theweatheroutlook

Remove ads from site

BaryBazz
09 February 2021 17:49:27


Chart image


 


Chart image


Chart image


Chart image


Chart image


I'd take this NOW 


Originally Posted by: Gooner 


 


My order is in please !!!

Brian Gaze
09 February 2021 17:49:47


 


Why don't you run it off ICON or ARPEGE?


Then you'd have a high res model initiating another high res model.


Might give interesting results.


Plus it would be avalible alot earlier than if you did it from the GEM or ECM.


 


Originally Posted by: Quantum 


I'd considered it but the second line was why I concluded it would not be a good route to go down. There is also the issue with dataset sizes and resolutions. My guess is that starting with a very high resolution would slow things down.

Brian Gaze
Berkhamsted
TWO Buzz - get the latest news and views 
"I'm not socialist, I know that. I don't believe in sharing my money." - Gary Numan
Brian Gaze
09 February 2021 17:52:18


Slightly O/T but it keeps being mentioned.


Vanishing snow in easterly winds is simply sublimation (evaporation from solid to vapour)


I first noticed this in January 1976 during a bitterly cold spell of south-easterlies after snow some days earlier.


Strong dry sub-zero winds are a feature of this set-up.


Originally Posted by: Sevendust 


For the thousandth time it really isn't. There would not  be puddles forming if it was sublimation. The 2 plausible reasons posted are:


1) Heat radiating back or penetrating clouds


2) Latent heat in the ground


I realise that sublimation will be taking place if temps are below 0C but that wasn't the primary cause of snow loss here yesterday. 

Brian Gaze
Berkhamsted
TWO Buzz - get the latest news and views 
"I'm not socialist, I know that. I don't believe in sharing my money." - Gary Numan
Russwirral
09 February 2021 17:56:25
ECM will be telling tonight. METO and BBC keep commenting this cold spell could last for some time...

into the Models and there are two camps forming, those in favour of a breakdown to milder Atlantic, or those in favour of Cold winning, the latter being very dry for the most part

GFS and ICON want to try a snowy breakdown of sorts, but cold remains beyond the weeked

GDPS and 00 ECM going for Snow -> quickly milder cold finishes this weekend

Will ECM stay in the latter camp?

Weather station:
https://www.wunderground.com/personal-weather-station/dashboard?ID=IWIRRAL24#history 
Saint Snow
09 February 2021 17:59:14


 


For the thousandth time it really isn't. There would not  be puddles forming if it was sublimation. The 2 plausible reasons posted are:


1) Heat radiating back or penetrating clouds


2) Latent heat in the ground


I realise that sublimation will be taking place if temps are below 0C but that wasn't the primary cause of snow loss here yesterday. 


Originally Posted by: Brian Gaze 


 


It's the dry surfaces immediately following the disappearance of my snow sprinkles that is 'funny' about this spell.


 


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
squish
09 February 2021 18:02:43
If it reverts back it won't be a surprise. We have seen the models flip in tandem quite a lot recently, which probably shows how fine margins can have a big eventual outcome down the line. Always the case to an extent but much more so in a reverse pattern such as this when the the physics will keep wanting to revert to the norm and the equations don't perhaps have the same computing power in the operational runs we see compared to the wealth of data the professionals enjoy. Or they are just going from experience...which as far as I know computer models lack ;)

D.E.W on Dartmoor. 300m asl
Russwirral
09 February 2021 18:04:15


 


 


It's the dry surfaces immediately following the disappearance of my snow sprinkles that is 'funny' about this spell.


 


Originally Posted by: Saint Snow 


 


TO be fair to Brian


We had a very similar shower activity over night and woke to majority of it on the floor this morning.  


 


However during today weve had a succession of showers, with nothing to show for it. 


 


Today has been bright with sunshine.


 


So taking the sun out of resulted in the snow staying, so deduction is its surface heating?


Weather station:
https://www.wunderground.com/personal-weather-station/dashboard?ID=IWIRRAL24#history 
Sevendust
09 February 2021 18:06:10


 


For the thousandth time it really isn't. There would not  be puddles forming if it was sublimation. The 2 plausible reasons posted are:


1) Heat radiating back or penetrating clouds


2) Latent heat in the ground


I realise that sublimation will be taking place if temps are below 0C but that wasn't the primary cause of snow loss here yesterday. 


Originally Posted by: Brian Gaze 


Disagree. I've seen this a number of times in the past

Joe Bloggs
09 February 2021 18:10:36


 


For the thousandth time it really isn't. There would not  be puddles forming if it was sublimation. The 2 plausible reasons posted are:


1) Heat radiating back or penetrating clouds


2) Latent heat in the ground


I realise that sublimation will be taking place if temps are below 0C but that wasn't the primary cause of snow loss here yesterday. 


