Scotland Regional Discussion - January Part 2

[howham]

Temp 3.2C, dp -2.6C and sunny. Can see some bubbly clouds to the east though...

[LomondSnowstorm]

halfway across the country but will they be snow or is the precipitation being overegged? perhaps not with the trough feature on the fax could just mean decent precipitation and greater inland penetration.....but will it be snaw

Precipitation off the North Sea is rarely overestimated but very often underestimated, so I wouldn't worry about that. The convection off the east coast at the moment looks pretty vigorous. Most levels look like ticking the snow box - the uppers, the 'lower' uppers, the freezing level, the Theta-E (needs to be below 15C and is progged at 12C), the dewpoint for most after 9pm http://expert-images.weatheronline.co.uk/daten/proficharts/en/nae/2012/01/29/basis06/ukuk/taup/12013000_2906.gif

But there is corridor of marginality, probably Fife westwards, where it will be iffy even after midnight. Now if the showers are heavy enough we could still see snow - the dewpoint never dropped below about 0.8C on the 17th December 2009 and we had about 3 inches then, but it could be an issue. If I were the MO I'd be putting out at least a yellow warning to cover their backs - given the history I'd say we have 50% chance of >2inches of snow somewhere, probably around Angus/East Perthshire.

[Scottish-Irish Skier]

- given the history I'd say we have 50% chance of >2inches of snow somewhere, probably around Angus/East Perthshire.

I'm sure it was by accident that you missed out 'and Eastern Scottish Borders'....

[A Winter's Tale]

GFS 6z looks say yes to easterly but a dry one for us and our fellow southeners. In fact, there's been an upgrade in the easterly flow starting today and until Tuesday/Wednesday as the -6C uppers are over us for much of the time as the east has a decent easterly flow. For those living in the east, expect to have more snow in the coming days that what London is likely to experience next week judging by GFS 6z so far.

[edo]

Precipitation off the North Sea is rarely overestimated but very often underestimated, so I wouldn't worry about that. The convection off the east coast at the moment looks pretty vigorous. Most levels look like ticking the snow box - the uppers, the 'lower' uppers, the freezing level, the Theta-E (needs to be below 15C and is progged at 12C), the dewpoint for most after 9pm http://expert-images...013000_2906.gif

But there is corridor of marginality, probably Fife westwards, where it will be iffy even after midnight. Now if the showers are heavy enough we could still see snow - the dewpoint never dropped below about 0.8C on the 17th December 2009 and we had about 3 inches then, but it could be an issue. If I were the MO I'd be putting out at least a yellow warning to cover their backs - given the history I'd say we have 50% chance of >2inches of snow somewhere, probably around Angus/East Perthshire.

Precipitation off the North Sea is rarely overestimated but very often underestimated, so I wouldn't worry about that. The convection off the east coast at the moment looks pretty vigorous. Most levels look like ticking the snow box - the uppers, the 'lower' uppers, the freezing level, the Theta-E (needs to be below 15C and is progged at 12C), the dewpoint for most after 9pm http://expert-images...013000_2906.gif

But there is corridor of marginality, probably Fife westwards, where it will be iffy even after midnight. Now if the showers are heavy enough we could still see snow - the dewpoint never dropped below about 0.8C on the 17th December 2009 and we had about 3 inches then, but it could be an issue. If I were the MO I'd be putting out at least a yellow warning to cover their backs - given the history I'd say we have 50% chance of >2inches of snow somewhere, probably around Angus/East Perthshire.

cheers LS I like the phrase "a corridor of uncertainty" kinda sums up winter so far...... are there charts for the Theta-E or are you doing the calculaton yourself? I read up a little bit on it there as It was yet another new factor for my brain

[A Winter's Tale]

The flow over Scotland looks stronger than that further south? Borders, Lothians, Fife, Angus, Aberdeenshire and E Highlands would enjoy some snow from that.

[LomondSnowstorm]

http://cdn.nwstatic.co.uk/gfsimages/gfs.20120129/06/138/h500slp.png

6Z looks fine, marginally stronger flow than yesterday. Certainly doubt it'd be dry given the current southeasterly doesn't look dry http://cdn.nwstatic.co.uk/gfsimages/gfs.20120129/06/21/h500slp.png

All model output very good for cold, upstream signals and the strat. supportive of height rises to Greenland next. Either via a mid latitude high with the PV dropping out of Scandi or from an undercutting low (or both perhaps) could be very, very snowy for Scotland, all parts of Scotland, perhaps even Rockall and St Kilda.

