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Heavy Weather 2013
31 January 2019 10:30:56

06z GFS has the band dying in situ around London. 


Mark
Beckton, E London
Less than 500m from the end of London City Airport runway.
Gandalf The White
31 January 2019 10:39:46

GFS 06z snow cover by 06.00 Friday 



Location: South Cambridgeshire
130 metres ASL
52.0N 0.1E


eddied
31 January 2019 10:55:39

Ok - so a bit of consistency starting to appear now. Many of the main points have been hinted at for a while though to be fair.

Looks like anywhere north of a line from Aberystwyth to Colchester isn't likely to see much from this, until you get back into the showery regime futher north again.

Within this southern zone, it currently looks like the pivot is also 'stretching the front' reducing the intensity east of the Solent. West of this is best - so South Wales, southern Cotswolds and Salisbury Plain down towards the New Forest looking like getting the highest totals. I think these might be in the 10cm realm.

To the east of this, I still think that the Weald, South Downs and Surrey Hills could still do well. There may not be as much front left, but neither is it moving fast, and any snow will be falling onto an already present base layer and frozen ground. Could be in the 5cm realm.

Chilterns and Essex might get a couple of cm.

Layered on top of this base picture are the variables of air being drawn in from the east from the Thames estuary, which may or may not be a big factor, undercutting and giving a boost to frontal activity... dependent too on whether any minor lows run east ahead of the main low. Any boost from these or resulting compression of the isobars could increase totals in this south-eastern sector. I could see an amber extending eastwards later, but these additional factors mean it's all less certain than the sw, where the front is literally knocking on the door already, so I don't blame the Metoffice for waiting and seeing. Check back in a few hours!


Location: Reigate, Surrey 105m ASL

Winter 22/23
Days snow falling: 4
Days snow on ground:8
Max snow depths: 6cm (December 19th ish)

Summer 2022 max 39C on July 19th
Summer 2021 max: 32C on July 18th
Summer 2020 max: 36C on July 31st
Rob K
31 January 2019 11:00:08
^^sounds like a fair assessment. GFS and ARPEGE both going for 2cm here, Euro4 just nudges into the 5-10cm category. With recent falls there has been next to nothing here at 73m but noticeably more just 30m higher at the top of the A30 ridge, so altitude is likely to play a part. I'm hoping to see 5cm+ on the common at 100m by the morning.
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
snow_dann
31 January 2019 11:00:17


Ok - so a bit of consistency starting to appear now. Many of the main points have been hinted at for a while though to be fair.

Looks like anywhere north of a line from Aberystwyth to Colchester isn't likely to see much from this, until you get back into the showery regime futher north again.

Within this southern zone, it currently looks like the pivot is also 'stretching the front' reducing the intensity east of the Solent. West of this is best - so South Wales, southern Cotswolds and Salisbury Plain down towards the New Forest looking like getting the highest totals. I think these might be in the 10cm realm.

To the east of this, I still think that the Weald, South Downs and Surrey Hills could still do well. There may not be front left, but neither is it moving fast, and any snow will be falling onto an already present base layer and frozen ground. Could be in the 5cm realm.

Chilterns and Essex might get a couple of cm.

Layered on top of this base picture are the variables of air being drawn in from the east from the Thames estuary, which may or may not be a big factor, undercutting and giving a boost to frontal activity... dependent too on whether any minor lows run east ahead of the main low. Any boost from these or resulting compression of the isobars could increase totals in this south-eastern sector. I could see an amber extending eastwards later, but these additional factors mean it's all less certain than the sw, where the front is literally knocking on the door already.


Originally Posted by: eddied 


 


Can it take a re-route up the M54 on this line to include Walsall and then it can go south on the M6. Thanks in advance 

Rob K
31 January 2019 11:04:14

HIRLAM has 8-15cm of snow quite widely across the far south, although that is total of falling snow, not necessarily accumulation (although I would hope most would settle).


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
eddied
31 January 2019 11:05:26

^^sounds like a fair assessment. GFS and ARPEGE both going for 2cm here, Euro4 just nudges into the 5-10cm category. With recent falls there has been next to nothing here at 73m but noticeably more just 30m higher at the top of the A30 ridge, so altitude is likely to play a part. I'm hoping to see 5cm+ on the common at 100m by the morning.

Originally Posted by: Rob K 


 


I think altitude is less of an issue this time round. It will settle faster where there is already a base layer as I say above, and orographics might play a small part, but Tuesday's snow was so marginal that at 200m ASL it was snowing a good hour or two before it turned to snow at 50m ASL just a mile or so apart. We saw this clearly in Reigate. This front is cold enough ahead that it will be snow from the beginning, top to bottom.


