Storm Ciara - Strong Winds & Potential Snow **TECHNICAL DISCUSSION**

Nqp15hhu

JanuarySnowstor wrote: »

Why are Met Eireann not mentioning the significant risk of snowfall tomorrow in the South? All models are showing it yet they continue with the old saying 'West and North'
A bit more detail please Met Eireann you see the same charts as we do!!!

Because the freezing level tomorrow in Ulster is 400-500m whilst it is 600-700m in Southern Ireland. So it is not productive for low level snow there.

If you sign into Meteociel and look at the snow level charts you will see that the snow falling level there is about 400m whilst it’s 100m or lower in Ulster.

The “system” coming up from the south is actually a warm front.

Mortelaro

Nqp15hhu wrote: »

Because the freezing level tomorrow in Ulster is 400-500m whilst it is 600-700m in Southern Ireland. So it is not productive for low level snow there.

If you sign into Meteociel and look at the snow level charts you will see that the snow falling level there is about 400m whilst it’s 100m or lower in Ulster.

The “system” coming up from the south is actually a warm front.

No,its not a warm front,its actually an occlusion bumping into cold air with sub or equal to 528 dam
It certainly supports snowfall in munster and south leinster on modestly high ground away from coasts

Nqp15hhu

Well I have had a look at the icon charts and the freezing level rises to as high as 800m, as this system comes in..

Places north of Dublin are best placed for low level snowfall tomorrow.

JanuarySnowstor

Indeed it is a warm front but it only skirts the South and you would expect that as it clears the ppn will quickly turn to snow. I expect rain first but perhaps an hours worth of snow as it clears...

sparrowcar

Skerries harbour

Nqp15hhu

JanuarySnowstor wrote: »

Indeed it is a warm front but it only skirts the South and you would expect that as it clears the ppn will quickly turn to snow. I expect rain first but perhaps an hours worth of snow as it clears...

The freezing level comes down to 500m after 7pm so yes.

Mortelaro

JanuarySnowstor wrote: »

Indeed it is a warm front but it only skirts the South and you would expect that as it clears the ppn will quickly turn to snow. I expect rain first but perhaps an hours worth of snow as it clears...

Well yeah you're right in that sense,its effectively a cold and warm front attached to each other
Your description of what it might do is better than mine tbh
It is tipping in to 528 dam entirely so modest high ground away from the coast should see it turn

Nqp15hhu

For snow to fall at sea level you need the freezing level at 500m at an absolute minimum, especially in a saturated atmosphere.

So the snowline will be about 400m there tomorrow.

Gonzo

showers may start turning wintry after 1am tonight, showers dying back to the west and north as the night goes on.



Showers becoming more widespread tomorrow bringing a mixture of rain, hail, sleet and snow, especially over high ground.

Rain getting into the south-west will turn to sleet and snow over high ground and push eastwards across southern coastal counties. Snow more likely on the northern edge of the front away from the coast. It may get as far north as Wicklow.



Rain/sleet/snow clears the south Monday evening and showers die back to the west and north with mostly dry conditions across the east, south and some midland areas.



Tuesday, more of the same, wintry showers becoming more widespread, heaviest across the north and west, more isolated in the east then milder for Wednesday.

lying snow looks limited to areas above 300 or 400 meters with snow at lower levels in parts of Northern Ireland and Donegal.

m17

Wales

lcasey90

Massive amounts of rain falling in athlone can't remember when iv Seen rain this heavy

Mortelaro

Nqp15hhu wrote: »

For snow to fall at sea level you need the freezing level at 500m at an absolute minimum, especially in a saturated atmosphere.

So the snowline will be about 400m there tomorrow.

Not necessarily, but I'm not expecting sea level snow anyway at or about 528 dam

Nqp15hhu

Mortelaro wrote: »

Not necessarily, but I'm not expecting sea level snow anyway at or about 528 dam

It depends on the scenario but in a showery scenario the freezing level being at 800m would just yield rain for most.
Tomorrow, it will depend on the intensity of the rain and the wind speed. The snowfall line could fall to 200-300m.

burren

In the Netherlands max gust from Ciara so far was 129km/h on Vlieland, island off the NW coast. Strongest winds still to arrive. Was on the beach near Hoek van Holland earlier this afternoon. Nice and windy enough but no full blown storm yet. See video impression at https://drive.google.com/file/d/1-ybaIDT7DO493t01iADo23gstGJF0dhK/view?usp=drivesdk

Mortelaro

Nqp15hhu wrote: »

It depends on the scenario but in a showery scenario the freezing level being at 800m would just yield rain for most. It will depend on the intensity of the rain and the wind speed.

The snowline could fall to 200-300m.

The freezing levels can drop in showers
Allied to that you need to watch dewpoints on the higher ground and we aren't talking mountain tops

Nqp15hhu

Mortelaro wrote: »

The freezing levels can drop in showers
Allied to that you need to watch dewpoints on the higher ground and we aren't talking mountain tops

It can but there is a maximum extent to which it can fall and 800m is quite high.

