Greenland Express: Snow showers possible from Monday night

M.T. Cranium · 12-01-2018 12:27am

GFS bias may have something to do with trying to average out air mass conditions over hilly terrain, when everyone lives in the lowest 20% of the terrain, perhaps it leads to a disparity between validated weather over the grid square, and human experience of the weather predicted.

I think it's more than just that, but it would be a factor over higher parts of the north and west.

But yes it goes into the forecast calculation that GFS can have a cold bias in the medium term. ECM deep lows at 120h are not always to be trusted either.

What you like to see as a forecaster is ECM colder than GFS and GFS shifting towards that -- then you're talking.

nacho libre · 12-01-2018 1:12am

http://www.bbc.co.uk/weather/features/42657127

Interesting beeb(bbc) forecast

Look at all the snow waiting in the wings by Monday night. Mountainy man might be snowed in by Wednesday.

IMG_0193.JPG.260575fc5c3033a38849a03b7de4bb46.JPG

IMG_0193.JPG.260575fc5c3033a38849a03b7de4bb46.JPG

Donegal Storm · 12-01-2018 1:51am

typhoony wrote: »

was it not a shortlived NWesterly followed by a colder Northerly?

2010 was the real deal if we're talking about a Greenland Express, the airmass dropped from the deep Arctic in Northern Greenland to the north of Ireland in little more than 24 hours. The coming week could be interesting in the north and west but won't be remotely close to that event

Oneiric 3 · 12-01-2018 2:53am

Forecast chart (850 hPa temps + isobars) for the middle of next week:

Compare this with a chart from this day last year, very similar, but colder air over the nearby north Atlantic region in general:

Daily max temps on the 12th & 13th of January last year ranged between 3c and 7c over the country (highest along western coasts) while minima ranged between about -0.7c (Knock Apt) and 3.0c, with the weather being showery with a wintery mix of rain, hail sleet and some brief snowfalls for favoured areas.

Keep in mind that 850 temps got down to below -7.0c at times between the 12th & 13th last year, while current forecasts (from the ECMWF at least) do not have 850 temps falling below this threshold for the upcoming spell as of yet.

Images from the Icelandic Met Office.
Temp data from Met Éireann.

vickers209 · 12-01-2018 8:02am

Met eireanns forcast this morning

EARLY NEXT WEEK: Becoming increasingly blustery and showery; showers turning wintry later Monday into Tuesday with falls of sleet and snow increasingly more likely. The focus of the wintry showers will be across the north and west with some accumulations likely - but all areas will be at risk with some thunder occurring locally too. Much colder, with maxima of only 3 to 6 degrees Celsius (north to south). Feeling even colder with an added wind chill effect. Frost and ice also, mainly for sheltered areas owing to sustained brisk winds.

Villain · 12-01-2018 8:18am

Higher Resolution GFS shows closer to the likely reality.

M.T. Cranium · 12-01-2018 8:19am

Greenland all stops more like it perhaps?

Still it is coming from Greenland, this part is true.

Gaoth Laidir · 12-01-2018 8:29am

Oneiric 3 wrote: »

Forecast chart (850 hPa temps + isobars) for the middle of next week:

Compare this with a chart from this day last year, very similar, but colder air over the nearby north Atlantic region in general:

Daily max temps on the 12th & 13th of January last year ranged between 3c and 7c over the country (highest along western coasts) while minima ranged between about -0.7c (Knock Apt) and 3.0c, with the weather being showery with a wintery mix of rain, hail sleet and some brief snowfalls for favoured areas.

Keep in mind that 850 temps got down to below -7.0c at times between the 12th & 13th last year, while current forecasts (from the ECMWF at least) do not have 850 temps falling below this threshold for the upcoming spell as of yet.

Images from the Icelandic Met Office.
Temp data from Met Éireann.

Facebook tells me I posted this image 1 year ago today...

Kermit.de.frog · 12-01-2018 9:22am

Solid model forecasts this morning for the cold snap beginning on Monday.

I'll update OP after the 12 pm output.

Not counting chickens yet but looks good at the moment.

Rebelbrowser · 12-01-2018 9:42am

Gaoth Laidir wrote: »

Facebook tells me I posted this image 1 year ago today...

And sadly Id take that happily!

MJohnston · 12-01-2018 10:09am

This is a very accumulations-oriented forum, I've noticed! Nobody else like me just love the actual snowfall, and don't really care about whether it sticks around for too long?

booferking · 12-01-2018 10:10am

M.T. Cranium wrote: »

Greenland all stops more like it perhaps?

Still it is coming from Greenland, this part is true.