Location: Reigate, Surrey 105m ASL

Winter 22/23
Days snow falling: 4
Days snow on ground:8
Max snow depths: 6cm (December 19th ish)

Summer 2022 max 39C on July 19th
Summer 2021 max: 32C on July 18th
Summer 2020 max: 36C on July 31st
Rob K
31 January 2019 11:07:32

WRF 6Z run is a lot less promising for the SE than the 0Z run was.


 


0Z: 



 


6Z:



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
eddied
31 January 2019 11:09:51


WRF 6Z run is a lot less promising for the SE than the 0Z run was.


 


0Z: 



 


6Z:



Originally Posted by: Rob K 


 


That's the frontal stretch at play I guess.


 


Still just a model prediction mind. Not that long ago it was modelled to blat northwards at pace to visit the midlands leaving us in rain...


Location: Reigate, Surrey 105m ASL

Winter 22/23
Days snow falling: 4
Days snow on ground:8
Max snow depths: 6cm (December 19th ish)

Summer 2022 max 39C on July 19th
Summer 2021 max: 32C on July 18th
Summer 2020 max: 36C on July 31st
kmoorman
31 January 2019 11:13:08


HIRLAM has 8-15cm of snow quite widely across the far south, although that is total of falling snow, not necessarily accumulation (although I would hope most would settle).


Originally Posted by: Rob K 


 


Mouth-watering for those living on the Sussex coast....    even if I have to drive a couple of miles inland :)


Home: Durrington, Worthing, West Sussex. (16 ASL)
Work: Canary Wharf, London
Follow me on Twitter @kmoorman1968
Bafan
31 January 2019 11:13:10


 


Amber warning duly issued!  You now have 14 hours of heavy snow (mostly 95%+ chance too) so even if the MetO are only half right, you should have a very decent fall, and more than the 10cm stated.  Time to get excited! 


Originally Posted by: Chiltern Blizzard 


laughinglaughinglaughing


Helen
Tredegar, SE Wales, 330m
nsrobins
31 January 2019 11:13:25

It should be noted that there are some pretty tidy returns in the main area swinging in from the SW, with convective elements producing sceptics (sic. Sferics lol).
If that were to maintain itself and be in snow form then there could be local accumulations of >15cm in the south later.
The Amber is justified IMO and I wouldn’t rule out an adjustment up should the above develop.
Also note whilst flow is onshore just now (S Coast up to 5C), from 2pm flow backs ESE then E, drawing in lower dps even to the coast. A rain to snow event for coastal areas Weymouth east IMO.


Neil
Fareham, Hampshire 28m ASL (near estuary)
Stormchaser, Member TORRO
Gandalf The White
31 January 2019 11:14:59




Looks like anywhere north of a line from Aberystwyth to Colchester isn't likely to see much from this, 


Originally Posted by: eddied 



Thanks for that - your line passes right over our area.....  I'll have to make sure I'm looking out of the windows that face south....



Location: South Cambridgeshire
130 metres ASL
52.0N 0.1E


kmoorman
31 January 2019 11:16:21


It should be noted that there are some pretty tidy returns in the main area swinging in from the SW, with convective elements producing sceptics (sic. Sferics lol).
If that were to maintain itself and be in snow form then there could be local accumulations of >15cm in the south later.
The Amber is justified IMO and I wouldn’t rule out an adjustment up should the above develop.
Also note whilst flow is onshore just now (S Coast up to 5C), from 2pm flow backs ESE then E, drawing in lower dps even to the coast. A rain to snow event for coastal areas Weymouth east IMO.


Originally Posted by: nsrobins 


 


I'd hope the colder air / lower DPs will arrive before the precipitation


Home: Durrington, Worthing, West Sussex. (16 ASL)
Work: Canary Wharf, London
Follow me on Twitter @kmoorman1968
tallyho_83
31 January 2019 11:18:15

Less promising for the SE and E but this means more promising for the S and SW:


 


Met Office has now issued an Amber weather warning for snow for below parts:


https://www.metoffice.gov.uk/public/weather/warnings#?date=2019-01-31&id=da2cef65-d414-4d8c-968e-ae65224819ec


Amber warning
Snow
between Thu 14:00 and Thu 21:00


Created:


10:23 on Thu 31 Jan 2019 GMT

Regions and local authorities affected:



  • London & South East England

  • South West England

  • Wales




Further details


A band of rain will arrive from the southwest on Thursday afternoon, quickly turning to snow and becoming heavy at times. 3 to 7 cm is likely to accumulate quickly - within two to three hours - with up to 10 cm in some places. The highest snowfall accumulations are likely to be in areas above 150 metres or so.





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


Tim A
31 January 2019 11:20:53

https://expert-images.images-weatheronline.com/daten/proficharts/web/en/euro4/2019/01/31/basis06/ukuk/weas/19020203_3106.gif



Euro4 doesn't look that great for the south, but I am not a fan under most circumstances (it did pick up the Manchester snow well though)


 


In fact if that comes off, its the NE and Scotland that should be more concerned about snow.


