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

Gonzo

This all just proves how difficult it is to get real snow from a westerly. It takes a while for the cold air to filter in and when it does filter in there are warm sectors at every turn.

It needs proper winds to bring the showers across the country and very unstable air to bring a more prolonged section of snow showers as long as there isn't a warm sector involved.

The downside of the high winds is any showers don't last very long and once showers are finished, snow melt sets in rapidly as daytime temperatures rarely stay lower than 3C or 4C in a showery westerly. The higher windspeeds may also make it more difficult for ice to form which can also gradually melt any lying snow, even at night.

For lying snow and a decent chance of getting proper snow showers, a -10C temperature @ 850hpa offers a more realistic chance of seeing snow fall which sticks properly, getting this from a westerly or even north-westerly is difficult to say the least with 2,000km of warm seas modifying the air. The current cold snap is getting the -7 or -8C uppers over us, which is borderline/marginal but even this is good going from a westerly.

This is why for me an unstable northerly or proper easterly are the only real snowmakers for lower ground with a fraction of the sea track, much colder wind direction, often much colder uppers, less warm sectors, much better dp's and the possibility of ice days.

Sadly we often spend 8 or 9 winters trying to chase down one of these rare easterly's/northerly's during winter. At this stage I would say we are overdue a proper winter easterly, it's been 10 years. The Beast From The East/Storm Emma was more of an early Spring event as it crossed over into March.

Meteorite58

Ferocious squally hail / rain showers going through here in Kerry, a winters night if there ever was one.

10 min avg 42 km/h atm, gusting into the 80's, high gust 85 km/h

4.0C giving a windchill o f -3C

7.2mm

The tide was extremely high tonight, was passing over Blennerville Bridge just outside of Tralee on the Dingle road and big waves were breaking over the bridge tossing large clumps of seaweed onto the road, never saw it as bad there before.

Meteorite58

Just shows you how convective in nature the weather is, sferics record for the last 24 hrs .



Most recent

sparrowcar

Gonzo wrote: »

This all just proves how difficult it is to get real snow from a westerly. It takes a while for the cold air to filter in and when it does filter in there are warm sectors at every turn.

It needs proper winds to bring the showers across the country and very unstable air to bring a more prolonged section of snow showers as long as there isn't a warm sector involved.

The downside of the high winds is any showers don't last very long and once showers are finished, snow melt sets in rapidly as daytime temperatures rarely stay lower than 3C or 4C in a showery westerly. The higher windspeeds may also make it more difficult for ice to form which can also gradually melt any lying snow, even at night.

For lying snow and a decent chance of getting proper snow showers, a -10C temperature @ 850hpa offers a more realistic chance of seeing snow fall which sticks properly, getting this from a westerly or even north-westerly is difficult to say the least with 2,000km of warm seas modifying the air. The current cold snap is getting the -7 or -8C uppers over us, which is borderline/marginal but even this is good going from a westerly.

This is why for me an unstable northerly or proper easterly are the only real snowmakers for lower ground with a fraction of the sea track, much colder wind direction, often much colder uppers, less cold sectors, much better dp's and the possibility of ice days.

Sadly we often spend 8 or 9 winters trying to chase down one of these rare easterly's/northerly's during winter. At this stage I would say we are overdue a proper winter easterly, it's been 10 years. The Beast From The East/Storm Emma was more of an early Spring event as it crossed over into March.

We are getting dangerously close to that cross over where the strength of the daytime sun and longer daylight hours start to work against decent accumulations as well.

Not given up on winter just yet though.

JanuarySnowstor

Well the shower that passed here was heavy wet snow so we are nearly there now for full on snow. Upper 850 temperatures continue to fall away this evening and tomorrow. Example tomorrow at noon we are sitting under -8 uppers whereas today that was -4 at best.
Coinciding with the cold uppers over a warm ocean should kick off some stronger convection through the night. Heavy snow showers that stick are a definite possiblity later but of course only time will tell. It could equally just become cold and drier...

