Model output discussion 8th Feb - Cold for now, but then what?

[JBMWeatherForever]

This is a disappointing easterly no matter which way you look at it. Considering how cold the continent has been recently, we have been yet again unlucky in the way things have panned out.  However given the way the models are currently behaving, and the fact that the Atlantic seems so week at the moment, I still think that before winter is done we will see a notable cold spell.

Hints at a notable and potent northerly seem to be continually being shown. Considering where I live (on a mild island) where on March 28 2013, we had one of the worst Blizzards in living memory, I don't buy into the idea that winter is over meteorologically speaking on the 1st March.  If you do, then you may find that you get a big shock!

[summer blizzard]

5 hours ago, Singularity said:

 

A vast difference between GFS (left) and UKMO (right) with respect to how the lows in the N. Atlantic and E. Canada are behaving on day 5.

The standoff continues, with the GFS version screaming of southwesterly flows heading our way while UKMO looks more inclined to offer the chance of a mid-Atlantic ridge, but only if the eastern of the two lows can escape cleanly east. As has been said so very often lately - the extent to which the current kick in GLAAM can amplify the upstream pattern will be the deciding factor.

Turns out UKMO looks close but not quite sufficient for the mid-Atlantic high, though it seems the one over us could stick around or even grow stronger should the ridge from the Azores merge with it having bridged across to the north of the low dropping down by Iberia. Possibly the overall position for the weekend would be a bit west of what we see from this model for Friday - so a cool, dry weekend with overnight frosts. Just have to ignore the Go For Storms model.

Speaking of which, even as that seemingly unavoidable major blocking signal begins to take shape for the late days of the month, the model still finds a way to hammer at us;

Looking a few days earlier, it's not hard to imagine what should have happened instead;

- though the sheer scale of that vortex over Scandinavia is in part a result of its zonal enthusiasm before hand piling unstable air into the region, so something that dramatic seems a bit over the top.

GFS has a wave 1 displacement pushing the vortex towards Scandinavia in the stratosphere. It must believe that we'll see a troposphere effect. 

[Frosty.]

It will soon be time to wave goodbye to this lame easterly according to the Gfs 18z tonight. Early next week still looks chilly but winds gradually veer southerly and from wednesday it becomes milder, not super mild but still a lot milder than we have now.

Edited February 11, 2017 by Frosty.

[Chris.R]

1 minute ago, Frosty. said:

It will soon be time to wave goodbye to this lame easterly according to the Gfs 18z tonight. Early next week still looks chilly but winds gradually back southerly and from wednesday it becomes milder, not super mild but still a lot milder than we have now.

Winds will veer southerly;  sorry, mr pedantic here. 

[Frosty.]

10 minutes ago, Chris.R said:

Winds will veer southerly;  sorry, mr pedantic here. 

 the end result is much milder air..

Ps..welcome back knocker :- )

Edited February 11, 2017 by Frosty.

[Singularity]

22 minutes ago, summer blizzard said:

GFS has a wave 1 displacement pushing the vortex towards Scandinavia in the stratosphere. It must believe that we'll see a troposphere effect. 

That's one of the other parts you've identified there, and a reason why I'm so interested in any scope for even a half-hearted MJO phase 8 response building a ridge toward Greenland. As yet the fog refuses to clear on how exactly the MJO is and will be behaving.

[weathernuts]

8 minutes ago, Frosty. said:

No, back southerly from easterly actually, but the end result is much milder air..

Ps..welcome back knocker :- )

Clockwise change is 'veer' eg Easterly to southerly.Anti clockwise is 'back'

[Nick F]

Both GFS and ECM displace the sPV back to NW Russia/northern Scandi by around T+120, currently its centred over N Greenland/ N Pole.

If you remember last time this happened in late January we saw the zonal flow in the troposphere strengthen over the Atlantic, with the NWP churning out zonal charts out to day 15, something similar at the moment it looks too. But IMO we could eventually see mid-Atlantic ridging building north as the core of the trop PV moves over Svalbard and Norway while more amplification works downstream, certainly at day 10 the flow is looking more amplified over N America on 12z EC.

