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Brian Gaze
26 November 2017 11:49:16

New thread...


GEFS 06z updates continues to suggest temperatures will be close to or below average for much of the next 16 days. Here are the 2m temperatures:


Brian Gaze
Berkhamsted
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Joe Bloggs
26 November 2017 12:02:23

I’m not sure if anyone has posted the 00z ECM ensemble set but these continue to paint a cold picture in the longer term. 


http://www.weathercast.co.uk/meteo/eps/ensemble-tt6-london.gif


Plenty of cold clustering with only a few rogue runs going mild. 


Manchester City Centre, 31m ASL
Retron
26 November 2017 12:05:44


New thread...


GEFS 06z updates continues to suggest temperatures will be close to or below average for much of the next 16 days. Here's are the 2m temperatures:


Originally Posted by: Brian Gaze 


And here are the 850s, compared to the mean (nb - I guess that's calculated "on the fly" by WZ rather than being a field in the GRIB data - a shame, as it's handy to see at a glance just how far above/below things are):



It's been a long time coming, but there's now good agreement of a departure some 7 degrees below the mean. It's been a while since we last saw one of those in December.


Incidentally, here's the equivalent from 7 years ago. Note how even then a warmup was lurking in the depths of FI.



And as Joe says, the EPS are persistent with their cold outlook which, as a coldie, is encouraging!

Leysdown, north Kent
White Meadows
26 November 2017 12:11:02
Can you just clarify EPS for me please?
Retron
26 November 2017 12:13:40

Can you just clarify EPS for me please?

Originally Posted by: White Meadows 


It's the Ensemble Prediction System - the name of the mainstream ECMWF ensembles.


Here's another link to see more of the EPS, following on from the weather.us one yesterday:


http://wx.graphics/models/ecmwf/eps.php


 

Leysdown, north Kent
White Meadows
26 November 2017 12:23:08
Thank you Retron
some faraway beach
26 November 2017 13:42:49


 


And here are the 850s, compared to the mean (nb - I guess that's calculated "on the fly" by WZ rather than being a field in the GRIB data - a shame, as it's handy to see at a glance just how far above/below things are):



It's been a long time coming, but there's now good agreement of a departure some 7 degrees below the mean. It's been a while since we last saw one of those in December.


Incidentally, here's the equivalent from 7 years ago. Note how even then a warmup was lurking in the depths of FI.



And as Joe says, the EPS are persistent with their cold outlook which, as a coldie, is encouraging!


Originally Posted by: Retron 


Thanks for posting that graph which we were being half-encouraged by and half-fretting over this day in 2010 ("sadly the ensemble soon flattens the pattern"/"plenty of runs already signalling how cold synoptics are unsustainable in the Modern Winter").


Shows how seven days is as far as the model output can take you in these set-ups.

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.
doctormog
26 November 2017 15:58:26
http://www.wetterzentrale.de/maps/GFSOPEU12_93_1.png 

A few more small tweaks will bring that t850hPa -10°C isotherm onshore to the mainland http://www.wetterzentrale.de/maps/GFSOPEU12_78_2.png


The 12z UKMO run (still coming out) also looks cold midweek with a northerly flow before becoming for anticyclonic from the west but still cold.

Aberdeen
Current conditions (personal WS) 
Brian Gaze
26 November 2017 16:08:47

Next weekend looks could be interesting in central and south eastern England.


Brian Gaze
Berkhamsted
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"I'm not socialist, I know that. I don't believe in sharing my money." - Gary Numan
doctormog
26 November 2017 16:14:22

Before that point there is plenty of interest. One of many charts that could illustrate the point.



 


 

Aberdeen
Current conditions (personal WS) 
doctormog
26 November 2017 16:23:21

This chart potential never a truer word
Originally Posted by: ballamar 

">https://www.theweatheroutlook.com/twodata/gfs.aspx?run=12&charthour=180&chartname=mslp500&chartregion=na-region&charttag=500hPa%20GPDM


Agreed, there could be a few very interesting charts around in coming days if that one is anything to go by.

Aberdeen
Current conditions (personal WS) 
nsrobins
26 November 2017 16:26:45
The 12Z GFS could be about to put a mocker on the ‘Northerlies can’t deliver any more’ theory. FI shaping up for a decent arctic blast.
Neil
Fareham, Hampshire 28m ASL (near estuary)
Stormchaser, Member TORRO
Maunder Minimum
26 November 2017 16:33:12

The 12Z GFS could be about to put a mocker on the ‘Northerlies can’t deliver any more’ theory. FI shaping up for a decent arctic blast.

Originally Posted by: nsrobins 


Was about to post that myself - amplification is back on the agenda for next weekend on the 12z.

New world order coming.
David M Porter
26 November 2017 16:36:39

UKMO 12z:


http://old.wetterzentrale.de/pics/Rukm961.gif


http://old.wetterzentrale.de/pics/Rukm1201.gif


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


 

Lenzie, Glasgow

"Let us not take ourselves too seriously. None of us has a monopoly on wisdom, and we must always be ready to listen and respect other points of view."- Queen Elizabeth II 1926-2022
Rob K
26 November 2017 16:41:23


UKMO 12z:


http://old.wetterzentrale.de/pics/Rukm961.gif


http://old.wetterzentrale.de/pics/Rukm1201.gif


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


 


Originally Posted by: David M Porter 


 


UKMO not buying the renewed push from the north any more by the looks of things. Shame as the GFS is lovely. 

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
Quantum
26 November 2017 16:44:08

That GFS12Z is really something. The key is not to get to excited by any one run; the view of the ECM will be very important. I seem to remember many occasions where the GFS flip flop with one upgrading and the other downgrading. In almost all cases the most pessimistic run, generally, is the one that actually comes off. 

