Scotland/Alba weather discussion - Jan 2021 onwards

[Norrance]

My ws says snow as dies my heart. Head and gut say sleet though. Today a rarer weather type for me earlier on. Freezing fog. Mist patches hanging around all day in low parts.

Had to nip up to Aberdeen this afternoon for a wee job. Frost lingering in the shade all the way up and remnants of last weeks snow still about from Dundee to just past Forfar. 
Now cloudy at 1C.

[Benvironment]

Just now, Norrance said:

My ws says snow as dies my heart. Head and gut say sleet though. Today a rarer weather type for me earlier on. Freezing fog. Mist patches hanging around all day in low parts.

 

Yep it was pretty spectacular from the Bathgate Hills today. A very settled layer of fog in the Forth Valley, with the Ochils and the three Forth bridges poking up through  Eerily calm.

[scottishandy]

3 minutes ago, Norrance said:

My ws says snow as dies my heart. Head and gut say sleet though. Today a rarer weather type for me earlier on. Freezing fog. Mist patches hanging around all day in low parts.

Had to nip up to Aberdeen this afternoon for a wee job. Frost lingering in the shade all the way up and remnants of last weeks snow still about from Dundee to just past Forfar. 
Now cloudy at 1C.

Above the mist was the place to be today, really quite pleasant up there. 

 

[Sceptical]

Cold start this morning, -6C heading through Torphins on Deeside. This has been an impressive cold spell that started mid November.

[Ross B]

44 minutes ago, Ross B said:

Sleet falling here too, promising for later... 

The temperature is continuing to drop and its almost full on snow 

[Hawesy]

50 minutes ago, Norrance said:

My ws says snow as dies my heart. Head and gut say sleet though. Today a rarer weather type for me earlier on. Freezing fog. Mist patches hanging around all day in low parts.

Had to nip up to Aberdeen this afternoon for a wee job. Frost lingering in the shade all the way up and remnants of last weeks snow still about from Dundee to just past Forfar. 
Now cloudy at 1C.

Great view driving into St Andrews today. Fog and mist lying over the Tay and then the Angus and Perthshire mountains gleaming solid white beyond in the sun. 

[JamesM]

15 minutes ago, Ross B said:

The temperature is continuing to drop and its almost full on snow 

Whereabouts are you in terms of “south Glasgow?” I am around 8 miles south west of Barrhead, at 130 metres, and its full on rain here. Not even a hint of sleet. 

[asjmcguire]

6 minutes ago, CatchMyDrift said:

I'm told via my Facebook weather page that it's snow in Peebles, Selkirk and up the Megget Valley and rain  or sleet everywhere else in the Borders.

Can confirm, definitely rain in this part of the Borders....

[Bullseye]

16 minutes ago, Ross B said:

The temperature is continuing to drop and its almost full on snow 

Looked at this post and decided to have a wee look on the window, can confirm now turned to light snow here from sleet earlier. Interesting and promising I hope anyway. @Stormeh may also have snow as he isn't far away from me based on previously snaw 

[Penicuikblizzard]

My lamppost says rain ️ 

[Ross B]

3 minutes ago, JamesM said:

Whereabouts are you in terms of “south Glasgow?” I am around 8 miles south west of Barrhead, at 130 metres, and its full on rain here. Not even a hint of sleet.

I'm at the edge of Newton Mearns. The lamppost confirms full on snow now. 

[Kayemill]

It was snowing here when I got home but now it’s just a bit of a mix. 

[Ross B]

6 minutes ago, JamesM said:

Whereabouts are you in terms of “south Glasgow?” I am around 8 miles south west of Barrhead, at 130 metres, and its full on rain here. Not even a hint of sleet. 

Just to show how marginal it is, if you look at the traffic Scotland weather stations it's 2.1c at Lochwinnoch but 0.7c near Darnley on the M77.

[Cheggers]

Can confirm as expected rain here

[Penicuikblizzard]

BBC ramping up the snow tomorrow night, Eastern Scotland 5-10cm on low ground and 20-30cm on high ground. 30-40cm on high ground central and Northern Scotland

[Stormeh]

Oh snaw!

[Penicuikblizzard]

My lamppost has updated to sleet/wet snow lol

Edited January 19, 2021 by Penicuikblizzard

[101_North]

My lamp post was flickering a bit just then.  Not sure it can be arsed watching the sleet get heavier either! 

[JamesM]

17 minutes ago, Ross B said:

I'm at the edge of Newton Mearns. The lamppost confirms full on snow now. 

My father-in-law is in the Mearns and does better for snow in marginal events than we do here, despite him being at a lower level. It’s odd. I am sure there is a detailed technical reason for it! 

[Geedawg]

Getting lighter here now. But more than i expected today so far!

[shuggee]

Still wet sleet here at 0.6°C. Pouring down under the yellow radar. 

[snowidea]

Rain here  

[WhiteXmas]

31 minutes ago, Ross B said:

Just to show how marginal it is, if you look at the traffic Scotland weather stations it's 2.1c at Lochwinnoch but 0.7c near Darnley on the M77.

I suspect things will become less marginal as the hours go past. It seems to me like we have a really good potential setup here for many

[Scottish-Irish Skier]

#unexpectedsnaw

You can see the remains of the snawman fae last week.

Edited January 19, 2021 by Scottish-Irish Skier

[LomondSnowstorm]

The ECMWF is coming out and again looks pretty reasonable for snow potential. One indicator that may be useful from their page is the 925hPa temperature - while I've previously used the 950hPa 0C level from the Euro4 for example as a decent indicator of where snow is likely the low surface pressure means 0C and 925 hPa is probably good enough in this setup to highlight where we're likely to see proper snow.

For tonight, this is what we have:

And the precipitation for the same timescale:

Comparing with the FAX charts from earlier:

 

Basically, the southern edge of the warm front that's currently edging northwards towards us is the dividing line between snow to low levels (well 50m or so and a bit inland at best) and rain. The other factor that's going to limit snow potential further east is the surface wind:

 

Dewpoints are likely to rise just a bit too much for snow in most of eastern Scotland even if you do get a bit of intensity, so you'll need a bit of elevation here for anything much tonight. Here's a comparison of the NMM forecast skew-ts for midnight tonight to illustrate, between North Lanarkshire and Fife:

 

While this isn't a massive difference on the face of it that 70m extra on the freezing level and slightly more 'stable' layer near the surface compared to the one on the left is probably enough to make a difference.

 

Comparing for the key timeframe tomorrow night, at midnight, and we can see that it's very finely balanced at the 925hPa level on the ECM:

There's a few factors impacting here - firstly the upper warm sector associated with the low, with the 850hPa 0C line not too far off the coast:

This is not too likely to impact away from the eastern Borders and coastal Aberdeenshire but because of the uncertainty over the track of the low any westward correction could lead to rainfall, most likely freezing rain, even to higher levels in the east.

There will also be the coastal modification at the surface, both in the northeast with the northerlies and potentially towards western coasts. This will depend on the shape of the low, which has varied a bit, as a more easterly flow would introduce additional areas of marginality on top of the upper warm sector.

In general, though, surface temperatures and freezing levels look reasonable enough on the NMM at least, sub 500m away from the northeast:

and surface temperatures around 1C on the ECMWF:

I'll do another post on the UKV, which I see has just updated, and precipitation totals later on, but I just wanted to give an overview of what to look out for in the next day or two from a marginality perspective.

 

I think it's starting to turn sleety here which makes sense with reports of temperature of 0C in Airdrie but primarily just wet for now - I wouldn't be surprised to end up with a slight covering by around midnight though.