Yorkshire and E England regional discussion

[bazookabob]

4 hours ago, Adam lufc said:

Missed again. Amber too far north. 10cm low ground typical really.

Again? Didn't you get about 4 inches on Friday?! 

[summer blizzard]

Triple point visible on radar over western Scotland now. The warm front bit has mostly degenerated to drizzle.

[Harsh Climate]

Can't see any snow today at all, maybe wake up to a nice supprise tomorrow morning with the rain at very least turning to snow. 

[summer blizzard]

7 minutes ago, Harsh Climate said:

Can't see any snow today at all, maybe wake up to a nice supprise tomorrow morning with the rain at very least turning to snow. 

Met Office maps show the 0C line expanding from about 18.00 and now generate interest from about 2am onwards but for today yes, nothing to get excited about.

...

For any Yorkshire members here, which of you are over 200m asl so we can monitor your snowline dropping.

[Harsh Climate]

In terms of the future I think the met office amber warning pretty much sums up where I think the bulk of the lowland snow will fall over the next 10 days. When I say lowland I mean below about 130m.

You look at a lot of the models and the protracted battleground event's I think we are just a tad bit too much on the southern flank of the cold air to the north/ northeast for the most part.

I think events will be similar to last fridays albeit a bit more marginal. Above 1000ft ignore what I say everything is looking very rosy indeed, above 600ft still everything looks pretty good but once you get below say 400ft looks very marginal indeed, for the most part.

Yes low lying areas tomorrow should see upto 5cm, maybe a bit more if the precipitation is heavy enough and sticks around long enough but we could suffer the fate over the next week or so what I suffered last friday, heavy snow falling all day adding up to no more than measly 2cm covering of wet snow/slush.

Still bags of time for change, I just say keep an eye out on the track of these attacking lows/shortwaves in the future, we want them to be just a bit further south..

 

Here's an example, with any similar repeat to today/tomorrows event we want the very top of the attacking lows centre to be just south of yorkshire, I've always found that to be a very good marker. See here it's just a tad further north, which is why scotland/northernmost parts of england have that nice met office amber warning.

[Guest]

15 minutes ago, summer blizzard said:

Met Office maps show the 0C line expanding from about 18.00 and now generate interest from about 2am onwards but for today yes, nothing to get excited about.

...

For any Yorkshire members here, which of you are over 200m asl so we can monitor your snowline dropping.

My work at Grenoside is approx 220m.

I will be available to update throughout tomorrow from about 8am.

[Harsh Climate]

18 minutes ago, summer blizzard said:

Met Office maps show the 0C line expanding from about 18.00 and now generate interest from about 2am onwards but for today yes, nothing to get excited about.

...

For any Yorkshire members here, which of you are over 200m asl so we can monitor your snowline dropping.

Yeah I will certainly be keeping an eye out on what those areas report later on. Be also interested seeing how quickly it turns in southern scotland and north east england. 

[Harsh Climate]

Temperature dropped 0.5c here (otley) in last hour, now 1.5c.

[SouthYorks]

Icon still going for snow into North Eastern parts of Yorkshire from around midnight and reaching South Yorkshire/North Derbyshire for around 8-9am.  It continues to show a couple of of hours of moderate snow followed by  8-10 hours of light snow before it leaves our region.  
 

As others have said, elevation is likely to be key but if Icon is correct everyone could see some snow falling even if not settling.  

Edited January 13, 2021 by SouthYorks

[LeeSnowFan]

1 minute ago, SouthYorks said:

Icon still going for snow into North Eastern parts of Yorkshire from around midnight and reaching South Yorkshire/North Derbyshire for around 8-9am.  It continues to show a couple of of hours of moderate snow followed by  8-10 hours of light snow before it leaves our region.  
 

As others have said, elevation is likely to be key but everyone could see some snow falling even if not settling.  

some say its not a reliable model?

