Scotland Regional Discussion - January Part 2

[Cheggers]

Aye, looking very tasty.

In the meantime, might need me winter tyres up soutra the morn...

What's the chance of it just being rain like the last few?

LS looking forward to your summary later, imagine the MT is in meltdown mode.

[Scottish-Irish Skier]

, imagine the MT is in meltdown mode.

Ok. I'm going in. Wish me luck....

[lorenzo]

Hazmat suit not required in MT this evening, all is an oasis of cold courtesy of the GFS delivering a monster 12z and the UKMO seemingly coming on line, going to be an interesting Fax update later this evening.

Some of the ensemble runs for GFS are straight into the deep freeze for the start of February, very encouraging. Now begin the countdown to 96-72-48... still on a knife edge for how quick the evolution will occur.

Much to be positive about tonight, hope the 18z continues the theme.

[Hairy Celt]

Cheggers, tried to PM you and then saw your note so I'll just have to put this in public.

To anyone considering having a vasectomy! Don't do it unless it's vital that your partner doesn't get pregnant and there are no other options. This is because there is a much higher risk of post-op complications than are commonly acknowledged by MDs, mostly quite harmless in themselves but both poorly understood and often painful. Do some research online 'post vasectomy pain' is a good start. I had the snip 10 years ago and had 18 months of wonderful pain-free sex then it all went downhill. Since then I have had several episodes where the pain is such that sex is just not an option... The incidence of PVP is disputed but is somewhere between 5% and 20%, although your GP may scoff. Ask around as well - I know of 2 colleagues with similar problems, all of us in our 40s.

Still no Aurora...

[Cheggers]

Still no Aurora...

Will have a read up, but it needs to happen, I only have to smile and .......... either that or separate continents.

Clear calm night disrupted by the copper chopper searching for someone. 1C.

[LomondSnowstorm]

Ok, a short term summary:

Temperatures are currently falling away nicely across central and eastern parts, 0.8C here presently, with dewpoints north of the Forth widely below 0C:

http://www.weatherca...r-stations.html

Cloud is starting to roll in from the Atlantic now http://www.knmi.nl/d...20123_2045.html so temperatures further west are unlikely to fall any further, though further east we might be able to eek out an air frost. Precipitation is set to arrive around 3-6am across central areas (http://expert-images...012403_2318.gif) with the front itself not actually arriving until 12pm:

So the key question is what will be falling out of the sky when you all wake up at an ungodly hour to check the lamp post? Well at first glance, it doesn't appear promising for most http://expert-images...012403_2318.gif However, note that around Glasgow temperatures at hill level are going to be below 0C. What appears to be responsible for this temperature drop? Well I've seen it multiple times before with occlusions and I'd suggest that the precipitation intensity causing radiative cooling begins to outweigh the initial temperature rise caused by encroaching cloud cover. This lowering of freezing levels is even more pronounced to the northeast, where surface cold ahead of the front and an, albeit fairly shallow, land based flow will lower temperatures as precipitation starts to fall. Skew-t for Edinburgh:

And by 6am:

Note that the dewpoint remains above 0C: this may be the biggest issue for eastern areas. While temperatures across the layers may be fine for snow, dewpoints above 0C are far from ideal. So what looks likely is this: fleeting snowfall for western areas away from the coasts where it will be all rain - for coastal areas anywhere it's likely to be rain because dewpoints are starting from a much higher point. If your dewpoint at the moment is above 0C I'd say you have almost no chance of seeing snow, unless you have elevation on your side because in that instance temperatures are likely to drop with you as the front hits. The main risk for lowland snowfall looks to be for inland central eastern areas, potentially also for places like Penicuik with a bit of elevation. If you end up with it starting as snow and remaining intense you could see 2-3 inches realistically in areas populated by creatures other than sheep, but two things will stop the snowfall: milder uppers (http://expert-images...012412_2318.gif)

and a lack of precipitation http://expert-images...012415_2318.gif

That's why Aberdeen city and anywhere north of Inverness are excluded from this - the front simply won't reach you.

My map from a similar setup in February or March last year I think

Not too dissimilar as far as snow risk goes, but perhaps more orange in the southern uplands and less so right at the east coast. We had an inch off that, and I reckon we'd be pretty lucky to see an inch of snow tomorrow morning.

Anyway, what next? A potential rain to snow event on Wednesday night from a cold front passing west:

http://cdn.nwstatic.co.uk/gfsimages/gfs.20120123/18/54/ukpaneltemp.png

http://cdn.nwstatic.co.uk/gfsimages/gfs.20120123/18/54/ukprec.png

with showers, potentially of snow and potentially in quite organised bands, following through on Thursday http://cdn.nwstatic.co.uk/gfsimages/gfs.20120123/18/66/h850t850eu.png

Not exactly a feast of snow in the short range, but hardly a famine either, and anyway that might all be about to change....

[scottishandy]

So can I assume I'm in with a good chance then? Current temp 0.2, DP -1.

Love a bit of school run carnage, that's what snow tyres are for.

[Snowlover2]

Current temp here 1.5 dp -2.3

[Northernlights]

Will have a read up, but it needs to happen, I only have to smile and .......... either that or separate continents.

Clear calm night disrupted by the copper chopper searching for someone. 1C.

