johncs2016
18 November 2017 00:04:06

Originally Posted by: Shropshire 


 


 


A characteristic of the modern era has been shortwave development and phasing of Low pressure in the Atlantic to maintain the jet stream, it isn't bad luck when it happens over and over again. 


Clearly the worst case scenario has come to pass again, a West based NAO that just becomes the normal zonal train as the Greenland heights lessen. Time to hunker down and brace ourselves for us a lengthy period of Atlantic systems with attendant wind and rain. 



Looks like the "Winter Is Over" posts are starting to appear already, and we aren't even into the start of the meteorological winter just yet. However, I wouldn't be surprised if this assessment isn't that far from the true reality. We do after all, have a very cold stratosphere which wants to shift everything towards a more zonal and milder pattern and even though there is likely to be some blocking around Greenland in the very near future, it is going to be very difficult for that sort of northern blocking to be sustained for any length of time as long as the stratosphere remains in that current, very cold state.


To me, there is therefore only one way that this is likely to go since that is likely to percolate down into the troposphere eventually which to me, can only really mean a mild and zonal outcome in the end especially if heights continue to remain quite high over France and Iberia as the current model output is suggesting. Of course, I'm not going to make any assumptions here and so, we can't rule out the possibility that the northern blocking might win out and that we get some decent cold weather (this is one scenario where I hope that I am wrong), but that just doesn't look very likely to me.


 


The north of Edinburgh, usually always missing out on snow events which occur not just within the rest of Scotland or the UK, but also within the rest of Edinburgh.
Gandalf The White
18 November 2017 00:12:34

The ECM 12z ensemble suite has completed the steady transformation towards a solid mild outlook



Almost total agreement on mild weather dominating through the period from Monday.  The clusters predicting a cold spell next week has gone no the cluster towards the end of the period is in a smaller minority.


The beginning of winter is now within the grasp of the low resolution output but nothing wintry seems to be on the horizon yet.


Location: South Cambridgeshire
130 metres ASL
52.0N 0.1E


Whether Idle
18 November 2017 08:15:14

This morning's 120 ECM illustrates perfectly the futility of a Greenland High in isolation.  The UK is flooded by warm upper airs (at best, some PM returning but massively modified).  For a Greenland High to advect cold to the great bulk of the UK, it needs to either be super-massive in its southern extent, and/or heights to our South and East need to be much lower.


  ecm 120


 


Dover, 5m asl. Half a mile from the south coast.
Solar Cycles
18 November 2017 08:26:08

Originally Posted by: Whether Idle 


This morning's 120 ECM illustrates perfectly the futility of a Greenland High in isolation.  The UK is flooded by warm upper airs (at best, some PM returning but massively modified).  For a Greenland High to advect cold to the great bulk of the UK, it needs to either be super-massive in its southern extent, and/or heights to our South and East need to be much lower.


  ecm 120


 


The key is lowering heights over Europe and the Med, until we see those we’ll only ever get fleeting glimpses of RPM/AM air I’m afraid.

Ally Pally Snowman
18 November 2017 08:32:23

Ukmo looks much improved this morning though very close to something special again. heavy snow showers for Scotland. 


 


http://old.wetterzentrale.de/pics/Rukm1441.html


 


Bishop's Stortford 85m ASL.
doctormog
18 November 2017 08:49:16
The GFS op run is somewhat on the chilly side up here for large parts of the run this morning too. Still somewhat undecided up here once the chilly weekend is out of the way.

It does look like day 5 and 6 will have milder upper air. Before and after looks somewhat less certain. As the cooler airmass is (unsurprisingly) to the north then that is where things will be most finely balanced.
ballamar
18 November 2017 08:58:34

Originally Posted by: Ally Pally Snowman 


Ukmo looks much improved this morning though very close to something special again. heavy snow showers for Scotland. 


 


http://old.wetterzentrale.de/pics/Rukm1441.html


 



potentially under playing strength of Atlantic but on the face of it promising chart

Gavin D
18 November 2017 09:16:51

Op and mean at odd's again later next week


some faraway beach
18 November 2017 09:43:19

Originally Posted by: Ally Pally Snowman 


Ukmo looks much improved this morning though very close to something special again. heavy snow showers for Scotland. 


 


http://old.wetterzentrale.de/pics/Rukm1441.html


 



Just shows what an Azores low can do.


2 miles west of Taunton, 32 m asl, where "milder air moving in from the west" becomes SNOWMAGEDDON.
Well, two or three times a decade it does, anyway.
Gooner
18 November 2017 09:54:11

Originally Posted by: some faraway beach 


 


Just shows what an Azores low can do.



And if that links with the GH 


Remember anything after T120 is really Just For Fun



Marcus
Banbury
North Oxfordshire
378 feet A S L


Gooner
18 November 2017 10:31:17

Think more Northern areas could see some wintry ppn later in the week


Remember anything after T120 is really Just For Fun



Marcus
Banbury
North Oxfordshire
378 feet A S L


Ally Pally Snowman
18 November 2017 10:33:55

Originally Posted by: Gooner 


Think more Northern areas could see some wintry ppn later in the week



 


Yes the GFS 6z has taken a couple more steps to a colder solution.  The jet seem to want to dig further south which is good.


 


Bishop's Stortford 85m ASL.
Gooner
18 November 2017 10:40:15

You’d be happy with the 6 z if verified Michael 


Remember anything after T120 is really Just For Fun



Marcus
Banbury
North Oxfordshire
378 feet A S L


Ally Pally Snowman
18 November 2017 10:40:22

LOL GFS 6z goes northerlytastic at 240z. nice GH as well. gfs has almost come full circle this morning 


Bishop's Stortford 85m ASL.
Rob K
18 November 2017 10:50:06

Originally Posted by: Ally Pally Snowman 


Ukmo looks much improved this morning though very close to something special again. heavy snow showers for Scotland. 


 


http://old.wetterzentrale.de/pics/Rukm1441.html


 



Not that different from the ECM, and we know where that goes. Flat as a pancake.


Yateley, NE Hampshire, 73m asl
"But who wants to be foretold the weather? It is bad enough when it comes, without our having the misery of knowing about it beforehand." — Jerome K. Jerome
Russwirral
18 November 2017 13:00:37

Its nice to see some northerlys that are asscoiated with a GH... rather than being a toppler managed by an azores high.


 


Cant remember the last time insaw something like that


doctormog
18 November 2017 16:09:51
Quite significant differences between the UKMO and GFS 12z op runs by 120hrs (again)

http://www.wetterzentrale.de/maps/UKMOPEU12_120_1.png 
http://www.wetterzentrale.de/maps/GFSOPEU12_120_1.png 
Bertwhistle
18 November 2017 16:15:15

Even on the latest run there is a persistent 1060mb+ for all of next week over Greenland. What's missing is either a larger cell of this intensity, or better still a worthwhile rise of pressure N of Scandinavia, to link up. Without this, the result is a beautifully long fetch of easterlies, too far north in our meridian; the Atlantic lows are finding a route through.


Bertie, Itchen Valley.
'We'll never see 40 celsius in this country'.
Whether Idle
18 November 2017 17:31:13

What catches my eye is the meridional nature of the jet ducking and weaving poleward then toward the tropics.  The attendant ridge - trough - ridge pattern is clearly in evidence on the Met O 144.  And yes, we are in the mild trough part (apart from Scotland's northern half). Those SL HP cells are big - the one to our S and E stretches from the Sahara to the Urals!!


met o 144


Dover, 5m asl. Half a mile from the south coast.
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