[Kasim Awan]

It is possible to make a snow forecast, one has to just be aware of the uncertainties involved and communicate them. Failure to communicate and identify the risks involved imo carry more weight & potential responsibility afterwards. It's always worth giving a fair probabilistic view than remaining glued to the fence. With that in mind, the below is my post in the Mod thread I have had a request to post on here.

Yes, you effectively covered my point about the uncertainty as all the unorganized precip will do is prevent the ground environment below 200 metres (which is where there is marginality) from being conducive.

Given the projection of a well defined area of precipitation tomorrow, the outcome of some snow to lower levels producing a lowland area of snow maybe no greater than 5-25,000km^2 (up to 10% of the UK) with accumulations of 1-6cm in the favored stretch is fairly high in confidence. Of course, there are mechanisms which increase snow with altitude (orographic lift, lower temperatures, lower ground temperatures), and this means locally 20cm+ is possible for somewhere like Queensbury tomorrow. This is most favoured to occur across West Yorkshire, South Yorkshire, Notts, Derbs, into the North & East Midlands before moving towards the home counties. Even in this situation, there will be marginality on the north, south, west and eastern side of the snow area which will all result from slightly different thermodynamic mechanisms. North & east - lack of evap cooling. West -Fohen effect, lack of evap cooling. South - lack of cold air and low dew point injection from east. Defining which areas will see this is very uncertain and is down to nowcasting, however this does not take away or limit the main precip area evap cooling derived snow from verifying.

A strong consensus (70%) of weather models show this area verifying, the uncertainty is more to do with placement further south. The outcome of snow to lower levels in the Northern areas is not a certainty infact far from it however, the probabilistic forecasting method is always the way to go with consensus whilst leaving room for other possibilities which is what I've done, and you have covered here. Other outcomes include a more northerly track (some of Harmonie runs) and a more unorganized precipitation regime. However, I feel at this moment it would be unrealistic to go with 50/50 or even say "too close to call" for the precip further north at least, given the data for the triple point system which I am looking at. This does not discount a more unorganized precip area from occurring, just gives it a chance of say 25% whilst remaining aware that the higher confidence of snow for some areas (S Yorkshire, North & East Midlands) means imo a warning is valid from both an impact and likelihood perspective. Further south there is a risk of some snow too which of course will be bounded by the same spatial marginality mentioned above. Uncertainty is always the case with snow it's about doing the best one can with the data provided and forecasting knowledge to warn the public beforehand.

 

[winterof79]

What a screamer of a post from Kasim in the mod thread. I've asked if he will pop it in here. 

Cheers bud. 

Edited January 13, 2021 by winterof79

[Empire Of Snow]

39 minutes ago, summer blizzard said:

Met Office maps show the 0C line expanding from about 18.00 and now generate interest from about 2am onwards but for today yes, nothing to get excited about.

...

For any Yorkshire members here, which of you are over 200m asl so we can monitor your snowline dropping.

180asl (179 to be exact) here. Will report any changes from rain to sleet or snow. Transition to snow should be around 2am. It will be a nice surprise if snow starts falling before that time but seems unlikely. 

[dannyspeighty]

Im on the Chevin looking over towards Ilkley at about 170m so will try keep an eye on the snow line if one arrives Although that said the moors just look grey and wet at the moment. 

[LeeSnowFan]

3 minutes ago, Kasim Awan said:

It is possible to make a snow forecast, one has to just be aware of the uncertainties involved and communicate them. Failure to communicate and identify the risks involved imo carry more weight & potential responsibility afterwards. It's always worth giving a fair probabilistic view than remaining glued to the fence. With that in mind, the below is my post in the Mod thread I have had a request to post on here.

Yes, you effectively covered my point about the uncertainty as all the unorganized precip will do is prevent the ground environment below 200 metres (which is where there is marginality) from being conducive.

