Significant Snow risk - Monday 29th/Tuesday 30th

nacho libre

To_be_confirmed wrote: »

On that point of snow sticking on wet ground:

A few weeks ago, there was a snow event one Saturday night in the greater Dublin Area. I can't be arsed finding out what date, but much of Kildare and Meath and north Co. Dublin saw an inch or snow. That started off as heavy rain and I followed its progress during the evening turning to sleet and then becoming heavier and turning to wet snow. As the snow became more solid and "dry" it began to stick. It only took 5 minutes for that heavy snow to start sticking and it was barely below freezing at the time.

There were also reports of wet snow which managed to stick on cars etc. in Galway on 30th December and I remember thinking what difference a drop of half a degree would have made. Snow is capable of sticking to slush so if the temperatures are right, it will stick no matter how wet the ground is.

Having said, the model predictions still look too "perfect" to believe, given the number of LP systems that ended up having a warmer than expected cold sector or a myriad of other mishaps that we've seen on this forum too. I'll believe the < -7 degree 850mb temperatures when I actually see the measurements on Tuesday evening.

Edit: Irishdub14 has beat me to the point about that Saturday night!:p

just to add to that at the end of the so-called big freeze. i had very heavy snow in a near gael for four hours that started to stick in spots even though the ground was extremely wet. however once the air temperature dropped by half a degree around 5 pm it started sticking readily. i ended up with 3 and a half inches of snow by 9pm. lord knows how much there would have been if it had stuck from the very beginning. it eventually stopped snowing at 1 am that night!

Deep Easterly

One or 2 splashes of sleet on the window now!

darkman2

The country is on the edge of a very steep gradient in temperatures with a mild sector to the Southeast but this will clear away and the colder air will dig in behind. It will be an interesting day tomorrow. Still, some snow should fall in the North/West Midlands and even the Southwest down to low levels at times this evening and tonight. The main snow event is not till tomorrow evening onward for most but the North will see snow before then.

redsteveireland

Temp down 0.5 in the last hour to 4.0C now, giving a windchill of -0.4C.
source www.oranmoreweather.com

redsteveireland

Deep Easterly wrote: »

One or 2 splashes of sleet on the window now!

It's easy to excite us these days! Sleet even gets an exclamation mark! I love it!

Deep Easterly

redsteveireland wrote: »

It's easy to excite us these days! Sleet even gets an exclamation mark! I love it!

Back to rain!!

lucernarian

seamus wrote: »

Would I be right in thinking that ground temperatures are key here? There's nothing to say that water cannot be liquid @ zero degrees for a certain amount of time. So if the ground temps are sufficiently cold (0 or less), then there's no reason why the snow should melt on the wet ground because the water is already at or below freezing.

Not exactly. The ground will never be at 0 degrees after it has been raining except perhaps on the very surface. The trick is in the temperature of the snow itself. Ice has a bit less than half the heat capacity of water, so (depending on exact circumstances of course) the ice will need to be at -2 degrees or so to cool down an equivalent amount of water at +1 to its freezing point. If the snow was continually falling but the air temp was about 1.5 degrees for example, then there would need to be an awful amount of snow to counteract the air temperature being 1.5 degrees too high as well as reduce the grass temperature to zero. And in those circumstances, the snow would melt reasonably quickly whether the ground was wet or not beforehand!

Lumi

Heavy sleety rain & temperature has dropped to 3.6c. I'm beginning to take the forecasts for snow later a bit more seriously now

Deep Easterly

Fionagus wrote: »

Heavy sleety rain & temperature has dropped to 3.6c. I'm beginning to take the forecasts for snow later a bit more seriously now

3.7c here. Temperature of the actual rain is 3.2c.

14.2mm of rain so far today.

redsteveireland

3.7°C (38.7°F), Apparent temp -1.8°C

Deep Easterly

redsteveireland wrote: »

3.7°C (38.7°F), Apparent temp -1.8°C

What part of the best county in Ireland are you in Red?

Dr. Kenneth Noisewater

Deep Easterly wrote: »

What part of the best county in Ireland are you in Red?

No he's in Galway!

redsteveireland

Deep Easterly wrote: »

What part of the best county in Ireland are you in Red?

That would be Oranmore at present.

munsterlegend

Deep Easterly wrote: »

What part of the best county in Ireland are you in Red?

but he is in galway?!

seems spring like down south - dry even a hint of sun! where is this cold weather? i'll be shocked/amazed if i see snow.

i'd say tomorrow's potential even is an east/north affair as opposed to the south and west?

