Cold Spell - Feb 7th to 13th 2021 - Chat

mickger844posts

Gonzo wrote: »

The front stalls over Leinster, produces 12 to 14 hours of snow and then fizzles out and winds go back into the east. A few flurries still going Friday morning.

If this happened it would be an orange level warning at the very least and possibly red.

In fairness to Michelle Dillion she has highlighted this on all her forecasts on tv since yesterday. At least an Orange Warning and named storm if GFS 18z verifies.

M.T. Cranium

Two trends stand out -- upgrade potential for breakdown snow, and second cold spell after the mild intrusion on weekend 13th-14th. That second cold spell at this point looks entirely dry with potentially very cold nights.

Have noticed the GFS trend towards less sea effect snow for Ireland Mon-Tues, not sure I buy that part especially as the same guidance now shows more sea effect snow in Britain. I would think the two processes should act in phase not a Peter robbing Paul situation, but of course there are lots of other sources of guidance on that question. I would not expect the cold on Mon-Wed to be bone dry all over Ireland anyway, with those uppers and a fairly stiff east wind it seems counter-intuitive. Also it's coming in rather quickly, Sunday night could see some localized weak streamers starting to fire up (northeast coast mainly).

Danno

Just been skirting in an out of this briefly today, but what I see I like.

This, I think is the gift that will keep on giving. Wouldn't be surprised to see sustained snow coverings right out 'till Partick's Day with very few mild days.

Betting the house? Hell yes!

When Met Eireann put snow over Sherkin Island on their 5-day outlook chart, from 5 days out, it raises eyebrows.

pad199207

These are quite remarkable runs I have to say. Those in Leinster really need to keep an eye on the end of the week.

ninebeanrows

Somebody get JS a stool

ninebeanrows

Round 2

Good ole pub run of a Saturday never lets us down

TheMilkyPirate

-12c uppers pushing into South East Ireland

ninebeanrows

On a more serious note, could really disrupt vaccine roll-out in the EU this February

Lolabear2020

Really enjoying this thread the last few days. Even if the snow doesn’t follow through the rollercoaster is great to follow and a welcome escape from the other pandemic discussions. Well done and thanks to all the posters sharing all their information and wealth of knowledge. Could anyone recommend where is best to learn how to read these charts for a complete novice ? Thanks

PokeHerKing

ninebeanrows wrote: »

On a more serious note, could really disrupt vaccine roll-out in the EU this February

No problem with keeping them cold tho!

Davaeo09

Danno wrote: »

When Met Eireann put snow over Sherkin Island on their 5-day outlook chart, from 5 days out, it raises eyebrows.

I've had the pleasure of living on sherkin for 12+ months and I got to view some of the locals photographs/videos from both 2018 BFTE and Ophellia
Both were extreme events for Sherkin and surrounding Islands

On an opposite note the summer I spent there was an absolute stunner too. Often had warm days when my family at home in Kilkenny had low sea clouds rolling dulling their days.

This photo is from a local photographer
https://imgur.com/CLAOYHD

HansKroenke

ninebeanrows wrote: »

Round 2

Good ole pub run of a Saturday never lets us down

My excitement at seeing the word "pub" followed by the sudden deflation as I remember the 6 Nations kicks off tomorrow for Ireland with no pubs open can only be described as like an ice dagger to my heart.

Oneiric 3

giveitholly wrote: »

Just Leinster or could parts of Munster and connacht get in on the action?

North Connacht and Ulster are actually more favoured on this run than Leinster. I think some on here should do a course in journalism or something, as they seem to have already have the base skill in telling you only what they want you to know.

But in all seriousness, imagine getting this excited about an 18z 'pub run' that is still (almost) a week away. Surely those charts would be better off in the FI thread?

M.T. Cranium

The 18z GFS is quite a change for the extent of the mild incursion, it never even reaches most of Britain, so that there's a snow-covered source of deep cold at hand for the renewed cold now depicted for Ireland after Sunday. This may turn into a long-duration cold spell for all of Britain and parts of northern and eastern Ireland with the mild incursion mainly limited to the south and west, possibly one day to around 6-8 C with rain briefly in other areas (Saturday most likely). On higher terrain that would have little effect so any snow pack building up on hills in Ireland would be retained adding more immediate sources of surface modification once the cold returns. Also this sequence should bring down SST values in the Irish Sea by about 2 C deg.

The reason I am skeptical about low sea effect snowfall rates Monday-Wednesday is that the contrast between 850 mb and 8-10 C SST appears near perfect for streamer development, and the wind speeds while brisk will not be a major deterrent. I noticed on the post from Oneiric3 earlier that the output actually spans a wide range and the ops has a lower output than most ensemble members. Would go with the higher ensemble members in this scenario.

