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Bertwhistle
17 January 2016 19:03:19

ECM and JMA showing great 'potential' at T192 with High Pressure over Scandanavia and a chance of retrogression. Could is be our next stab at some decent cold?

Originally Posted by: Karl Guille 


 


The alignment of the high looks all wrong to me but at 240 there's definitely something cooking.


http://www.theweatheroutlook.com/twodata/chart.aspx?chart=/charts/ecm/240_mslp850.png?cb=350


Bertie, Itchen Valley.
Retire while you can still press the 'retire now' button.
Whether Idle
17 January 2016 19:03:48

...and back to the pseudo-reality of the models...


here's the ECM in FI: Pressure rising to the N.  Worth keeping a weather eye on.



 


Dover, 5m asl. Half a mile from the south coast.
Retron
17 January 2016 19:04:04


Yes a solid collective from most output for a return to south westerlies 


Once locked in to this pattern we can expect a written-off February until evidence appears of a SSw or other freak pattern changing driver.


Originally Posted by: White Meadows 


That's a mighty brave call there!


Personally, given that GEFS is touting high pressure over us (= frosts this time of year) and that the ECM run has the SW'lies lasting all of two and a bit days... well, I'll say no more.


Leysdown, north Kent
Quantum
17 January 2016 19:06:09

Here we go, that rare green shading is starting to appear!



I suspect as it moves south east we may also see yellow which I have never seen modelled for the UK before. Quite amazing.


This is the problem at relying on 850hpa temperatures; you miss amazing situations like this. The end of the week looks freezing in the east with possible ice and freezing rain! 


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.
SJV
17 January 2016 19:07:56


 


Yes a solid collective from most output for a return to south westerlies 


Once locked in to this pattern we can expect a written-off February until evidence appears of a SSw or other freak pattern changing driver.


Originally Posted by: White Meadows 


I'll hold you to that  We had similar predictions of a written off January in reference to December's pattern, and look what we've had recently (btw referring to the pattern change rather than the severity of it!). 


I can see the milder, or at least average weather returning until the end of the month but beyond that is anyone's guess, and I cannot stress that word enough 'guess'. 

Bertwhistle
17 January 2016 19:11:13


Here we go, that rare green shading is starting to appear!



I suspect as it moves south east we may also see yellow which I have never seen modelled for the UK before. Quite amazing.


This is the problem at relying on 850hpa temperatures; you miss amazing situations like this. The end of the week looks freezing in the east with possible ice and freezing rain! 


Originally Posted by: Quantum 


How bizarre Q- the colour key shows pluie verglacante as green, as does the map and yet the literal key at the top has it as 'violet'.


Bertie, Itchen Valley.
Retire while you can still press the 'retire now' button.
Quantum
17 January 2016 19:12:19

Only by midday friday do we loose our cold source from France and things can finally warm up. 



Still that is utterly insane, 2C in the north east with 5C uppers; never seen anything like it. Okay yes I have under HP inversion conditions, but this is nothing like this; the 850hpa winds are strong southwesterly. 


Why is no one commenting on this? Biggest freezing rain event possible in years if this comes off. I'd say its similar to 2012 when the synoptics were similar, but this one is more impressive.


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.
Snow Hoper
17 January 2016 19:16:43


 


Must admit, the ECM 240 today is tasty - an ideal precursor to some deep cold advection from the NE. (How so, I hear some people ask - well, look at the kinks in the jet upstream, then note that they'll encourage heights to be "pulled back" westwards... along with that cold to the east!)


One swallow doesn't make a summer, but it's an interesting chart. Let's see whether it's a one off, or whether it'll be repeated tomorrow!


(And also worth mentioning that it's worlds away from the G(E)FS and its pressure rises over the UK... not that that means much at this range!)


 


Originally Posted by: Retron 


ECM 240hrs indeed. Would like to see it repeated over the next few runs, but we'll worth keeping an eye on.


Going to war over religion is like killing each other to see who has the better imaginary friend.


Home : Thorndon, Suffolk.
White Meadows
17 January 2016 19:23:21


Only by midday friday do we loose our cold source from France and things can finally warm up. 



