Snow and Ice Warning : Thursday/Friday 7th/8th December

Kermit.de.frog · 02-12-2017 5:24am #1

This is a developing situation that could prove disruptive.

Currently the models are more than flirting with a much colder regime for Ireland and the real risk of some prolonged snowfall can not be ruled out.

As a northerly or north-northeasterly is the likely outcome it is northern areas that will take the brunt.

However there are two things in particular to watch.

On Wednesday a period of rain and strong winds will sweep up from the southwest. Initially it will be pleasantly mild and wet. However during Wednesday night and for Thursday as really cold air digs in from the north there is a real prospect this could turn to snow temporarily as temperatures plunge rapidly nationwide.

This is not nailed. What's maybe more certain is that after that bitterly cold air becomes entrenched and heavy snow showers follow - with another real prospect of troughs and polar low type features through Thursday night and Friday that would enhance snowfall for a good chunk of the country and lead to disruption.

Friday looks very cold indeed. Temperatures may struggle above freezing and may remain below over snow covered ground.

Specifics can't be nailed yet. Definitely be aware and keep an eye on forecasts.

It could be a 48 to 60 hour "event" but every chance it could go beyond that but lets keep this within the realm of the more realistic time frame. This applies until Friday night, but we will soon be able to elaborate further and in much more detail.

There is good enough cross model agreement.

More anon!

sparrowcar · 02-12-2017 7:24am

There ain't no party like a Kermit club party....

Bring on the white gold

kod87 · 02-12-2017 7:34am

I want snow as much as anyone but this thread is a bit optimistic and over the top IMO. There is potential there but it certainly didn't need its own thread at this stage but we shall see

ninebeanrows · 02-12-2017 7:37am

That is an impressive change in airmass in 24 hours!

ECM0-120.GIF?02-12

JanuarySnowstor · 02-12-2017 7:38am

Looks like a northerly toppler to me with max 36 hour event

sparrowcar · 02-12-2017 7:40am

kod87 wrote: »

I want snow as much as anyone but this thread is a bit optimistic and over the top IMO. There is potential there but it certainly didn't need its own thread at this stage but we shall see

"Turning much colder, snow likely" is over the top now? How exactly?

If it said "We're all going to freeze to death next week and huge snow drifts will bring the country to a standstill" then that would be over the top.

It's just an aknowlegement of unusual weather ahead that's all, take a deep breath.

kod87 · 02-12-2017 7:50am

sparrowcar wrote: »

"Turning much colder, snow likely" is over the top now? How exactly?

If it said "We're all going to freeze to death next week and huge snow drifts will bring the country to a standstill" then that would be over the top.

It's just an aknowlegement of unusual weather ahead that's all, take a deep breath.

I was thinking more this
"What's maybe more certain is that after that bitterly cold air becomes entrenched and heavy snow showers follow - with another real prospect of troughs and polar low type features through Thursday night and Friday that would enhance snowfall for a good chunk of the country and lead to disruption.

Friday looks very cold indeed. Temperatures may struggle above freezing and may remain below over snow covered ground.''

Most of that is over the top fantasy that reflects what he wants to happen not whats actually indicated.

Kermit.de.frog · 02-12-2017 8:12am

kod87 wrote: »

I was thinking more this
"What's maybe more certain is that after that bitterly cold air becomes entrenched and heavy snow showers follow - with another real prospect of troughs and polar low type features through Thursday night and Friday that would enhance snowfall for a good chunk of the country and lead to disruption.

Friday looks very cold indeed. Temperatures may struggle above freezing and may remain below over snow covered ground.''

Most of that is over the top fantasy that reflects what he wants to happen not whats actually indicated.

I think that's a bit unfair. It is, to all intents and purposes, scientific analysis and personal intuition I am working off.

Could be wrong of course. I don't think it will be that wrong to be honest.

But let's see. Glad to take any criticism if it does not work out. Have done before.

force eleven · 02-12-2017 8:57am

Gfs was showing the apocalyptic storm in the North Sea by next weekend last night. Looked way over blown, compared to the more sober ECM. Certainly looks like we will get a northerly next weekend, but it looks transient and how potent is undetermined just yet. I am only about 15% convinced of a disruptive spell of weather next weekend, and not just because its the firms Christmas party on Saturday...;)

Gaoth Laidir · 02-12-2017 10:22am

Though it's still well out in FI, the 00Z ECM is showing -9°C 850s briefly over Ireland, so that's a good start. I don't see much potential for disruption, though, as the upper trough is not as severe as the GFS, and is very limited on the GEM. 700 and 500 hPa temperatures are way colder on the GFS than the others, so the potential for deep convection and polar lows is of course exaggerated in that model. But as the whole airmass looks like originating over Greenland and moving quickly southeastwards it should give a lower snowline than last week.