Originally Posted by: Brian Gaze 


LOL reminds me of our little tiff in the BFTE. 😂😂😂


Deja vu or what?!


Manchester City Centre, 31m ASL
Saint Snow
09 February 2021 18:32:06


 


 


TO be fair to Brian


We had a very similar shower activity over night and woke to majority of it on the floor this morning.  


 


However during today weve had a succession of showers, with nothing to show for it. 


 


Today has been bright with sunshine.


 


So taking the sun out of resulted in the snow staying, so deduction is its surface heating?


Originally Posted by: Russwirral 


 


As I said yesterday, there's various factors at play.


Yesterday I woke to a dusting covering all surfaces and still snowing. An hour later, with cloudy conditions & no sun, the snow on roads and pavements had literally disappeared without trace - no hint of moisture left behind. The dusting on the cover over the patio table was still there, but this again just disappeared shortly after when I next looked (I literally went outside to look at the fabric; no hint of moisture)


Attributing it to one reason is folly.


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
marco 79
09 February 2021 18:44:33
Back to model output...if we have a sinking HP over Europe then inevitable that the Atlantic will push energy North...lot of the output puts Northern blocking weakening too, around Greenland specifically..personally there is still a fair bit to play for...especially the cold block to our East...lots of scenarios likely in the coming days..
Home : Mid Leicestershire ...135m ASL
Quantum
09 February 2021 18:45:12

15Z COSMO and ICON look slight improvements on the 12Z set.


 

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.
icecoldstevet
09 February 2021 18:46:14


 


 


As I said yesterday, there's various factors at play.


Yesterday I woke to a dusting covering all surfaces and still snowing. An hour later, with cloudy conditions & no sun, the snow on roads and pavements had literally disappeared without trace - no hint of moisture left behind. The dusting on the cover over the patio table was still there, but this again just disappeared shortly after when I next looked (I literally went outside to look at the fabric; no hint of moisture)


Attributing it to one reason is folly.


Originally Posted by: Saint Snow 


 


It could just have 'blown away' as it was very windy and the snow by us was like small beads and not really 'sticking', it was moving around all over the place.

Cornwall - 50 Metres Above Sea Level - 1 Mile From The Atlantic Coast
Hippydave
09 February 2021 18:48:58

ECM Op looks rather quicker to sink the block tonight although signs HP builds back in after a brief Atlantic interlude. 

Home: Tunbridge Wells
Work: Tonbridge
Rob K
09 February 2021 18:51:56


ECM Op looks rather quicker to sink the block tonight although signs HP builds back in after a brief Atlantic interlude. 


Originally Posted by: Hippydave 


Yes it spins up a GFS style dartboard which blows the block away but never far away. 

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
KevBrads1
09 February 2021 18:55:21


 


For the thousandth time it really isn't. There would not  be puddles forming if it was sublimation. The 2 plausible reasons posted are:


1) Heat radiating back or penetrating clouds


2) Latent heat in the ground


I realise that sublimation will be taking place if temps are below 0C but that wasn't the primary cause of snow loss here yesterday. 


Originally Posted by: Brian Gaze 


There was an article in the Weather journal on the disappearance of the late January 1996 snowfalls, I think it was described as a dry melt. I remember that one well, the snow just seem to disappear. 

MANCHESTER SUMMER INDEX for 2021: 238
Timelapses, old weather forecasts and natural phenomena videos can be seen on this site
http://www.youtube.com/channel/UCgrSD1BwFz2feWDTydhpEhQ/playlists
fairweather
09 February 2021 18:56:33


 


For the thousandth time it really isn't. There would not  be puddles forming if it was sublimation. The 2 plausible reasons posted are:


1) Heat radiating back or penetrating clouds


2) Latent heat in the ground


I realise that sublimation will be taking place if temps are below 0C but that wasn't the primary cause of snow loss here yesterday. 


Originally Posted by: Brian Gaze 


I think it is latent heat from the ground. I have supporting scientific evidence! I measured the soil temperature in a snowless patch where it had thawed. Temp at 10 cm was 1.5C. Air temp was 0.1C. DP was -2.5C. Also snow remaining on roofs, cars and all surfaces that don't have direct conductivity with soil. Grass thawing only slightly - air gap between blades only partial soil contact. I have a plastic grate running across my patio. All of the slabs have  no snow. The plastic grid which has a 10cm air gap underneath still has 3 cm of snow. Also with a low DP wouldn't there be warmer ground water vapour permeating up from the soil to try and reach equilibrium at the surface?

