eastern flank up towards scandi look like they are on the cusp of being discharged south and heights are slowly nudging up into Greenland. This is far from a done deal yet! 

[That ECM]

Meto have low confidence moving forward, I wonder why? 

[blizzard81]

The ecm just steadfastly refuses to play ball. 

[Connor Bailey Degnan]

Morning all, quite a big upgrade for snow potential in the short term. Mainly eastern areas, could see some decent accumulations. Western areas always tending to stay dry. Longer term, so many questions marks. Will we retrogress? Or will the stubborn ecm win out? All to play for

[Scandinavian High.]

Staying  cold next week cold south easterly says with us though out next week south easterly could be raw because of  strength of wind not looking mild to me and as time goes on could get even colder again maybe from the north east.

[terrier]

So another good run from the gfs overnight output. Also another nice ukmo. Unfortunately the ecm still remains steadfast in wanting to bring a southerly flow into next week. But it would certainly feel cold at the surface from the ecm output. So in summary becoming colder from tomorrow with snow flurries for eastern areas not a bad place to be for early Feb. And who knows we could get a second bite at the cherry which could be more potent than this spell happy days. 

[January Snowstorm]

Reality check = we have cross model agreement on things turning milder on Monday ( mild as in melting any snow but still feeling raw in the wind )

Short term really does look good as that cold pool has expanded and should give some of us a dusting Sat/Sun...

I suppose we always want more rather than enjoying what we have. With global warming at record levels we should really be thankful there's any chance of snow 

[Newberryone]

9 hours ago, Rocheydub said:

Strictly not model related, as I am not quoting any particular NWP or any particular run, but overall, this has the feeling of a rather special term of weather from a cold lover's perspective, and I feel that we are on the cusp and precipice of something remarkable. My reasoning? I've seen the various models display predictions like this before and with supportive shows by the MJO too... It's all just too good. It just has too strong of a likelihood. 

I'm beginning to switch my attention to lamp post watching at the weekend.... I'll enjoy this for what it is... The beginning of a cold spell! Have fun all. Hope you squirreled your nuts away!

That was a mighty brave call considering it wasn't as you say model related. I'd be somewhat surprised if your line of thought is similar this morning having seen the 00z Ecm. Looks decent enough up until Sun but worryingly is holding firm on less cold conditions becoming established thereafter.

[Ali1977]

The GEM looks about best for more widespread snow options, the GFS keeps the best chance for Midlands North. The cold is guaranteed but snow chances still open to change.  It does look like being a shorter cold spell (850 wise) than modelled a few days ago, I'm just hoping the models are that clueless beyond the weekend that we can turn things round a bit and keep the Synoptics for wintery showers beyond the weekend, before a more potent shot from the North!!

Edited February 7, 2017 by Ali1977

[TEITS]

Little has changed in my opinion. Still uncertainty who gets the heavier snow showers at the weekend (N England/Scotland or S England) the GFS has this for the N whereas the ECM/UKMO has the risk further S.

As for next week we need to accept it will turn less cold. Beyond we could have a S,ly draw from Africa or a bitter N,ly from the Arctic.

[Nick F]

00z GFS/GEFS still keen to keen to retrogress the Scandi block over to our NW in day 10-15 period, while keeping low heights over SW Europe and dropping low heights down across Scandi - which may lead to to a northerly down the line.

Yesterday's EPS z500 mean hinted at this idea too, though less strong signal, certainly this morning's 00z EC high res not keen on this idea, so maybe another outlier from its members.

Although we see the transfer of +ve height anomalies west to the NW with time on ENS guidance, there is fairly good agreement on the  surface high over Scandi sinking south in the medium range, which will cut-off the deep cold advection from Russia, but we are still left with a chilly SEly flow until at least Thursday next week on 00z GFS op, when it turns 2m temps into double figures across the far south.

I think the main reason why we are not seeing the easterly sustain is because there is no jet, of any strength, returning SW across northern Europe beneath the Scandi blocking high to maintain low heights over central Europe and prevent the block sinking.

Looking at the strat forecasts, both ECM and GFS seem keen for a displacement toward Scandi/NW Russia by day 10, rather than a split as was advertised by GFS a few times recently, if there is a connect between the strat PV and trop, then that maybe why we are seeing the blocking retogress towards Greenland in the means and trop PV dropping toward Scandi longer term.

We also have the MJO phase 7/81 amplification working through around 15-18th - which will probably aid in the next trop displacement after its brief rebound toward the pole/Greenland and the MJO will help maintain high latitude blocking from mid-month, perhaps most likely to our NW?

Shorter term, I think Thursday-Friday we will see some snow flurries in the E/SEly flow, perhaps light snow showers towards east coast, Saturday looks like best chance of moderate to perhaps locally heavy snow showers along east coast, as a trough develops in the isobars to the east over N Sea and upper cold pool moves west and enhances lift.

