[Model output discussion - proper cold spell inbound?]

Spectacular mean showing heights in Svalbard/Greenland area. As many of the more knowledgeable on here have said, when the ENS signal is that strong, it's usually on the ball, or thereabouts. Likelihood is that we will see extensive northern blocking. The only issue is whether it will be positioned and orientated favourably to deliver cold to this isolated, lonely island...

[Model output discussion - proper cold spell inbound?]

This doesn't make any sense. How on earth is the PV still present in Greenland after such a massive strat warming and reversal? It's that which is preventing heights building north towards Greenland. Something isn't right here. 

[Model output discussion - proper cold spell inbound?]

9 minutes ago, Captain Shortwave said:

I think Lorenzo's post in the strat thread is worth a read, as to me it certainly offers an explanation on why we saw the strong signal for the UK to turn cold from around the 19th/20th and why this signal has somewhat vanished from the model output.

It seems that a few days ago we were getting a clean separation between the two lobes of the polar vortex throughout the layers of the stratosphere which pretty much gave a clean route for heights to build in the Atlantic and allow a flow from the east to develop as a result. The reality is that the two lobes don't stay separated for a long enough time with the Siberian lobe transferring to the stronger Canadian lobe which prevents the strong ridging in the Atlantic which allowed the quick route to cold. Someone may correct me on this though as I probably have misinterpreted something here.

I have linked the post below.

 

So what does this leave us with, well surely all imperical evidence would suggest that whilst heights remain low towards Greenland and Canada, surely the strength of the jet coming off the eastern seaboard should weaken and potentially pull back west in time which should allow heights to build northwards over Europe. Could this develop into a proper cold easterly over time remains uncertain but the extended outlook still favoured a continental feel to our weather though it looks more likely to be cold and frosty rather than snowy.

Good post, people really should take a look at the link. Explains why models may be struggling here. 

[Model output discussion - proper cold spell inbound?]

The SSW still hasn't fully occurred and the models are still trying to get a grasp on it. They've gone back and forth for a few days now. I really don't like the look of this morning's runs but we should stay patient. Whatever the models are showing by Wednesday, we can be fairly confident that that's what will happen I think. 

[Model output discussion - proper cold spell inbound?]

2 minutes ago, TEITS said:

No panicing from me. After nearly dying from Pneumonia/Sepsis and being in intensive care two weeks ago, I find snow and cold spells to be the least of my worries. Obviously I would like to see a decent cold spell but it isn't the end of the world for me should it not occur. This is why I can view the model output objectively without emotion.

Hard to beat pneumonia and sepsis as I've witnessed from personal experience. Respect. 

[Model output discussion - proper cold spell inbound?]

1 hour ago, bluearmy said:

but note the 'shortwave' features develop as it heads towards the 'warm' north sea. we don't want uppers that low headed this way because im not sure they have a chance to make it past the Scandinavian coastline and the flow gets cut off. ironically, you don't want lower than -15 uppers headed west out of scandi

What about 1987?

 

Edit- didn't notice someone already picked it out!

[Model output discussion - proper cold spell inbound?]

People are calling the cold spell (which hasn't even started yet) dead already hahaha. This forum really doesn't fail to amaze me at times. 

The SSW HASN'T HAPPENED YET. Wait until it happens, and then talk about extended EPS. The way some of you talk about model runs you'd think they're right every time. 

In the last few runs, in terms of GFS, we've had Greenland highs, Scandinavian highs and Arctic highs. That's the sort of theme we need to continue. 

[Model output discussion - proper cold spell inbound?]

Polar vortex in Greenland causing issues here. SSW might sort it out imminently though... 

[Model output discussion - proper cold spell inbound?]

Now I'm not an expert by any means, but I think people are paying far too much attention to the models. There are numerous changes in the atmosphere currently underway and the model output in a week's time will be vastly different to the output we're getting today, that's for sure. 

It's more important to look at the teleconnections at this stage. There are three main big factors for me. 1) Massive MJO pulse in a blocking-favourable phase. 2) A very clean SSW with a split. One look at Judah Cohen's tweets and it's evident that this really is significant. Likens it to 1985, which was one of the coldest in history for the US and was bloody cold here too.  3) Low sunspot activity- correlates with colder winters here in the UK.

The teleconnections are aligning so to speak. Have patience and in 7 days the models will hopefully have clocked on. Until then, expect some bizarre output! 

[Stratosphere and Polar Vortex Watch]

7 hours ago, Matthew. said:

March 2012, minor warming, sunny and warm,

March 2016, SSW, dull and cool

Jan 2013, SSW, March severely cold with snow

March warmings come too late to have any wintry effect

[Model output discussion - proper cold spell inbound?]

Not sure how good this would be for North East England. These sort of synoptics are perfect for South East and Southern England really 

[Model Output Discussion - cold spell to end Autumn]

For what it's worth, last week's cold spell wasn't really modelled to deliver much snow and up until the last minute, uppers looked mediocre. However, in Newcastle in my area at 130m, I had the most snow showers I've seen in years thanks to a late trough in the North Sea. Moral being, even if certain areas aren't modelled to be hit with snow, surprises always pop up, especially in such an unstable flow. So I'd say the vast majority of the UK has a good chance of wintry precipitation from Thursday onwards. 