Given the projection of a well defined area of precipitation tomorrow, the outcome of some snow to lower levels producing a lowland area of snow maybe no greater than 5-25,000km^2 (up to 10% of the UK) with accumulations of 1-6cm in the favored stretch is fairly high in confidence. Of course, there are mechanisms which increase snow with altitude (orographic lift, lower temperatures, lower ground temperatures), and this means locally 20cm+ is possible for somewhere like Queensbury tomorrow. This is most favoured to occur across West Yorkshire, South Yorkshire, Notts, Derbs, into the North & East Midlands before moving towards the home counties. Even in this situation, there will be marginality on the north, south, west and eastern side of the snow area which will all result from slightly different thermodynamic mechanisms. North & east - lack of evap cooling. West -Fohen effect, lack of evap cooling. South - lack of cold air and low dew point injection from east. Defining which areas will see this is very uncertain and is down to nowcasting, however this does not take away or limit the main precip area evap cooling derived snow from verifying.

A strong consensus (70%) of weather models show this area verifying, the uncertainty is more to do with placement further south. The outcome of snow to lower levels in the Northern areas is not a certainty infact far from it however, the probabilistic forecasting method is always the way to go with consensus whilst leaving room for other possibilities which is what I've done, and you have covered here. Other outcomes include a more northerly track (some of Harmonie runs) and a more unorganized precipitation regime. However, I feel at this moment it would be unrealistic to go with 50/50 or even say "too close to call" for the precip further north at least, given the data for the triple point system which I am looking at. This does not discount a more unorganized precip area from occurring, just gives it a chance of say 25% whilst remaining aware that the higher confidence of snow for some areas (S Yorkshire, North & East Midlands) means imo a warning is valid from both an impact and likelihood perspective. Further south there is a risk of some snow too which of course will be bounded by the same spatial marginality mentioned above. Uncertainty is always the case with snow it's about doing the best one can with the data provided and forecasting knowledge to warn the public beforehand.

 

fantastic post thank you so much

[Kasim Awan]

3 minutes ago, LeeSnowFan said:

fantastic post thank you so much

No problems, I know the geography of West Yorkshire and unlike SW England & Wales the number of roads you have >300m is very high, most roads going out of the Yorkshire valleys are high. So it would be irresponsible to not properly highlight the risk. Call me unprofessional but I think the Met warning needs updating asap otherwise it's going to be another last minute call.

[winterof79]

7 minutes ago, dannyspeighty said:

Im on the Chevin looking over towards Ilkley at about 170m so will try keep an eye on the snow line if one arrives Although that said the moors just look grey and wet at the moment. 

Always a tricky drive the chevin when I first learned in the 80s

[winterof79]

2 minutes ago, Kasim Awan said:

No problems, I know the geography of West Yorkshire and unlike SW England & Wales the number of roads you have >300m is very high, most roads going out of the Yorkshire valleys are high. So it would be irresponsible to not properly highlight the risk. Call me unprofessional but I think the Met warning needs updating asap otherwise it's going to be another last minute call.

Whereabouts are you in Buxton I do a fair bit of work over that way

[Kasim Awan]

2 minutes ago, winterof79 said:

Whereabouts are you in Buxton I do a fair bit of work over that way

On the way to Flash pal.

[Scott Ingham]

17 minutes ago, Kasim Awan said:

It is possible to make a snow forecast, one has to just be aware of the uncertainties involved and communicate them. Failure to communicate and identify the risks involved imo carry more weight & potential responsibility afterwards. It's always worth giving a fair probabilistic view than remaining glued to the fence. With that in mind, the below is my post in the Mod thread I have had a request to post on here.

Yes, you effectively covered my point about the uncertainty as all the unorganized precip will do is prevent the ground environment below 200 metres (which is where there is marginality) from being conducive.

