Post-Christmas Cold Discussion

darkman2

Just to avoid confusion with the current situation in the other thread I think next week's potential cold deserves it's own at this stage because it is looking like a potent cold spell of weather beginning after St Stephen's Day.

Christmas Day and St Stephen's Day will be slightly milder days then what we have now. Though still cold it won't be quite as cold and it will be wet at times. After St Stephen's Day the signs are increasingly pointing toward a return of what could, potentially, be an even more serious run of events as we head to New Year with East or Northeasterlies setting in. Also a major snow event could occur this time next week. But it's too early to be specific.



Bitter Northeasterly winds





So basically turning colder again from St Stephen's Day. More Later.

nacho libre

i know it's more than likely subject to change but the gfs showed the cold lasting right through to the early days of january and possibly beyond. of course when the atlantic oscillation thingy(nao) finally goes back into positive terrirtory we've more than likely had it. it's just a question of when that happens

darkman2

In a general sense there is no end in sight to the pattern. HP remaining to the North. LP to the South and East. So it looks good for the cold to continue for a good while longer. I say "good" but also there are some people like the elderly and drivers (even pedestrians) for whom this is not very good at all. A thought should be spared for those directly adversely affected because it really is not very nice for some people. I don't mind the snow myself (At least your unlikely to fall and break your neck) but the very icy conditions are lethal. Take care.

maquiladora

12Z GFS throws us an easterly too :

maquiladora

maquiladora wrote: »

12Z GFS throws us an easterly too :

Thats a master Easterly-it would have everything.
low 850's,lowdp's and plenty of near gale force precip.

The cynic in me thinks though that even if that trend continued,all we'd end up with is a slack flow with pressure too high and 850's of -5 or so and thickness around 530...

maquiladora

And after that easterly, a snowy northerly....deep in FI...

nacho libre

i prefer this chart myself:)



we could be talking about organised snow showers if this comes off.

greysides

we could be talking about organised snow showers if this comes off.

Would you define the word 'organised' as used in this context please.

nacho libre

greysides wrote: »

Would you define the word 'organised' as used in this context please.

well i could be wrong, but going by the chart above me, we could be talking about prolonged showers in the north and north west, and, unlike the previous cold period, the showers could be more widespread across the rest of country. the ideal scenario for widespread heavy snow across ireland is a polar low. in that situation we don't usually have to worry about the snow turning back to rain or sleet as it spreads southwards

darkman2

Latest UKMO chart




The madness starts on Monday :P

Won't happen folks.
It's well into the believe it when I see it territory.

As I said you'll be disappointed.

maquiladora

Deleted User wrote: »

Won't happen folks.
It's well into the believe it when I see it territory.

As I said you'll be disappointed.

Oh I know its FI, the best charts are always in FI. :pac:

nacho libre

maquiladora wrote: »

Oh I know its FI, the best charts are always in FI. :pac:

and sometimes dreams do come true:)

Leeside

I've spent the bones of three weeks following threads suggesting snow just might be on the way. I've yet to see even one flake. However, I'm prepared to wait another while. As nacho libre says "sometimes dreams do come true"

LEIN

nacho libre wrote: »

and sometimes dreams do come true:)

Agreed

jambofc

bring on the dreams

Wibbler

I'm also in the 'believe it when I see it' group.

Following this current spell, as a Dub, has been draining. I never knew there were so many ways for it *not* to snow in the east when it was cold.

Perhaps this is the reason we love snow so much - we see so little of it.

200motels

Well Ididn't see a flake of snow, but I live in hope for next week.

Wibbler

Wibbler wrote: »

I'm also in the 'believe it when I see it' group.

Following this current spell, as a Dub, has been draining. I never knew there were so many ways for it *not* to snow in the east when it was cold.

Perhaps this is the reason we love snow so much - we see so little of it.

Actually all that went wrong today was the wind came in off the warm sea.
Our weak cold pool hadn't come from the east in the first place so the air abovethe irish sea was too warm.
Last week it was a different story as there was a cold originated feed into the irish sea which is why the east wind that time gave snow.

Edit:

Oh and the other thing that went wrong was I predicted snow for irish1 aka villian in Tullow.
That usually calls the warm air like a good clairvoyant does ghosts ...

FI continues to toy with a northeaster this morning for late next week followed by a straight northerly.
Leaving aside the fact that it's FI and likely not to happen [except in the UK] it's absolutely useless for most of this country.
Sleety showers in the East briefly followed by a dry cold northerly away from the north coast.