But it's still only way out in FI.

mickger844posts · 02-12-2017 11:05am

Gaoth Laidir wrote: »

Though it's still well out in FI, the 00Z ECM is showing -9°C 850s briefly over Ireland, so that's a good start. I don't see much potential for disruption, though, as the upper trough is not as severe than the GFS, and is very limited on the GEM. 700 and 500 hPa temperatures are way colder on the GFS than the others, so the potential for deep convection and polar lows is of course exaggerated in that model. But as the whole airmass looks like originating over Greenland and moving quickly southeastwards it should give a lower snowline than last week.

But it's still only way out in FI.

Gaoth Laidir always the voice of reason on these threads. The only real gripe i would have about the thread is its title. When is snow ever Likely in Ireland especially 5 or so days away. Respect to Kermit for putting it out there and of course most would be hoping for some sort of event but a long way off yet.

Larbre34 · 02-12-2017 11:08am

At this time of year I dont get out of bed for anything progged at more than +36 hours, and ye shouldnt either.

JanuarySnowstor · 02-12-2017 11:14am

The 06z run really ups the ante with widespread snow falling Thurs/Fri

sjb25 · 02-12-2017 11:20am

JanuarySnowstor wrote: »

The 06z run really ups the ante with widespread snow falling Thurs/Fri

I no it most likely will all change but feck it

dexter647 · 02-12-2017 12:02pm

Personally I think you have jinxed it Kermit as it's still a long way off....fingers crossed though:)

pistolpetes11 · 02-12-2017 12:48pm

Gaoth Laidir wrote: »

Though it's still well out in FI, the 00Z ECM is showing -9°C 850s briefly over Ireland, so that's a good start. I don't see much potential for disruption, though, as the upper trough is not as severe as the GFS, and is very limited on the GEM. 700 and 500 hPa temperatures are way colder on the GFS than the others, so the potential for deep convection and polar lows is of course exaggerated in that model. But as the whole airmass looks like originating over Greenland and moving quickly southeastwards it should give a lower snowline than last week.

But it's still only way out in FI.

When you tell me its going to be an event I will happily get on board , until then its all FI for me but lovely charts to look at ,

I do hope KDF is correct as the the two smallies have never really experienced a snow event and would love it for them , Im only slightly interested in it ........... yeah right :P:P:P:P:P

Gonzo · 02-12-2017 1:11pm

be great if this happens but it's all such a long way off. The charts can change 20+ times between now and Thursday.

pauldry · 02-12-2017 1:18pm

If I never looked at any charts of we were living in the 1940s id be saying

Jaysis this past few weeks has been colder than recent late Autumn Winters
Surely something cold is in the pipeline soon .

Id say wel definitely get cold with wintry showers but it is quite possible we will get snowfall in december this year in my opinion.

The mild muck of other years just isnt there

E.g last year it was 11 to 13c many many days

So far this year we are struggling to reach double figures.

Cue mildest weather on record

Rock Lesnar · 02-12-2017 1:37pm

Kermit starts a snow thread, its definitely and officially winter on the boards weather forum now

Gaoth Laidir · 02-12-2017 1:55pm

The ECM has numerous light showers feeding in from the northwest later next week, with a rain/snow mix (green/orange), but activity is mostly along Atlantic regions, limited elsewhere. They could produce some brief flurries over land as they die out further east but totals look small at the moment.

And it's still way out in FI...

Radar

Gonzo · 02-12-2017 2:10pm

right now the charts are showing very cold conditions lasting from next Thursday afternoon to the following Tuesday. If the charts do work out, next Friday has the potential to be the coldest day since December 2010, certainly far colder than the recent cold spell. Far too early to tell about where snow will fall and if snow will fall.

Wine Goddess · 02-12-2017 2:46pm

I know, I know it's FI, and the usual arguments about it being too early to tell, which I agree with, but for me, half the fun of being on this brilliant forum is to see the FI charts and get excited!
Yes 120+ is too soon to tell.
Yes the low could move away.
Yes the high could break down.
Yes the 500 hPa could get warmer.
Yes it could be a northeasterly rather than an easterly.
But, it's fun, it's FI, it's great to follow it and hope.
I really enjoy reading charts, seeing people get excited about the possibility of snow, it's what makes this forum so great.
Let us have our dreams, unlikely though they may be!
.

