theweatheroutlook

Remove ads from site

Crepuscular Ray
10 December 2014 09:35:27
Frequent squalls of sleet here...lovely!
Jerry
Edinburgh, in the frost hollow below Blackford Hill
Skreever
10 December 2014 10:18:48
Heavy sleet showers and storm force winds
Veteran of winter of 62/63
By Scapa Flow, Orkney
Jonesy
  • Jonesy
  • Advanced Member Topic Starter
10 December 2014 10:29:20


Still looking like a significant snowfall early Fri am for Higher areas N Midlands and into N England generally.
Also the threat of a wind event S UK remains, with a deepening trough zipping across and closing as it exits into the N Sea. The phasing of this feature with the jet streak will determine the severity but as this stage an upper end event is low risk IMO.


Originally Posted by: nsrobins 


Weather type GFS Fr 12.12.2014 06 GMT


 


http://expert-images.weatheronline.co.uk/daten/proficharts/en/2014/12/10/basis06/ukuk/rart/14121206_1006.gif

Medway Towns (Kent)
The Weather will do what it wants, when it wants, no matter what data is thrown at it !
Saint Snow
10 December 2014 10:32:49


My crayon drawings have returned. Snow risk for the entirety of 24 hours today. Note this map only is useful for low ground including towns and cities, snow risks for even a small amount of elevation will be virtually 100% today. Interpret this map as the probability of you seeing snow if you live in that region. And by snow I mean something the average guy on the street can agree with, not 2 slightly icy raindrops under a lamppost. This is one of the hardest snow maps I have ever done, because none of the models agree with each other, and neither do the snow benching parameters. Above all else though, I base my decision on the entire atmosphere, which revolves around the use of skew-t diagrams. The upshot is that if the winds were light the snow probability would be very high, as it is, we are just (but definitely) on the wrong side of marginal. The weird thing is, it will take hardly any elevation to change this, even 100m could be enough. So because of all of this the map is rather homogenous and topped out, there is no place in the UK that has a high risk of seeing snow today, but there is a widespread low risk. Note that by thursday we will be on the other side of marginal. 



Originally Posted by: Quantum 


 


Cheers for this, Quantum - I do like your 'crayon drawing' snow risk maps



Martin
Home: St Helens (26m asl) Work: Manchester (75m asl)
A TWO addict since 14/12/01
"How can wealth persuade poverty to use its political freedom to keep wealth in power? Here lies the whole art of Conservative politics."
Aneurin Bevan
Crepuscular Ray
10 December 2014 10:37:09
Interestingly as the sleet squalls blow through, if you look up you can see millions of snowflakes hurtling along probably only 200m up. Unsurprisingly as each squall clears the Pentland Hills are turning whiter. It's down to 2 C in the city during the squalls and with such a strong wind it's hell out there!
Jerry
Edinburgh, in the frost hollow below Blackford Hill
The Beast from the East
10 December 2014 10:50:52

Its glorious down here. Wall to Wall sunshine and hardly a breeze


You bloody Jocks are living in another country. If only you'd voted for independence, we wouldn't have to listen to you crowing about your snow

"We have some alternative facts for you"
Kelly-Ann Conway - special adviser to the President
Jonesy
  • Jonesy
  • Advanced Member Topic Starter
10 December 2014 11:18:02

Navigate to the air field cam then wait till it pans out to the East and you can see the sea 


http://visit.shetland.org/shetland-webcams


The lighthouse cam is a good one too http://visit.shetland.org/shetland-webcams

Medway Towns (Kent)
The Weather will do what it wants, when it wants, no matter what data is thrown at it !
Owen Cummins
10 December 2014 12:43:29


My crayon drawings have returned. Snow risk for the entirety of 24 hours today. Note this map only is useful for low ground including towns and cities, snow risks for even a small amount of elevation will be virtually 100% today. Interpret this map as the probability of you seeing snow if you live in that region. And by snow I mean something the average guy on the street can agree with, not 2 slightly icy raindrops under a lamppost. This is one of the hardest snow maps I have ever done, because none of the models agree with each other, and neither do the snow benching parameters. Above all else though, I base my decision on the entire atmosphere, which revolves around the use of skew-t diagrams. The upshot is that if the winds were light the snow probability would be very high, as it is, we are just (but definitely) on the wrong side of marginal. The weird thing is, it will take hardly any elevation to change this, even 100m could be enough. So because of all of this the map is rather homogenous and topped out, there is no place in the UK that has a high risk of seeing snow today, but there is a widespread low risk. Note that by thursday we will be on the other side of marginal. 