My experience over the years has been pain free if that's of any reassurance. (Wife offered me the option of a 'homer' -with kitchen knife- or a visit to the surgeon .... guess which I went for!!) Currently 0.4c with ground freezing up

[A Winter's Tale]

GFS 18Z has so far blown the easterly away but perhaps it has over exaggerated the strength of the jet. Best to ignore this run?

[Aaron]

GFS 18Z has so far blown the easterly away but perhaps it has over exaggerated the strength of the jet. Best to ignore this run?

00z and 12z over 06z and and 18z any day :winky:

[Cheggers]

My experience over the years has been pain free if that's of any reassurance. (Wife offered me the option of a 'homer' -with kitchen knife- or a visit to the surgeon .... guess which I went for!!) Currently 0.4c with ground freezing up

At least the knife was more in keeping with surgery, mine was 2 bricks or surgery. :wacko:

Temp 1.4C DP -3

[A Winter's Tale]

To my untrained eye, GFS 18z is one of the worst runs that we could have hoped for after the 12z. Azores Hi, PV alive and kicking, zonal train.......!!!!!!!!!!!!

[Blizzardo]

As cloud has moved in temperature up from 0.5c to 1.2c with dewpoint of -0.2c. Unless precipitation is heavy I'll probably be just the wrong side of marginal for snow overnight.

[Northernlights]

To my untrained eye, GFS 18z is one of the worst runs that we could have hoped for after the 12z. Azores Hi, PV alive and kicking, zonal train.......!!!!!!!!!!!!

Computer based models are so unreliable for consistentcy nothing to beat cheviot ewe or tabby cat forecasting models. keep the faith, Sorry fillings anaesthetic must be getting to me after nearly an hour in the dentists chair, the trends your friend !

[edo]

HC you have given me the ammo I need...no sure How I can explain that due to some bloke on a weather thread im just no doing it but it's worth a shot

Great analysis LS and 18z always going to be a step back but surely 1 pattern must emerge and win soon...when will we see cross model agreement again

Meanwhile 0.9 here up from -1 an hour ago and DP at -1.1

I'm expecting sleet when I get up tomorrow

[West Highland Storm]

Ah Vasectomies, when I went under the knife,I was up second on the day, in the ward prior to surgery starting they wheeled away the first victim who was up first, we knew each other and we realised we were in for the same op, so I shouted over to him as he left the ward "I'm up next, so away and get his eye in", back came the reply "Aye at least I'm going in while the knifes still sharp".

[Hairy Celt]

At least the knife was more in keeping with surgery, mine was 2 bricks or surgery. :wacko:

Temp 1.4C DP -3

I'd take the 2 brix over what I've had for the last 10 years. Trust me, you have a 1 in 20 chance of never wanting to... Ach, stop the sh11t HC and away to bed.

[blitzen]

Here you go!

http://www.flickr.com/photos/curiousexpeditions/504628353/lightbox/ Mrs Cheggers gets to keep the key though!

[LomondSnowstorm]

And now to the longer term outlook:

As you all know I assume the models today appear to have swung back towards an easterly. We have a tough to model situation at the moment because it revolves around a shortwave dropping off the main trough into Europe http://www.meteociel...20-21.GIF?23-17

This basically acts to turn the flow easterly, keeping the high propped up and delaying ridging with the Azores High until the UK was already under a continental flow

http://www.meteociel...44-21.GIF?23-17

The GFS is similar, but with added shortwave complications http://cdn.nwstatic....132/h500slp.png

Ensembles are all over the place, but they're of a much lower resolution, so I wouldn't be too concerned about that at the moment. The potential if any of the three 12Z outputs verify out to 144 are huge - blolcking to the northeast backing west, undercutting starting to occur, cold pools springing up across mainland Europe, snow potential galore.

However, it's not a done deal yet - the Azores high linking up early with the russian high with the shortwave backing east into the block gives a monumentally different outcome: http://cdn.nwstatic....114/h500slp.png leads to http://cdn.nwstatic....216/h500slp.png

Best to wait till the morning again to resolve this one - the pub run is notoriously garbage at dealing with, well any kind of setup, but that doesn't mean that this outcome is wrong. This issue WILL be resolved, one way or the other, in the next 36 hours at absolute most. I'd say 60/40 in favour of easterly, but expect to wake to raging zonality tomorrow because it would be a tough flip to take were it to go that way.

Edited January 23, 2012 by LomondSnowstorm

[edo]

I'd take the 2 brix over what I've had for the last 10 years. Trust me, you have a 1 in 20 chance of never wanting to... Ach, stop the sh11t HC and away to bed.

well at least we ken what yer no away to bed for

[Hairy Celt]

well at least we ken what yer no away to bed for

Ermm... it's not like that all the time thank christ or I don't think I'd still be here. I see you're away... counting sheep perhaps?

Edited January 23, 2012 by Hairy Celt

[edo]

Ermm... it's not like that all the time thank christ or I don't think I'd still be here. I see you're away... counting sheep perhaps?

Lol nah was on the PS3 for some late night footy...I'm a night bird... Anyway off to count sheep now to get some zzzz before watching sleet in morning

[Cheggers]

Oh well, as expected, rain!

[Blizzardo]

Some slushy deposits and wet snow falling but at 1.5c and dewpoint 0.3c just not quite low enough.