Model output discussion - Winter has arrived and the hunt for cold is on

[Mucka]

UKMO giving a little interest this morning with decent Arctic heights and Russian high ridging into far East of Scandi. Still away from a cold block but at least it is a brick or two in the zonal mixer.

 

Edited December 9, 2019 by Mucka

[feb1991blizzard]

The UKMO always seems to be right against the collective suite when its showing the mild outcome but never when its showing cold!

[feb1991blizzard]

Better ending coming up here. WAA about to begin - not perfectly aligned (YET)

[Big Dave]

Sorry, what is WAA?   The Q&A page has been closed for some reason.  Thanks in advance.  

[feb1991blizzard]

Warm air advection, you need it directed poleward ideally if you want to disrupt the polar vortex so not going to be perfect on this run, when it gets right into the polar vortex it can if its very potent split the vortex not just in the troposhere but the lower part of the stratosphere as well disrupting the zonal flow. Its better when there is another bout from  the pacific as well as our side of the pole - that is called Wave 2 - ie - 2 waves - the number of areas of high heights gaining lattitude.

Pressure on the vortex here - squeezed from both sides led to what was to follow.

 

Edited December 9, 2019 by feb1991blizzard

[Jordan S]

Ahh Christmas day has now appeared at the end of the Gfs run in FI so let's see what it's showing..

Just in time for Christmas day and the as some call it the "euro slug" (stubborn high pressure sat over mainland Europe) is in full swing! With low pressure to the west being held somewhat at bay drawing up very mild air over the country.. unsettled for the north drier for the south but this is just a snapshot don't take it literally.

Edited December 9, 2019 by jordan smith

[Big Dave]

31 minutes ago, feb1991blizzard said:

Warm air advection, you need it directed poleward ideally if you want to disrupt the polar vortex so not going to be perfect on this run, when it gets right into the polar vortex it can if its very potent split the vortex not just in the troposhere but the lower part of the stratosphere as well disrupting the zonal flow. Its better when there is another bout from  the pacific as well as our side of the pole - that is called Wave 2 - ie - 2 waves - the number of areas of high heights gaining lattitude.

 

 

Thank you, appreciated. 

[Ali1977]

18 minutes ago, jordan smith said:

Ahh Christmas day has now appeared at the end of the gfs run in FI and let's see what it's showing..

Just in time for Christmas day and the "euro slug" (stubborn high pressure sat over mainland Europe) returns in full swing! With low pressure to the west drawing up very mild air over the country.. unsettled for the north drier for the south but this is just a snapshot don't take it literally. 

Thankfully only 2/3 ENS show the pesky EuroSlug, hoping that trend disappears quickly . There are more showing blocky scenarios too.

[That ECM]

This place is hard work when the output is hard going 

 

T120 and t144 for all 3. Fairly evident why we have a strong flow from west to east, sometimes nw/se but mobile. We have had worse looking nh profiles in winters gone but at the moment it’s not great. 

‘However things change and we keep looking to see if and when this happens.  In the mean time preferably no more willy waving competitions would be good.

[Dennis]

the air into wednesday will have  snow ideas by euro4 

[Captain Shortwave]

Well week 2 seems to be promising to proper slow down in the mobile patter we will see this week. Unfortunately it appears the resulting amplification is building a ridge over Europe with an Atlantic trough.

This doesn’t look like a Bartlett set up with the general weakening of low heights over the Arctic. It will be interesting if we see a trend to build a significant ridge to our east during the last third of the month and what ramifications there might be.

[Polar Maritime]

UKV snow possibilities for Wed/Thur/Fri.

[West is Best]

4 minutes ago, Polar Maritime said:

UKV snow possibilities for Wed/Thur/Fri.

Thank you for this. It's really good. Is there any chance you could post up some of later on Thurs e.g. 15h00, 18h00 and 21h00? Sorry to ask but it's Election Day and it's looking a bit fiery.

