The hunt for cold - Model discussion (late November)

[phil nw.]

It's the old story i am afraid when we see a large chunk of pv to our north west.A sharp temperature gradient is created coming off the eastern seaboard re-enforcing the Atlantic jet.

It just flattens any attempt at prolonged ridging.We do get some incursions of polar air at times especially further north but the pattern is quite mobile for now with everything going west to east.The modeling of those+ve hts to our north east remain interesting but ens.outputs are still keeping them at arms length at the moment.  

[Spah1]

Let’s hope the GFS control is on the money. 

[blizzard81]

1 minute ago, Steve Murr said:

It just goes to show that models in protracted blocking scenarios almost always over estimate the atlantic-

A total back track from the ECM tonight towards a slower evolution & potential undercutting especially when you compare 168 V 144 today 

GFS still more amplified but most scenario lead to cold leaking SW out of Scandi --

 

Where did all those zonal posts go??m

Lol. Personally, I am still reserving judgement. After all, it's just one op run. The ecm ens should be very revealing later - for good or bad. Also like I said above, we need to see that positive run built upon and hopefully improved on in subsequent runs. 

[Seasonality]

42 minutes ago, jules216 said:

Tried some reverse psychology @bluearmy 

The GFS main run turned out OK at the end. But you know when you see Azores high being menacingly advected towards Iberia it does give you an uneasy feeling. We know that about now most of the recent Decembers went pear shape for the whole of Europe basically. It would be a shame that a nice signal for central EU through would vanish that quickly. Did you get much snow in your neck of the woods @Seasonality in recent days? I am now counting days and will be leaving Ireland after 14 years on 15th of December. Location where I will be living got around 20cm yesterday and had -7C today lunchtime

Not much in the way of snow, but lots of bright cold weather. 

[blizzard81]

Quite a happy ending to 12z jma tonight

[carinthian]

5 hours ago, carinthian said:

Afternoon all. The resort Advent Path opens later this afternoon ,starts in the village square and ends at the hutte on picture below . Always a popular walk for the children and lasts till Christmas Eve. Thick snow on the ground, frosty night air  and the sweet smell of hot glog in the air , a sure sign of Christmas around the corner. Still no change to the last forecast from over here, charts still have a mild period for Southern Britain , less so for Northern Britain out to 168t , then a rise of pressure around the British Isles in period 168t-240t . During this period a sharpening of the Scandinavian trough becoming a feature. Longer term charts 10-15 days , showing some very low temps over Scandinavia to develop during this period with possible encroachment into NE Britain. Still a long way off but one that keeps occurring in their own model ( possible Arctic high showing its hand with a developing Ac air mass to advect SW  following the low pressure / trough disruption  as mentioned. This would be a rare feature but one that would deliver real cold, however, as always the British Isles will be close enough for the Atlantic to repel. Still lots  of chopping and changing over the next day or so but that Arctic high seems very persistent.

Just for a bit of fun for you cold lovers. Much of Europe in the freezer by Mid - December as shown on the GEFS latest Control run, especially Scandinavia . Those are mid -day temps !

[JBMWeatherForever]

Like the ECM run and where it seems to be heading. Lots of very cold air not far away and if the run went out any further I think it would be pulling that cold air into the UK. Overall looks promising for coldies heading into December, very promising indeed !   

[Kirkcaldy Weather]

From an article on the met office website

Meteorological winter season

The meteorological winter begins on 1 December 2018 and will end on 28 February 2019.

Astronomical winter season

The astronomical winter begins on 21 December 2018 and ends on 20 March 2019.

https://www.metoffice.gov.uk/learning/seasons/winter/when-does-winter-start

so going by that winter cannot be over as it has not even begun yet, yes a spell of weather influenced by the Atlantic has moved into the UK but will this continue for the entire upcoming winter?

given the tendency for the GFS to overdo the lows at this time of year / in FI and the fact that we have already seen heights building from scandi > Iceland and over towards Greenland in the past few weeks this could be a possible recurring pattern this winter, (anyone who is so sure that we are headed for a non stop zonal winter perhaps they could provide the lottery numbers too being able to predict things well into the future)

Even tonight's ECM has a signal for above average heights in the arctic 

 

 

 

So in summary 

Is winter over? 

 

 

Will there be chances for colder weather to develop this winter?

 

Should people get hung up on every hr of every model run?

NO (as GP mentioned there is the chance for heights to build to our NE)

 

So winter is not over, highly unlikely to be zonal all winter and there is the possibility of heights rising to our NE during December.

A song to remember for those that believe it will be zonal all winter.

 

[Mike Poole]

ECM ensemble mean at T192:

There are indications of, yes, the Arctic high, also maybe south of Greenland, interestingly.  The spread is the most interesting chart, here same time:

The most uncertain area of the entire NH is UK and westerly approach to it.  More rounds to run, this one...

[bluearmy]

8 minutes ago, Mike Poole said:

ECM ensemble mean at T192:

There are indications of, yes, the Arctic high, also maybe south of Greenland, interestingly.  The spread is the most interesting chart, here same time:

The most uncertain area of the entire NH is UK and westerly approach to it.  More rounds to run, this one...

