Cold Spell - Feb 7th to 13th 2021 - Technical Discussion

Rock Lesnar

Yeah Gonzo, looks like the Met office forecast there i saw showed snow over much of the midlands and east during the early hours of saturday followed by rain during daylight hours

JCX BXC

Very mixed signals here for West Clare on the models, some suggesting accumulations and others not. It appears certain any snowfall will be a matter of 2-4 hours before turning to slop, however I hope we'll be in a situation where the first snowfall will settle, something nice to look at for a while.

nacho libre

Oneiric 3 wrote: »

10 day forecast from the UK Met:

https://www.youtube.com/watch?v=i1ldY5qCgEY

https://www.youtube.com/watch?v=i1ldY5qCgEY

They talk of mild weather coming in for next week but they are not altogether certain either.

A very interesting forecast, so much good details there for the lay person. I would like to think that low sitting out there in the Atlantic will help to send Warm Air further north, leading to heights later on. Maybe it's wishful thinking, though.

Oneiric 3

We got another very slight air frost last night and the ground (soil) is still very soft and squelchy so no hard frost at ground level at all, which even in the lamest of easterlies it normally wouldn't be. I recall shortly before the epic snow of 2000 arrived the ground was rock hard to the extent that it was like concrete. You could bounce a coin off it if you were so inclined.

Oneiric 3

nacho libre wrote: »

A very interesting forecast, so much good details there for the lay person. I would like to think that low sitting out there in the Atlantic will help to send Warm Air further north, leading to heights later on. Maybe it's wishful thinking, though.

We've had heights to our north or around that area pretty much all winter. and nothing but fleeting wet/semi-wet snow 'events' and mediocre temperatures pretty much throughtout. I say enough. It is time for the sky to thunder and roar.

Donegal Ken

UPDATE

Status Yellow - Snow/Ice warning for Dublin, Louth, Meath, Cavan and Monaghan
Met Éireann Weather Warning

Update: Scattered hail or snow showers continuing for a time this evening with some accumulations in places and icy stretches on untreated surfaces.

Valid: 16:00 Wednesday 10/02/2021 to 20:00 Wednesday 10/02/2021

Issued: 16:43 Wednesday 10/02/2021

DOCARCH

Mod Note: Some posts moved to other thread: https://www.boards.ie/vbulletin/showthread.php?t=2058155857&page=293

I suspect this thread will be busy again this evening, so keep it 'technical'.

Danno

Donegal Storm wrote: »

Can anyone point to a frontal snow event that actually worked out for us over the past 20 years? Maybe I'm forgetting some but off the top of my head I can't think of anything memorable

Haven't looked at the models much this week but just off past experience I'd guess we'll end up with either a weak front with minimal accumulation apart from a few lucky spots or else a more active front that turns into a transitional mess for low ground. We get rarely hit the sweet spot in between

Hoping I'm wrong but the Irish climate rarely fails to disappoint

I think it was either 2006 or 2007 but an atlantic front came through and dumped quite a lot of snow, and all the front fell as snow.

It was certainly a surprise and I remember Evelyn Cusack being surprised by it too on the Six-One weather that evening. There was no deep pool or prolonged easterly before the event, it kind of came out of the blue in a mild winter!

nacho libre

.

Gaoth Laidir

Kermit.de.frog wrote: »

Have to disagree there. Frontal zone hitting this type of airmass. Not wet snow. It's intensity you need to watch.

850hpa temperatures tomorrow evening



Here is the aftermath on Friday...



Note the struggle to shift the deep cold air mass.

Ground temps are not freezing but it won't take much that is persistent to settle either.

Swings and roundabouts.

Note how the frontal gradient is aligned with the height lines (wind), so the front is stalling and dying out.

Below it shows how active the front will be tonight well off to our southwest but the dynamics flop just as it reaches us. The parent low is just too far west. Needed it 5 degrees further east.

munsterlegend

Gaoth Laidir wrote: »

Note how the frontal gradient is aligned with the height lines (wind), so the front is stalling and dying out.

Below it shows how active the front will be tonight well off to our southwest but the dynamics flop just as it reaches us. The parent low is just too far west. Needed it 5 degrees further east.

If it was all rain it would be that 5 degrees east! Hopefully it might surprise us.

Humberto Salazar

Every hour, the snow potential or amount thereof is decreasing. It's been a bitterly disappointing spell. Seasoned watchers knew this, but the chickens are home to roost now.

D9Male

I have been spending so long looking at Thursday - > Friday potential and it really could go either way for Dublin.