ECM fi is toying with variations on a similar theme.

peasant

metcheck cooks up this little fantasy for next year:



whey-hey ...a Fantasy Island blizzard

Deep Easterly

Have to say I like this chart (ECM 120hrs)



Looks like a really raw winter's day over Ireland. Brrrrrrrr.

nacho libre

:pac:

Gonzo

I cant see this working out after the current cold spell, I never knew there was so many ways to prevent it snowing in the east of Ireland till now.

Wibbler

Gonzo wrote: »

I cant see this working out after the current cold spell, I never knew there was so many ways to prevent it snowing in the east of Ireland till now.

I guess that pre Internet it often went that way even in the less snow starved parts of the 20th century. The ready access to satellite, model and radar output has revealed just how tricky it is for all the pieces of the jigsaw to fall into place for us.

Deep Easterly

Deep Easterly wrote: »

Have to say I like this chart (ECM 120hrs)



Looks like a really raw winter's day over Ireland. Brrrrrrrr.

Is that not just recirculating air from Biscay though?
Biscay is hardly renowned for being a source of snow.(sorry I'm snow starved since the beasterly's fleeting visit last week and feeling the effects of it)
In fact if that low would just feck off southwards,we'd have proper low dewpoint air from the North east

Gonzo

Gonzo wrote: »

I cant see this working out after the current cold spell, I never knew there was so many ways to prevent it snowing in the east of Ireland till now.

As I said in the other thread,we're an island in the atlantic.
What we have now are 2 things,the weak remains of atlantic maratime [slightly] modified polar air and a still athmosphere at a time when the nights are at their longest.
Considering we are as far if not further north than Boston [I think] then still nights with that mass,a very very cold night can make.
Bring in the atlantic fronts though and it's swept away after a short time.

Bring them in against a stiff prolonged northerly or a Beasterly and you have a january 1982 scenario.
Very very rare due to geography unfortunately.

darkman2

Deleted User wrote: »

Is that not just recirculating air from Biscay though?
Biscay is hardly renowned for being a source of snow.(sorry I'm snow starved since the beasterly's fleeting visit last week and feeling the effects of it)
In fact if that low would just feck off southwards,we'd have proper low dewpoint air from the North east

Possible major snow event in the making there. Those fronts to the Southwest will be coming up against cold air to the North. The LP should slide under Ireland from there as the colder air brushes up against it. Classic widesread snow situation. Where the uncertainty is is how far North the Precip will be





UKMO has it slightly further North. ECM has it slightly further South (though the precip still reaches Leinster). I predict this forum will light up the closer we get to this.

peasant

Deleted User wrote: »

Considering we are as far if not further north than Boston [I think] .

Try Edmonton, Canada for size

possible cold rain event too dm2 and going on recent events probable.
Wheres the cold air coming from? And how cold?

That chart you show with the lines idicating snow...wasn't there one of them posted the other day sub 48 for yesterdays non event?

No major grounds for optimism.
Bring on a proper beasterly I say.

mike65

People forget how far north we are cos of the gulf stream, next stop is not Boston - its Cartwright, Labrador

darkman2

Deleted User wrote: »

possible cold rain event too dm2 and going on recent events probable.
Wheres the cold air coming from? And how cold?

That chart you show with the lines idicating snow...wasn't there one of them posted the other day sub 48 for yesterdays non event?

No major grounds for optimism.
Bring on a proper beasterly I say.

BB im not quite sure your approaching the dynamics of a situation like this correctly. The cold air is there



As the depression approaches it sucks in cold air from the North. We do not need sub -5 850hpa temps in a situation like this for various reasons not the least of which is evaporative cooling. (sub -5 is there though). In a situation like this as the LP gets squeezed and the occlusion grinds up against the cold air at it's Northern flank it gets colder and colder. Watch this over the next couple of runs - the air will get colder. Rain readily turns to snow. Expect a steep thermal gradient to emerge between North and South of the Occluded front. If you are on the Southside of it (which seems unlikely atm) you have little chance of snow. In fact in a truly classic situation it is quite possible for it to snow in Dublin at 0C and be 11C and rain in Cork! (I remember those days). Not saying it will happen but do keep an eye on it.