Edited February 7, 2017 by Nick F

[Frank Trough]

42 minutes ago, Wayneywoo said:

I can't remember, this winter, the last time ECM predicted anything with confidence, correctly beyond +72...

Only when UKMO/GFS agree for a few consecutive runs would I bother with ECM.

The previous blocking episode earlier in the winter the ECM absolutely nailed in the long/mid range. The ECM admittedly had the blocking too far north initially but at the same time frames the GFS was smashing westerlies all the way to Russia. Don't rule out the ECM view of things longer term.

As is typical in winter the focus on here is always day 10. but in this case we have an easterly setting up at t+48 so the real interest is the much nearer term for now. FAX charts over the next couple of days are going to be of great interest.

[Singularity]

The interaction of lows leaving three southern US and that over Iberia is a major troublemaker for next week, but I'm not convinced they will join forces such as is currently being shown. It would be a rare occurrence although I think I've seen a few historical cases where it happens - but that's with the jet roaring on through the Med. with a big easterly affecting the U.K.

Confusing times. It almost looks like the models are trying to have a phase 7 and a phase 8 MJO response simultaneously, which is weird.

Longer term, hints the main blocking goes west of Greenland but that doesn't fit with the MJO signal or a vortex split. If vortex just displaced to Siberia instead though that would be an issue. Not seen strat charts yet today.

[blizzard81]

23 minutes ago, terrier said:

So another good run from the gfs overnight output. Also another nice ukmo. Unfortunately the ecm still remains steadfast in wanting to bring a southerly flow into next week. But it would certainly feel cold at the surface from the ecm output. So in summary becoming colder from tomorrow with snow flurries for eastern areas not a bad place to be for early Feb. And who knows we could get a second bite at the cherry which could be more potent than this spell happy days. 

The ecm has been struggling on and off all winter,  not to mention the ecm monthly lol.  The ecm was the only model that didn't really go for this easterly in the first place. Think back to late last week with those dodgy runs .  It has been poor in the 6 day plus range all winter. Was better before the upgrade. 

[northwestsnow]

21 minutes ago, TEITS said:

Little has changed in my opinion. Still uncertainty who gets the heavier snow showers at the weekend (N England/Scotland or S England) the GFS has this for the N whereas the ECM/UKMO has the risk further S.

As for next week we need to accept it will turn less cold. Beyond we could have a S,ly draw from Africa or a bitter N,ly from the Arctic.

Id stick with the euros, although snow showers could break out anywhere , fwiw i still think Se England/ Se midlands area will do best.

[blizzard81]

2 minutes ago, Singularity said:

The interaction of lows leaving three southern US and that over Iberia is a major troublemaker for next week, but I'm not convinced they will join forces such as is currently being shown. It would be a rare occurrence although I think I've seen a few historical cases where it happens - but that's with the jet roaring on through the Med. with a big easterly affecting the U.K.

Confusing times. It almost looks like the models are trying to have a phase 7 and a phase 8 MJO response simultaneously, which is weird.

Longer term, hints the main blocking goes west of Greenland but that doesn't fit with the MJO signal or a vortex split. If vortex just displaced to Siberia instead though that would be an issue. Not seen strat charts yet today.

Thanks for that post. I was wondering what could be behind these ecm runs. I thought the US would have something to do with it lol. They generally do. 

[Guest]

Please note: I have copied this post across to the "in depth thread" should anyone wish to discuss any points that I have raised and share their views in a less frantic environment

DAILY EUROPEAN TEMPERATURE AND PRESSURE CHECK No. 5  

FURTHER GREAT NEWS - THE DEEP COLD POOL IS MARCHING WESTWARDS INTO EUROPE

In the build up to our cold spell, I feel that it will be useful to keep up-to-date with the current and trending temperature and pressure changes in Europe. I will try to produce these on a daily basis for the next few days around 0730 to 0800 (although I am away on a business trip this Friday so no update then and Saturday’s will be around 1300). This will show how the pattern is evolving and allow us to monitor the extent and the severity of the cold that we might expect.

Firstly, I simply do not understand some of the negativity on here. Here is a summary of my take on developments. Our weather will be coming from an easterly quarter for much of the next 10 days and we will soon be part of a massive cold pool that covers a vast amount of western Asia, Russia and north-east Europe and now Scandinavia and it’s all heading our way. There is no energy in the Atlantic to shift this at all as far as the eye can see and the surface cold will almost certainly become intense and entrenched. Temperatures almost always turn out lower than initially predicted in this type of set up. There will also be some extremely low dew points and the 850s, despite a greater variability, will be very low at times with several breakaway colder pools likely to head down through the flow.

There are more than strong hints of a switch to a broad northerly later in week 2 and later in the month we may see switches between northerlies and easterlies a few times with the HLB somewhere between Scandinavia and Greenland. For more details and analysis of this please refer to my last full report on Sunday (see page 105). Since then everything has been going in the right direction. The models will still fluctuate on the finer detail for the first week (very uncertain where and how much snow we shall get but at least some seems highly likely) and even more so in week 2 nailing down the transition from “cold” conditions to “cold” conditions (no typo there !).  At worst, just several days of slightly less cold weather.