[LomondSnowstorm]

cheers LS I like the phrase "a corridor of uncertainty" kinda sums up winter so far...... are there charts for the Theta-E or are you doing the calculaton yourself? I read up a little bit on it there as It was yet another new factor for my brain

http://expert-images...012921_2906.gif

Another factor is wet bulb T <2C http://expert-images...013000_2906.gif

Pas de probleme!

edit: 6Z must now be getting a reputation as the 'Scottish run' - yesterday's heavily favoured us for snow as does, it appears, todays.

Edited January 29, 2012 by LomondSnowstorm

[LomondSnowstorm]

Ok, final update before I switch to revision. NMM increases extent and intensity of precipitation, more in line with the thoughts I posted above. The core of the precipitation is almost destined to be Angus/South Aberdeenshire simply because of the wind direction being so southerly, but that doesn't mean it'll be confined to there. Convergence lines hint that Eastern Borders and East Lothian might do a bit better through the day tomorrow, and -8C uppers are still going to be hanging about by then too...

[lorenzo]

This morning Sat rep is good at explaining events into this evening, arrows always help !

Cleaner image from Norway Met shows the jet carving through.

Watching the animation you can see the SC Sheets spilling off the landshelf, very slack flow. Have enjoyed watching that block on this Sat feed over the last couple of days it really isn't for shifting...

Edited January 29, 2012 by lorenzo

[A Winter's Tale]

GFS 6z was pretty good with a slightly better flow. And there was hints of the Scandi Hi ridging towards Iceland and Greenland. The GFS over estimates the jet and blows the link away and initially we see some large snowfalls. The Scandi Hi lasts throughout but I believe that the GFS was overestimating the jet and underestimating the high.

[Hiya]

Is anyone else not worried that the last 8 runs of nice charts have all been cold outliers on the gfs? Potential for some massive dispointment down in the south-east.

[Scottish-Irish Skier]

Showers incoming from Aberdeen up to Peterhead.....

Is anyone else not worried that the last 8 runs of nice charts have all been cold outliers on the gfs? Potential for some massive dispointment down in the south-east.

I've got to fly via heathrow in a couple of weeks. Last thing I need is 1 cm of snow and a light frost down there. Will be chaos!

[Hawesy]

+4.8c currently in a very light SEly breeze. Fair skies.

[howham]

First shower arrives... Rain.

[Zerouali lives]

Just about to say - I went outside before the showers arrived and experience told me they would be rain - it's not nearly cold enough out there for snow at the moment, definitely a warm sea influence today.

Surprised its rain at Oldmeldrum though

[howham]

4.0C here.

[Zerouali lives]

The real cold won't arrive until after midweek anyway, not sure how well Aberdeen will fare though, Westhill will do better where I work

[lorenzo]

Here are a couple of NMM predictions for today. Colder air arriving later this afternoon into the evening, hopefully the mucky drizzle turns out good later.

[Guest]

First photo is my parents' front garden this morning, still with some patchy snow from Thursday afternoon. Just shows the shelter that trees give from the elements, there is very little snow left anywhere else locally below 300-400m...this is at just under 150m:

A couple of random photos from recent travels...any guesses where these were taken? First one is easy and was taken on Friday morning, I will be stunned if anyone gets the second one:

[Northern Strath]

Been out doing the fire wood this morning. Was thinking how dark it can be here among the trees. Every winter nature does me a turn and brings enough snow to snap some big branches and let more light in, not had that this winter yet. Being from the heelands im pasty enough as it is so can we please get a northerly or north easterly flow at some point in this up-coming cold spell? I need more vitamin D or im going to end up looking like this

Currently 2.2C

[edo]

cheers LS enjoy your revision....hope the kids appreciate it.....assuming yer a teacher and not still at school right off to have a cycle still trying to lose the exra stone santa brought me for xmas.....laters Peeps

[Scottish-Irish Skier]

That drizzley warm front has begun to obviously retreat back westwards over the past hour or so. Showers pushing in from the east; ok, rain for now but could be wintry as the day progresses.

[Scottish-Irish Skier]

A couple of random photos from recent travels...any guesses where these were taken? First one is easy and was taken on Friday morning, I will be stunned if anyone gets the second one:

First one: The hot and cold filled rolls van is missing. Welcome home. Wave when you pass me.

No idea on the second.

Edited January 29, 2012 by scottish skier

[BleakMidwinter]

. Being from the heelands im pasty enough as it is so can we please get a northerly or north easterly flow at some point in this up-coming cold spell? I need more vitamin D or im going to end up looking like this

You know the traditional Scots diet, before the Industrial Revolution chained us all to wheat-flour, was abnormally high in Vitamin D?

Get your grannie's cookbooks out and get stuck into the oily fish, oats and Kale!

Still dry here in Edinburgh... I'm now just waiting... til dark, when it'll be over to Lamp Post Watch.

Edited January 29, 2012 by BleakMidwinter