The most marginal snow events are the best.

darkman2

darkman2 wrote: »

BB im not quite sure your approaching the dynamics of a situation like this correctly. The cold air is there



As the depression approaches it sucks in cold air from the North. We do not need sub -5 850hpa temps in a situation like this for various reasons not the least of which is evaporative cooling. (sub -5 is there though). In a situation like this as the LP gets squeezed and the occlusion grinds up against the cold air at it's Northern flank it gets colder and colder. Watch this over the next couple of runs - the air will get colder. Rain readily turns to snow. Expect a steep thermal gradient to emerge between North and South of the Occluded front. If you are on the Southside of it (which seems unlikely atm) you have little chance of snow. In fact in a truly classic situation it is quite possible for it to snow in Dublin at 0C and be 11C and rain in Cork! (I remember those days). Not saying it will happen but do keep an eye on it.


The most marginal snow events are the best.

I don't doubt your sincerity in looking for what we want out of this but those isobars show a flow out of biscay and a long sea track which like last night makes a snow event in East wales maybe but not Mumbles or Dublin and certainly not anywhere in the south east.

I'm not concerned though.
Like you ,I'll keep watching but hopefully over the coming days you'll have better charts than that to show me
Those are rain ones away from lugnaquilla.

Deep Easterly

Deleted User wrote: »

Is that not just recirculating air from Biscay though?
Biscay is hardly renowned for being a source of snow.(sorry I'm snow starved since the beasterly's fleeting visit last week and feeling the effects of it)
In fact if that low would just feck off southwards,we'd have proper low dewpoint air from the North east

Don't be fooled by the isobars BB! The warm sector in that chart is way to the south, Isobars only relfect lines of equal pressure as you know yourself, we are still very much on the cool side there. What is driving the low is that very fact. Cool on the northern side while warm air attempts to make it up northwards. I think anything can happen with a chart like that, but if it verified, rain or snow, it will feel cold in that breeze.

They fooled me last night DE
Fool me once as they say...

Anyhow that won't be the chart that verifies.
The good thing [/scrapes barrel] is that as you say we are in a cold zonal affair as opposed to mild.
So at least mother nature has less work to do to give us snow when she's in the humour.

Women can be very difficult at times

nacho libre

just keep telling yourself it won't happen to avoid disappointment;)

It won't happen
It won't happen.
Shur it can't happen!

darkman2

Yes it can occording to the 12z GFS. Quite a snow event for Monday and Tuesday - Not exactly light years away;)

Isn't this the same gfs that gave a snow event for here yesterday though at short notice

12z is a much better feed of cold surface air alright

http://www.wetterzentrale.de/pics/Rtavn1261.png

http://www.wetterzentrale.de/pics/Rtavn1381.png

Now thats fantastic..

It won't happen though
It won't happen.

mickger

darkman2 wrote: »

Yes it can occording to the 12z GFS. Quite a snow event for Monday and Tuesday - Not exactly light years away;)

Hopefully this will happen. As you said its not light years away

darkman2

It's the frontal system im concentrating on













:pac:

http://www.wzkarten.de/pics/Rtavn1441.png

Thats a january '87 set up.
Shy on -10 850's in that part of FI but it's a major step in the right direction and hello low dewpoints

http://www.wetterzentrale.de/pics/Rtavn15010.png

See the dp's up there? Thats where I want our air streaming down from

Anyhow enough of this pie in the sky...I want some real pie and it's on the table with custard
ciao !

Duiske

darkman2 wrote: »

It's the frontal system im concentrating on



:pac:

Looks fantastic

Actually, from start to finish the 12z is great.

The great Michael Hurricane what hurricane Fish isn't too enthusiastic about those fronts on the low Dm2 turning to snow.

He expects winter to come down behind them though as they feck off southwards.
Heres his analysis as of today presumably only with the 6z ,ecm etc:

http://www.netweather.tv/index.cgi?action=michaelfish;sess=

Elmer Blooker

mike65 wrote: »

People forget how far north we are cos of the gulf stream, next stop is not Boston - its Cartwright, Labrador

Exactly, I would say THE ENTIRE northern hemisphere north of 50 degrees is snow covered at the moment. We cant switch off the gulf stream unfortunately but it would be nice to get more of our weather from the Eurasian landmass not just in winter but in summer too.

Deep Easterly

Latest ECM at 144hrs:



cold, raw theme continues.

Deep Easterly

Deep Easterly wrote: »

Latest ECM at 144hrs:



cold, raw theme continues.

Much better fetch there on that one!

ninebeanrows

I prefer

ninebeanrows

It isn't getting any warmer anytime soon.