Su Campu

Back in February soil temperatures were way colder than the 6-8°C they are now. I reckon there is virtually no chance of seeing snow stick below 200m, except maybe in one or two parts of Ulster where orographically-enhanced falls may be enough to do it.

Deep Easterly

munsterlegend wrote: »

but he is in galway?!

seems spring like down south - dry even a hint of sun! where is this cold weather? i'll be shocked/amazed if i see snow.

i'd say tomorrow's potential even is an east/north affair as opposed to the south and west?

I am just wondering if that clearer section over the south will kick off a couple of thundery type showers? Hard to tell although they are not really forecast.

munsterlegend

Su Campu wrote: »

Back in February soil temperatures were way colder than the 6-8°C they are now. I reckon there is virtually no chance of seeing snow stick below 200m, except maybe in one or two parts of Ulster where orographically-enhanced falls may be enough to do it.

you're building yourself up for a fall?! is that prediction for all week or just for tonight/tomorrow?

i'd reckon places in the north leinster and connacht will see some snow below 200 m this week. as for munster unlikely at these levels.

darkman2

The first of the 12z models is out.

This is a blizzard potential tomorrow night allbeit on a model I would not regard as as accurate as some of the others. But interesting none the less at such a short range.












All models agree on snow but there is a slight variation in timing by about 6 hours and slight deviations in the strength of the wind. Will post the GFS charts shortly.

lucernarian

Two NRA stations about 30 km apart are showing a nearly 3 degree gradient! I believe they're roughly at the same ASL. The station at New Inn on the N3 is showing 2.9 degrees and the station to the north of Navan is showing 5.6 degrees.

I've been looking at the latest satellite images and station reports from around the UK/Irl. There's nothing particularly noteworthy that I've spotted. It appears that the second low in the Bay of Biscay is travelling as projected towards the immediate south of Brittany.

Edit: NRA weather station site is here in a graphical map format. http://www.trafficweather.info/roadWeather/rwisMap.jsp?client=208

Deep Easterly

Interesting range of temps across the country at 4pm on the met reports:



:eek:

Su Campu

munsterlegend wrote: »

you're building yourself up for a fall?! is that prediction for all week or just for tonight/tomorrow?

i'd reckon places in the north leinster and connacht will see some snow below 200 m this week. as for munster unlikely at these levels.

For the next 24-36 hours. Note I said for it to stick. There may be wet snow to lower levels but I wouldn't expect it to stick. After that the really cold air sets in, in which case any LARGE organised convective systems could produce it to lower levels, but with shower activity quickly dying out in the evening, nighttime showers will be confined to the north and west, where ground temperatures may be cold enough for some accumulation in the heaviest of these.

Dr. Kenneth Noisewater

Wet snow has arrived in Oranmore!

Very wet snow, still can hear raindrops mixed in

wild handlin

Hi all,

Started snowing here outside Enniskillen in the past 20 mins or so.

Well, large snow flakes mixed in with the rain. Call it sleet!!:D

Wind blasting directly N NW at the moment, getting very cold out, just lit the fire! brrrr!!

Deep Easterly

Still 100% rain in Tuam.. 39m asl.

darkman2

Snow watchers in the UK willo be looking at Ireland and drooling over these charts whilst at the same time thinking "jammy bastards":D


Tomorrow 8pm



2am



Wednesday 8am



Tomorrow evening







The forecast is basically the same as it was this morning. No discernable change.

nacho libre

the wind has picked up so the cold air must be digging in:)

the rain, with bits of sleet thrown in for good measure, has got lighter now.

nacho libre

Deep Easterly wrote: »

Still 100% rain in Tuam.. 39m asl.

i hate to repeat myself, but what can you expect living in Tuam. even the snow has the good sense to stay away:p

owenc

wild handlin wrote: »

Hi all,

Started snowing here outside Enniskillen in the past 20 mins or so.

Well, large snow flakes mixed in with the rain. Call it sleet!!:D

Wind blasting directly N NW at the moment, getting very cold out, just lit the fire! brrrr!!

Oh yes has cooled down dice earliers 5c .. 2.5c now maybe snow earlier than midnight... I just hope you arnt getting snow because your in a heavier burst.. Is this going to stall??

Deep Easterly

nacho libre wrote: »

i hate to repeat myself, but what can you expect living in Tuam. even the snow has the good sense to stay away:p

Buff alert!

thecretinhop

christ its lashing down here now very intense a bit of wet snow in it as well


edit: big fecking flakes it snowing heavily and raining at the sametime claregalway