South West and Central Southern England Regional Weather Discussion 08 Feb 2021 Onward

[Wiltshireweatherwatcher]

22 minutes ago, wiltshire weather said:

Still nothing this far east but I live in hope!

Met office have updated their long range outlook and pretty much have removed talk of cold until beginning of March, and even that has been toned down from before! Just a small chance for cold returning next weekend still so I'll hold on to that  

Thursday 18 Feb - Saturday 27 Feb

This period begins with temperatures much milder than recent, with temperatures returning to around or slightly above average for most, with some mild spells being seen in the south and west. There remains a small chance to return to wider colder conditions for the weekend, but the likelihood is low. The UK looks to be split broadly northwest to southeast in terms of the general weather types with the west and northwest more likely to see wet conditions with strong winds at times, and the east and south east more likely to remain drier, fine, and settled. Under these settled conditions we may see temperatures falling back to average or below, and with increased incidence of overnight frost and fog. Any snowfall most likely becoming restricted to the Scottish mountains.

Updated: 16:00 (UTC) on Sat 13 Feb 2021

Saturday 27 Feb - Saturday 13 Mar

Into late February there is a signal for higher than average pressure to sit close to or over the UK, with likely drier and more settled conditions prevailing. Temperatures likely to return back to around, if not below, average with a greater chance of cold spells during this time, bringing an increased threat of widespread frost and a very uncertain chance of snow. Towards mid-March there are signs of returning to a more unsettled period, with milder interludes more likely once more.

Updated: 16:00 (UTC) on Sat 13 Feb 2021

That’s been well watered down and backs up what the models are now showing.

Interesting it’s taken a few days before the Met lessened down the chance of an easterly set up reestablishing itself. 

I think that’s pretty much it for our part of the world for this winter. Any further snowfall likely to be transient or confined to higher ground.

 

[offerman]

I have a question about evaporative snow.

how does the snow reach the ground in places like Norway and Sweden where they will have extremely low Due points and dry air as in Germany too? 
is it because we are an island or something? 
 

I thought having a large landmass would make it harder for snow to reach the ground and actually generates now because it’s just land where is the sea can provide moisture for the snow that theoretically you would think would come more inland not always fizzle out from the west or the east. 

[kumquat]

Aaaaannnnnddddd it's sleet. More rain and ice pellets.

[CheesepuffScott]

A few flurries in the wind.. currently 0.1°C down from 1.7°C earlier

[kumquat]

3 minutes ago, offerman said:

I have a question about evaporative snow.

how does the snow reach the ground in places like Norway and Sweden where they will have extremely low Due points and dry air as in Germany too? 
is it because we are an island or something? 
 

I thought having a large landmass would make it harder for snow to reach the ground and actually generates now because it’s just land where is the sea can provide moisture for the snow that theoretically you would think would come more inland not always fizzle out from the west or the east. 

There's a good conversation here:

 

But it's a very difficult conversation to be had when discussing it over a variable geographic region.

[Frosty_wsm]

Ah well I guess there's one bonus to not having lying snow, we don't end up all depressed seeing it melting & getting washed away by the rain! 

BBC weather just now talking of possible 14c/15c by the end of the week, the sounds very appealing I must admit. 

Edited February 13, 2021 by Smartie

[CheesepuffScott]

Got ice pellets falling now, quite noticeable as it is tapping on the foliage and ground

[nettie]

Just looked out window and noticed there is light snow falling .  Completely surprised as I wasn't expecting anything.

[Wiltshireweatherwatcher]

Just now, CheesepuffScott said:

Got ice pellets falling now, quite noticeable as it is tapping on the foliage and ground

Yup that’s what we’ve got here tapping away on the windows.

[kumquat]

41 minutes ago, Wiltshireweatherwatcher said:

That’s been well watered down and backs up what the models are now showing.

Interesting it’s taken a few days before the Met lessened down the chance of an easterly set up reestablishing itself. 

I think that’s pretty much it for our part of the world for this winter. Any further snowfall likely to be transient or confined to higher ground.

 

I wish we could see their models. To me, it's the missing link between us amateurs and the "professionals." I understand monetizing proprietary code but there's no transparency.

Edited February 13, 2021 by kumquat

[wiltshire weather]

I'm still hoping to at least get a few flakes this afternoon so I can say we've had 4 consecutive weekends with falling snow!