 

 

[West is Best]

There should be little reason for despair. It's the first week of December and the weather is extremely lively. If it's only snow that floats your boat there's some of that in the mix this week. The more serious point is that mobility is much better than a stagnant dirty high. And there's some FI eye candy appearing in the ensembles too

Edited December 9, 2019 by West is Best

[Newberryone]

Fl so hopefully this will not play out as presently forecast but it has been more than hinted at in recent days that some kind of settling down period was on the cards nearing the second half of Dec. Doubt many will have any issues with that considering all the recent rain but when it comes at the price of having an unwanted visitor in the form of our old friend uncle Barty I’m not so sure. 

Edited December 9, 2019 by Newberryone

[Dennis]

a rough week it seems 

Edited December 9, 2019 by Dennis

[Nailed-on Nigel]

2 hours ago, Big Dave said:

Sorry, what is WAA?   The Q&A page has been closed for some reason.  Thanks in advance.  

I believe it stands for Warm Air Advection. I think it describes a situation where you have an area of low pressure 

pumping warmer air into the high latitudes, such as Greenland, helping to build high pressure there, and so it can be favourable for colder 

conditions for Western Europe, like the opposite of what we have currently. That said, I'm no expert. 

[mountain shadow]

17 minutes ago, Newberryone said:

Fl so hopefully this will not play out as presently forecast but it has been more than hinted at in recent days that some kind of settling down period was on the cards nearing the second half of Dec. Doubt many will have any issues with that considering all the recent rain but when it comes at the price of having an unwanted visitor in the form of our old friend uncle Barty I’m not so sure. 

I think this is where we're heading unfortunately as the PV winds up and pulls the jet stream back North with Euro heights resulting. 

We then need to wait for zonal winds to drop again in February/March for a proper cold spell to develop. 

Unless a SSW occurs beforehand. 

[northwestsnow]

As always with a 10 day chart its a leap of faith but i wonder if EC is suggestive of something BA alluded to previously about the chance of a securo high towards Christmas.

Taking an optimistic slant on that chart if the high can ridge far enough north then perhaps we could dig something more seasonal out of the bag just in time for santa visiting 

Closer to the here and now, euro models offering something wintry for elevated areas in the north through this week,perhaps..

[Coopsy]

3 minutes ago, mountain shadow said:

I think this is where we're heading unfortunately as the PV winds up and pulls the jet stream back North with Euro heights resulting. 

We then need to wait for zonal winds to drop again in February/March for a proper cold spell to develop. 

Unless a SSW occurs beforehand. 

This is just an alternative way of saying winter is over. Do you really think that if that chart happens there's no prospect of any cold spell until Feb/March (SSW aside)?

[LRD]

2 hours ago, Big Dave said:

Sorry, what is WAA?   The Q&A page has been closed for some reason.  Thanks in advance.  

It might stand for Waiting (for) Arctic Air. A late autumn and winter phenomenon suffered by Internet weather watchers of a cold persuasion where we cling to any straw and cold-weather hope that weather computers offer. Usually resulting in disappointment, mild depression and an urge to relocate to Canada

An example of this is me thinking that the UKMO looks pretty good this morning. But is likely to result in being brought back to reality inside 24 hours or less with subsequent runs looking hopeless

Edited December 9, 2019 by LRD

[Dennis]

GEM looks promising - High coupling possible Russ/NortPole and Azores/Greenland/Northpole

[mountain shadow]

4 minutes ago, Coopsy said:

This is just an alternative way of saying winter is over. Do you really think that if that chart happens there's no prospect of any cold spell until Feb/March (SSW aside)?

All of the seasonal forecasts point to a mid Atlantic low and Euro heights. I don't think I've seen any cold NW Europe forecast. 

The PV is now ramping up and the Strat and Trop are coupling which will increase the chances of a Euro high.

Who knows though, we might get lucky and squeeze a Scandi high in there, but I'm sceptical.

[Frosty.]

Looking through the GEFS 0z there is some hope for coldies on the cusp of christmas, it's NOT the form horse by any means but so what!!..it's a possibility!!!!❄

 

[ArHu3]

Does anyone know why the ecmwf mjo forecast keeps being all over the place for the past few weeks whilst gfs has a clear signal?