Model Output Discussion - cold spell to end Autumn

[Summer Sun]

UKMO extended snow on the northern edge?

[Djdazzle]

24 minutes ago, steveinsussex said:

Steve M isn’t getting excited so that tells me enough

I love Steve Murr’s posts, analysis etc, but to be fair even when he does get excited, 9 times out of 10 things still go wrong for coldies.

 

 

 

Edited December 5, 2017 by Djdazzle

[feb1991blizzard]

1 minute ago, Nick L said:

To add a further perspective, the last frame of the 15z UKV goes out to +120 (Sunday 15:00) has it rain even on the leading edge south of Manchester.

That's a quality model isn't it as well?

[Troubleatmill]

1 minute ago, Dean E said:

I swear if I hear that 'North of the M4' again, i'll move to Alaska!

ECM joins the GFS with the uncertainties in my opinion, this is a very fluid (or solid) situation which needs more days and possible could be down to the 'nowcasting' time frame with this type of setup.

Haha! I think most regions have there own variations too. Like here in Lancashire its the m6 corridor, anything west of it is rain, sure the south east, north east, midlands, south west, wales & scotland all have them. Pop up on Sunday..ill show you what i mean lol! Sunday is going to shift we are only on Tuesday...which way is to be decided. Think BA is right in that by tomorrow tea we should have a decent though not fixed idea ?

[Glacier Point]

Very cold eps trickling out right now...

[Nick L]

1 minute ago, feb1991blizzard said:

That's a quality model isn't it as well?

Well it's ridiculously high resolution (1.5km, Euro4 is 4km for example) but that doesn't necessarily mean accuracy  

[markw2680]

Why are people so fascinated about Sunday and after? What about the cold few days before hand? Just enjoy them and then see where we stand come Saturday, after all it’s only Tuesday so things will change probably quite a lot before the BIG day!! Relax a tad

[carinthian]

8 hours ago, carinthian said:

Morning all. The end of last week our service providers puts us on a snow alert for this weekend ( See above post ) . The updated fine mesh model we use has forecast 15cm between Fri evening and Sunday morning and a further 50 cm possible from Mon -Thursday. However, this high resolution model we use will provide a more accurate and very localised snow forecast with-in 48 hours of the event .  Our portal service forecaster thinks the UK for the most part over the next 7 days will remain under cold uppers and in battle line zone . Pressed further, a succession of sliders on a increasingly southerly track with a 70% chance of snowfall on their snow model , particularly Northern England. I am told that is fairly high % at this range. Exact tracks cannot be determined at this present time and still open to variance. Advice from them for you lot, wait for Exeter forecast updates, this is likely to happen soon. Good luck . Still great charts from what I can make out.

C

 

 The latest GEFS 500mb control run for next Tuesday shows the sliders taking a more southerly track as highlighted in the above post send earlier. When fronts reach the cold block over the British Isles the pressure gradients tend to fall greatest in a southerly direction and could even slow the process of exit. So the model outputs could easily show a more southerly correction over this weekend, hence forecast of snow amounts and location will still be open to change. However, from our snow models indicates 70% chance of snow later next Sunday from the first slider to affect Northern England. However, I have a inkling tomorrows model will include parts of the Midlands to increase its snow chance %. Still too early for fine mesh models to predict snowfall amounts with much precision as the first slider has still yet to resolve.

C

[georgiedre]

3 minutes ago, Glacier Point said:

Very cold eps trickling out right now...

What does this mean gp?

[feb1991blizzard]

1 minute ago, Nick L said:

Well it's ridiculously high resolution (1.5km, Euro4 is 4km for example) but that doesn't necessarily mean accuracy  

Yes I was looking on this on the modelling page on the UKMO website, trying to work out which part of the location forecasts, weather maps, BBC Graphics etc are generated by which models, there's another one as well that's in the development stage, I wonder if that's the one that the £97m is being invested in or not.

[Geordiesnow]

I think the main rule of thumb for this slider set up is that the further North and East you are within the main PPN band, the more likely it will be snow but positioning is crucial and so is the angle the trough comes in at also, you really don't want too see too much mild air coming into play thats for sure. A lot of posts mentioned they are expecting too see a westwards movement because of history but history means nothing too me. The trend(in my opinion) has been for the slider to occur further East which increases the anxiety as it means even less room for error but details is not going to be nailed down for another few days especially if we do see any westwards trends.