S.Essex, 42m ASL
fairweather
09 February 2021 19:00:25


 


Disagree. I've seen this a number of times in the past


Originally Posted by: Sevendust 


100% not sublimation here. Seen that many times. Needs dry air. Air saturated at ground level. Melt snow leaving puddles. See the explanation (for here) above.

S.Essex, 42m ASL
Rob K
09 February 2021 19:00:33


 


I think it is latent heat from the ground. I have supporting scientific evidence! I measured the soil temperature in a snowless patch where it had thawed. Temp at 10 cm was 1.5C. Air temp was 0.1C. DP was -2.5C. Also snow remaining on roofs, cars and all surfaces that don't have direct conductivity with soil. Grass thawing only slightly - air gap between blades only partial soil contact. I have a plastic grate running across my patio. All of the slabs have  no snow. The plastic grid which has a 10cm air gap underneath still has 3 cm of snow. Also with a low DP wouldn't there be warmer ground water vapour permeating up from the soil to try and reach equilibrium at the surface?


Originally Posted by: fairweather 


The weird thing with the ground heat theory though is that the last place for the snow to melt, for me at least, is bare soil! Today it disappeared from the grass, but the bare soil on the veg patch and the frozen muddy area where the grass had got trampled was still covered with frozen snowflakes. 


Surely if it was ground heat then bare soil ought to melt the snow too!

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
fairweather
09 February 2021 19:03:24

GFS 12z clearly thinks mild air will win by next week and now Thomasz  is agrreing that it looks like mild air will win by Monday/Tuesday. Doubt it will be that mild and will it be widely preceded by snow is the question.

S.Essex, 42m ASL
Polar Low
09 February 2021 19:09:41

To be honest I Think both Sevendust  and Brian are both right lots of factors to consider.


very important one is that thermal conductivity is not a constant and varies with different matter.


Plastic is poor in thermal conductivity  in comparison with soil or tarmac Hence it’s ability to stay on plastic longer.


 




 


I think it is latent heat from the ground. I have supporting scientific evidence! I measured the soil temperature in a snowless patch where it had thawed. Temp at 10 cm was 1.5C. Air temp was 0.1C. DP was -2.5C. Also snow remaining on roofs, cars and all surfaces that don't have direct conductivity with soil. Grass thawing only slightly - air gap between blades only partial soil contact. I have a plastic grate running across my patio. All of the slabs have  no snow. The plastic grid which has a 10cm air gap underneath still has 3 cm of snow. Also with a low DP wouldn't there be warmer ground water vapour permeating up from the soil to try and reach equilibrium at the surface?


Originally Posted by: fairweather 

mulattokid
09 February 2021 19:17:12


15Z COSMO and ICON look slight improvements on the 12Z set.


 


Originally Posted by: Quantum 


 


LOL .  I have to remind myself where I am.


 


There is me thinking a 'slight improvement' means it will be less cold.   Then my heart sinks when I remember I am currently outside of the real world view of comfort. 

Located in West London

"Everything in life is our fault, but that's not our fault!"
Anonymous friend of Quentin Crisp
tallyho_83
09 February 2021 19:30:22

12z GEM for Sunday 12pm: - Double figure temps into SW



12z GFS Op for Sunday 12pm: - Temps merely reaching +3c



 

Home Location - Kellands Lane, Okehampton, Devon (200m ASL)
---------------------------------------
Sean Moon
Magical Moon
www.magical-moon.com


Quantum
09 February 2021 19:31:35


 


The weird thing with the ground heat theory though is that the last place for the snow to melt, for me at least, is bare soil! Today it disappeared from the grass, but the bare soil on the veg patch and the frozen muddy area where the grass had got trampled was still covered with frozen snowflakes. 


Surely if it was ground heat then bare soil ought to melt the snow too!


Originally Posted by: Rob K 


I think people are overcomplicating this.


The melting only really occurs from about 11am to 2pm. A light dusting occured with me at just after 3pm which has not melted despite marginally positive temps between then and now.


Its the sun. Unless you have deep, compacted snow cover 300W/m^2 is alot and will make quick work of a thin patchy snow cover.


Thick cloud helps, but only brings it down to around 100W/m^2 during the showers.


I imagine a truly heavy shower or persistent snow would bring it down to 50W/m^2 which is what you need really.


 


 

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
09 February 2021 19:37:43

Regarding sublimation.


Is the snow sublimating?


Yes. It always is, and with low dewpoints sublimation occurs at a faster rate. 


But snow patches dissapearing in the middle of the daytime is not due to sublimation, that is nearly all melting. Though of course thin films of water will then evaporate quickly into dry air.


 

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.

Remove ads from site

Ads