KingdomRushed

sparrowcar wrote: »

We are getting dangerously close to that cross over where the strength of the daytime sun and longer daylight hours start to work against decent accumulations as well.

Not given up on winter just yet though.

.

I've given up on it. Even the Beast from the East was showing in the models at this stage in 2018. There's little chance now of anything proper. Next stop Paddy's Day.

I agree with everything said above about snow from the northwest. It's crap. Even the pictures people share where it has accumulated, it has that horrible sticky already melting appearance. I am almost 40 years old and can say in my lifetime the only proper freezes, decent snow in Ireland has come from the east or the north east or at a push the north. Icicles, powder snow, drifts, the sense of real cold.

Maybe it was different when the ice-cap expanded further south in the winter

Danno

KingdomRushed wrote: »

.
Maybe it was different when the ice-cap expanded further south in the winter

Ice extent is as far south this year as much as if not moreso than anytime in the last 15 years.

pauldry

I'd say if ice extent went as far south as Spain there still be a pool of cold water around Ireland

Oneiric 3

redsteveireland wrote: »

I would imagine the Athenry station is alot more sheltered than Mace head.

Funny thing is, my spot in Galway would be more sheltered than Athenry in westerly type weather but I tend to record higher winds than that station. Another curious trait between here, Athenry and Mace Hd is that Mace Hd, despite its ultra-exposed location, tends to record lower rainfall totals overall, despite having higher long-term average totals than either Tuam or Athenry, to the point where I am becoming a little questioning of official figures from M.H.

davidsr20

All gone quiet here. Are we looking at a downgrade all

Meteorite58

Big showers keep steaming in, looks like mostly wet precipitation in nature tonight so far, recent sfrics Roscommon area. Certainly not cold enough in Atlantic coastal counties at lower levels for anything to stick. More snow showers early morning perhaps.

5.4C here near Tralee, very windy

Rebelbrowser

Decided lack of pink on the radar.

Suspect best chance for lying snow (as always in these set ups) will be snow that falls ca 5 or 6am. But even that would melt quickly enough. Silence on here a bit deafening.....

Gaoth Laidir

Snow warnings for the airports.

Knock EIKN AD WRNG 02 VALID 110100/111000 SNOW FBL 3 to 5 CM FCST NC=

Dublin EIDW AD WRNG 02 VALID 110030/111000 SNOW FBL LESS THAN 1 CM FCST=

Casement EIME AD WRNG 05 VALID 110030/111000 SNOW FBL LESS THAN 1 CM FCST=

Cork EICK AD WRNG 02 VALID 110200/111100 SNOW FBL LESS THAN 1 CM FCST=

Lastest wet-bulbs still struggling to get down. Saturated and flooded ground may be contributing to keeping them up.

pauldry

Even though the wind sounds ferocious out there temperature here has gone from 3.4c to 2.3c in the last hour. Theres hope.

But I'd say heavy hail will be all the white we get with bits on car in the morning.

Morby

What's the weather supposed to be like for Wednesday, I'm supposed to be getting a flight out of Knock then, any chance of it being cancelled due to the weather?

Rebelbrowser

Morby wrote: »

What's the weather supposed to be like for Wednesday, I'm supposed to be getting a flight out of Knock then, any chance of it being cancelled due to the weather?

Basically no

Nqp15hhu

I don’t get the pessimism.

We are currently under a warm sector. However, temperatures at the moment are still relatively low at 3c, so that’s a positive.

I was just out and it is snowing above 200 metres. So this compounded with the fact that the atmosphere is going to cool by 3c by 5am (-7/-8c 850pha) would suggest to me that any showers will be of snow by early morning.

Surely the snow we had earlier today proves that this system is capable of producing low level snow?

Although I would say that this air mass is very saturated. The snow that I have seen lying has been very wet.

Nqp15hhu

Gaoth Laidir wrote: »

Snow warnings for the airports.

