Model output discussion - Into 2021

[Scott Ingham]

2 minutes ago, bluearmy said:

Compare the length of time it’s taking that system to drop se on the gfsp ....60 hours and counting by T210.  we’ve twice seen lows deepen dramatically and drop within 24 hours in December. 

Recurring theme.

Its a topic thats created noise on twitter.

Angular momentum has consitently been under modelled. 

Leading to wave events being under modelled.

This is the first genuine looking post ssw run ive seen.

 

[Ventnor Viking]

1 minute ago, Harsh Climate said:

lol it's only the 2nd january and you are basically writing this winter off!  

This cold spell far from finished and we are lucky to have such a promising set-up this early in winter, with a SSW event to come! 

We have 3 months where extreme winter conditions can occur so plenty of time to see something. And I don't want to hear about but it's too late in the winter to get god propper snow in march because march 2013/14 was one of the coldest ever in places, with a ton of snow at leeds bradford airport that lasted weeks, at least a week un melted. 

Certainly not writing the winter off. As I stated,  there will be cold around, thats hardly writing off. When you look to the east - no cold and when you look to the north its very moderated and very inconsistent. I could be like many others, including yourself and say what "might" or "could" happen, but I'd like to stick to what is being shown which is no real deep cold and the modelling is always being pushed back....

[IDO]

4 minutes ago, bluearmy said:

Compare the length of time it’s taking that system to drop se on the gfsp ....60 hours and counting by T210.  we’ve twice seen lows deepen dramatically and drop within 24 hours in December. 

Yes, when the music stops we want to sit in the colder synoptic, so crucial that we keep the UK in the cold whilst in the early throws of the SSWE? Compare where the music may be stopping on the 06z to the 12z:

It maybe many days of potential -v- waiting for the SSW effects in a holding pattern?

 

[MATTWOLVES 3]

I'm happy with the UKMO again and this model seems to be leading the way with its consistency.

A quick heads up from Matt Hugo saying he thinks the GFS as been bullish to break down the cold spell,due to the fact it not wanting to move the MJO out of the I/0..This is unrealistic and the MJO Is set to move East. Sounds like its having a struggle to work out what's going on...nothing new there then. And thanks to Matt for bringing good updates.

Edited January 2, 2021 by MATTWOLVES

[Battleground Snow]

Still scope for a colder easterly from the 4th -7th based on this scatter

 

 

[Chiltern_Blizzard]

15 minutes ago, Scott Ingham said:

Back on track and lessons learnt on run to run over reactions! All is still extremely promising my friend

Long time watcher of this forum but just signed up...

It does seem to be that these are always 10 + days away. Can I ask ...when do these become a reality? As the models for today, 10 days ago were showing similar...

[Scott Ingham]

Look at the secondary runner low @bluearmy at the end. 

If im on the right train of thought and slowing westerlies leads to this its going to be fun on here following the snow line

but ill take it before a beast especially living north!

[ICE COLD]

2 minutes ago, Battleground Snow said:

Still scope for a colder easterly from the 4th -7th based on this scatter

 

 

Shannon is definitely in the room and only a few days out .

[IDO]

Just now, MATTWOLVES said:

I'm happy with the UKMO again and this model seems to leading the way with its consistency.

A quick heads up from Matt Hugo saying he thinks the GFS as been bullish to break down the cold spell,due to the fact it not wanting to move the MJO out of the I/0..This is unrealistic and the MJO Is set to move East. Sounds like its having a struggle to work out what's going on...nothing new there then. And thanks to Matt for bringing good updates.

The UKMO 12z run sits within the gefs as a cluster so quite viable. The issue is both ecm and gfs ops messed with this solution quite a few runs ago and have moved away from it since. We do not see the ensembles on the UKMO so do not know where this solution sits, though we can assume, like the gefs, there are 3-4 clusters? The 12z follows on as I would have expected from the 0z at d6 so it is consistent.

[Ventnor Viking]

2 minutes ago, Battleground Snow said:

Still scope for a colder easterly from the 4th -7th based on this scatter

 

 

It would be unlikely, unfortunately. The deep cold (-10 or lower) is  up in Siberia. 

[Scott Ingham]

3 minutes ago, Harsh Climate said:

I think it's too early for the SSW to kick in, I'm thinking more like late january/ early februrary.  

Not for me mate. Historically i would yeah but take a read of @chionomaniac post earlier. 

Theres nothing stopping a very quick downwell when we are reversing off such a low value in the lower strat to begin with 

[ICE COLD]

IMBY chart of the day

[Battleground Snow]

Just now, Ventnor Viking said:

It would be unlikely, unfortunately. The deep cold (-10 or lower) is  up in Siberia. 