[Frosty.]

15 minutes ago, weathernuts said:

Clockwise change is 'veer' eg Easterly to southerly.Anti clockwise is 'back'

Yes apologies, you and chris are of course right.

[feb1991blizzard]

11 minutes ago, Nick F said:

Both GFS and ECM displace the sPV back to NW Russia/northern Scandi by around T+120, currently its centred over N Greenland/ N Pole.

If you remember last time this happened in late January we saw the zonal flow in the troposphere strengthen over the Atlantic, with the NWP churning out zonal charts out to day 15, something similar at the moment it looks too. But IMO we could eventually see mid-Atlantic ridging building north as the core of the trop PV moves over Svalbard and Norway while more amplification works downstream, certainly at day 10 the flow is looking more amplified over N America on 12z EC.

Looking at the pure output, the EPS 0z graph didn't look favourable for that solution though but GEFS has done for aa while, strange though that the UKMO text forecast lately suggesting dry and slightly below average temps late feb and milder weather in March pushing in from west, if I was going to write a forecast myself based on output, I would be more inclined to suggest colder and +ve PPN anolalies the further North and west with snow over Northern Britain (not just on the hills) and dryer in the SE.

[nick sussex]

Well its painful viewing at the moment and we're back to chasing another opportunity. This winter has been  a case of much promise and not much delivery in terms of cold and snow and with only a few weeks left we don't have a lot of time to play with. As Nick F just posted we might see a bit more amplification feeding downstream. With the PV and deeper cold to the ne if we could manage some decent amplitude theres a chance to get some cold south. But I think at this point its best to lower expectations and see whether the models might start throwing up some more amplified solutions over the next few days.

[kumquat]

I saw snow lying on the grass last night and I saw it falling through the cold air. That's no mean feat for the SW.

Let's pluck up the courage and see this through until winter's end.

A beast of cold air to our North @144 ECM

As the vortex migrates so we will get another chance.

 

 

[knocker]

This morning's GEFs anomaly is, not surprisingly, similar to yesterday so keeping this in mind the morning's det. run holds no surprises'

The block to the east is quickly eroded starting Tuesday with the wind veering southerly as fronts push in from the west bringing much warmer air, initially to the west. Thereafter the Azores ridge consolidates it's position and with a general westerly upper flow a N/S split ensues with the south tending to remain dry whilst fronts and intermittent rain belts  track  around the ridge generally effecting the north west. Temps quickly returning to average, maybe even a little above.

 

Edited February 12, 2017 by knocker

[knocker]

Essentially the ecm is similar to the GFS only varying in the detail of any encroachment of frontal systems from the west as it evolves a slightly different interpretation of the timing of the interplay between the Atlantic and Azores airmasses.

[Guest]

DAILY EUROPEAN TEMPERATURE AND PRESSURE CHECK No. 9  

THE COLD POOL IS LOSING ITS GRIP – FINAL “WINDING UP” REPORT

Unfortunately, I am going to have to concede that it now seems highly likely that the winds will veer towards the south during the next few days and mild air is making steady progress through France towards the UK. The pressure pattern is no longer conducive to bringing the cold pool back towards us – we needed a much more east to west orientated HP. It did show a lot of potential a few days ago but things went rather pear-shaped since then. There is no point on my continuing these daily reports, so I shall do a shorter closing analysis. In the highly unlikely event of a dramatic change for the better, I will be back!

Now, I shall pick up from my last “check” (on page 19 of this thread) which was a “bumper” edition. This took us to February 11th. 

European Surface Temperature Charts:

               Current "live"                                      Feb 12th 0650                                  Feb 11th    1250                               Feb 11th  0650                                   Feb 10th 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:  The deep cold (purple area) has hardly weakened but it has not progressed any further west in the last 3 days. The cold pool in central and western Europe has weakened slightly and is being steadily eroded from the south and south-west. Daytime maxima have been rising but the nighttime minima have remained quite low. All this can be seen by comparing the two "0650" and the two "1250" charts.