Knock EIKN AD WRNG 02 VALID 110100/111000 SNOW FBL 3 to 5 CM FCST NC=

Dublin EIDW AD WRNG 02 VALID 110030/111000 SNOW FBL LESS THAN 1 CM FCST=

Casement EIME AD WRNG 05 VALID 110030/111000 SNOW FBL LESS THAN 1 CM FCST=

Cork EICK AD WRNG 02 VALID 110200/111100 SNOW FBL LESS THAN 1 CM FCST=

Lastest wet-bulbs still struggling to get down. Saturated and flooded ground may be contributing to keeping them up.

Where did you get this?

Gaoth Laidir

Nqp15hhu wrote: »

Where did you get this?

The warnings from Met Éireann's aviation service and the wbt from here

https://meteologix.com/ie/observations/ireland/wet-bulb-temperature/20200210-2200z.html

Nqp15hhu

I will say I have noticed this air mass is particularly saturated. I think that might be having an impact on the snowline

Any snow I have seen has been extremely wet and moist, almost had water within it.

RobertKK

This is from BBC weather.

https://twitter.com/kilkenny_met/status/1227008751749693440?s=21

Cw85

Currently 3 degrees in Carlow town and lashing rain

watlantic

The thing is that the temp. is still too high for snow, but it drops very rapidly during squalls. Before the latest squall here (near Westport) the temp was 4,9ºC, now it has dropped to 2,3ºC within 3 mins, less than half the previous value. Hoping and believing that the wind will gradually go a bit more WNW from the v¡current W and be a bit less intense during sqalls. That should bring a bit more wintry precipitation.

Donegal Storm

davidsr20 wrote: »

All gone quiet here. Are we looking at a downgrade all

Going pretty much exactly as all the main models predicted, i.e. any lying snow confined to the usual high ground.

Expecting to wake up to a dusting again in the morning but as always with westerlies it'll quickly turn to a slushy mess and melt once the sun's up

Had a good covering of hail here earlier but even that's mostly melted now and currently raining, ground is totally saturated so cant see anything that does fall lying for long

pauldry

60mm of rain since the start of Ciara....n 1mm of hail

redsteveireland

RobertKK wrote: »

This is from BBC weather.

https://twitter.com/kilkenny_met/status/1227008751749693440?s=21

So damn all really, another belter of a hail shower gone through here. Probably as good as it will get.

Gaoth Laidir

watlantic wrote: »

The thing is that the temp. is still too high for snow, but it drops very rapidly during squalls. Before the latest squall here (near Westport) the temp was 4,9ºC, now it has dropped to 2,3ºC within 3 mins, less than half the previous value. Hoping and believing that the wind will gradually go a bit more WNW from the v¡current W and be a bit less intense during sqalls. That should bring a bit more wintry precipitation.

[pedant]That's actually only a 0.9% drop, as the absolute scale should be used for such calculations[/pedant] :pac:

But speaking of the wind, 700 hPa winds across the Atlantic today are around 10-20 knots weaker than forecast a few days ago, which means more time for modification in that roundabout route it's taking to the south. We'll see how it goes overnight.

Nqp15hhu

The temperature has been gradually dropping here, we are down to 2.5c from a peak of 3.5c, but the dew points are still positive.

Nqp15hhu

Donegal Storm wrote: »

Going pretty much exactly as all the main models predicted, i.e. any lying snow confined to the usual high ground.

Expecting to wake up to a dusting again in the morning but as always with westerlies it'll quickly turn to a slushy mess and melt once the sun's up

Had a good covering of hail here earlier but even that's mostly melted now and currently raining, ground is totally saturated so cant see anything that does fall lying for long

To be fair the proper cold air hasn’t arrived yet.

Oneiric 3

Must admit, I'm not all that arsed about seeing snow tonight or tomorrow. I just hope that those who are looking for it see some. Temps at all levels will be at their coldest in the early morn so if it is to happen, it'll more likely happen around then.