JanuarySnowstor

Bear in mind a lot of Southern areas are above 400m inc populated areas of Cork city. Take the Cork Dublin motorway as an example, just after Mitchelstown this road goes well above 400metres. This event has the potential to cause chaos on this road if it snows for several hours. So I guess my point is quite a number of people live over 400metres particularly in the South. Another example is Cork airport which is 400metres plus above sea level yet is more or less in Cork city. My whinge is Met Eireann should mention this occlusion and that there is a level of doubt whether it's rain or snow. After all the charts are showing this disturbance for days now

Donegal Storm

JanuarySnowstor wrote: »

Bear in mind a lot of Southern areas are above 400m inc populated areas of Cork city. Take the Cork Dublin motorway as an example, just after Mitchelstown this road goes well above 400metres. This event has the potential to cause chaos on this road if it snows for several hours. So I guess my point is quite a number of people live over 400metres particularly in the South. Another example is Cork airport which is 400metres plus above sea level yet is more or less in Cork city. My whinge is Met Eireann should mention this occlusion and that there is a level of doubt whether it's rain or snow. After all the charts are showing this disturbance for days now

Think you're mixing up your metres and feet there, I don't think there's a single settlement in the whole country above 400 metres. Looking at maps.ie the Mitchelstown motorway is only around 130m at its highest

Rougies

JanuarySnowstor wrote: »

Bear in mind a lot of Southern areas are above 400m inc populated areas of Cork city. Take the Cork Dublin motorway as an example, just after Mitchelstown this road goes well above 400metres. This event has the potential to cause chaos on this road if it snows for several hours. So I guess my point is quite a number of people live over 400metres particularly in the South. Another example is Cork airport which is 400metres plus above sea level yet is more or less in Cork city. My whinge is Met Eireann should mention this occlusion and that there is a level of doubt whether it's rain or snow. After all the charts are showing this disturbance for days now

Are you confusing feet and metres? That motorway goes nowhere near 400m. It's at around 100m all the way from Mitchelstown to Cahir. The highest point I can find is about 180m here:


https://www.openstreetmap.org/#map=15/52.2222/-8.2909&layers=C

Also what populated area are above 400m? I would say zero.

JanuarySnowstor

Must be thinking feet rather than metres. I'll say one thing though am 100% certain that road will see snow to a disruptive level tomorrow as will Cork Airport

Gaoth Laidir

According to the GFS the 516 dam line will reach the northwest coast on Tuesday, though I doubt that it will be that low. More like 520 dam. Still enough to give some falling snow in heavy showers, especially with the strong winds.

528 dam rarely cuts it for snow in Ireland, except in a warm-frontal cold air scenario.

davidsr20

My last snow dream for this winter is vanishing fast things like high ground sleet and possible are not what I want to hear.

Nqp15hhu

JanuarySnowstor wrote: »

Bear in mind a lot of Southern areas are above 400m inc populated areas of Cork city. Take the Cork Dublin motorway as an example, just after Mitchelstown this road goes well above 400metres. This event has the potential to cause chaos on this road if it snows for several hours. So I guess my point is quite a number of people live over 400metres particularly in the South. Another example is Cork airport which is 400metres plus above sea level yet is more or less in Cork city. My whinge is Met Eireann should mention this occlusion and that there is a level of doubt whether it's rain or snow. After all the charts are showing this disturbance for days now

400m? Really? That’s quite high!

Nqp15hhu

Gaoth Laidir wrote: »

According to the GFS the 516 dam line will reach the northwest coast on Tuesday, though I doubt that it will be that low. More like 520 dam. Still enough to give some falling snow in heavy showers, especially with the strong winds.

528 dam rarely cuts it for snow in Ireland, except in a warm-frontal cold air scenario.

So an upgrade? Surely that would guarantee snow?

Oneiric 3

Nothing of note here from 'Storm' Ciara, except maybe the 50mm + since yesterday. Wind was more of a nuisance than anything else. Ah well, maybe next time.



Jet shows up nicely in that image. Cool, cyclonic conditions to its north, and the clearly defined Azores High to its south.

nacho libre

davidsr20 wrote: »

My last snow dream for this winter is vanishing fast things like high ground sleet and possible are not what I want to hear.[/QUOTE



Worry not, i think there will be snow at lower levels during the night in the north and west over the next couple of days. There is some very cold air coming our way which won't be modified enough to be the wrong side of marginal at lower levels. I dont think there will be anything disruptive at lower levels, but places like Knock could see up to 10 cm.

DOCARCH

ME have updated warnings. Orange wind and coastal flooding warning now for counties along western seaboard.

Oscar Bravo

Status Orange - Wind warning for Donegal, Galway, Leitrim, Mayo, Sligo, Clare and Kerry

Storm Ciara will continue to produce very strong westerly winds in coastal areas with mean speeds of 65-80km/h and gusts generally between 110 and 130km/h.

A combination of Spring Tides and high seas will result in a significant risk of coastal flooding.

Valid: 06:00 Monday 10/02/2020 to 20:00 Monday 10/02/2020

Issued: 17:00 Sunday 09/02/2020

Oneiric 3

nacho libre wrote: »

Worry not, i think there will be snow at lower levels during the night in the north and west over the next couple of days. There is some very cold air coming our way which won't be modified enough to be the wrong side of marginal at lower levels. I dont think there will be anything disruptive at lower levels, but places like Knock could see up to 10 cm.

My thoughts too. Nothing we don't see a least a couple of every winter.

Can clearly see where these showers are coming from in this sat image below, more from the Labrador sea than Greenland. Not much troughing to be seen at this stage in the flow to organise the showers, but these can spring up at any time, so who knows.

JanuarySnowstor

Metociel euro 4 really going for snow as well with some really cold air moving in from Monday lunchtime. Those who think it will be mainly dry away from coasts are mistaken with such a powerful jet overhead imo