Originally Posted by: Quantum 


 


Could I just ask why is it so hard to get snow lately? Over the past few days bar yesterday where I live the temperature has ranged from 4c to 0c yet the most we have received is sleety snow in the early hours. During the day including today all I have got is hail pellets but mostly icy rain.


Looking at upper profile it is definitely conductive to snow, so why is it raining? Does it look any better for here or is it going to be more of the same? I was looking forward to seeing some snow at this week but surprisingly it is only raining. Even on the hills above 200m the most they have gotten is a slushy deposit, we were up on the hills earlier and the snow was nearly rain. 


It seems lately every time snow is forecast we just get icy rain..

Quantum
10 December 2014 12:46:06

Interestingly as the sleet squalls blow through, if you look up you can see millions of snowflakes hurtling along probably only 200m up. Unsurprisingly as each squall clears the Pentland Hills are turning whiter. It's down to 2 C in the city during the squalls and with such a strong wind it's hell out there!

Originally Posted by: Crepuscular Ray 


Yeh, I hope you can see why I had such difficulty doing my prediction! I think it has worked out rather well though with widespread sleet but only isolated snow.  

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.
Quantum
10 December 2014 12:50:22


 


 


Could I just ask why is it so hard to get snow lately? Over the past few days bar yesterday where I live the temperature has ranged from 4c to 0c yet the most we have received is sleety snow in the early hours. During the day including today all I have got is hail pellets but mostly icy rain.


Looking at upper profile it is definitely conductive to snow, so why is it raining? Does it look any better for here or is it going to be more of the same? I was looking forward to seeing some snow at this week but surprisingly it is only raining. Even on the hills above 200m the most they have gotten is a slushy deposit, we were up on the hills earlier and the snow was nearly rain. 


It seems lately every time snow is forecast we just get icy rain..


Originally Posted by: Owen Cummins 


This is the big danger about using 850s, I've talked about this before, in the MO thread a few days ago I posted a few corrections that need to be applied, unfortunately it seems even they are inadequate in this case.


What we seem to have is a fairly low lapse rate, i.e the temperature is simply not falling quickly enough with elevation. This in itself would cause me to predict blanket rain, were it not for another factor: very dry air, and very low dew points. The dryness of the air works against the low lapse rate and is very conductive to snow, so this would lead me to predict snow for everywhere given the marginality were it not for a third factor! This being the very strong winds, which do now allow us to take advantage of the dry air through evaporational cooling. The upshot of all these factors is that with a very small amount of elevation you will get snow easily, but as it stands only sleet at lower levels.


But note, this will change tommorow, tommorow is expected to be a much easier day to predict, and while not everywhere will be cold enough for snow, there will be some areas that definitely will be. 

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.
Owen Cummins
10 December 2014 12:51:45

Interestingly as the sleet squalls blow through, if you look up you can see millions of snowflakes hurtling along probably only 200m up. Unsurprisingly as each squall clears the Pentland Hills are turning whiter. It's down to 2 C in the city during the squalls and with such a strong wind it's hell out there!

Originally Posted by: Crepuscular Ray 


 


The inland hills are whitish here but again last night all I got was sleety icy rain even at 2c. 

Owen Cummins
10 December 2014 12:57:36


 


This is the big danger about using 850s, I've talked about this before, in the MO thread a few days ago I posted a few corrections that need to be applied, unfortunately it seems even they are inadequate in this case.


What we seem to have is a fairly low lapse rate, i.e the temperature is simply not falling quickly enough with elevation. This in itself would cause me to predict blanket rain, were it not for another factor: very dry air, and very low dew points. The dryness of the air works against the low lapse rate and is very conductive to snow, so this would lead me to predict snow for everywhere given the marginality were it not for a third factor! This being the very strong winds, which do now allow us to take advantage of the dry air through evaporational cooling. The upshot of all these factors is that with a very small amount of elevation you will get snow easily, but as it stands only sleet at lower levels.


But note, this will change tommorow, tommorow is expected to be a much easier day to predict, and while not everywhere will be cold enough for snow, there will be some areas that definitely will be. 


Originally Posted by: Quantum 


 


Thank you. The temp is 4c and raining now but it doesn't want to drop, I am looking up and I too can see the snow moving along in the air, its not too far up as I seem to be getting a few flakes coming down in the heavier bursts.


I think a few degrees would make a substantial difference.  So you think it will snow tomorrow? 