Donegal Storm · 02-12-2017 2:56pm

Surprisingly good ensemble agreement right out to 8 days

Strong winds in these setups usually mean hail showers well inland in the NW though and showers will be fast moving so I wouldn't expect much, if any snow accumulation for most of us, 850hPa temps are nearly always a couple of degrees warmer on the day as well. Fermanagh, Cavan Tyrone etc likely get plenty of snow though, especially if the 6z GFS comes close to verifying

Interesting charts though, would love to be on the Donegal coast for some big thundery hail squalls

ninebeanrows · 02-12-2017 2:59pm

I think the predicted charts are definitely out of the FI range!

gfs-0-120.png?6

The cold rush begins at T120 on the latest GFS. However, as SU alludes to - the models have toned down the intensity of the low pressure and whilst previous runs showed the potential for the cold to undercut the precipitation bands- the latest output does not. This results in a very cold arctic Northwesterly giving hail/sleet/snow showers to areas exposed, but very little if any precip likely in the east.

Gaoth Laidir · 02-12-2017 5:02pm

Meanwhile the ICON is throwing a spanner in the works and is showing a deepining low tracking southeastwards right over Ireland on Thursday. This would divert the coldest air westwards and increase its sea track, so not good for snow.

Meteorite58 · 02-12-2017 5:31pm

Thurs / Fri / Sat looking extremely cold especially Fri. Strong enough wind expected also bringing the windchill very much into effect

Just for sport.

pad199207 · 02-12-2017 5:43pm

It’s going to be one of those events where everything will have to come together. A very rare thing to happen in this country.

What can go wrong will go wrong.

Charts are encouraging though because they do show parameters conducive to snow for many areas but it’s still a good few days away.

GFS and UKMO pretty much in agreement on this. I have a feeling the ECM will be in agreement too.

Meteorite58 · 02-12-2017 6:03pm

Looking so cold next Fri

Meteorite58 · 02-12-2017 6:18pm

Strong Jet Fri / Sat with Ireland in a stiff N'ly airflow

I can feel the cold from here !

Oscar Bravo · 02-12-2017 6:21pm

Bring it on! This low cloud and non descript weather may be ok for shoppers but very boring otherwise!!

joujoujou · 02-12-2017 7:40pm

Yeah, bring it on!

But wait until I've winter tyres put on the right place.

Gaoth Laidir · 03-12-2017 12:08am

One thing to note is that although the 850 temperatures on Friday (around -9 °C) are colder than those on Thursday (-7ish), they are around 100 metres higher up, so in reality there is no real difference in the vertical profile. Friday would not be colder than Thursday.

Kermit.de.frog · 03-12-2017 1:05am

Hi all,

Can we at least try to keep regional biases in check. :P Just because Dublin may (or may not, we don't have that full picture yet) avoid the worst of the cold snap in terms of snow does not mean others will have any less,

I'm a Dub and would love to see snow in my location but delighted to see all the pics and news from the locations that do get snowfall.

Not much has really changed in the forecast from the OP through today. Maybe a little less likely to see back edge snow from the front in to Thursday (excepting high ground of course).

Thursday night, Friday and in to Saturday the snow showers still piling in to the north and northwest - also west and southwest coasts. Strong enough breeze, some of these will get well inland.

Temperatures, no change, really struggling from Wednesday night.

No point in speculating further than Saturday - every chance the cold period could continue allbeit in a different way - rain trying to approach from the northwest coming up against the colder airmass could turn to snow for some. Not enough detail to go in to that yet.

More or less on track.

JanuarySnowstor · 03-12-2017 7:36am

Potent toppler sums it up really.
A bit like the one a few days ago but a fraction colder.
Some snow for high ground in North and West.

Kermit.de.frog · 03-12-2017 9:38am

A fraction colder? Nothing has changed with the forecast in the OP. Snow will not be confined to high ground nor will it be confined to the north and west. It's what happens from Saturday that should be the focus of speculation. Thursday, Friday pretty much nailed.

BLIZZARD7 · 03-12-2017 10:05am

Some snow depth charts from this mornings ECM - *Obviously will be subject to lots of change*

Friday -

Sunday -

server down · 03-12-2017 10:05am

Kermit.de.frog wrote: »

A fraction colder? Nothing has changed with the forecast in the OP. Snow will not be confined to high ground nor will it be confined to the north and west. It's what happens from Saturday that should be the focus of speculation. Thursday, Friday pretty much nailed.

You putting your reputation on that? Snow on lower ground in the east and south east on Thursday/Friday?