Still that is utterly insane, 2C in the north east with 5C uppers; never seen anything like it. Okay yes I have under HP inversion conditions, but this is nothing like this; the 850hpa winds are strong southwesterly. 


mWhy is no one commenting on this? Biggest freezing rain event possible in years if this comes off. I'd say its similar to 2012 when the synoptics were similar, but this one is more impressive.


Originally Posted by: Quantum 


Ground temps looking too high for freezing rain?!


country file has double figures by the end of week for the foreseeable.


 


 

Quantum
17 January 2016 19:27:07


 


Ground temps looking too high for freezing rain?!


country file has double figures by the end of week for the foreseeable.


 


 


Originally Posted by: White Meadows 


This is the end of the cold spell though, at this point things are warming up. Believe it or not WRF predicts a widespread ice day for the east on Thursday. These synoptic are very interesting; this happened in 2012 but not to the extent it is happening now. 


 


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.
nsrobins
17 January 2016 19:28:14


 


That's a mighty brave call there!


Personally, given that GEFS is touting high pressure over us (= frosts this time of year) and that the ECM run has the SW'lies lasting all of two and a bit days... well, I'll say no more.


Originally Posted by: Retron 


Darren I confess that post was replying to my 'conclusive' statement, albeit before today's ECM. Given how ECM itself has not covered itself very well either I still maintain the most likely scenario from Thursday is ten days plus of the Atlantic.


The +240 ECM however does have 'that' look about it.


Neil
Fareham, Hampshire 28m ASL (near estuary)
Stormchaser, Member TORRO
KevBrads1
17 January 2016 19:34:58


 


Darren I confess that post was replying to my 'conclusive' statement, albeit before today's ECM. Given how ECM itself has not covered itself very well either I still maintain the most likely scenario from Thursday is ten days plus of the Atlantic.


The +240 ECM however does have 'that' look about it.


Originally Posted by: nsrobins 


I looked at the Manchester GFS 12z ensembles and what struck me is apart from the around the 23rd to 25th January, how few preciptation spikes they are and how high the SLPs are.


If it is 10 days plus of Atlantic, its a weak one going off GFS ensembles.


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nsrobins
17 January 2016 19:39:27


 


I looked at the Manchester GFS 12z ensembles and what struck me is apart from the around the 23rd to 25th January, how few preciptation spikes they are and how high the SLPs are.


If it is 10 days plus of Atlantic, its a weak one going off GFS ensembles.


Originally Posted by: KevBrads1 


It is indeed a 'modified' flow as high pressure will be close to the south, keeping rainfall rates down especially compared to recently. And as it stands there is very little in the way of snow in the offing from Friday. BUT - a week is a very long time in this business, especially at the moment, so there's always time for change.


Neil
Fareham, Hampshire 28m ASL (near estuary)
Stormchaser, Member TORRO
Chiltern Blizzard
17 January 2016 19:41:29


Only by midday friday do we loose our cold source from France and things can finally warm up. 



Still that is utterly insane, 2C in the north east with 5C uppers; never seen anything like it. Okay yes I have under HP inversion conditions, but this is nothing like this; the 850hpa winds are strong southwesterly. 


Why is no one commenting on this? Biggest freezing rain event possible in years if this comes off. I'd say its similar to 2012 when the synoptics were similar, but this one is more impressive.


Originally Posted by: Quantum 


Very interesting possible weather.... I've experienced proper freezing rain only once... At the end of December 1995 iirc.  a max of -1 with solidly frozen ground after a frigid end to the month.  A few flakes to start off with then rain for many hours, giving everything a 1cm+ skin of ice... Lethal to get about in though!


Rendlesham, Suffolk 20m asl
Rob K
17 January 2016 19:49:15


 


That's a mighty brave call there!


Personally, given that GEFS is touting high pressure over us (= frosts this time of year) and that the ECM run has the SW'lies lasting all of two and a bit days... well, I'll say no more.


Originally Posted by: Retron 


 


Yes I don't think we've seen the last of cold weather in January. The ECM looks quite promising already.