I had previously been worried about the marginal effects of the sea air coming from the south east. Then I was worried about the rain shadow from the Wicklow Mountains. I am starting to appreciate that both of those factors might not impact snow potential too much.

Now it seems the main concern is the intensity of precipitation....goodness it is is so hard to get lying snow in Ireland!

We might be waiting until Saturday now!

munsterlegend

Humberto Salazar wrote: »

Every hour, the snow potential or amount thereof is decreasing. It's been a bitterly disappointing spell. Seasoned watchers knew this, but the chickens are home to roost now.

Thank you Little Humberto Salazar snowy old me.

Pitch n Putt

Looking like an hour or two of snizzle at most. Once Met Éireann started mentioning this in the media it was a dead duck.
Had they said rain and sleet we may of had a chance.

squarecircles

lots of snow graphics in the south and west

Villain

The greatest model of them all?

https://twitter.com/MetEireann/status/1359565653775159296?s=20

Gaoth Laidir

And bizarrely, the latest Cork TAF only goes for light sleet from 10 am tomorrow. Similarly Shannon.

TAF EICK 101700Z 1018/1118 09015KT 9999 FEW020 BKN030
BECMG 1022/1024 11020G30KT
BECMG 1107/1109 12025G40KT 4000 -RA BKN008
TEMPO 1110/1118 2500 -RASN BKN003=

TAF EINN 101700Z 1018/1118 10012KT 9999 FEW020 BKN050
BECMG 1100/1102 10017G27KT
BECMG 1109/1111 12020G32KT BKN014
TEMPO 1110/1118 4000 -RASN BKN009
PROB30 TEMPO 1110/1118 1800 -SNRA BKN004=

munsterlegend

Gaoth Laidir wrote: »

And bizarrely, the latest Cork TAF only goes for light sleet from 10 am tomorrow. Similarly Shannon.

TAF EICK 101700Z 1018/1118 09015KT 9999 FEW020 BKN030
BECMG 1022/1024 11020G30KT
BECMG 1107/1109 12025G40KT 4000 -RA BKN008
TEMPO 1110/1118 2500 -RASN BKN003=

TAF EINN 101700Z 1018/1118 10012KT 9999 FEW020 BKN050
BECMG 1100/1102 10017G27KT
BECMG 1109/1111 12020G32KT BKN014
TEMPO 1110/1118 4000 -RASN BKN009
PROB30 TEMPO 1110/1118 1800 -SNRA BKN004=

Are those tafs not compiled by met Éireann? I suppose Cork airport is close to coast if not high enough up.

JCX BXC

I've always found the TAF's interestingly conservative. Perhaps it's just me, but I've noticed a definite decline in quality from them since Air Traffic collapsed, it's as if they're just thrown together.

irishfeen

Sorry this was not technical

redsteveireland

Villain wrote: »

The greatest model of them all?

https://twitter.com/MetEireann/status/1359565653775159296?s=20

One model to rule them all

thecretinhop

squarecircles wrote: »

lots of snow graphics in the south and west

BANK!

Tyrone212

Leitrim and West Ulster area currently looking good for Saturday on the latest ECM. Snowfall accumulation below.

https://weather.us/model-charts/euro/northern-ireland/snow-depth-in/20210213-1300z.html

Rebelbrowser

thecretinhop wrote: »

BANK!

I know this was said earlier in the week but those graphics are awesome, they make things self explanatory. My take away is it could be a good day with the kids in the snow tomorrow. Any rain likely to be after nightfall.

justy182

Tyrone212 wrote: »

Leitrim and West Ulster area currently looking good for Saturday on the latest ECM. Snowfall accumulation below.

https://weather.us/model-charts/euro/northern-ireland/snow-depth-in/20210213-1300z.html

South East Ulster also looking heavy on the other models it seems too 6-8 inches on some of them. Not sure of the accuracy of these anyway though. Seem to change all the time

davidsr20

thecretinhop wrote: »

BANK!

Jesus that looks great for the west

squarecircles

snow really does put the fear of god in gerry,you could see the relief in his face as the forecast ended.

he must be thrilled the mild muck is on its way back

Nqp15hhu

justy182 wrote: »

South East Ulster also looking heavy on the other models it seems too 6-8 inches on some of them. Not sure of the accuracy of these anyway though. Seem to change all the time

It’s centimetres not inches.

squarecircles

davidsr20 wrote: »

Jesus that looks great for the west

yeah i thought id post it since reading this thread youd swear connaught had broken off the country and drifted out into the north atlantic.