Crepuscular Ray
10 December 2014 13:06:56
Amazing squall at noon here in Leith. Horizontal large hail, bright lightning and ferocious wind. Quite exciting working on the Royal Yacht today!
Jerry
Edinburgh, in the frost hollow below Blackford Hill
Medlock Vale Weather
10 December 2014 14:48:42

Latest EURO4 snow accumulation up to early Friday morning


http://expert-images.weatheronline.co.uk/daten/proficharts/en/euro4/2014/12/10/basis06/ukuk/weas/14121206_2_1006.gif


 

Alan in Medlock Valley - Oldham's frost hollow. 103 metres above sea level.
What is a frost hollow? http://www.weatheronline.co.uk/reports/wxfacts/Frost-hollow.htm 
micahel37
10 December 2014 14:58:11

Met office snow warnings for Friday have been reduced in area. Looks like they are going for a more southerly track for Fridays low.

Polbeth, West Lothian 150m asl
Jonesy
  • Jonesy
  • Advanced Member Topic Starter
10 December 2014 15:01:04


Met office snow warnings for Friday have been reduced in area. Looks like they are going for a more southerly track for Fridays low.


Originally Posted by: micahel37 


Yeah, 2-5cm at lower levels during rush hour I would imagine will cause a few travel problems.


 

Medway Towns (Kent)
The Weather will do what it wants, when it wants, no matter what data is thrown at it !
Saint Snow
10 December 2014 15:03:05


Latest EURO4 snow accumulation up to early Friday morning


http://expert-images.weatheronline.co.uk/daten/proficharts/en/euro4/2014/12/10/basis06/ukuk/weas/14121206_2_1006.gif


 


Originally Posted by: Medlock Vale Weather 


 


So, places with a bit of altitude, then?



Martin
Home: St Helens (26m asl) Work: Manchester (75m asl)
A TWO addict since 14/12/01
"How can wealth persuade poverty to use its political freedom to keep wealth in power? Here lies the whole art of Conservative politics."
Aneurin Bevan
Medlock Vale Weather
10 December 2014 15:06:41


 


 


So, places with a bit of altitude, then?



Originally Posted by: Saint Snow 


Probably - over 300m again where no one lives lol

Alan in Medlock Valley - Oldham's frost hollow. 103 metres above sea level.
What is a frost hollow? http://www.weatheronline.co.uk/reports/wxfacts/Frost-hollow.htm 
Owen Cummins
10 December 2014 15:17:31
It really annoys me when the weather says snow on high hills because most people if not all do not live up there.
noodle doodle
10 December 2014 15:17:42

Interestingly as the sleet squalls blow through, if you look up you can see millions of snowflakes hurtling along probably only 200m up. Unsurprisingly as each squall clears the Pentland Hills are turning whiter. It's down to 2 C in the city during the squalls and with such a strong wind it's hell out there!

Originally Posted by: Crepuscular Ray 


 


Nice bit of sleet in the face up at Fairmilehead this morning  better than the frozen rain on the pavement on monday though , ye gods that was treacherous


though just to prove the difficulty in snow forecasting, the met office has been predicting snow for my locality (eh10) for wed/thurs/fri since about monday, but it's always 5/6 hours in the future and ends up turning to rain (for eburgh itself) or sleet (for my eh10 postcode) in the actuality. If I'd believed their prediction on tuesday I should have an igloo by friday.


snow


And yes, hopefully by dissing their prediction a foot of the stuff will drop out the sky now  - to be fair as many others have pointed out 9 days of winter so far has given more than the whole of last winter

micahel37
10 December 2014 15:31:40

Same for me. Plenty of snow in the automated forcasts but the forecasters are saying what snow there is will be to higher levels.


I have seen the automated forecasts overcook snow in the past, I suspect either that they don't take altitude into account sufficiently, or they are biased towards presenting the "worst" weather scenario rather than the most likely.


 

Polbeth, West Lothian 150m asl
Quantum
10 December 2014 15:48:18

It really will become way more favourable for snow by tomorrow though even for low levels.


 

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.
Owen Cummins
10 December 2014 15:56:38
It is deceiving though as its just 3c but raining. Really really ice cold today.

A day that should've seen snow really.
Owen Cummins
10 December 2014 15:57:10


It really will become way more favourable for snow by tomorrow though even for low levels.


 


Originally Posted by: Quantum 


 


The met office have me down for snow tomorrow and tomorrow night so maybe. 

micahel37
10 December 2014 16:04:39


It really will become way more favourable for snow by tomorrow though even for low levels.


 


Originally Posted by: Quantum 


I don't see it for low levels to be honest, too much wind churning up the air to get decent evaporative cooling. Wintry showers and maybe a bit of slush for more exposed rural areas will be our lot.


Best chance will be overnight Thur/Fri but even that is looking to be constrained to around the Scotland/England Border area and the North West.


The hills can look forwards to a decent accumulation though. We might see the Scottish Ski season get going soon.

Polbeth, West Lothian 150m asl

Remove ads from site

Ads