GFS  0z February 12th T+6 European Charts:                         GFS 0z February 11th T+6 European Charts: 

                         850 Temps                                                                                   850 Temps 

                                                 

COMMENT:   Compare today's charts with yesterday's.  The main pool of 850s with sub -8c temps has actually expanded southwards but it has weakened considerably on it's western and south-western sides. The breakaway area of sub -12c temps over Scandinavia and Denmark has mixed out and only a thin slither of sub -8c temps remain. The 0c to +4c temps have pushed northwards through France during the last 24 hours.

European Surface Pressure Charts:

                Current "live”                                    Feb 12th 0650                                 Feb 11th    1850                                 Feb 11th  0650               Current Met Office Fax: 0600 Feb 12th              

                                       

COMMENT:  The HP has only weakened slightly but it has taken on a far more north to south shape assisting with the southerly breakdown. The warm front shown on the fax chart is the leading edge of the milder air. 

Overall, it was fun producing these reports when there seemed to be so much potential but it has been hard to put a brave face on things during the last couple of days. I do have a stubborn streak and only gave up on this cold spell long after many of you guys had and after defying the changing model output! We now need to focus on the chances of our next cold spell for later this month.

I'll be back this evening with my latest full weekly report and I'll have a look ahead then

 

Edited February 12, 2017 by Guest
Correcting typos and to ensure that all the links and charts work properly.

[bluearmy]

little of note for coldies showing up at the moment. GEFS has a mobile picture through week 2 with heights highest sw of the uk and lowest over scandi. Eventually we see an appetite to drop the troughing further south and close enough to make a difference here. The gems seem a little more interested by the very end of the month than the GEFS in a better scandi trough set up. Basically, with some possible response to events high up/MJO forcing we could see a more wintry period at the turn of the month. From a purely imby POV it doesn't really interest me but plenty on here are of a coldie perspective and live in areas which could benefit. 

 

[knocker]

Coming along nicely

[snowbunting]

10 hours ago, JBMWeatherForever said:

This is a disappointing easterly no matter which way you look at it. Considering how cold the continent has been recently, we have been yet again unlucky 

Not for me. This has been a cool calm and quite dry sunny winter up here. The easterly has coincided with the long weekend. Perfect. 

[Robin2012]

13 minutes ago, knocker said:

Coming along nicely

For a newbie like myself and many others could you tell us what is `coming along nicely` please?

[bluearmy]

9 minutes ago, Robin2012 said:

For a newbie like myself and many others could you tell us what is `coming along nicely` please?

Spring

[Summer Sun]

Some rain might be possible in the far north at times but on the whole, UKMO keeps it dry and settled into the weekend

But changes may be afoot at t168 with more of a northwesterly flow bringing wind and rain to many parts

I say may as ECM has the high closer by so whilst not as mild it would be mostly dry

Edited February 12, 2017 by Summer Sun

[Robin2012]

1 minute ago, bluearmy said:

Spring

Great, that's my learning sorted for another day then! the models have made fools of most forecasts many times this year but as an observer only and without any evidence I don`t believe that's the end of any cold or snow this winter, we have seen very quick flips in the models but that is just my opinion of course, we all have them.

 

[carinthian]

I might be reading this chart wrong but the continental block is still there at 144t on the latest UKMO run. The UKMO has been the less progressive model for much of the winter and in many ways the most consistent with its out -puts up to 144t time span. The fax charts up to 96 h still show the block dominating. The latest 168t shows some limited Polar progress into Northern Britain but I would not be surprised to see high pressure to dominate for most and possible relocation in later runs this week as the Atlantic zonal flow runs out of steam, yet again.

C

[markw2680]

2 hours ago, knocker said:

Essentially the ecm is similar to the GFS only varying in the detail of any encroachment of frontal systems from the west as it evolves a slightly different interpretation of the timing of the interplay between the Atlantic and Azores airmasses.

Iv got to be honest I'm blooming glad to see you back, always a fair view of the models.

[Matthew.]

GFS 6z like the ECM has the high easing south for next weekend but close enough to allow a Atlantic SW,ly to develop. Feeling mild Saturday into Sunday

Edited February 12, 2017 by Matthew Wilson