Model Output Discussion - Into Winter

[andy989]

I’m going to keep my head screwed on for a good few days yet.  I might allow myself to get just a little bit excited if all this is still showing tomorrow morning (we know the morning runs often kill the dream) 

Edited November 30, 2023 by andy989

[Vikos]

2 hours ago, Hotspur62 said:

I just can’t believe how mild the US is by 10th December(would post chart if I knew what I was doing).Is that the effect of the Canadian warming?.Over to our shores and its incredible the uncertainty of the models for just 72hrs and the implications that has going forward to the middle of next week.I still think the less cold conditions will prevail but for how long is anybody’s guess.Fascinating times and I think that Northern England and Scotland may not warm up much at all!!

El Niño… slightly displaced Jet over N. America

 

[john mac1]

29 minutes ago, danm said:

Crikey! I’m in Lapland from 13th-16th December. Could be absolutely frigid. 

As long as the pool of intense cold remains, we are potentially not far off tapping into something special. Just need the synoptic pattern to set up favourably. 

Thin layers mate and lots of them. WS there a few years ago and the coldest it got was -32. The warmest -18

[SollyOlly]

3 minutes ago, andy989 said:

I’m going to keep my head screwed on for a good few days yet.  I might allow myself to get just a little bit excited if all this is still showing tomorrow morning (we know the morning runs often kills the dream) 

Spot on. I've been 'lurking' for a few years before I joined the forum, so have seen many an appiriation fade away like Scotch mist in the morning...! In all seriousness, I've had too many experiences of waking to see what was looking like a nailed on promising run or set of charts suddenly do a backflip, handstand and double-back, so I don't count chickens these days (albeit I do mix metaphors).

[Dennis]

3 minutes ago, Mike Poole said:

 

  But could it, really?  We will see…

All the best

Mike

o yes it will be 

[Dennis]

the MJO forecast today and forecast : The GEFS and ECMWF ensembles are in good agreement that the MJO will remain amplified and propagate eastward into the Maritime Continent and Western Pacific during the next 2 weeks.

so 5-7 phase

time , can be quicker then we think now 

[iceman1991]

1 hour ago, Cheshire Freeze said:

I feel we’re on the cusp of something potentially extreme into December. That cold to the E has been building steadily for a while now.

How confident are you Cheshire from your experience majour cold spell hitting uk and do you think it will be a Scandi high easterly winds or a Greenland high ? 

 

[alexisj9]

2 hours ago, Mike Poole said:

It strikes me that there are 3 options with this Atlantic lows meet cold pool thing:

1. The lows disrupt to form a train of small lows that can slide and follow a southerly jet and track south.
2. A deeper low gets stalled on the approach to the cold air, and resulting WAA pumps up heights into Scandi (like ECM 12z).
3. A deeper low barges straight through and obliterates the cold pool (at least as far as it affects the UK).

The third is the only one that carries the risk of fully unleashing the Atlantic subsequently.

We’ve been watching this for a while now, where’s your money?  

Mines on one, but two could happen too., hopefully not 3 or at least not to the extent of the big storms on the GFS anyway.

[near northampton]

Just now, iceman1991 said:

How confident are you Cheshire from your experience majour cold spell hitting uk and do you think it will be a Scandi high easterly winds or a Greenland high ? 

 

Both scenarios are highly unlikely, how many times have the above occurred in the last 20 years?

[alexisj9]

2 hours ago, sebastiaan1973 said:

This is some serious cold. Anomaly chart for temperature at 2 meter.

For my little corner France needs to join the blue.

[I remember Atlantic 252]

4 minutes ago, alexisj9 said:

Mines on one, but two could happen too., hopefully not 3 or at least not to the extent of the big storms on the GFS anyway.

3 for me, but no scientific reason, just a feeling

[WYorksWeather]

Because why not, I'll do a bit of a live look at GFS 18z as it comes in.

T+24 - nothing interesting particularly at this stage of course. -6C prevails, so snowfall still somewhat likely.

 

[snowking]

Well despite the memories of December 2012 still being scarred into my hippocampus, I always prefer the chase for scandi-based heights than Greenland ones.

Why? Well you’re probably all sick of me banging on about NWP’s tendency to overestimate height rises to our NW in the medium range. What we’ve found, however, many times down the years is that modelling at longer ranges tends to underestimate the potential strength of blocking to our north-east, mostly it would seem due to the distribution of split flow energy coming out of the jet stream across the Atlantic always tending to err more towards putting greater-than-reality strength into the northern arm. Then as modelling counts down closer to T+0 we tend to see lows taking a more southerly track with the chain reaction of subsequent events conspiring to leave us with an even stronger high than modelled at longer distances.

Now as ever with one of my posts (where’s the fun in getting off the fence) there is a caveat - one of the big spoiling factors which seems to have increased in frequency in recent years is the reluctance of the Azores high to just bloody well sling it’s hook and leave us some space for lovely Genoa-ish low heights to help draw in the coldest air from our east (presumably due to climate change-linked expansion of the Hadley cell). This has, many times, left the UK frustratingly on the periphery of some really severe winter outbreaks across the North Sea.

That, at this stage, would be my major watch factor.

I am far more enthused at the prospect of this potential chase than I have been with the recent spell - impressive and nice to see as it is/has been so early in the season, it never inspired much confidence in anything too impressive snowfall wise.