Cold is developing in situ over North east Europe at the moment at the prime time of the year for it to happen. Models struggle with this, hence why only -5 was modelled a few days ago

[LeeSnowFan]

looking good!

[chionomaniac]

15 minutes ago, Scott Ingham said:

@chionomaniac

Look at the slowing down of that low pressure in the atlantic at 264 hours.

That is the first sign of the ever slowing and easterly turning zonal winds.

Thoughts?

It goes from this 

 

To this!

Westerlies are dead!!

Yep. Certainly looks like it. The jet stream to our west has been slow all of December so no surprise to see it grind to a halt post SSW. 

I’m still awaiting that true frigid run that eventually verifies, but patience is the key here as I suspect we will have a fairly long window of opportunity..........

[Ventnor Viking]

1 minute ago, Battleground Snow said:

Cold is developing in situ over North east Europe at the moment at the prime time of the year for it to happen. Models struggle with this, hence why only -5 was modelled a few days ago

It could develop, I personally cant see it happening so quickly within a couple of days and then making it to us. Seems very unlikely. 

[bluearmy]

5 minutes ago, Scott Ingham said:

Look at the secondary runner low @bluearmy at the end. If im on the right train of thought and slowing westerlies leads to this its going to be fun on here following the snow line

but ill take it before a beast especially living north!

both gfs runs have a runner of sorts ...... ecm had one yesterday ....always a chance of something headed into the base of the trough  (if one exists - both trough and runner!)

 

2 minutes ago, Scott Ingham said:

Not for me mate. Historically i would yeah but take a read of @chionomaniac post earlier. 

Theres nothing stopping a very quick downwell when we are reversing off such a low value in the lower strat to begin with 

9 minutes ago, Harsh Climate said:

I think it's too early for the SSW to kick in, I'm thinking more like late january/ early februrary.  

We aren’t talking about a strongly neg AO showing yet nor atmosphere in reverse - just a stalling of the flow ..... which is evident on those gfs 12z runs with a gentle rise in heights across the polar field 

[Tim Bland]

️

[winterof79]

8 minutes ago, Scott Ingham said:

Look at the secondary runner low @bluearmy at the end. 

If im on the right train of thought and slowing westerlies leads to this its going to be fun on here following the snow line

but ill take it before a beast especially living north!

It takes a look and retreats tout suite

[Scott Ingham]

1 minute ago, chionomaniac said:

Yep. Certainly looks like it. The jet stream to our west has been slow all of December so no surprise to see it grind to a halt post SSW. 

I’m still awaiting that true frigid run that eventually verifies, but patience is the key here as I suspect we will have a fairly long window of opportunity..........

Im encouraged.

Id not seen any run show signs of reversal so in my head this is a bit of a milestone per se.

I am as well wed have to be extremely unlucky not to tap into something sùb -10 upper air when we have a reversal that is showing to stay reversed for a minimum of 14 days!

The split would be a juicy cherry on top.....

[Ice Day]

FI is certainly providing some entertainment, with some 'interesting' options starting to show themselves on both the GFS and Para - interestingly at a very similar timescale.  

  

Keep an eye on the ensembles for some true bonkers runs to start showing up.  

[bluearmy]

Gfsp is more reasoned than gfs in its development of more solid mid Atlantic ridge again by day 12. 

Edited January 2, 2021 by bluearmy

[IDO]

Looking at the gefs at d8 something is happening and if this is not a rogue suite then it is very interesting. The op seems tame compared to some of the members:

 

[Harsh Climate]

8 minutes ago, bluearmy said:

both gfs runs have a runner of sorts ...... ecm had one yesterday ....always a chance of something headed into the base of the trough  (if one exists - both trough and runner!)

 

We aren’t talking about a strongly neg AO showing yet nor atmosphere in reverse - just a stalling of the flow ..... which is evident on those gfs 12z runs with a gentle rise in heights across the polar field 

 Yes but there can still be a brief stalling of the atlantic flow during any set-up, doesn't mean it's the precursor to a full SSW event.

Like I believe before this upcoming SSW event takes place I think there will be a brief milder or less cold period. 

Like November 2010 when it's ready I think it will just come in and hit hard was massive northern hemisphere blocking and reverse zonal winds. Just my opinion but these are notoriously slow burners and I don't think it will have any effect on our weather until the end of the month or february.

I've seen SSW forecast in february before but never materialised until april/may with fantastic synoptics, all so late lol.

Edited January 2, 2021 by Harsh Climate

[Anthony Burden]

Icelandic low back on the menu,GFS slowly drags it to the east of us.

Still needing to take anything beyond 168 hrs with a pinch of salt,will the east/northeasterly 

be replaced with a northerly,in the mean time cold with snow showers possible anywhere

with temperatures looking to drop from midweek.