The hunt for cold - Model discussion (late November)

[blizzard81]

It looks increasingly likely now that the Atlantic is going to break through during the middle of next week - in quite a potent fashion as well, it has to be said. Who can say how long that will last for? Not me for sure. However, the short lived milder zonal spell may have been underestimated somewhat. I expect the meto to change their wording on tomorrow's update. A downgrade for coldies I suspect. 

[Glacier Point]

Worth noting that in the day 4 - 10 timeline the sub-tropical jet will get very energised over the Southern US. That ties in nicely with an El Nino tropical signal, enhanced through passage of a tropical wave. Without any strong blocking feature to the north / far NE, and no scrambling of the upper level polar westerlies across the North Atlantic, we will be exposed to a poleward returning 200 hPa flow.

That's not expected to last much beyond day 10, so chances are that an eddy will form in our locale setting up a ridge over NW Europe and trough becomes more slow moving to our west. Next phase of ridge development over NW Europe very much on the cards during the 10-21 day period. Stress that doesn't necessarily mean instant cold, and we could still get trapped the wrong side of a ridge for a time.

Edited November 21, 2018 by Glacier Point

[blizzard81]

Low after low barrelling out of the US on the ecm op. 

[Stuie]

2 minutes ago, northwestsnow said:

Yes of course.. its still outside reliable but i really think we ought to be accepting the block isnt going to hold...

As a coldie i am hoping it does.. but the evidence is becoming overwhelming that it will be blown away..

Fair enough, your view and by the weekend this may show signs of this but you have to ask yourself, if the scenario was showing extreme cold at that juncture, would you be as confident of that happening?

Until the spread around the 26th? is firmed up, you can`t really call anything with any with any confidence.

[blizzard81]

3 minutes ago, Glacier Point said:

Worth noting that in the day 4 - 10 timeline the sub-tropical jet will get very energised over the Southern US. That ties in nicely with an El Nino tropical signal, enhanced through passage of a tropical wave. Without any strong blocking feature to the north / far NE, and no scrambling of the upper level polar westerlies across the North Atlantic, we will be exposed to a poleward returning 200 hPa flow.

That's not expected to last much beyond day 10, so chances are that an eddy will form in our locale setting up a ridge over NW Europe and trough becomes more slow moving to our west. Next phase of ridge development over NW Europe very much on the cards during the 10-21 day period. Stress that doesn't necessarily mean instant cold, and we could still get trapped the wrong side of a ridge for a time.

I guess this is what the meto are seeing as well. 

[Met4Cast]

I took the morning/afternoon off from model watching because sometimes it's nice to take a break. Lots of talk of zonal in here but does it actually hold up against the models outside of the Det runs? Well, no.

Whilst there’s no deep cold currently in the offering, I wouldn’t be so quick to jump the gun on zonal, Atlantic weather taking over either. Blocking once again upgraded as it comes into the models reliable timeframe (latest ECM)

Day 7 GEFS mean shows low pressure out to the West with some heights still across Scandinavia, this is our possibly brief Atlantic incursion

Day 10, look whats happened. The Atantic low has backed way out West, little signal either way across Europe/UK however but certainly nothing “zonal” (though granted, anything past day 4/5 is a push in terms of reliability at the moment)

Day 16 (just for fun, this one. Way too far out) But there’s a signal for a return to blocking across Scandinavia

EPS day 7 (cropped because these charts are behind a paywall) shows the attempted Atlantic incursion but has more prominent blocking across N/NE compared to the GFS

Extended EPS day 10-15 shows blocking waning but remaining in the general area of NE/E of the UK, Sceuro but not a strong signal - Same signal as the GEFS with the low backing out West, i.e NO zonal signal. 

Atlantic incursion is looking increasingly likely esp. for Western locations, how far East this gets remains uncertain. MJO, angular momentum etc all favourable for blocking going into December. I am not seeing full zonal weather whatsoever. If anything, a brief Atlantic kick that'll quickly fade in the face of strengthening/re-organising blocking.

Have a good evening x

Edited November 21, 2018 by Daniel Smith

[sorepaw1]

If The Atlantic does win out it shows signs of some pretty stormy weather and high rain fall totals at times 

It doesn't look zonal meek and mild.

Edited November 21, 2018 by sorepaw1

[mulzy]

Yes, it looks like an unsettled period days 7-10 (at least).  Just hope rain amounts are reasonable and we can avoid any flooding.  It's the last thing we want in the run-up to Xmas.

[nick sussex]

Can we order GEFS number 14!

