Model output discussion - Closing in on Christmas

[keithlucky]

2 minutes ago, CreweCold said:

Need to see some cold uppers. That's one of the most tepid NW airflows I've seen in December.

That's the problem Iceland is not that cold atm,above 0c by day.

[Daniel*]

Becoming even clearer...

[Cheshire Freeze]

2 minutes ago, Scott Ingham said:

I agree mate. Wont matter if we get the super low heights over us though at this time of the year with it an organised area of precipitation and not convection

Look at the NH view for 850s at 216. I don't ever remember seeing so much warmth around the edges in late December. You usually see it end of Feb/early March as warmth starts to head N with the increasing daylight.

It's shocking.

[Scott Ingham]

Just now, CreweCold said:

Look at the NH view for 850s at 216. I don't ever remember seeing so much warmth around the edges in late December. You usually see it end of Feb/early March as warmth starts to head N with the increasing daylight.

It's shocking.

Yeah I agree with you its quite stark how warm that whole area is at this time of the year. Id still bet good money on a lot of snow though if the polar low drops south although we would have issues with were relying on convection from a warm irish or north sea

[Ravelin]

Irrespective of who has moved to who, and this argument is getting very tiring, no complaints if this was the eventual outcome at t216... 

[Kasim Awan]

Well, we are seeing model alignment towards a very nice progression..

I personally would like to see improved ridging & tilting of the ridging at Newfoundland on the next few runs at 120-144h for added confidence.

Plus the ECM still leaves room for sliding lows which would deepen the cold pool to our east whilst providing means of polar low development.. The stronger Greenland high on the GFS is certainly not a guarantee, however in both cases the trajectory is cold it has to be said

[Ali1977]

1 minute ago, Ravelin said:

Irrespective of who has moved to who, and this argument is getting very tiring, no complaints if this was the eventual outcome at t216... 

The ECM looks great, and regardless of the forecast 850s not being that cold I imagine it’ll feel very cold and there will be snow about. I expect upgrades with this now, might not get a white Xmas but a white end to December is looking increasingly likely .

[swfc]

1 minute ago, Ravelin said:

Irrespective of who has moved to who, and this argument is getting very tiring, no complaints if this was the eventual outcome at t216... 

Yes your correct. The ec at 240 hours also is in a very good place on the nhp. The 850s arnt spectacular but taken in isolation the ec is all good be it fi and all other caveats. Good start to the day

[Daniel*]

Bit disappointing the day 10 considering you can always trust a low of eastern seaboard to steamroll through if the low went SE it would encourage even more WAA and more poleward ridge. Lots of interest at the moment.

[NewEra21]

Still not impressed with the lack of cold, looks like a lot of cold rain to me. Of course some places will get lucky, but there will be a huge slice of marginality. 

Nowadays anything from the north just doesn't seem to cut it, we always need a much more easterly component to bring the true cold in.

The charts look great on face value, they scream cold. And then you look at them and the cold just isn't there. It's pretty disheartening to finally see these great looking charts, but then without the cold you'd associate with them.

Edited December 20, 2020 by NewEra21

[carinthian]

On 19/12/2020 at 06:44, carinthian said:

Good morning . Following on from the above post, seems ECM have down graded that pre Christmas low and tracked further south but still shows it affecting the south with possible snow to the highest ground of the Southwest.  All main models seems to show the same chart profile now at 144t ( below from UKMO ) which seems to have been the most consistent of the models out at that range. Now whats is to develop during the period 144t-240 I ask our team ?   After a temporary warm up over Boxing Day , a cold front will move through the British Isles next weekend introducing a NW ly flow with the Greenland low expected to be centred near to the Low countries by the 29th ( still a long way off I ask )? Yes, but they think that is what the UKMO charts will be showing out at that range. So risk of snow increases towards New Years Eve for Blighty . Too early to predict location .

C

Morning all. Have a follow on update from the team regarding the above post. They still favour the position of the low as now being shown by the latest GFS run for 29th December. They also expect UKMO charts at that range will have similar features ( maybe a bit further to the NW ). The good news is the British Isles will then be set on the colder side of the low as being shown on most model height profiles at 850mb level. I ask for the chances of snowfall for the British Isles, the %  rate this morning is 20%  for the 29th December, which is in effect quite high, especially if the models continue to hold their present prgress to a colder outlook..That % rate increases by 10% per day. The area is based on the SE of Britain. So looking at the GFS chart for that day , precipitation would likely to be of a convective type.  Meanwhile in the Austrian Alps the snow model is showing snowfall for Christmas Eve and Christmas Day which should nice. Hope you guys get to see some soon!

C

 

[KTtom]

14 minutes ago, CreweCold said:

Look at the NH view for 850s at 216. I don't ever remember seeing so much warmth around the edges in late December. You usually see it end of Feb/early March as warmth starts to head N with the increasing daylight.

