Model Output Discussion - cold spell to end Autumn

[Methuselah]

A chart that very-clearly screams potential...though for what is anyone's guess.

[jvenge]

Just a suggestion, but to those who struggle with certain aspects of the model output, consider looking at MeteoGrams for your particular location, or somewhere close. It kinda resolves the whole "will it snow or won't it?" "What temperature will it be?" about each model run. And keep in mind the range when doing so. Precipitation is a fickle beast :-)

[bluearmy]

9 minutes ago, BLAST FROM THE PAST said:

Ridging in Atlantic on 15th (day 10 ecm) for me looks right, GFS 6z more amplified around then compared to 00z so again looks right.  The weekend coming will see very cold air around so chances are there.......and to claim heavy snow or it will be dry is still too early.  Let’s enjoy ......’at least it won’t be mild’

BFTP

I also think that ridging close to the uk makes more sense end week 2 than a Scandinavian ridge. With that Canadian vortex looking menacing I doubt that can retrogress but heading north or northeast is feasible 

[Methuselah]

One for the December Fog Index, methinks:

[Iceaxecrampon]

Goodness.

 

Talk about a double whammy.

[Daniel*]

I don’t recall ever seeing such a cliff edge drop on the ENS well not in my time. Here in London we go from +5C 850hPa on Thursday to -10C temps in the space of 24 hours, that’s comparable to what you see in CONUS.

 

Edited December 5, 2017 by Daniel*

[bluearmy]

1 minute ago, Daniel* said:

I don’t recall ever seeing such a cliff edge drop on the ENS well not in my time. Here in London we go from +5C 850hPa on Thursday to -10C temps in the space of 24 hours, that’s more what you see in CONUS.

 

Thundersnow In the mid noughties springs to mind. Don’t think it’s that unusual tbh 

[Mark Parsons]

I've been reading with amusement the expectations expected from this artic blast, back to basics chaps, get the cold in first then see what happens! With a strong arctic flow of this kind anything could happen.......

 

 

[Daniel*]

1 minute ago, bluearmy said:

Thundersnow In the mid noughties springs to mind. Don’t think it’s that unusual tbh 

 It is very unusual IMO. Perhaps not so, for the far north but such a swing is a rarity it’s very impressive.

[Daniel*]

12 minutes ago, Iceaxecrampon said:

Goodness.

 

Talk about a double whammy.

One thing for certain somewhere in the country, is going to get a pasting. Place your bets..

[mulzy]

1 hour ago, shaky said:

Ecm looks to be on the money here!!if it was to be correct then what an epic fail for gfs at just around 120 hours!!ecm has got slated quite a bit recently aswell!!

ECM is the gold standard, GFS is cannon fodder.

[karlos1983]

Control brings the snow risk south into Monday morning.

I’m really intrigued by this setup and can’t wait to watch which way it goes. Inevitably there will be winners and losers snow wise, but hey ho that’s life.

where we go after is particularly interesting. 

 

[mulzy]

50 minutes ago, Daniel* said:

Interestingly beeb has 6C for London on Friday it’s so off it’s laughable.. As TEITS puts it (good to see you back) maximums between 2-3C many parts of Scotland will hover around freezing at most. 

Time will tell as ever - 2/3C probably right for most of the country but for London 4/5C is probably spot on.

[karlos1983]

Just now, mulzy said:

Time will tell as ever - 2/3C probably right for most of the country but for London 4/5C is probably spot on.

Yeah probably does sound about right, however it will feel sub zero in the wind almost everywhere I would imagine 

[Biensie]

40 minutes ago, musician said:

I've really missed you TEITS. As a learner and still a learner I always looked forward to your posts as they seemed to me to be the most reliable and balanced.  I've been really put off by all this recent bickering ansdwas thinking of taking a break from this site for a few days until things calmed down - that is unless you are going to be posting on here! Thanks.

Take it from me, you won't take a break.  I say the same every year, you will get the hump as things don't go the way you want them too.  You will hang on to every word as the ramping to cold gets to fever pitch and just wait for the cards to come tumbling down  As for taking a break, you will be sneaking back in, you just won't be able to help yourself, its a winter addiction!

[Chesil View]

16 minutes ago, meh said:

How's the 'slider's always correct westward while the EC adjusts to the GFS' hypothesis holding up?

At six days out its anyones game.

[jvenge]

7 minutes ago, mulzy said:

Time will tell as ever - 2/3C probably right for most of the country but for London 4/5C is probably spot on.

In general, models will give a min value and max value for the same time and then forecasters are left to come with, well, a forecast. Sometimes this difference is bigger than others and can be quite huge at times.

So, based on the ECM output, since this is the output thread, between 2-4 is the range for much of London on Friday.

[Chris101]

Still happy with the overall pattern on the 06 up to around Sunday, gonna be a few runs yet to give some confirmation on exact position of the slider.

Not really looking much further than that for now, though I have seen the chances of another ridge building, hopefully it will firm up a bit once this week's spell gets going.

[carinthian]

On ‎01‎/‎12‎/‎2017 at 13:31, carinthian said:

This latest chart from GEFS has put our resort of significant snow alert for weekend 9/10 th December. Further discussion with portal service providers talk of a increased chance of Scandinavian block to form by possible as early as Mid month with Western Europe in the firing line of a battle zone. Asked for further clarification ( sign of strengthening cold block to the NE ). All sounds good to me if goes to plan.  

 

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

 

[Daniel*]

18 minutes ago, mulzy said:

Time will tell as ever - 2/3C probably right for most of the country but for London 4/5C is probably spot on.

Hmm I’m going for 3C. GFS notorious for overdoing temps shows 4C for the London area. Just look at how cold the Scottish Highlands are maximum temperatures at 1500 well below freezing. 

[Mark Parsons]

Maximum temps are as they are maximum , it may only be for an hour during the day or not even reach that max forecast , it doesn't necessarily mean all day........to much emphasis on this I think, we have an  evolving synoptic pattern we have been starved of which more interesting than worrying about the temperature........ 

[Duane S.]

8 minutes 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

 

Cheers C. Any thoughts / clues on the following week yet from the portal?

A couple of weeks ago I booked up the 2 weeks either side of Christmas in the lower Porte Du Soleil, on the back of the impressive start to the season and how things were looking for this period. Normmally a very risky period for skiing in the lower Northern Alps, but seems like the right call now

[bluearmy]

The good news from the eps clusters is that the op cluster (around 20%) is too flat  and north compared to others. The control cluster (45%) is better than the op but still not quite as good as it needs to be but at this stage there is less of a step back from the largest cluster to where we need to be to bring a decent snow event to a large part of the country 

[Daniel*]

5 minutes ago, Mark Parsons said:

Maximum temps are as they are maximum , it may only be for an hour during the day or not even reach that max forecast , it doesn't necessarily mean all day........to much emphasis on this I think, we have an  evolving synoptic pattern we have been starved of which more interesting than worrying about the temperature........ 

I’m taking over the MOD thread  

fair point, but if temperatures are not cold enough no snow it’s a vital necessity. I agree with your semantics certainly been a number of years, since I’ve seen anything particularly of interest. 

Edited December 5, 2017 by Daniel*

[bluearmy]

Max temps are not so relevant Daniel - it’s dew points that matter