Scotland - Weather Chat

[frogesque]

Report form my iceometer today:

 

 

Waterfall at the back is still flowing but very iced up, bird  jacuzzi in the middle is still flowing but most of the pond is well iced over. Frost will be starting to get into the ground now so if we do get snow it should lie nae problem.

[snowy owl]

Ground Rock solid. Still sheet ice and some shaded snow preserved in the cold temps. Actually much sunnier today than was forecast.

Some very intriguing signs from the trop and models for something potentially Colder again by next weekend. Although it's not going to be all that "warm" before then either.

Actually liking the lack of mud.

Here's to more fun watching the weather story unfold

Edited January 21, 2015 by snowy owl

[November13]

Snowy I think you are correct. Friday is about average to mild,Saturday is colder, with snow potential. Sunday looks like the hairdryer day, and then it's back to cool with cold spells. It's not a disaster by any means.

[Hairy Celt]

Temp's not been above 0C since Sunday afternoon near Bettyhill, the ground's hard as nails and surface water is disappearing. Well, more like undergoing phase change... which makes me wonder, can snow and ice turn straight to gas without being liquid?  I've seen a lot of snow disappear the last couple of days with subzero temps, occasional weak sun and a steady breeze.

[howham]

I grew up in Kemnay and we had our fair share of snow.

Yes it is Dyce so a little more elevated than those in the other cities. It used to be Craibstone until relatively recently so even more elevated then.

My cousin lived in Kemnay until a couple of years ago and can confirm that it can be a really snowy place compared with Aberdeen itself.

[Northernlights]

Temp's not been above 0C since Sunday afternoon near Bettyhill, the ground's hard as nails and surface water is disappearing. Well, more like undergoing phase change... which makes me wonder, can snow and ice turn straight to gas without being liquid?  I've seen a lot of snow disappear the last couple of days with subzero temps, occasional weak sun and a steady breeze.

Yes it can its called sublimation seems to occur in late winter more often with the combination of very low temperatures and very dry air. Its happening here also.

Edited January 21, 2015 by Northernlights

[moffatross]

... can snow and ice turn straight to gas without being liquid?  I've seen a lot of snow disappear the last couple of days with subzero temps, occasional weak sun and a steady breeze.

Yep, sublimation leads to quite rapid loss in low dew points.

 

http://en.wikipedia.org/wiki/Sublimation_(phase_transition)

[Hairy Celt]

Thanks for the notes on sublimation. I thought that was something that happened in the Culture 

 

More photos of the solid phase then:

 

 

Looks like another subzero day and night coming for here - anyone else getting successive ice days? I guess here we're 'favoured' due to the air coming over all the snow of the north Highlands, but there must be more inland places not getting above zero?

 

edit - I seem to have fkd up the fkduploader

Edited January 22, 2015 by Hairy Celt

[Norrance]

The temperature has risen a couple of degrees in the last hour or two here as cloud has drifted in from the North Sea on the light SE breeze. No precipitation here though radar shows some to my East and my daughter tells me that it is snowing lightly in Forfar just now.

1C with cloud cover now.

[Northernlights]

We have had two ice days on the trot now and we may get third one tomorrow. Currently -3.5c.

[Scottish-Irish Skier]

can snow and ice turn straight to gas without being liquid?

 

Sure. It's called sublimation.

 

You'd need air passing over snaw/ice that had a water content lower than it should be in equilibrium with said snaw / ice at specific pressure and temperature.

 

If so, snaw / ice will sublime direct to the vapour phase  as it tries to reach equilibrium by saturating the air.

 

Causes evaporative cooling# as the phase transition is endothermic. Will suck the heat ('latent heat' of vapourisation) right out of the ground and harden the frost as a result.

 

CO2 dry ice is a classic example. At room P, it 'melts' directly to gaseous CO2.

 

EDIT

 

 

Yep, sublimation leads to quite rapid loss in low dew points.

 

http://en.wikipedia.org/wiki/Sublimation_(phase_transition)

 

Aye. Low dew point = air undersaturated with water. Hence higher snaw / ice evaporation rates.

 

Can cause the soil to become like concrete as moisture in it is more shielded from evaporation due to burial but yet it provides the heat (soil cools) for surface snaw/ice to sublime.

 

 

 

#this so does not happen during heavy snow / rain to snow events.

Edited January 21, 2015 by scottish skier

[Hairy Celt]

It's a bit counterintuitive though, isn't it? One of the first bit of P4 physics is the transitions between ice, water and steam, with the tricky bit about steam not really being gas. So then young Master SS pipes up, loud and clear, 'but Miss, in a closed system-' 'SS, I've told you before, we learn by aggregating knowledge, year by year, and you won't learn the systems approach until Higher Physics...'