Given the projection of a well defined area of precipitation tomorrow, the outcome of some snow to lower levels producing a lowland area of snow maybe no greater than 5-25,000km^2 (up to 10% of the UK) with accumulations of 1-6cm in the favored stretch is fairly high in confidence. Of course, there are mechanisms which increase snow with altitude (orographic lift, lower temperatures, lower ground temperatures), and this means locally 20cm+ is possible for somewhere like Queensbury tomorrow. This is most favoured to occur across West Yorkshire, South Yorkshire, Notts, Derbs, into the North & East Midlands before moving towards the home counties. Even in this situation, there will be marginality on the north, south, west and eastern side of the snow area which will all result from slightly different thermodynamic mechanisms. North & east - lack of evap cooling. West -Fohen effect, lack of evap cooling. South - lack of cold air and low dew point injection from east. Defining which areas will see this is very uncertain and is down to nowcasting, however this does not take away or limit the main precip area evap cooling derived snow from verifying.

A strong consensus (70%) of weather models show this area verifying, the uncertainty is more to do with placement further south. The outcome of snow to lower levels in the Northern areas is not a certainty infact far from it however, the probabilistic forecasting method is always the way to go with consensus whilst leaving room for other possibilities which is what I've done, and you have covered here. Other outcomes include a more northerly track (some of Harmonie runs) and a more unorganized precipitation regime. However, I feel at this moment it would be unrealistic to go with 50/50 or even say "too close to call" for the precip further north at least, given the data for the triple point system which I am looking at. This does not discount a more unorganized precip area from occurring, just gives it a chance of say 25% whilst remaining aware that the higher confidence of snow for some areas (S Yorkshire, North & East Midlands) means imo a warning is valid from both an impact and likelihood perspective. Further south there is a risk of some snow too which of course will be bounded by the same spatial marginality mentioned above. Uncertainty is always the case with snow it's about doing the best one can with the data provided and forecasting knowledge to warn the public beforehand.

 

Brilliant as always.

Highlights the complexities involved.

Get yourself in an area of heavy prolonged precipitation and low levels will hit 1-6cm quite easily. 

Watch the radar after midnight if your in an area like this curtain twitch.

No one should certainly be saying high ground only as its not mo where near if anything odds favour both high and low without it being certain dependant on the things kasim has wrote!!

[winterof79]

7 minutes ago, Kasim Awan said:

On the way to Flash pal.

Just done a stone job at Brandside bit hilly. 

[Harsh Climate]

I can see why the met office warning for today/ tonight is in the area where it is and parts of scotland/north east england are in the orange area.

A quick glance at the dew points and uppers tomorrow really does not look conductive for snow fall south of yorkshire, south yorkshire may just be alright later tomorrow morning.

I think similar areas to last friday should probably be best primed for snowfall, although a bit more marginal this time around. In our region I would expect biggest low lying totals in north/west yorkshire and sweet spot being somehwere in the yorkshire dales, probably geenhow hill. Obviously north york moors could get a pasting. 

Can't see more than 1 or 2 cm low ground south of yorkshire.

[Cheese Rice]

It's pretty clear looking at the models that there is going to be a notable rain shadow east of the pennines with the bulk of the heavier precipitation skirting the south and west of the region. 

Met office high resolution model highlights this nicely. 

Along with the GFS 

It's all well and good highlighting the freezing level dropping under heavier precipitation and that will still happen, but to expect lying snow at sea level is unlikely without any meaningful intensity. 

 

[Cheese Rice]

17 minutes ago, Scott Ingham said:

No one should certainly be saying high ground only as its not mo where near if anything odds favour both high and low without it being certain dependant on the things kasim has wrote!!

Just to clarify your implying that it could be rain on high ground and at the bottom of the hill under heavier ppn it would be snowing? I don't see how in any situation the odds would favour low ground for snowfall, it would always favour high ground first. 

Edited January 13, 2021 by Cheese Rice

[Scott Ingham]

3 minutes ago, Cheese Rice said:

It's pretty clear looking at the models that there is going to be a notable rain shadow east of the pennines with the bulk of the heavier precipitation skirting the south and west of the region. 

Met office high resolution model highlights this nicely. 

Along with the GFS 

It's all well and good highlighting the freezing level dropping under heavier precipitation and that will still happen, but to expect lying snow at sea level is unlikely without any meaningful intensity. 

 

It needs to be 3mm per hour for 1 hour for evap cooling (the dark blue) this is definitely forecast