Putting that miracle aside the two main issues in terms of salvaging current prospects are the movement of the PV and the high seeping towards Canada.

You end up with a two pronged attack which is too much to hold the Scandi high further north.

If you follow the miracle run  that keeps the high boxed in for longer and the PV whilst moving east does so further north. At this point redemption seems unlikely given the op runs.

Taking the op runs at face value it seems a few quieter days with a drop in temps as the Scandi high temporarily appears before the Atlantic moves in but the speed of that might still be revised.

[I remember Atlantic 252]

1 minute ago, nick sussex said:

Can we order GEFS number 14!

Putting that miracle aside the two main issues in terms of salvaging current prospects are the movement of the PV and the high seeping towards Canada.

You end up with a two pronged attack which is too much to hold the Scandi high further north.

If you follow the miracle run  that keeps the high boxed in for longer and the PV whilst moving east does so further north. At this point redemption seems unlikely given the op runs.

Taking the op runs at face value it seems a few quieter days with a drop in temps as the Scandi high temporarily appears before the Atlantic moves in but the speed of that might still be revised.

[Johnp]

1 minute ago, I remember Atlantic 252 said:

Woah - imagine this place if that had appeared on the op!

[blizzard81]

13 minutes ago, Glacier Point said:

Worth noting that in the day 4 - 10 timeline the sub-tropical jet will get very energised over the Southern US. That ties in nicely with an El Nino tropical signal, enhanced through passage of a tropical wave. Without any strong blocking feature to the north / far NE, and no scrambling of the upper level polar westerlies across the North Atlantic, we will be exposed to a poleward returning 200 hPa flow.

That's not expected to last much beyond day 10, so chances are that an eddy will form in our locale setting up a ridge over NW Europe and trough becomes more slow moving to our west. Next phase of ridge development over NW Europe very much on the cards during the 10-21 day period. Stress that doesn't necessarily mean instant cold, and we could still get trapped the wrong side of a ridge for a time.

Something along these lines hopefully?

[Met4Cast]

P.S.

P14 GEFS is an incredibly clean evolution on how cold COULD still happen with full undercutting and 0 Atlantic milder air getting up into the mix, incredibly clean evolution, actually..

Imagine if the Op had gone that way this evening..

[Seasonality]

25 minutes ago, Stuie W said:

Day 8.... once upon a time that was FI...

It still is

[BLAST FROM THE PAST]

2 hours ago, northwestsnow said:

Can't see many encouraging signs on GFS Fred... looks zonal all the way out to the end?(After day 6/7).

Don’t go too far, it’s pretty ok up to then and indeed the GFS(p) is point of note of angle of movement of LPs, the propensity of cold to still lap our shores is there...although ECM is not good.  Atlantic intrusion is likely....but how is the point.  

 

BFTP

Edited November 21, 2018 by BLAST FROM THE PAST

[Cheshire Freeze]

1 hour ago, Glacier Point said:

Nino is here, and has been for some time since October. We are playing real time Nino climatology here, which suggests December may be a touch too soon on cold backing sufficiently far west. That said, +ve height anomalies to our east and NE and low to the west are exactly what we should expect.

GEFS mean 12z starting to rebuild a ridge across NW Europe as the MJO quickly cycles through the Indian Ocean.

CFS stratospheric modelling continues to look 'interesting' for last week of December, which would have some merit given recent musings.

Funnily enough, I was looking at the output and thinking '2009' Unsettled for the UK for a time but without any really deep troughing to our N.

I believe that was a Modoki el Nino Pacific SST signature?

[Allseasons-Si]

Mid December it is then

[Methuselah]

I'm guessing (as I can't view it) that this arvo's GFS FV3 hasn't come to our rescue, this time?

[BlueHedgehog074]

Feel a retreat from model watching is needed. At least for a few days anyway. It’s just become too fatiguing keeping an eye on every run and it occupies too much time, especially with that disobedient cyclone in the Atlantic that most charts show could break through next week. Although there are variations as the models handle this.

Do feel there’s enough evidence to suggest the Atlantic coming back - the 12Z ECMWF, for me, looks unappealing with Low Pressure racing past the UK like a Great Western Railway train in the dreamland timeframe. But there may still be enough room for the Atlantic to become less of a feature, and/or Low Pressure not breaking through further East at all.

I almost wanted to throw my large toy la-la out of that pram, but think I’ll hold on to it for now. Maybe might be in for a surprise after a little break from the maddening charts.

The next few days the models seem to agree to a continued theme of blocking to our North and Low Pressure to the South, with some further spells of showers or longer spells of rain in the cool Easterly to South-Easterly flow. Mostly for Southern UK areas, although even these areas could see some brighter spells at times. A chance of some frost and mist at night, particularly over Northern areas where the Northern UK High would be more influential.