Twitter: @QuantumOverlord (general), @MedicaneWatch (medicane/TC stuff)
2023/2024 Snow days (approx 850hpa temp):
29/11 (-6), 30/11 (-6), 02/12 (-5), 03/12 (-5), 04/12 (-3), 16/01 (-3), 18/01 (-8), 08/02 (-5)

Total: 8 days with snow/sleet falling.

2022/2023 Snow days (approx 850hpa temp):

18/12 (-1), 06/03 (-6), 08/03 (-8), 09/03 (-6), 10/03 (-8), 11/03 (-5), 14/03 (-6)

Total: 7 days with snow/sleet falling.

2021/2022 Snow days (approx 850hpa temp):

26/11 (-5), 27/11 (-7), 28/11 (-6), 02/12 (-6), 06/01 (-5), 07/01 (-6), 06/02 (-5), 19/02 (-5), 24/02 (-7), 30/03 (-7), 31/03 (-8), 01/04 (-8)
Total: 12 days with snow/sleet falling.
doctormog
26 November 2017 16:44:19


 


 


UKMO not buying the renewed push from the north any more by the looks of things. Shame as the GFS is lovely. 


Originally Posted by: Rob K 


A bit premature Rob as the GFS does not have the next northerly properly setting up until a few days later. http://www.wetterzentrale.de/maps/GFSOPEU12_144_1.png


It is conjecture as the charts do not go out that far on the UKMO but you cannot rule out a second northerly blast based on output at 144hr out.


Also, as Q says, even though it looks nice the GFS 12z op run is just one run in isolation at the moment. One possibility. One opportunity for disappointment 

Aberdeen
Current conditions (personal WS) 
Gooner
26 November 2017 16:50:21

@Rob you seem to have such negative views , why are you presuming UKMO is correct , you are only looking to 144....

Remember anything after T120 is really Just For Fun



Marcus
Banbury
North Oxfordshire
378 feet A S L


Shropshire
26 November 2017 17:03:03

I'm not a great fan of the UKMO at T144 in terms of accuracy, but it does show what can go wrong. We don't want to see the Atlantic trough head North like that and phase with other Lows to the NW. We want to see it under the Atlantic blocking as the GFS and hopefully the ECM will show later. 

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David M Porter
26 November 2017 17:05:16


I'm not a great fan of the UKMO at T144 in terms of accuracy, but it does show what can go wrong. We don't want to see the Atlantic trough head North like that and phase with other Lows to the NW. We want to see it under the Atlantic blocking as the GFS and hopefully the ECM will show later. 


Originally Posted by: Shropshire 


This is not the first time I have seen someone question the accuracy of the UKMO 144hr charts. I'd be interested to know how these charts compare for accuracy against the 144hr charts on the GFS and ECM op runs.

Lenzie, Glasgow

"Let us not take ourselves too seriously. None of us has a monopoly on wisdom, and we must always be ready to listen and respect other points of view."- Queen Elizabeth II 1926-2022
Rob K
26 November 2017 17:05:37


@Rob you seem to have such negative views , why are you presuming UKMO is correct , you are only looking to 144....


Originally Posted by: Gooner 


I'm not "presuming it's correct", im just discussing what it shows. There's no route back to a northerly from those charts. It's no more or less likely than the GFS, I'm just discussing the range of outputs, which is the point of this thread! I'm not sure why that is "negative"?

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
Whether Idle
26 November 2017 17:09:03

The 12Z GFS could be about to put a mocker on the ‘Northerlies can’t deliver any more’ theory. FI shaping up for a decent arctic blast.

Originally Posted by: nsrobins 


Good to see you enter the debate.


It is beyond doubt that there are many lurkers and posters who would love to see an "old school northerly" deliver some deep cold.  This would be a very popular outcome, especially IMBY.


 In the meantime, the wait continues.


 

Dover, 5m asl. Half a mile from the south coast.
David M Porter
26 November 2017 17:19:49


 


I'm not "presuming it's correct", im just discussing what it shows. There's no route back to a northerly from those charts. It's no more or less likely than the GFS, I'm just discussing the range of outputs, which is the point of this thread! I'm not sure why that is "negative"?


Originally Posted by: Rob K 


I know where you're coming from Rob and I don't disagree with what you say about the UKMO. That said, it's only one run from one model. GFS at the same timeframe looks more positive for a potential reload from the north and it will be interesting to see what ECM comes up with an hour or so from now.


Much as UKMO is a very important piece of the overall jigsaw, it isn't the be-all and end-all.

Lenzie, Glasgow

"Let us not take ourselves too seriously. None of us has a monopoly on wisdom, and we must always be ready to listen and respect other points of view."- Queen Elizabeth II 1926-2022
Gusty
26 November 2017 17:21:13


Good to see you enter the debate.


It is beyond doubt that there are many lurkers and posters who would love to see an "old school northerly" deliver some deep cold.  This would be a very popular outcome, especially IMBY.


 In the meantime, the wait continues.


Originally Posted by: Whether Idle 


Persistence pays. I'm in agreement that northerlies are nowhere near as punchy as they were 50 years ago due to the aforementioned reasons. HOWEVER...bang the door long enough and hard enough and we may just get a result.


In a warming world significant cold events will still occur. 50 years ago a deep cold northerly cold could normally deliver after a couple of attempts....these days it probably needs three attempts.


Encouraging output for the coldies today...next weekend's less cold incursion is in doubt. Look north and east is the word on the street tonight. 

Steve - Folkestone, Kent
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