 

Yeah, concrete - I stumbled over a tuft of grass earlier that was doing a good impression of a well-decorated breeze block. Oof.

Edited January 21, 2015 by Hairy Celt

[Scottish-Irish Skier]

It's a bit counterintuitive though, isn't it? One of the first bit of P4 physics is the transitions between ice, water and steam, with the tricky bit about steam not really being gas. So then young Master SS pipes up, loud and clear, 'but Miss, in a closed system-' 'SS, I've told you before, we learn by aggregating knowledge, year by year, and you won't learn the systems approach until Higher Physics...'

 

Ha. Aye.

 

Well, if you can see it, it's not a gas, but droplets of liquid is the general rule of thumb.

 

'Steam' is a grey area term. Boiled water is a gas. The stuff you can see in the bathroom when having a shower is not - it is condensed water vapour (gas condensed to liquid droplets in the air).

 

I was not quite as detailed... Technically, water does not 'see' the air (oxygen nitrogen) at atmospheric conditions. Water does it's own thing; acts like the air isn't there. The air is not saturated nor unsaturated with water; the 'space above the ice snaw' is or is not - with gaseous water. So, if snaw / ice detects the space next to it doesn't have snaw/ice or enough gaseous water, it will evaporate to correct the balance. Easier to talk about 'air' though. The 'dew point' in terms of weather actually has really nothing to do with air - it is equilibrium between liquid/solid water and its gas phase...

 

Don't get me started on latent cooling (e.g. when heavy snaw drops the temperature to zero).

 

---------

 

Frost starting again here.

 

Still got me cm or two or crust snaw. Thankfully not cold enough to freeze my screenwash again past couple of morns.

Edited January 21, 2015 by scottish skier

[edo]

So is keeping snow not hard enough that now we can lose it through sublimation..... HTF lol

[NorthernRab]

Freezing here, just hit -8'C!

[Cheggers]

Grey and just below freezing here, snaw just about in tact on untouched surfaces around the garden, but not going to last once we creep above zero by Friday.

[snowy owl]

Blooming chilly again tonight. At least having some cold and frosts has felt more like winter, even though here in the east we've had v little snow.

[Hairy Celt]

Freezing here, just hit -8'C!

 

Quickly dropped to -5C at dusk but then the cloud came back (not before a sight of the thinnest sliver of a setting new moon) so now back up to a balmy -1C. Nasty wind chill effect though.

 

MT veterans are weighing up the chances of an other cold spell in the not too distant future so this seems like a half decent - if not very snowy - winter after all.  Just been attending to some storm-damaged trees for next winter's fuel too...

[Hawesy]

Evening all,

+3c here on the Fife Riviera. More nice than ice day since temps have been above zero throughout.

Models continue to be of interest in the short and longer term. Okay so the chance of getting snow on the ground here seems as slim as ever but I take a broader view of what's on offer!

[GrangemouthBairn]

Had been hovering around 0.4C since 4pm but has dropped to -0.4C in the last hour. Cloud looking as if it might be breaking but it's hard to see because it's dark outside!

[Northernlights]

Coldest morning of the winter here at -8c. Starry skies and frosted windows. Not bad "A Cold Hearted Winter" Pretty much spot on in my locality.

Edited January 22, 2015 by Northernlights

[Hawesy]

Morning all,

+2c here in Crail, no air frost last night. -1c at Leuchars.

-11c at Aviemore @ 7am.

[NorthernRab]

Morning! -7.3'C here after an overnight low of -8.5'C making it the coldest night of the winter. Not a breath of wind and cloud to the south blocking out the morning sun. Needless to say after so many ice days that the ground is bone dry away from the remaining snow and frozen solid.

[blitzen]

Morning.  0.9c/0.5c/SSW overnight only -0.5c here.   Grey and a bit misty.

Really hoping this morning's ECM operational is on the money.   This would explain Weatherbell's comment on the 15th that USA and Europe would experience brutal cold at the same time at the beginning of February?  ECM has the  Canadian lobe of the vortex being cut off and dropping into the states therefore allowing a  low to engage with the Euro trough and eventually create  an absolute beast of a northerly.   It's 10 days away, which is the right timeframe but  of course the GFS isn't interested.   Has to be something like this though to involve both areas.   Their confidence in their statement back then has really bugged me and I am certainly following developments with interest.   We shall see.

Edited January 22, 2015 by Blitzen

[GrangemouthBairn]

Was -1.2 when I got up at 8.15. My weather station only gives the minimum temperature since it started working so all I know is that it wasn't colder than last night which puts an end to the run of 4 consecutive nights of breaking my record. Similarly cloudy and misty to yesterday morning but with some more breaks