Model output discussion - Closing in on Christmas

[Kasim Awan]

GEM also in with stronger wave breaking around Newfoundland. The upstream result is a progression towards the GFS solution.

[Methuselah]

So, what have we here...heights between 522 and 528, a very slack wind-pattern and T850s of somewhere near -4C -- which, to me, look like a forecasters' nightmare: it might (in any given locality) rain, it might sleet, it might snow?

    

[Matt H]

It’s ironic that the people eager to apply the highest level of scepticism to a synoptic chart at day 10 (rightly so in my opinion) are the first people to also moan about the uppers on the same charts and take them literally. 

[phil nw.]

Good to see the re-amplifying in the Atlantic post Christmas-but.

I hope the pattern doesn't evolve quite like that around days 8/9 GFS.That's a broad trough over us with the cyclonic circulation mixing out the coldest air.We can see some of coming up through S.Europe into the mix.This makes things too marginal for widespread lying snow and we would be grinding our teeth over this.

An almost great setup with a decent Greenland block,it only needs a small adjustment se to usher the deeper cold into the UK.

It may recover later if we see further upstream amplification,let's see.

[MATTWOLVES 3]

14 minutes ago, Northwest NI said:

Yes a perfect Greeny high on that chart. Anyone going to venture into saying this  is now nailed on?

I tell you what,this Low pressure system could easily pull SE and bring significant snowfall to a few areas,those uppers may be marginal at present but this is very much subject to change. 

And yes I'm willing to say this is looking nailed on now..not the metal kind of nails you use with an hammer though...I was thinking more like the no nails you squirt out of a gun. im willing to be shot down for this prediction, I'm completely suited and booted ready for it.

Sorry guys but my reactions button as frozen due to overuse

Edited December 20, 2020 by MATTWOLVES

[bumpydogz]

2 minutes ago, MKN said:

Wont matter under deep low pressure and reduced day light hours - 3/4 would likely be ok. 

Please can you explain why deep low pressure and reduced daylight hours would make any difference, outside of that which would already have been factored into the modelling ? Genuine question.

[Weathizard]

Stop worrying about 850’s at this range, they tend to upgrade closer to the time based on previous and there’s so many more other factors to take into account.

The usual brigade of party poopers are out, this chart is at day 6 so within reliable timeframe, 2 weeks ago I wouldn’t have dreamt of seeing this at day 6.

[Mike Poole]

With all this focus (rightly) on a stinking run from the GFS, it is worth remembering that we were watching to see if the GEM and ECM come on board this evening.  Big tick for the GEM here at T180:

[NewEra21]

I know it's not too wise to wish things eastwards, but if the trough over us would just trend a bit further E/SE. Then we truly would open the freezer doors!

That's all I'm hoping to see in future runs!

[ianmm94]

Look at that piece of PV sliding down the east coast of greenland, heading towards the trough of low pressure over the UK...

 

Edited December 20, 2020 by ianmm94

[dragan]

Quite an odd period coming up according to all the latest models more or less.

Despite charts showing very rare charts indeed, the weather at ground level won’t be too extreme.

Sleet/snow for higher ground (perhaps 250m plus ? )

And in any clearer periods frosts look highly likely if the wind speed allows.

[I remember Atlantic 252]

Just now, NewEra21 said:

I know it's not too wise to wish things eastwards, but if the trough over us would just trend a bit further E/SE. Then we truly would open the freezer doors!

That's all I'm hoping to see in future runs!

Aye, needs to move east, like Dec 4th at the moment

[nick sussex]

Can you get snow off a sw flow which is sourced to the ne.

If the GFS evolution is correct then that’s a good test . Its ironic that we often chase upstream amplification and now there’s too much !

A middle ground solution between the GFS and UKMO would be good .

[NewEra21]

1 minute ago, Mike Poole said:

With all this focus (rightly) on a stinking run from the GFS, it is worth remembering that we were watching to see if the GEM and ECM come on board this evening.  Big tick for the GEM here at T180:

Love the look of the GEM, trough further to the east of us and opening up the doors to the colder air.

[Scott Ingham]

28 minutes ago, Met4Cast said:

I'm still not overly optimistic despite the output. Where is the forcing for a sustained Greenland block? The MJO is currently in the COD & forecasting what that's going to do continues to be incredibly difficult. The CFS does tank the AAM which might give some support for a decent block, however given the lag on that the GFS block would be too fast. 

Its off the back of a moderate and next week major EAMT event. This has driven AAM. Models struggle with these events. They nearly aleays underplay them hence the uogrades as we get closer

[Devonshire]

13 minutes ago, Met4Cast said:

Lower sea ice + a warming world means

don't worry: now post-Solar-Grand Maximum, heading for Grand Solar Minimum and new little Ice Age - chill!

[Scott Ingham]

20 minutes ago, radiohead said:

So frustrating to see fantastic output like this...

With uppers in the range of just -2 to -4 at the same timeframe

The positioning of the area of low pressure is so frustrating. The deep cold air is held away to our northwest. If only the low pressure was further southeast...That's what I am hoping to see in future runs.

Put these to the back of your mind the models wont have an idea properly until T'72. If we dont get snow from this set up ill skip through Rotherham Town Centre naked and record it!

[sheikhy]

Control follows the op!!if ecm follows the gfs op then the house is gona be brought down!!!

[NewEra21]

6 minutes ago, terrier said:

I’m sorry but yes we are seeing some nice output  this evening but those uppers are garbage. We are looking at cold rain for most of the U.K. unless you are up on high ground in the north these aren’t great cold rain and sleet really don’t float my boat thanks. 

Yep, it's why we need that trough over us to get a bit further E/SE. So we can then actually get the colder air in, currently the coldest air is going into the Atlantic, we just need a slight shift Eastwards!

Edited December 20, 2020 by NewEra21

[swfc]

Whatever your thoughts are on the gfs 12z 10 days onwards in fi  there would be no way back for the Atlantic and PV which has headed east on its holidays. Enjoy the synoptics and leave the details. In all probability be a different scenario Tom. Great nhp

[Matt H]

9 minutes ago, Mike Poole said:

With all this focus (rightly) on a stinking run from the GFS, it is worth remembering that we were watching to see if the GEM and ECM come on board this evening.  Big tick for the GEM here at T180:

Uppers are also slightly better on the GEM as well for those that are interested.

[V for Very Cold]

2 minutes ago, Scott Ingham said:

Put these to the back of your mind the models wont have an idea properly until T'72. If we dont get snow from this set up ill skip through Rotherham Town Centre naked and record it!

You’ll get icicles! 

[phil nw.]

2 minutes ago, NewEra21 said:

Love the look of the GEM, trough further to the east of us and opening up the doors to the colder air.

Yes a good point.Just compare the 2 at t216,this is the GEM

A straight northerly,direct from the pole,colder air not mixing.Ironically with a quite a modest ridge.It's all about the alinement of that trough.

I would prefer a Greenland block as it would likely hold the pattern longer and enable that deep cold over the Pacific side of the pv to eventually track across towards our side.

[Kentish Snowman in Yorks]

1 minute ago, sheikhy said:

Control follows the op!!if ecm follows the gfs op then the house is gona be brought down!!!

But the uppers!!! 

[Ali1977]

busy In here tonight, don’t know why look at those uppers heading in from the north