It's shocking.

The problem is it isn't a straight northerly, i.e. origins from the pole.. following  the lines, if you break wind in your back garden you will smell it a couple of days later after its visited Finland! 

[Daniel*]

2 minutes ago, KTtom said:

The problem is it isn't a straight northerly, i.e. origins from the pole.. following  the lines, if you break wind in your back garden you will smell it a couple of days later after its visited Finland! 

You would expect it to be colder.

 

[sheikhy]

Brilliant ecm and moved towards the gfs!!a middle ground solution wont be too bad at all!!ukmo is disgusting!

[Jason M]

34 minutes ago, KTtom said:

The problem is it isn't a straight northerly, i.e. origins from the pole.. following  the lines, if you break wind in your back garden you will smell it a couple of days later after its visited Finland! 

You hit the nail on the head. This is essentially the point some of us have been making for the last few weeks. The wind direction per se isn’t the only factor, it’s where the air mass originated. These big bowling ball weather systems are probably not going to deliver what most people want on here as we need either a genuine arctic airmass or a polar continental. Although winds are from the north the airmass is closer to a polar maritime albeit it could actually be argued its a heavily modified returning tropical continental airmass. In essence a similar concept to how we end up with warmish north westerlies from a round shaped high sitting of the west coast of Ireland (which we also see in the output this morning).

40 years ago this set up would have been a couple of degrees colder and therefore just about adequate. These days unless it’s a true arctic airmass we really need need a continental type flow as it tends to be colder in the lower parts of the atmosphere.

Whilst not the only factor at play here it is an example of global warming in action and it’s only going to get harder to get snow as the years roll on. Winter now arrives in Moscow in mid November most years whereas even 15 years ago it would be mid or late October. 

We could actually do with the pattern shifting East and sacrificing any first cool spell so as to pull some colder air down across continental Europe. We might never benefit from it, but at least that way there would be a cold pool to draw on later.
 

Edited December 20, 2020 by Jason M

[Ultima Thule]

2 minutes ago, sheikhy said:

Brilliant ecm and moved towards the gfs!!a middle ground solution wont be too bad at all!!ukmo is disgusting!

UKMO and ECM are close at 144, haven't a clue what you are on about.

[mulzy]

Looks like the more amplified solutions from days 8-10 dominate the EPS.  Much better mean than last night.

[TSNWK]

3 minutes ago, mulzy said:

Looks like the more amplified solutions from days 8-10 dominate the EPS.  Much better mean than last night.

Most positive post of morning for me.  I was worried yesterday on the trending on ECM means yesterday.  

[sheikhy]

4 minutes ago, Ultima Thule said:

UKMO and ECM are close at 144, haven't a clue what you are on about.

Okay maybe im viewing them wrong!!i correct myself then and i will say ukmo will look brilliant like the ecm with a scandi trough and atlantic high from 168 hours onwards!!!woohoo!!!

[swfc]

8 minutes ago, sheikhy said:

Brilliant ecm and moved towards the gfs!!a middle ground solution wont be too bad at all!!ukmo is disgusting!

You think? Ukmo looks OK to me ie Atlantic shut off ie West to east flow, Heighths possibly moving north then lower Heighths hopefully moving sse threw the UK. Not a freeze but still a decent path to be on even with all the current fluctuations and caveats. Thinking its not a bad outlook and start to the day sheikhy

[nick sussex]

The UKMO is hard to judge as it only goes upto day 6 .

It’s less developed with the eastern seaboard low but apart from that not sure there would be any undue drama as it’s still amplified in that area .

Regardless not sure it’s done itself many favours over recent days , it’s still flailing about with the low to the sw and seems to have been wrong within T96hrs.

Actually I was being too kind to it , last nights output was wrong at within T72hrs with that low to the sw ! 

 

Edited December 20, 2020 by nick sussex

[Jason M]

Another point to consider this morning is that with such a large area of low pressure the charts at days 7,8 and 9 will not be picking up on secondary lows (Nicks famous short waves). As we get nearer the time expect things to get messy with smaller systems popping up and delaying things.

[Chesil View]

10 minutes ago, Jason M said:

Another point to consider this morning is that with such a large area of low pressure the charts at days 7,8 and 9 will not be picking up on secondary lows (Nicks famous short waves). As we get nearer the time expect things to get messy with smaller systems popping up and delaying things.

........Or enhancing things

[Daniel*]

11 minutes ago, Jason M said:

Another point to consider this morning is that with such a large area of low pressure the charts at days 7,8 and 9 will not be picking up on secondary lows (Nicks famous short waves). As we get nearer the time expect things to get messy with smaller systems popping up and delaying things.

And giving surprise snow events in more slack cyclonic flow. Like this.

[That ECM]

At t240 we have this. With this mean. I added the last one for all those who love to see problems and disappointment.