Tim
NW Leeds
187m asl

 My PWS 
Heavy Weather 2013
31 January 2019 11:23:15


Less promising for the SE and E but this means more promising for the S and SW:


 


Met Office has now issued an Amber weather warning for snow for below parts:


https://www.metoffice.gov.uk/public/weather/warnings#?date=2019-01-31&id=da2cef65-d414-4d8c-968e-ae65224819ec


Amber warning
Snow
between Thu 14:00 and Thu 21:00


Created:


10:23 on Thu 31 Jan 2019 GMT

Regions and local authorities affected:



  • London & South East England

  • South West England

  • Wales




Further details


A band of rain will arrive from the southwest on Thursday afternoon, quickly turning to snow and becoming heavy at times. 3 to 7 cm is likely to accumulate quickly - within two to three hours - with up to 10 cm in some places. The highest snowfall accumulations are likely to be in areas above 150 metres or so.





Originally Posted by: tallyho_83 


 


They really need to remove the London & South East tag. Its misleading as the amber warning area on the map doesn't cover that region.


Mark
Beckton, E London
Less than 500m from the end of London City Airport runway.
Rob K
31 January 2019 11:27:22


 


 


They really need to remove the London & South East tag. Its misleading as the amber warning area on the map doesn't cover that region.


Originally Posted by: Heavy Weather 2013 


Yes it does. The problem is that they call the region "London and Southeast England", making it sound as if London is included, when in fact only the SW parts of the region (New Forest, mostly) are included in the amber. If you click the "London and Southeast England" tab under the warning then it expands to show which areas in that region are covered, i.e Hampshire.


I do agree that the regions on the Met Office site are not very helpful, as it gives warnings for the whole region even if only one little corner is covered. Then the media spin that to "amber warnings issued for London" when that isn't true.


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
Heavy Weather 2013
31 January 2019 11:33:57


 


Yes it does. The problem is that they call the region "London and Southeast England", making it sound as if London is included, when in fact only the SW parts of the region (New Forest, mostly) are included in the amber. If you click the "London and Southeast England" tab under the warning then it expands to show which areas in that region are covered, i.e Hampshire.


I do agree that the regions on the Met Office site are not very helpful, as it gives warnings for the whole region even if only one little corner is covered. Then the media spin that to "amber warnings issued for London" when that isn't true.


Originally Posted by: Rob K 


Your quite right; just 


But in all seriousness; its been like this for years and you'd have expected them to notice the floor in the system.


The evening standard will probably have this on their front page this evening. London prepared for 'Danger to Live' snowstorm!


Mark
Beckton, E London
Less than 500m from the end of London City Airport runway.
Heavy Weather 2013
31 January 2019 11:35:52

As if by magic 


https://www.standard.co.uk/news/uk/danger-to-life-warning-with-snow-set-to-hit-london-and-south-after-days-of-chaos-in-uk-a4053961.html


 


Mark
Beckton, E London
Less than 500m from the end of London City Airport runway.
Maunder Minimum
31 January 2019 11:44:39

May not mean anything for us, but I can see the precipitation pepping up in the Bristol Channel.


Funny how the main band of precipitation in Ireland cannot make much headway into NI. Must be the Brexit hard border in operation.


New world order coming.
Quantum
  • Quantum
  • Advanced Member Topic Starter
31 January 2019 11:50:38
Convective potential here in the north just keeps upgrading. Arome is now in on it and it doesn't even like convection.
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.
Rob K
31 January 2019 11:54:06
Some seriously beefy radar returns in the SW approaches, 80mm/hr+ in places - let's hope it can hold itself together over land.
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
Stormchaser
31 January 2019 12:00:32

Good to see dew points drop back down to zero or thereabouts as the flow draws air across from the snowy lands of N. France. Every little helps in these situations, and that could be more than a little factor in this particular event.


It may be the reason why the Met Office have been so confident in the snow line reaching south of the model consensus.


If you have any problems or queries relating to TWO you can Email [email protected]

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2023's Homeland Extremes:
T-Max: 30.2°C 9th Sep (...!) | T-Min: -7.1°C 22nd & 23rd Jan | Wettest Day: 25.9mm 2nd Nov | Ice Days: 1 (2nd Dec -1.3°C in freezing fog)
Keep Calm and Forecast On
tallyho_83
31 January 2019 12:04:06


GFS 06z snow cover by 06.00 Friday 



Originally Posted by: Gandalf The White 


GFS do so poorly with precipitation totals - i really do think that is a bit OTT with the snow cover - I expect the peak heavy and most of the snow will be SE Wales and West country - including BRISTOL:


 



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


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