 


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
SJV
17 January 2016 19:57:21

ECM 216-240 is an interesting evolution to say the least 




?

UncleAlbert
17 January 2016 19:59:48
Its amazing......... just as the white flags go up, the ECM comes up with another northward shot of WAA around the Greenwich Meridion later in the run with support from the JMA and The GEM. This seems to be a recurring theme this winter. My feeling is that even if we do not see another potent cold snap after this week, we are all destined to go on being teased.
UncleAlbert
17 January 2016 20:11:50
Re my last post 'another potent cold snap'............. please refer to the projected 2014-2016 average for January!
Quantum
17 January 2016 20:19:46

It isn't just the GFS/WRF either take a look at the ARPEGE.



Unbelievably there is snow actually falling on the leading edge of that according to the ARPEGE look:



The temptation is to say the model 'has made an error', but it hasn't, don't forget lots of levels are modelled here the ARPEGE is perfectly aware how high 850hpa temperatures are. So how is snow possible at +6C 850hpa? Well it isn't, but the ARPEGE doesn't actually have a freezing rain parameter so it sees freezing rain as snow. Now lets look at the 2m temperatures; remember that 850hpa temp.


 



Lol, -2C in the east and 0C widely. What do you think is going to happen when you put a front slap over such a negative lapse rate?


Answer:


If the 850hpa temp is below zero: Snow 


If its around zero: Ice


If its above zero: Freezing rain.


 


 


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.
White Meadows
17 January 2016 20:22:37
Not if the ground is above 0c though, Q
doctormog
17 January 2016 20:24:21

Not if the ground is above 0c though, Q

Originally Posted by: White Meadows 


Which is why I posted this link a few posts above to show that for a large swathe the ground temperatures are below freezing (according to the GFS that is) http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=ukuk&MODELL=gfs&MODELLTYP=1&BASE=-&VAR=t1dm&HH=120&ZOOM=1&ARCHIV=0&RES=0&WMO=&PERIOD=


Quantum
17 January 2016 20:29:46

Also I'd point out that the true holy grail of precipitation in the UK is ice. I've seen Freezing rain but I've never seen ice before in the UK (I've been in an ice storm once in Iceland when a warm front came over). To get ice the snow should be almost melted but not quite, so when it passes through the cold layer it can re-nucleate. To get ice we would need, I recon, 850hpa temperatures to be no less than about +0.5C and no more than +1.5C and the 950hpa temperature should be subzero. I think this is possible.  


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.
Cumbrian Snowman
17 January 2016 20:33:46
Just a quick one on Freezing Rain

I thought this was rain falling through a layer of cold air near the surface and freezing, falling as what appears to be tiny hailstones

or is it when rain falls on frozen ground and freezes instantly- used be called shot ice I think.

Both cases I have experienced, here in Brampton the freezing on impact scenario was dangerous to say the least and lasted for several hours.
Ally Pally Snowman
17 January 2016 20:34:21

As has been said a very good looking ECM at day 10. JMA also looks very good at day 8. Hopefully we won't have to wait too long for another cold spell.


http://www.wetterzentrale.de/pics/Rjma1921.html


 


Bishop's Stortford 85m ASL.
David M Porter
17 January 2016 21:30:45

Its amazing......... just as the white flags go up, the ECM comes up with another northward shot of WAA around the Greenwich Meridion later in the run with support from the JMA and The GEM. This seems to be a recurring theme this winter. My feeling is that even if we do not see another potent cold snap after this week, we are all destined to go on being teased.

Originally Posted by: UncleAlbert 


There have been no white flags raised by me!


Much as the model output through most of December (prior to Xmas) was dire for coldies and there did seemt o be some people on the point of throwing the towel in, the one factor that was still in the favour of those wanting cold was that time was still very much on their side. Even though it ultimately come off, I imagine there couldn't have been many people during Christmas and New Year thinking that a few days into January, both GFS and ECM would be teasing us with major heights rises over Greenland.


The situation we were in during December was pretty hopeless for cold, but I think we've forward somewhat since then.


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

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