Is this still your forecast for next week below i think the will be widespread snow falls inland to low areas also not just high ground.

Falls of snow are quite likely by mid-week in higher parts of Connacht, west Ulster and west Munster

Elmer Blooker · 12-01-2018 10:35am

Donegal Storm wrote: »

2010 was the real deal if we're talking about a Greenland Express, the airmass dropped from the deep Arctic in Northern Greenland to the north of Ireland in little more than 24 hours. The coming week could be interesting in the north and west but won't be remotely close to that event

Lovely charts. The real deal as you say with northern blocking.
I know I might be labelled an east coast ... "if there aren't east coast streamers then its not a real winter" nimby but any chart in winter with a big Azores does nothing for me. I've seen so many winters ruined by a big Azores my chronic Azoresophobia is now incurable.

ECM1-120.GIF?12-12

Rebelbrowser · 12-01-2018 11:20am

The GFS 6z is showing a lp forming on Wednesday which I suspect complicates further our snow chances.....:mad:

Kermit.de.frog · 12-01-2018 11:25am

GFS throws up an interesting feature on Wednesday.

Could be some snow associated with that on it's northern flank but the model is on it's own with that for now.

Something to watch though.

Peatys · 12-01-2018 11:30am

MJohnston wrote: »

Nobody else like me just love the actual snowfall, and don't really care about whether it sticks around for too long?

The the initial shock of snowfall instantly pulls me back to the magic of being 5.
Then after two minutes, start hoping it doesn't stick so my wife's rwd car can get out of the estate!

Kermit.de.frog · 12-01-2018 11:31am

Let's all try to remain calm

All we need is to lose that shortwave in the GIN corridor.

Anyhow for the cold snap another solid run, bags of potential.

Shedbebreezy · 12-01-2018 11:38am

The Met Office just issued a snow warning for Northern Ireland.

18:00 on Monday until 23:55 on Tuesday
Frequent and heavy hail and snow showers are likely to affect many parts of Scotland and Northern Ireland from Monday evening, continuing for much of the day on Tuesday. Travel delays on roads are possible, with a small chance of cancellations to public transport. There is a small chance that power cuts will occur and other services, such as mobile phone coverage, may be affected. In addition some roads and pavements may become icy, increasing the chance of injuries from slips and falls.

The largest accumulations of snow will be over high ground with over 10 cm building up above 200 metres. At low levels, accumulations of the order 2-5 cm will be more typical. Showers will also be accompanied by hail and lightning at times, particularly across northern and western Scotland. Here, there is potential for disruption to power supplies from frequent lightning strikes. Strong winds are also expected, with the potential for temporary blizzard conditions and drifting of lying snow, particularly over high ground.

Confidence is high to issue it 3 days in advance. Those accumulations are just from Monday to Tuesday evening, and not just a high ground event as some have stated over and over. Looks very promising, good to have the experts on board.

pauldry · 12-01-2018 11:44am

Monday night will definitely snow so at least Tuesday will be a white out in NW

fraxinus1 · 12-01-2018 12:07pm

Very disappointed after reading MT’s forecast. This is basically a high ground event. Another blow for us snow lovers.spring Is rapidly approaching and there’s only realistically a 6 week snow window left. If this Greenland express doesn’t deliver then it’s game over.

MJohnston · 12-01-2018 12:26pm

fraxinus1 wrote: »

Very disappointed after reading MT’s forecast. This is basically a high ground event. Another blow for us snow lovers.spring Is rapidly approaching and there’s only realistically a 6 week snow window left. If this Greenland express doesn’t deliver then it’s game over.

Oh don't be talking silly - you're the same one who was saying it was game over in early December and then again approaching new years when you said we'd be getting loads of Atlantic muck and nothing else in January.

Kermit.de.frog · 12-01-2018 12:28pm

fraxinus1 wrote: »

Very disappointed after reading MT’s forecast. This is basically a high ground event. Another blow for us snow lovers.spring Is rapidly approaching and there’s only realistically a 6 week snow window left. If this Greenland express doesn’t deliver then it’s game over.

Variety of opinion is the spice of life.

Stick around here, you'll be grand!:cool:

pauldry · 12-01-2018 12:35pm

haha knew id jinx it .... should have kept stum:rolleyes:

pauldry · 12-01-2018 12:52pm

yes bloomin jet stream seems to have taken a punt further North leaving us in "slushmans" land

Just looked at the models (weather ones)

highdef · 12-01-2018 12:56pm

fraxinus1 wrote: »

there's only realistically a 6 week snow window left. If this Greenland express doesn’t deliver then it’s game over.