Just remember though, any naughty behaviour, name calling or constant off topic posts, and we have a nice, dusty, dark, basement full of cobwebs and spiders we can lock you up in.

[Stuie]

2 minutes ago, DiagonalRedLine said:

Feel a retreat from model watching is needed. At least for a few days anyway. It’s just become too fatiguing keeping an eye on every run and it occupies too much time, especially with that disobedient cyclone in the Atlantic that most charts show could break through next week. Although there are variations as the models handle this.

Do feel there’s enough evidence to suggest the Atlantic coming back - the 12Z ECMWF, for me, looks unappealing with Low Pressure racing past the UK like a Great Western Railway train in the dreamland timeframe. But there may still be enough room for the Atlantic to become less of a feature, and/or Low Pressure not breaking through further East at all.

I almost wanted to throw my large toy la-la out of that pram, but think I’ll hold on to it for now. Maybe might be in for a surprise after a little break from the maddening charts.

The next few days the models seem to agree to a continued theme of blocking to our North and Low Pressure to the South, with some further spells of showers or longer spells of rain in the cool Easterly to South-Easterly flow. Mostly for Southern UK areas, although even these areas could see some brighter spells at times. A chance of some frost and mist at night, particularly over Northern areas where the Northern UK High would be more influential.

Just remember though, any naughty behaviour, name calling or constant off topic posts, and we have a nice, dusty, dark, basement full of cobwebs and spiders we can lock you up in.

Before you have a break, the FV3 finally gets the jet south around the "juncture" of uncertainty, the 26th.... This is a big improvement on yesterday where it had it ploughing into southern UK

[BLAST FROM THE PAST]

1 hour ago, Quicksilver1989 said:

12z swingometers show a small switch back to mild, when the mild air arrives is still up in the air however.... but I'd say its very likely we will see some mild temperatures in the  next 10-14 days (fleeting or sustained? difficult to say). The build up of cold air over Greenland doesn't help and a west based -NAO looks to be developing. Strong SW'lies for a time look to be a possibility.

This is reflected by the swingometer from December 6th which looks to be the most predominantly mild yet.

We may have to be patient.... the switch to milder can be seen for the global temperature anomaly chart in 7 days time, UK now back to slightly above average. Plenty of cold to our east, a blocked weather pattern when looking at the NH as a whole but the cold not falling to where we want it - here... not yet anyway.

Global temperature anomaly +0.51C above average despite the low solar activity.

That is some major cold anomaly across Russia and Siberia (a massive Siberian HP must be in the offing).  With low solar activity now entering its deeper phase and no overnight immediacy of a drop off as the lag effect and Grand Minima expected 2030....that is one of the best I’ve seen in ages.  South America stands out too....that’s some anomaly....and so in the arctic.  Interesting snapshot, thanks for the continued posts of these.

 

BFTP

Edited November 21, 2018 by BLAST FROM THE PAST

[Stuie]

@bftp 

You have to imagine that blue road can`t end there and turn around. i haven`t seen the latest NAO but if it can stay -NAO, what a chance.

[Mike Poole]

Here's the spread on the ECM mean at T144 (key time) - it shows large uncertainty with the handling of this low, so I'd be reluctant to take any solutions off the table yet.

i also think there's a difference between full on zonal, the Atlantic barrelling through (or similar terminology), and a low pressure coming at us from the Atlantic in an otherwise largely blocked regime.  These seem to get blurred on here sometimes, in my opinion, I think the third one is where we are at with this problematic low.

 

Edited November 21, 2018 by Mike Poole

[Stuie]

3 minutes ago, Mike Poole said:

Here's the spread on the ECM mean at T144 (key time) - it shows large uncertainty with the handling of this low, so I'd be reluctant to take any solutions off the table yet.

i also think there's a difference between full on zonal, the Atlantic barrelling through (or similar terminology), and a low pressure coming at us from the Atlantic in an otherwise largely blocked regime.  These seem to get blurred on here sometimes, in my opinion, I think the third one is where we are at with this problematic low.

 

Best post i have seen since logging on, Mike.

[BlueHedgehog074]

14 minutes ago, Stuie W said:

Before you have a break, the FV3 finally gets the jet south around the "juncture" of uncertainty, the 26th.... This is a big improvement on yesterday where it had it ploughing into southern UK

That certainly looks encouraging lol.  Just one aspect that would be needed to carry the Low Pressure(s) further South.