George Sunsnow · 03-12-2017 10:12am

John Eagleton ‘the eagle’ on radio one at 755am this morning said heavy rain all day wenesday which may turn to snow wenesday night into Thursday as northerly winds dig in
Thereafter heavy wintry showers in ulster north leinster the west and southwest

The set up for wenesday onwards has the capability to bring snow wherever the front is on wenesday night/Thursday
After that snow showers could get into Dublin but especially Meath Louth Ulster Connaught and west Munster

Whether it’s s toppler remains to be seen

munsterlegend · 03-12-2017 10:34am

server down wrote: »

You putting your reputation on that? Snow on lower ground in the east and south east on Thursday/Friday?

A bit over the top? Reputation? It's an online forum not like he is representing met eireann!

Anyway snow in Ireland is always in the balance up to the last minute. Usually what can go wrong does but Thursday to Sunday will certainly be cold and seasonal.

pauldry · 03-12-2017 11:01am

Hard to believe any of this coming to fruition but I hope Im wrong.

As regards the snow depth charts does hail count as snow depth coz thats likely what Sligo town will get. Inland locations fair enough but hail isnt snow.

Id say Thursday and Friday we will get something Wintry just what

nacho libre · 03-12-2017 11:09am

I think it will be a toppler. However a potent two day toppler is fine by me if it leads to heavy snow showers piling into the north west on a stiff breeze, that means places further inland will get them too. I just hope this pattern of milder interludes, alternating with colder north westerly and and northerly air masses, continues till the end of the month.

Gaoth Laidir · 03-12-2017 11:38am

Kermit.de.frog wrote: »

Thursday, Friday pretty much nailed.

It's far from nailed. There's still significant variation in the models on the evolution of that low and the position of the ridge over Ireland. Again it looks like we may lie just a few hundred km too west, but we'll see. The ECM shows a shortwave feature dragging down higher theta values around the west of the low, which would reduce the cold, whereas the GFS again shows the coldest solution. It's still all to play for.

Xenji · 03-12-2017 11:48am

Coming back today from 5 days of up to -7C and snow, so hoping this pans out for the west later in the week, not looking forward to landing in the mildness later.

leahyl · 03-12-2017 12:03pm

Typical again, Cork and Waterford seem to be left out in the models :-(

George Sunsnow · 03-12-2017 12:03pm

Don’t be expecting a 2010
Expect heavy wintry showers in the areas outlined which will include snow
Where snow falls heavily it will settle

Not possible to be sure what comes after next weekend this far out

Pangea · 03-12-2017 12:16pm

pauldry wrote: »

As regards the snow depth charts does hail count as snow depth

Donegal Storm · 03-12-2017 12:28pm

Kermit.de.frog wrote: »

A fraction colder? Nothing has changed with the forecast in the OP. Snow will not be confined to high ground nor will it be confined to the north and west. It's what happens from Saturday that should be the focus of speculation. Thursday, Friday pretty much nailed.

You can't call something 6 days away nailed on :rolleyes:

This mornings ECMWF has 850hPa temps between -6 and -8C, roughly the same as what we've had a couple of times already recently. It's supported by colder air aloft this time but still every chance it'll be watered down in the coming days and we end up with the usual higher ground NW event.

server down · 03-12-2017 12:32pm

munsterlegend wrote: »

A bit over the top? Reputation? It's an online forum not like he is representing met eireann!

Anyway snow in Ireland is always in the balance up to the last minute. Usually what can go wrong does but Thursday to Sunday will certainly be cold and seasonal.

He’s fairly certain. And obviously he has an online reputation.

Itssoeasy · 03-12-2017 12:50pm

leahyl wrote: »

Typical again, Cork and Waterford seem to be left out in the models :-(

Well the shield was fixed after the last time.

Meteorite58 · 03-12-2017 1:15pm

Nice shortwave feature showing up on the latest GFS for early FRi running down the E of the country.That could have an influence on precipitation levels.
An evolving situation with the picture becoming clearer as we go on. The shape, track intensity of the system moving in over Ireland and the following N'ly airflow and influence of the other bodies of air will all be tweaked in the coming days. But that's the enjoyment of it for me, focusing in on the atmospheric minutiae and observing its interactions. It is great getting everybody's input, knowledge and experience for me as it is a great opportunity for learning.

gabeeg · 03-12-2017 1:44pm

It's Mrs Frog and the tadpoles I feel most sorry for.

It is they that must suffer much of the fallout from Kermit's reckless weather forecasts.

Snow and Ice Warning : Thursday/Friday 7th/8th December

Comments