Ok, you first say that there are 6 weeks left of opportunities for snow and then immediately say that if we don't get the snow next week, there is no chance of snow for the rest of the winter.

Can you explain your statement in further detail as it has me seriously confused.

Gonzo · 12-01-2018 1:00pm

yesterday I said alot can change and already this doesn't look quite as good as it did yesterday. The cold now arrives slightly later, will be Tuesday before the cold air digs in. Then back to slightly milder on Wednesday with a wet day for most of us, then colder again on Thursday and a slow return to mild over the weekend. This will all change again between now and Tuesday for better or for worse, this is still really 4 days away.

Shedbebreezy · 12-01-2018 1:20pm

I disagree Gonzo. Wednesday the northern edge will see snow. Doesn't look great elsewhere on Wednesday but it never did away from the North/North West. And I see no warm up for next weekend as you state. Blog below backs up claim.

John Hammond BBC weather man blog today. Sounds promising.

It’s the high ground of northwest Britain – where the wintry squalls will be quite incessant – that I am most concerned about. Feet of snow could fall on the mountains, with much larger drifts, thanks to the strong winds. However I also expect some large conurbations of Scotland, Northern Ireland and northwestern parts of England and Wales to be affected by some disruptive snow showers at times.

Further south and east, there will actually be plenty of sunshine, but even here some wintry showers are expected. Nobody is immune from a dusting of snow and overnight frost will be widespread.

For those hoping for just a brief cold snap, there’s not particularly good news on the horizon for the end of the week. There are the first signs of the jet stream developing a large and important kink in mid-Atlantic. In the process, those westerly winds will begin turn into northerlies.

So by the weekend I expect frosts to be quite hard, especially over snow cover. But although there will still be some wintry showers, plenty of fine and crisp weather is expected.

MONDAY 22ND JANUARY – SUNDAY 28TH JANUARY

Cold start – Milder later?

Not for the first time, the atmosphere looks to be edging into a ‘blocked’ pattern that the computer forecast models really hadn’t envisaged a few days earlier. Cold air will be established across the UK, with a contorted jet stream struggling to remove it.

The majority of model output suggests that the jet stream will reinvigorate, sweeping the block away, and introducing milder westerly winds as the week progresses. However, given the evidence of the last few weeks, I am not at all surprised to see from the latest output that this outcome is now far from unanimous.

My hunch is for another ‘battleground’ setting up in the vicinity of the UK. Fronts from the west will slowly and erratically try to dislodge the cold block to the east. In the process, we can expect a messy mix of rain and some snow, with temperatures slow to recover.

Oneiric 3 · 12-01-2018 1:25pm

ECM showing potential for hurricane force winds to develop off the southern tip of Greenland by early next week:

This air flow looks increasingly nasty to me. Regardless of temp or snow potential, it is going to feel bitter in those potentially very gusty westerlies next week.

Oneiric 3 · 12-01-2018 1:30pm

highdef wrote: »

Ok, you first say that there are 6 weeks left of opportunities for snow and then immediately say that if we don't get the snow next week, there is no chance of snow for the rest of the winter.

Can you explain your statement in further detail as it has me seriously confused.

He's probably learned from bitter experience.

Almost 6 weeks of winter has passed now and feck all has happened weather wise really; why should any one reasonably expect that the remaining 6 weeks should be any different?

George Sunsnow · 12-01-2018 1:58pm

Shedbebreezy wrote: »

The Met Office just issued a snow warning for Northern Ireland.

18:00 on Monday until 23:55 on Tuesday
Frequent and heavy hail and snow showers are likely to affect many parts of Scotland and Northern Ireland from Monday evening, continuing for much of the day on Tuesday. Travel delays on roads are possible, with a small chance of cancellations to public transport. There is a small chance that power cuts will occur and other services, such as mobile phone coverage, may be affected. In addition some roads and pavements may become icy, increasing the chance of injuries from slips and falls.

The largest accumulations of snow will be over high ground with over 10 cm building up above 200 metres. At low levels, accumulations of the order 2-5 cm will be more typical. Showers will also be accompanied by hail and lightning at times, particularly across northern and western Scotland. Here, there is potential for disruption to power supplies from frequent lightning strikes. Strong winds are also expected, with the potential for temporary blizzard conditions and drifting of lying snow, particularly over high ground.

Confidence is high to issue it 3 days in advance. Those accumulations are just from Monday to Tuesday evening, and not just a high ground event as some have stated over and over. Looks very promising, good to have the experts on board.

The vast majority of that forecast will probably be true in Scotland

Greenland Express: Snow showers possible from Monday night

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