Lets hope this next one is worth waiting for

[WYorksWeather]

The key setup visible at T+48. Cold retreating east slightly ahead of the low, but what will happen next? 

 

[Wold Topper]

4 minutes ago, alexisj9 said:

For my little corner France needs to join the blue.

Or bleu

[Uncertainty]

The main thing is we are now seeing a massive, extensive Ural block being progged. This will, if it persists, cause an ssw in January.

The mjo also looks really good  for a blast towards phase 7/8 as @Dennis and @Met4Cast and others have been flagging. 

Good to see the ec46 have a go at this as it’s struggled with mjo amp recently.

There are lots and lots of really interesting eps members but still no clear signal or direction for our weather at the surface in the extended. We need a lot more momentum to push the big Siberian high westwards though. We haven’t had many true winter (eg DJF) scandi highs with lows going under  drawing in snowy easterlies in the last decade now have we?? Have we even had one? Thousands have been modelled and I’m trying to think of one save late Feb 2018? Jan 18 had one that was a precursor to feb but not really snowy.

Finally Cansips is out tomorrow anyone else nervous lol
 

[WYorksWeather]

Is the low tracking further south again? Been away from the models for a while, but this looks like it at T+72? Milder (or rather closer to average) air beginning to intrude into the SW. Need to wait and see where the run goes from here.

 

[near northampton]

1 minute ago, Uncertainty said:

The main thing is we are now seeing a massive, extensive Ural block being progged. This will, if it persists, cause an ssw in January.

The mjo also looks really good  for a blast towards phase 7/8 as @Dennis and @Met4Cast and others have been flagging. 

Good to see the ec46 have a go at this as it’s struggled with mjo amp recently.

There are lots and lots of really interesting eps members but still no clear signal or direction for our weather at the surface in the extended. We need a lot more momentum to push the big Siberian high westwards though. We haven’t had many true winter (eg DJF) scandi highs with lows going under  drawing in snowy easterlies in the last decade now have we?? Have we even had one? Thousands have been modelled and I’m trying to think of one save late Feb 2018? Jan 18 had one that was a precursor to feb but not really snowy.

Finally Cansips is out tomorrow anyone else nervous lol
 

Disagree with the first part of your post but totally agree with the 2nd part some reality 

[blizzard81]

2 hours ago, Kentish Snowman in Yorks said:

Wow that ECM!  Almost the Easterly that a certain poster from Crewe has been touting for a while.  Fair play if it comes off!

And Dennis. More so in fact. 

[WYorksWeather]

Ridiculous Greenland high here at T+96. The low looks like sliding through the channel on this chart. 850hPa temps near average in the south but still somewhat colder than average further north.

 

[Midlands Ice Age]

5 minutes ago, WYorksWeather said:

Is the low tracking further south again? Been away from the models for a while, but this looks like it at T+72? Milder (or rather closer to average) air beginning to intrude into the SW. Need to wait and see where the run goes from here.

 

Two days away from -40C uppers in Siberia now (see the white spot).

Now that is unusual for the 1st December.

MIA

[blizzard81]

2 hours ago, Bricriu said:

That would be my fear. A case of close but no cigar. I hope I am wrong. Let's just say  the coldest upper air did some how make it all the way across to England, what would the uppers be after modification from  travelling over the warmer sea? Did -20 upper air clip the south east of England in Janaury 1987?

Something like that mate. 

[alexisj9]

2 hours ago, MATTWOLVES 3 said:

Mmmmm...mogreps 12z.

You can see that we look good for cold out too day 6...Take a little look and the clustering goes up towards milder conditions...but towards end of the run we seem to have a little support for a colder theme again..classic signs of the models not necessarily being convinced of it going milder,and more so of how long it will last.

The plot thickens.

Hmm, will look at the pressure ones rather than 850's, I think they might tell more.

[BLAST FROM THE PAST]

10 minutes ago, WYorksWeather said:

Is the low tracking further south again? Been away from the models for a while, but this looks like it at T+72? Milder (or rather closer to average) air beginning to intrude into the SW. Need to wait and see where the run goes from here.

 

Yes it is…..South is the word today….North tomorrow?

 

BFP

[snowking]

14 minutes ago, Uncertainty said:

The main thing is we are now seeing a massive, extensive Ural block being progged. This will, if it persists, cause an ssw in January.

The mjo also looks really good  for a blast towards phase 7/8 as @Dennis and @Met4Cast and others have been flagging. 

Good to see the ec46 have a go at this as it’s struggled with mjo amp recently.

There are lots and lots of really interesting eps members but still no clear signal or direction for our weather at the surface in the extended. We need a lot more momentum to push the big Siberian high westwards though. We haven’t had many true winter (eg DJF) scandi highs with lows going under  drawing in snowy easterlies in the last decade now have we?? Have we even had one? Thousands have been modelled and I’m trying to think of one save late Feb 2018? Jan 18 had one that was a precursor to feb but not really snowy.

Finally Cansips is out tomorrow anyone else nervous lol
 

I think this is very fair.

We can probably throw 2013 into the mix for this one - far from a true scandi high, more one of the rare sightings of the GIN corridor wedges. But again in that instance, modelling was not interested in any sort of height rises to the NE until it drew closer to T+0.

We’ve obviously come a long way since then modelling dynamics wise, but it’s going to be interesting to see it play out.