Clearly potential for hefty streamers through central and northern England and sometimes those almost make it to the west coast, some of the cloud structure is retained and then it speeds up the redevelopment over the Irish Sea.

My over-under for Dublin snow over the three days would be 10-15 cm range, with chances of it going well over that. This is before any breakdown snow. Not going to speculate on that until the morning forecast period.

lucernarian

Gaoth Laidir wrote: »

The inversion starts just below 700 hPa.

The model should still be able to give a fair approximation of moisture levels. Today's actual 12Z thete-e analysis is fairly consistent with what was forecast 3 days ago, meaning it's got the combination of temperature and moisture more or less correct.

The "kink" in the forecast radiosonde you posted earlier was rather slight at 700hPa. There was a much more pronounced kink nearer 600 hPa. I vaguely remember 2010 forecasts of theta-e and they didn't seem to account for what happened. The granularity of the models in these situations is important. It's still 2 days away.

Danno

M.T. Cranium wrote: »

The 18z GFS is quite a change for the extent of the mild incursion, it never even reaches most of Britain, so that there's a snow-covered source of deep cold at hand for the renewed cold now depicted for Ireland after Sunday. This may turn into a long-duration cold spell for all of Britain and parts of northern and eastern Ireland with the mild incursion mainly limited to the south and west, possibly one day to around 6-8 C with rain briefly in other areas (Saturday most likely). On higher terrain that would have little effect so any snow pack building up on hills in Ireland would be retained adding more immediate sources of surface modification once the cold returns. Also this sequence should bring down SST values in the Irish Sea by about 2 C deg.

The reason I am skeptical about low sea effect snowfall rates Monday-Wednesday is that the contrast between 850 mb and 8-10 C SST appears near perfect for streamer development, and the wind speeds while brisk will not be a major deterrent. I noticed on the post from Oneiric3 earlier that the output actually spans a wide range and the ops has a lower output than most ensemble members. Would go with the higher ensemble members in this scenario.

Clearly potential for hefty streamers through central and northern England and sometimes those almost make it to the west coast, some of the cloud structure is retained and then it speeds up the redevelopment over the Irish Sea.

My over-under for Dublin snow over the three days would be 10-15 cm range, with chances of it going well over that. This is before any breakdown snow. Not going to speculate on that until the morning forecast period.

In early December 2010 there was a mild incursion into much of Munster. I was at a family wedding in Kerry where it hit +10c around Killarney. Back home we were under deep snowfall and sub-zero temperatures.

IIRC the snowcover stopped just west of Roscrea then.

Danno

ninebeanrows wrote: »

On a more serious note, could really disrupt vaccine roll-out in the EU this February

On the plus side, if a refrigeration unit fails, just pop the gunk out on the yard to keep her cold! :pac:

Kermit.de.frog

M.T. Cranium wrote: »

The 18z GFS is quite a change for the extent of the mild incursion, it never even reaches most of Britain, so that there's a snow-covered source of deep cold at hand for the renewed cold now depicted for Ireland after Sunday. This may turn into a long-duration cold spell for all of Britain and parts of northern and eastern Ireland with the mild incursion mainly limited to the south and west, possibly one day to around 6-8 C with rain briefly in other areas (Saturday most likely). On higher terrain that would have little effect so any snow pack building up on hills in Ireland would be retained adding more immediate sources of surface modification once the cold returns. Also this sequence should bring down SST values in the Irish Sea by about 2 C deg.

The reason I am skeptical about low sea effect snowfall rates Monday-Wednesday is that the contrast between 850 mb and 8-10 C SST appears near perfect for streamer development, and the wind speeds while brisk will not be a major deterrent. I noticed on the post from Oneiric3 earlier that the output actually spans a wide range and the ops has a lower output than most ensemble members. Would go with the higher ensemble members in this scenario.

Clearly potential for hefty streamers through central and northern England and sometimes those almost make it to the west coast, some of the cloud structure is retained and then it speeds up the redevelopment over the Irish Sea.

My over-under for Dublin snow over the three days would be 10-15 cm range, with chances of it going well over that. This is before any breakdown snow. Not going to speculate on that until the morning forecast period.

I agree broadly. I'd be (pleasantly) surprised if we got over 10 cm in Dublin.

Nqp15hhu

Oneiric 3 wrote: »

North Connacht and Ulster are actually more favoured on this run than Leinster. I think some on here should do a course in journalism or something, as they seem to have already have the base skill in telling you only what they want you to know.

