Model output discussion - into the start of Winter

[summer blizzard]

The stall is no bad thing since we have limited cold air over Europe anyway. What it does is allow the primary jet to reorientate and shift the vortex.

[Captain Shortwave]

In all honesty the next 7-10 days will be a case of getting lucky under a slow moving modified polar maritime airmass. Some places could see some snow, but most will likely to be a mix of precipitation and of that it will be mostly rain away from high ground.

However the pattern setting up is probably the most blocked scenario seen in December for a long time and clearly further down the line we could inject some proper Arctic air, which could deliver the goods. The spell from November 2010 into December took its time to fully unleash its potential when finally at the turn of the month we saw cold air flood south through Scandinavia into Europe and the U.K. This could very well happen again at some point.

Edited November 29, 2020 by Captain Shortwave

[Radiating Dendrite]

1 minute ago, daz_4 said:

Exactly what I feared when ECM first showed this pattern at day 10. It gets stuck and then just fizzles out. Seems to me the next week is pretty much done deal and many places in Europe will enjoy very warm weekend. We are looking at the middle of December for any renewed interest. Deja vu really.

Might want to look at the meto update. Too many stressing about that low and not seeing the bigger picture.

[SMU]

GEM 198

[mulzy]

FWIW the GEM is very interesting from days 4 to 6.  It's most likely an outlier solution but it's on the cards.

[Griff]

20 minutes ago, Geordiesnow said:

I think the hope was maybe we would see enough eastwards adjustment to tap into Arctic air but now all it looks like is a big fat trough parked right over bringing us wet at times and windy weather. Nothing cold or wintry and as I say, don't rely on the east for cold, Scandinavia is going to go well above average temperatures wise because of the big fat trough over us. 

Atlantic heights are also going to quickly reduce and the ridge will collapse because its not going to end up in Greenland so as I say, wasted opportunity I'm afraid. 

More potential for snow in a cold zonal set up than this stalling low malarkey.

 

13 minutes ago, Griff said:

I don't know, could just be the gfs on steroids but it's obsessed with Atlantic blocking which I've never seen in my short time of following here. Wouldn't surprise me if it went all in on a huge Greenland block... 

Obviously I cursed it on this run!  

But some stonking blocks over the last few weeks in deep fi never never land... 

[summer blizzard]

19 minutes ago, Captain Shortwave said:

In all honesty the next 7-10 days will be a case of getting lucky under a slow moving modified polar maritime airmass. Some places could see some snow, but most will likely to be a mix of precipitation and of that it will be mostly rain away from high ground.

However the pattern setting up is probably the most blocked scenario seen in December for a long time and clearly further down the line we could inject some proper Arctic air, which could deliver the goods. The spell from November 2010 into December took its time to fully unleash its potential when finally at the turn of the month we saw cold air flood south through Scandinavia into Europe and the U.K. This could very well happen again at some point.

In that case the low stalled on the 19th and the snow arrived on the 24th, the undercut is not as good this time though.

People forget though that actually early Dec 18 was pretty cool as were a handful of other years early on so we will need to see how the pattern transitions.

[steveinsussex]

2 hours ago, Norrance said:

Hi guys. As the original poster said there is a thread for Met O forecasts so please use it.

Thanks.

When you say stuff like this please post a link to it

 

thanks 

[Allseasons-Si]

The gfs is like chalk and cheese compared to this morning's 06z run in fl so no news there

the GEM is a good run NH wise though.

[Griff]

Just now, Allseasons-si said:

The gfs is like chalk and cheese compared to this morning's 06z run in fl so no news there

the GEM is a good run NH wise though.

Sorry that was my doing

[phil nw.]

2 minutes ago, steveinsussex said:

When you say stuff like this please post a link to it

 

thanks 

Hi Steve,

There you go.

[West is Best]

This is classic GFS and it has been doing this for months. It was never a particularly stellar FI cold snap but the sudden 12z switch to the Atlantic doesn't, sadly, surprise me. It has been all over the place.

Who knows? 

[Snowmadsam]

'ello! Been lurking for about a week!

This is a blocked pattern coming up. This week was never gonna deliver a snow fest when it comes to this low. 

Relax, its still November. Things take time. The pattern is much more favourable than any I've seen for a good while. 

Long way to go! 

[Tim Bland]

Due to lack of interest the rest of this evenings GFS run has been cancelled .  We are going to review the GEM instead...which is far more exciting ...even the chance of pink snow at times!!

Edited November 29, 2020 by Tim Bland

[johnholmes]

One run and some of you go from living in heaven this morning to somewhere else this afternoon.

I can see no reason for this wild swop in thoughts.

Take a look at the wider view, nothing has changed in the actual pattern.

No charts but that is unusual for me, my thoughts follow my 500 mb ramblings of the past 2-3 days1

[IDO]

We lose the upstream Pacific ridge on the 12z GFS run, much flatter, so the whole pattern flattens out downstream from there:

12z >> 06z >>  

We really do need amplification to maintain this potential from the tPV visiting the other side of the NH? Otherwise by D15 we are back to square one:

 

[Eskimo]

1 minute ago, Tim Bland said:

Due to lack of interest the rest of this evenings GFS run has been cancelled .  We are going to review the GEM instead...which is far more exciting ...even the chance of pink snow at times!!

Ah yes, the infamous GEM snizzlestorm special. 

[SMU]

Not often you can compare operational runs & ENS with 2010

Edited November 29, 2020 by Steve Murr

[Geordiesnow]

29 minutes ago, Steve Murr said:

GEM 198

A chart which synoptically looks good but actually the weather won't be. Cool NE'ly winds with average to just slightly below average temperatures with rain showers in eastern areas. 

 

[Mike Poole]

3 minutes ago, Tim Bland said:

Due to lack of interest the rest of this evenings GFS run has been cancelled .  We are going to review the GEM instead...which is far more exciting ...even the chance of pink snow at times!!

The pink is freezing rain, Tim.  But I agree, it is a nice run, but again lacking cold air - this will come as we head further into December, provided the blocked patterns continue (I see no immediate reasons why they shouldn’t at the moment). 

[Eskimo]

2 minutes ago, Steve Murr said:

Not often you can compare operational runs & ENS with 2010

Steve, if you press and hold down the image you can press 'save image', instead of print screening your phone. 

[SMU]

Just now, PerfectStorm said:

Steve, if you press and hold down the image you can press 'save image', instead of print screening your phone. 

Cheers > easier that !

[Tim Bland]

3 minutes ago, Geordiesnow said:

A chart which synoptically looks good but actually the weather won't be. Cool NE'ly winds with average to just slightly below average temperatures with rain showers in eastern areas. 

 

-4 / -5c uppers, low DP due to the easterly flow and a cold surface gives a chance of snow / pink snow ...

[West is Best]

The thing is, I've been watching the GFS for months and it has forever been plumping for blocked scenarios which are, mysteriously, always out in FI. Then, up pops a return to Atlantic zonality and we are back in the usual cycle until the next FI blocking appears. Rinse and repeat. Call me a cynic but I've stopped paying any attention to anything beyond T168. 

We would need serious upstream blocking i.e. a proper Greenland High, a phenomenal Svalbard High or a fantastic mid-Atlantic High and we need them inside T168.

 

 

[Griff]

10 minutes ago, Tim Bland said:

-4 / -5c uppers, low DP due to the easterly flow and a cold surface gives a chance of snow / pink snow ...

Must be due to the infamous solar minima and increasing sunspot activity... The pink snow that is

 

Nothing horrific this evening thankfully, models trends still hold interest for December, and that is satisfactory.