[Glacier Point]

Surface temps 2c below, often 4c below average as a mean, right out to T360. That's a mean of 50 members, and widely across Western Europe within the trough

Edited December 5, 2017 by Glacier Point

[johnholmes]

Well, will it snow in 'my' back garden or will it be rain.

Why not try the 'will it snow' predictor?

It explains all the bits and is pretty reliable IF the actual ppn is over you. If no ppn is shown then you get nowt anyway.

Link coming up

 

[tight isobar]

2 minutes ago, Glacier Point said:

Surface temps 2c below, often 4c below average as a mean, right out to T360. That's a mean of 50 members

Thats a lot of members!!!?..

And all well below!!!!

@mean

Edited December 5, 2017 by tight isobar

[feb1991blizzard]

1 minute ago, Glacier Point said:

Surface temps 2c below, often 4c below average as a mean, right out to T360. That's a mean of 50 members

Hints of a scandi ridge been thrown up on there too, is this too Early or does it tie in with your thoughts.

[johnholmes]

Well, will it snow in 'my' back garden or will it be rain.

Why not try the 'will it snow' predictor?

It explains all the bits and is pretty reliable IF the actual ppn is over you. If no ppn is shown then you get nowt anyway.

Link coming up

 

 one of them, not sure where the other is but pretty much similar in what to use

Edited December 5, 2017 by johnholmes

[mulzy]

2 minutes ago, feb1991blizzard said:

Hints of a scandi ridge been thrown up on there too, is this too Early or does it tie in with your thoughts.

Yep, heights significantly higher to our north east in the extended range.  Let's hope this is the start of a trend...

[northwestsnow]

Yes  just watching the EC mean trickle out and northern Uk esp stays under the influence of the cold trough to our NE- 

Generally a PM flow which is of course good for those further north esp with altitude- should offer snowy suprises as the Atlantic lows zip into Europe on a generally SE trajectory.

I can appreciate its not fabulous for the south but up north i think esp the hills it will be white more often than wet.

PS im still seeing January 1984 to all this!!

Edited December 5, 2017 by northwestsnow

[Fozfoster]

On 12/1/2017 at 09:58, feb1991blizzard said:

True but its below 1 inch for the vast majority.

https://earth.nullschool.net/#current/wind/surface/level/orthographic=-16.51,58.79,447/loc=-73.252,33.936

Lows in coming.

not sure why feb1991 is quoted

[tight isobar]

5 minutes ago, mulzy said:

Yep, heights significantly higher to our north east in the extended range.  Let's hope this is the start of a trend...

...

In the trough...

Screams scandi-heights'  4c below...

@easterly!!! ??

surface temps!!!??

Edited December 5, 2017 by tight isobar

[bobbydog]

for future reference, when referring to a situation where a potentially exciting scenario turns into disappointment, the term "damp SQUIB" is used. a squib being a type of firework. you can see how a wet firework could lead to disappointment. instead of "oooh!" and "aaahhh!", "meh" or "pffft" would be a more likely utterance from the casual observer.

this is a damp squid- 

i have yet to find a situation where a wet cephalopod would be a good analogy but if i do, i will get back to you.

thanks 

[Frosty.]

I'm happy with tonight's Ecm 12z ensemble mean, it looks generally cold and unsettled beyond the arctic blast..looks pretty wintry to me all in all with no sign of mild returning after this thursday!

[Timmytour]

25 minutes ago, Djdazzle said:

I love Steve Murr’s posts, analysis etc, but to be fair even when he does get excited, 9 times out of 10 things still go wrong for coldies.

 

 

 

I'm a big fan of SM as well.

I'm reminded a little bit of the end of 2012 when excitement reached fever pitch and I think we got 'That ECM'

SM had called the shots pretty well as I recall, but then it all went very very wrong, even to the extent that Steve himself threw in the towel.

A few days later we got one of several bouts of glorious winter we were to enjoy in the first three months of 2013. 

Maybe we are in a similar place? I still think the calls on the general evolution are good...the timing is difficult to get spot on.  But if we get what we had back then but commencing four weeks earlier, I'll be a very happy boy trapped in an old man's body!!

Edited December 5, 2017 by Timmytour
Typos

[Daniel*]

6 minutes ago, mulzy said:

Yep, heights significantly higher to our north east in the extended range.  Let's hope this is the start of a trend...

Quite interestingly GFS 12z right in the final frames shows +ve heights to our north east with an easterly in the wings, like I say it’s good at spotting a signal far out.

[northwestsnow]

EC mean 120-