But in all seriousness, imagine getting this excited about an 18z 'pub run' that is still (almost) a week away. Surely those charts would be better off in the FI thread?

It’s good because it keeps us in the cold and crisp air. That’s all I care for!

Couldn’t give a monkeys about 8c, wind and rain.

Mimon

M.T. Cranium wrote: »

My over-under for Dublin snow over the three days would be 10-15 cm range, with chances of it going well over that.

Kunta Kinte

Dazler97 wrote: »

If it's yellow let it mellow

And if it`s orange?

nacho libre

M.T. Cranium wrote: »

Two trends stand out -- upgrade potential for breakdown snow, and second cold spell after the mild intrusion on weekend 13th-14th. That second cold spell at this point looks entirely dry with potentially very cold nights.
.

Just curious,how can you be sure it will be entirely dry at this stage?? Although your thoughts seem to reflect the Met Eireann monthly.

Danno

I spy with my little eye a potential for precipitation tomorrow over west Leinster and East Connacht spreading west... will temps be cold enough for snowfall?

nacho libre

Oneiric 3 wrote: »

North Connacht and Ulster are actually more favoured on this run than Leinster. I think some on here should do a course in journalism or something, as they seem to have already have the base skill in telling you only what they want you to know.

But in all seriousness, imagine getting this excited about an 18z 'pub run' that is still (almost) a week away. Surely those charts would be better off in the FI thread?

Well there is not much else to do by way of distraction in these strange times, so i can well understand how people are getting excited, but i fear i will need a stiff drink come the morning runs. i will be looking with one eye open

JCX BXC

It's really starting to hurt watching all the potential for everywhere other than the Western third of the country.

Oneiric 3

nacho libre wrote: »

Well there is not much else to do by way of distraction in these strange times, so i can well understand how people are getting excited, but i fear i will need a stiff drink come the morning runs. i will be looking with one eye open

The 18z GFS run is long known to be the Pied Piper of all model runs, but having said that even, I still don't see anything special about it. Good to see cold getting deep into the heart of the Continent - it has been a long time since we have seen something like that, but that's about it.

Gonzo

JCX BXC wrote: »

It's really starting to hurt watching all the potential for everywhere other than the Western third of the country.

keep the faith, once this week is over tonights GFS run has potentially a beast for next week followed by possibly it's uncle.

lucernarian

M.T. Cranium wrote: »

The 18z GFS is quite a change for the extent of the mild incursion, it never even reaches most of Britain, so that there's a snow-covered source of deep cold at hand for the renewed cold now depicted for Ireland after Sunday. This may turn into a long-duration cold spell for all of Britain and parts of northern and eastern Ireland with the mild incursion mainly limited to the south and west, possibly one day to around 6-8 C with rain briefly in other areas (Saturday most likely). On higher terrain that would have little effect so any snow pack building up on hills in Ireland would be retained adding more immediate sources of surface modification once the cold returns. Also this sequence should bring down SST values in the Irish Sea by about 2 C deg.

The reason I am skeptical about low sea effect snowfall rates Monday-Wednesday is that the contrast between 850 mb and 8-10 C SST appears near perfect for streamer development, and the wind speeds while brisk will not be a major deterrent. I noticed on the post from Oneiric3 earlier that the output actually spans a wide range and the ops has a lower output than most ensemble members. Would go with the higher ensemble members in this scenario.

Clearly potential for hefty streamers through central and northern England and sometimes those almost make it to the west coast, some of the cloud structure is retained and then it speeds up the redevelopment over the Irish Sea.

My over-under for Dublin snow over the three days would be 10-15 cm range, with chances of it going well over that. This is before any breakdown snow. Not going to speculate on that until the morning forecast period.

MTC, you're a font of wisdom on this forum. In this upcoming spell, there are a lot of mixed opinions about what is coming up but past experience is that these events deliver for at least some part of the island. Do you really think the upper-level windspeeds wont be an issue for the populated east coast? These might make the favoured areas look like winter wonderlands while most folk nearby are screaming with pitchforks

JCX BXC

JCX BXC wrote: »

It's really starting to hurt watching all the potential for everywhere other than the Western third of the country.

I'm a Bannerman like yourself, such is life. Getting an hour of snow from the frontal edge Thursday would represent a small victory. These set-ups invariably favour the east, don't begrudge them in the least. As long as somebody is happy, looking forward to seeing the photo montage on this thread!

Gonzo

10 to 15cm of snow through much of the country on Thursday. Some places close to 20cm.