Now, I shall pick up from my last “check” on page 112. This took us to February 6th.

European Surface Temperature Charts:

                 Current "live"                                Feb 7th 0650                                    Feb 6th    1250                                  Feb 6th  0650                                  Feb 5th 1250

     

Note that it is important to allow for min/max temps when comparing the charts. The 0650s are usually close to the minimums and the 1250s are usually close to maximums.

COMMENT:  Just look at how much that sub -20c purple area has expanded. Ahead of that, almost all of Scandinavia except for a few coastal spots is sub -5c with a lot of sub -10c temps. The darker blue shades of sub -5c has moved through eastern Europe and reached central Europe. It's all heading steadily towards the UK. All this can be seen by comparing the two "0650" and the two "1250" charts.

GFS  0z February 7th T+6 European Charts: 

            2m Surface Temps                                   850 Temps                                      500 hPa Temps

       

COMMENT:   Compare today's charts (above) with yesterday's  (below).  Note the further expansion of the "purple shades" area of sub -20c surface temps with a greater area below -24c and even a patch of sub -32c temps (light grey). The only piece of slightly less good news is that the pool of sub -20c 850s is slightly smaller but this is more than countered by the increase in the area of the sub -8c and -12c temps. There is quite a large area of breakaway sub -12c temps (with a centre of sub -16c temps) moving south-westwards through southern Scandinavia and northern Europe. Another extremely encouraging sign is the re-orientation and path of the sub -12c temps. Note how that part of the pool is now heading straight for the whole of the UK rather than slightly to our south. This change has happened as I predicted simply because of the development and changing shape of the Scandinavian HP pulling the cold through westwards on its southern flank.

GFS 0z February 6th T+6 European Charts: 

                2m Surface Temps                              850 Temps                                      500 hPa Temps

        

European Surface Pressure Charts:

               Current "live”                                   Feb 7th 0650                                   Feb 6th    1850                               Feb 6th  0650                                Feb 5th    1850  

                                         

   Current Met Office Fax: 0600 Feb 7th            GFS 0z February 7th T+6                 GFS 0z February 6th T+6    

                                                     

COMMENT:  Our Scandinavian anticyclone has intensified further and has just reach 1049 mb and is still slowly intensifying. It looks like it will reach some way over 1050 mb (perhaps as high as 1055 mb) which is more intense than any of the models were predicting (at least up to the 12z and 18z output yesterday). This should help strengthen the easterly flow and push the deeper cold (surface and uppers) closer to the UK more quickly than predicted. The centre of the HP is still edging very slowly west-south-westwards. I feel that it will maintain a very similar position for many days. The exact orientation of the flow will be partly dictated by the Mediterranean LP which has remained centred over Italy for over 36 hours now. This looks like a highly stable set up in terms of position and longevity. The flow looks like it will be east-south-easterly initially (with due east winds) as it moves into the UK during Wednesday and Thursday. Then, as the deeper cold air pushes around the HP it looks like the flow will veer slightly more to a direct easterly (with east-north-easterly winds). This should produce at least some snow flurries but there may be some snow showers along exposed eastern coasts as soon as Thursday (that's after perhaps a little snow as the stalling frontal system pushes back westwards tomorrow with the colder air already undercutting it). Then we need to look out for troughs and other disturbances running west-south-westwards through the flow. That cold front shown on the current Met Office chart is the leading edge of the much deeper cold air and one to keep an eye on. 

Overall, everything continues to move in the right direction - there is no need to worry about the variable 850s as they'll be generally low enough for any precipitation to fall as snow from late Thursday onwards as the dew points will be falling to sub zero by then. There will be pools of much lower 850s at times which might introduce greater convective activity - so there will be some good potential for at least some snow. We should be able to get a better idea of this by Thursday. I'll be back tomorrow.

 

Edited February 7, 2017 by Guest
Correcting typos and to ensure that all the links and charts work properly.

[bluearmy]

I'm going to check back through the ecm runs to see just how badly it has done on this weekend and into next week - sometimes we remember some parts and forget others. I suspect what is now about to verify will be somewhere between the less enthusiastic ecm ops and the colder gfs/gem ones. Perhaps the UKMO a bit closer but all the models now cut off the cold uppers early next week which was always the ecm problem as far as many were concerned 

what I do know is that the arcing journey that the upper ridge is about to take from the Azores to the Baltic was called by it before the other models so it certainly hasn't been wrong on everything 

 

[Weather-history]

GFS 0z now

And a week ago

And the 240hrs chart from that GFS run, somewhat of an easterly flow in the south

 

 

ECM 0z for now

And a week ago, ECM 0z for now

Thats the 240 hr chart from that ECM run, but where's the easterly?

 

Edited February 7, 2017 by Weather-history