[Model Output Discussion - cold spell to end Autumn]

22 minutes ago, Frosty. said:

I was very happy with the 6z mean, plenty of cold days, especially inland with temps hardly above freezing and plunging overnight, no sign of a return to mild once this current mild interval ends..really looking forward to this unstable Northerly arctic blast with troughs lining up to swing south...imagine how good Fridays fax will look

Reckon there's a chance of a polar low forming...? 

[Model Output Discussion - cold spell to end Autumn]

Anyone reckon there's a chance of a polar low developing in that northerly flow? 

[Model Output Discussion - cold spell to end Autumn]

I've gotta say the GFS ensembles are the best I've seen all season for sure. Lots of intra-model agreement as well as inter-model agreement. First time this season there's a very definite drop in temps with less scatter in the GEFS, with some bringing 850 temps below -10 for my area in the North East. Interesting week ahead. 

[Model Output Discussion 01/09/17]

2 minutes ago, - 40*C said:

I've just seen Gavins 12th Christmas update on you tube and I wish I hadn't. No sign of any winter come 10th December its just constant Autumnal wind and rain right out to the middle of January as we lock a very locked Atlantic pattern

.  

It's in FL so I'm really not concerned with long range output when the models have been struggling with short range modelling recently. The CFS has changed its tune regarding its long range forecast already I think so it's still all up in the air. I'd rather enjoy this current wintry spell than worry about Christmas for now

[Model Output Discussion 01/09/17]

This is a wait-and-see scenario. It's essentially GFS/ECM + other lowkey models Vs. UKMO. The UKMO could of course be correct and has been before. But currently the odds are in favour of very cold weather. 00z runs will be the most important for some time as to whether the GFS or ECM remain stubborn or move towards the UKMO. I wouldn't worry too much about the Fax charts atm but the 00z runs will shed a lot more light. Nervous few hours but good model watching regardless 

[Model Output Discussion 01/09/17]

13 minutes ago, bluearmy said:

They are ?

If the GFS really was an embarrassment to its programmers then we would look at it as we do NAVGEM or one of the other less known models. It’s verification isn’t so far behind the other models but granted it isn’t generally quite as good. 

if we had MOGREPS to look at then we would probably look less at gfs but we don’t so we do !! 

Gfs has it’s bias’ and we should look at the output knowing this and making interpretations/adjustments accordingly.

Agreed, but in winter in particular it performs quite poorly compared to Euros. Not sure about other seasons but in my experience the GFS regularly gets it wrong in winter. 

[Model Output Discussion 01/09/17]

This platform is hilarious. Just days ago the GFS was completely off just a couple of days out while the ECM/UKMO were more on the money. This time the ECM/UKMO are showing the cold and people are fully backing the GFS for some reason. One things for sure, I'd rather have the ECM/UKMO showing cold and the GFS showing mild than the other way round. Plenty to be optimistic about imo. GFS has been an embarrassment to its programmers the last couple of winters. Hopefully a similar situation here! 

[Model Output Discussion 01/09/17]

1 hour ago, northwestsnow said:

EC 0z although not as eye catching as the 12z is still below average after tomorrow right through to day 10 so not sure where the Beeb are getting mild with cold shots from?

Unless of course they place more stock in GFS? 

Saying that GEFS0z dont scream mild to me either- below average all the way through-

 

 

I'm pretty sure they don't haha. Gfs performance has been so poor over the past few winters and it was only last week it got it wrong only a couple of days out

[Model Output Discussion 01/09/17]

1 hour ago, blizzard81 said:

Well, either the coldies are suffering from model fatigue or are shocked by the upgrades on the 12z runs so far! 

Definitely the former after last week's shambles! 

[Model Output Discussion 01/09/17]

2 minutes ago, weirpig said:

Ecm what are you doing? 

Fantastic blocking. Best since last night. Where are the 'ECM is king' guys now?? ?

[Model Output Discussion 01/09/17]

1 minute ago, weirpig said:

Bet me to it  better heights on the ecm looks a stronger block 

Best block since the 18z last night. Maybe, just maybe... ?

[Model Output Discussion 01/09/17]

1 hour ago, Singularity said:

Well, it only took until the third time of asking to separate the troughs, so that's something I guess 

The stronger Arctic blocking on this run is notable. AO readings must have gone very low? In some ways we've gone fill circle, with the proper cold signal back to the final week of the month, having been severely teased about a possible earlier onset (and given the GEM 12z, this may yet continue depending on the ECM 12z). How... Amusing?

If I remember correctly something similar happened in either 2009 or 2010. Models repeatedly showing HLB and cold for UK, then signal dissappeared and then reappeared a week beforehand and verified. Still all up for grabs but hope something similar happens here.