Either way I would say that this winter has felt a bit more 'wintry like' than recent ones, so I'm ok with that. 

I've enjoyed this cold spell even without a decent snow event. If I can't have cold and snow in winter then cold, dry and frosty is the next best thing for me!

I'm pretty sure the models are all going to be showing the same sort of evolution over the next few days with high pressure centred somewhere to the south east of us with temperatures above average, during the day at least.

However, looking at the current NOAAA 500MB anomaly charts for the 6-14 day period, I think there is a possibility the high pressure will be centred further north, maybe even right over us. With the latest Meto update it will be interesting to see if the NOAA charts change to reflect this over the next few days or if they will continue to hold firm, in which case I would expect the operational models to start changing their outlook early next week.

Edit: How the GFS12z evolves after next weekend up until the Thurs at least is what I was expecting to see based on the NOAA charts.

Edited February 13, 2021 by wiltshire weather
Updated after GFS 12z

[kumquat]

Rain pepping up in the Channel lol. Couldn't make it up. Good old warm(ish), dense  RAIN

[Bristawl Si]

Sleet here now

[Bristawl Si]

Snow graupels now and for first time today it is settling on roofs and even our road. Has air temp dropped?

[noonoo418]

A last hurrah.... Final flakes of the winter? 

[MP-R]

1 hour ago, Smartie said:

Ah well I guess there's one bonus to not having lying snow, we don't end up all depressed seeing it melting & getting washed away by the rain! 

BBC weather just now talking of possible 14c/15c by the end of the week, the sounds very appealing I must admit. 

Bring it on - especially if it's sunny! 

[John88B]

Light snow in Yate. After a cold week, that at the start was looking promising, we finally have the lightest of dustings.

[Blizzardof82]

Current temp -0.3c with Dew point of -3.7c, ice pellets falling steady and given the road a sugar coating.

[Singularity]

The thing about the dew point is that it’s not just about the dew point... it’s about where it is relative to the air temp (dry bulb temp).

On the continent they often see subzero dew points but can also see subzero air temps more readily, so it may be -3 with a -4 dew point, in which case the relative humidity is high.

That’s the key measure - relative humidity. While subzero dew point air tends to be drier than higher dew point air, if the RH is high then snow can still occur in considerable amounts. 

Today the dry bulb temps have been 0-2 while dew points have been -6 to -4, giving RH of 50-60%. That’s hard going for snowflakes which take a while to reach the surface. Ice pellets fall faster so may be seen more readily - as has been the case in some spots this afternoon.

Rain also falls faster, hence we don’t tend to notice the dry air effect as much with that unless the surface air is seriously dry or air temps are high and air quite dry.

[noggin]

A very, very light dusting here.

[*Stormforce~beka*]

2 hours ago, Man Without Beard said:

Is there a problem with the radar? Showing widespread snow even here, but reality is completely dry!

Yes! And even that triangle of doom was wrong

[Jet Streak]

400ft up on the Purbeck hills this afternoon between Durlston and Dancing Ledge,  dry nothing falling from the sky, bitter wind still some ice pockets thawing out now!! 

[offerman]

35 minutes ago, Singularity said:

The thing about the dew point is that it’s not just about the dew point... it’s about where it is relative to the air temp (dry bulb temp).

On the continent they often see subzero dew points but can also see subzero air temps more readily, so it may be -3 with a -4 dew point, in which case the relative humidity is high.

That’s the key measure - relative humidity. While subzero dew point air tends to be drier than higher dew point air, if the RH is high then snow can still occur in considerable amounts. 

Today the dry bulb temps have been 0-2 while dew points have been -6 to -4, giving RH of 50-60%. That’s hard going for snowflakes which take a while to reach the surface. Ice pellets fall faster so may be seen more readily - as has been the case in some spots this afternoon.

Rain also falls faster, hence we don’t tend to notice the dry air effect as much with that unless the surface air is seriously dry or air temps are high and air quite dry.

Brilliant explanation , Thank you for that and also to the earlier poster who posted a link to explanations about all this too on the 2010 thread . 

[AWD]

Here come the much milder temperatures. 

[Frosty hollows]

Radar would have you believe it's snowing here- it lies! 3rd ice day of the week which has brought us loads of skating opportunity on the receding flood waters!