The day 10 spread says that Europe in general is going to be much more troughy than the mean shows 

[SMU]

55 minutes ago, blizzard81 said:

Lol. Personally, I am still reserving judgement. After all, it's just one op run. The ecm ens should be very revealing later - for good or bad. Also like I said above, we need to see that positive run built upon and hopefully improved on in subsequent runs. 

Yeah agree - but at least the ECM has started tracking back- The ECM with a minor tweak in pressure distribution isnt far away from the GFS control -!

also 168 yesterday / 144 today- ECM wedges a ridge in there

 

Edited November 28, 2018 by Steve Murr

[Mike Poole]

6 minutes ago, bluearmy said:

The day 10 spread says that Europe in general is going to be much more troughy than the mean shows 

Indeed, here's the chart at T240:

And it potentially gives the lie to the message some have been posting about high pressure in Europe being a barrier to a cold setup developing for the UK, I think that assumption may be challenged in the next few days.

[Cheshire Freeze]

2 minutes ago, Mike Poole said:

Indeed, here's the chart at T240:

And it potentially gives the lie to the message some have been posting about high pressure in Europe being a barrier to a cold setup developing for the UK, I think that assumption may be challenged in the next few days.

Looks like an inclination towards a S'ly tracking jet to me...certainly not depicting a HP scenario in the 'uncertain zone' there.

[bluearmy]

The extended eps mean looks very mobile with a strong Atlantic low anomaly and flat pattern - no sign of high slp over Europe though so cool zonal more likely than mild - the clusters could still be numerous - the control is very cold and quite snowy in the extended with a big sceuro trough and griceland high 

Edited November 28, 2018 by bluearmy

[blizzard81]

32 minutes ago, Steve Murr said:

Yeah agree - but at least the ECM has started tracking back- The ECM with a minor tweak in pressure distribution isnt far away from the GFS control -!

also 168 yesterday / 144 today- ECM wedges a ridge in there

 

As BA has just mentioned, the control looks absolutely pukka

[frosty ground]

15 minutes ago, bluearmy said:

The extended eps mean looks very mobile with a strong Atlantic low anomaly and flat pattern - no sign of high slp over Europe though so cool zonal more likely than mild - the clusters could still be numerous - the control is very cold and quite snowy in the extended with a big sceuro trough and griceland high 

I would say that’s a zonal outlook even if it’s not a classic SW/NE outlook

sounds like a westerly flow with it altering from north westerly to southwesterly if I’m reading you right

[The Eagle]

2 hours ago, TomSE12 said:

I realise, some members may have been offended by that post and I apologise. I should have used the term, "toy throwing".

Kind regards,

Tom. 

Hello Tom,

I'm not "offended" it by it at all. I'm not one of those offended easily. 

It's the graphical aspect that irks me a little. "Wrist slitting" is worse and seen it used a lot. 

No worries.

[frosty ground]

6 minutes ago, blizzard81 said:

As BA has just mentioned, the control looks absolutely pukka

Temps just getting below and around zero is puka? Or am I reading it wrong?

 

[blizzard81]

5 minutes ago, frosty ground said:

I would say that’s a zonal outlook even if it’s not a classic SW/NE outlook

sounds like a westerly flow with it altering from north westerly to southwesterly if I’m reading you right

That would be very good for early December. 

[Stuie]

3 minutes ago, frosty ground said:

Temps just getting below and around zero is puka? Or am I reading it wrong?

 

2M temps Frosty?

[SMU]

14 minutes ago, frosty ground said:

Temps just getting below and around zero is puka? Or am I reading it wrong?

 

If you take the T2M graph & assume its like the GEFS control (500mb heights ) then 0c max is a good temp - remember the wind direction would be NE do for a north facing coastal ( ish ) location like de bilt then the onshore flow would temper any low temps - infact get the flow across the Uk & we could measure similar values away from the East coast

You will only see mega cold debilt ENS when the air mass is due East PC ...

Edited November 28, 2018 by Steve Murr

[frosty ground]

13 minutes ago, blizzard81 said:

That would be very good for early December. 

Indeed get some decent wintry showers and even snow from such a setup even if it’s not long lasting

 

[frosty ground]

 

8 minutes ago, Steve Murr said:

If you take the T2M graph & assume its like the GEFS control (500mb heights ) then 0c max is a good temp - remember the wind direction would be NE do for a north facing coastal ( ish ) location like de bilt then the onshore flow would temper any low temps - infact get the flow across the Uk & we could measure similar values away from the East coast

You will only see mega cold debilt ENS when the air mass is due East PC ...

Good point Steve 

[Djdazzle]

You know things are looking grim for cold when day 10 charts are being talked about!

Things can flip but it’s only slight glimmers at the moment.

[SMU]

ICON 90/96 shows how allignment of the jet straddling the UK can be sink or swim for snowfall -

18z first ( more wintry with a southerly correction & more cold air undercutting )