Post-Christmas Cold Discussion

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.

Weathercheck

Weathercheck wrote: »

I prefer

Excelent-totally Excelent.

It'll never happen though :pac:

lucernarian

Some of these charts are ludicrous. I can't see all that happening in some sort of Feb '01 style blaze of glory.

M.T. Cranium

I would say there is at least a 50-50 chance now and perhaps more like 70-30 that a significant snowfall event will occur around 30-31 Dec into 1 Jan.

I was leaning towards rain south, sleet central and snow north if the event came in earlier and failed to capitalize on the energy peak 31 Dec 19z (full moon event) which from research would focus this developing Channel low and give it more of a thermal gradient squeeze.

But seeing the models now starting to trend more towards what would represent a "classic" timing line solution to this puzzle, with the low southeast of Ireland at event time, it could become a major snow producer.

Have to wait and see how the models evolve -- one thing that could go wrong is if the trend continues to change in the slower and more westerly direction bringing a stronger low up over southern Ireland. That would push the snow chances to the far north.

As for the longer term, this is obviously going to be a prolonged cold spell with this one brief interruption on the 26th. As it locks in, we are only just approaching now the coldest part of winter and SST values are sure to keep falling in this pattern. Could this perhaps be a winter to rival the big ones of the past? It needs more snow but already it is impressing with the cold.

Wibbler

Weathercheck wrote: »

It isn't getting any warmer anytime soon.

I've been watching the 850s for the last few days and the mean has been dropping over the runs. It's amazing seeing run after run of temps lower than the long term average for the entire run.

darkman2

Deleted User wrote: »

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=

Pfft

"a woman apparently rang the BBC earlier saying there was a hurrincane on the way - if your watching - don't worry - there isnt, having said that there will be a slight breeze in the Channel":pac:



Meanwhile feast your eyes on what the Japenese think

kkontour

love the snow, but a bit less of the very cold weather would be welcome.
This a picture outside my front door, and its like this on the roads for about 1mile.

Only the cold water to the kitchen sink is working now. TG Im going to family for dinner tomorrow.

Ox mountains, Sligo

200motels

Great chart if it happens.

ch750536

200motels wrote: »

Great chart if it happens.-snip-

Rain?

lucernarian

200motels, I think your chart there indicates rain across the southern half of Ireland?

200motels

To_be_confirmed wrote: »

200motels, I think your chart there indicates rain across the southern half of Ireland?

Could be but ah your right rain again.