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

nacho libre · 08-02-2021 8:43pm

The GFS scenario of earlier is what would happen if this winter was not one big tease, but of course that will fall into line soon enough. I started to lose interest in this event after I read the Met Eireann forecast this morning. Unfortunately at this stage, it's very rare to see upgrades once it starts going wrong. No doubt some people will see a good few hours of snow on Thursday, but for me snow that is then quickly washed away is rather pointless.

Nqp15hhu · 08-02-2021 8:52pm

nacho libre wrote: »

The GFS scenario of earlier is what would happen if this winter was not one big tease, but of course that will fall into line soon enough. I started to lose interest in this event after I read the Met Eireann forecast this morning. Unfortunately at this stage, it's very rare to see upgrades once it starts going wrong. No doubt some people will see a good few hours of snow on Thursday, but for me snow that is then quickly washed away is rather pointless.

Most models show the cold continuing to Sunday. That’s what the BBC forecast said too.

Cw85 · 08-02-2021 8:53pm

nacho libre wrote: »

The GFS scenario of earlier is what would happen if this winter was not one big tease, but of course that will fall into line soon enough. I started to lose interest in this event after I read the Met Eireann forecast this morning. Unfortunately at this stage, it's very rare to see upgrades once it starts going wrong. No doubt some people will see a good few hours of snow on Thursday, but for me snow that is then quickly washed away is rather pointless.

I'm very confused here, a lot of the regular good posters saying it looks like the cold spell will last through the weekend?

DOCARCH · 08-02-2021 8:56pm

Cw85 wrote: »

I'm very confused here, a lot of the regular good posters saying it looks like the cold spell will last through the weekend?

The models differ as to what will happen. I am sure one of them will be right (or be more right) than others....that's the only thing we can be sure of!

TheMilkyPirate · 08-02-2021 9:07pm

Cw85 wrote: »

I'm very confused here, a lot of the regular good posters saying it looks like the cold spell will last through the weekend?

Nacho is further west the front seems like it will dump most snow further east.

I would be more upbeat about Thursday as both the GFS and ECM show a good few hours of snow here (Wexford)

Cork2021 · 08-02-2021 9:09pm

Cork missing out?

nacho libre · 08-02-2021 9:19pm

Cork2021 wrote: »

Cork missing out?

Well, you may get a few hours of snow there before it turns to rain- especially the further north you are, but the closer you are to the coast the greater the risk of it being just rain or sleet from the get go.

nacho libre · 08-02-2021 9:21pm

TheMilkyPirate wrote: »

Nacho is further west the front seems like it will dump most snow further east.

I would be more upbeat about Thursday as both the GFS and ECM show a good few hours of snow here (Wexford)

Yes it looks good for you. I have a friend in Wexford who does not like snow. I know, i should unfriend him for this insolence:pac:

Gaoth Laidir · 08-02-2021 9:25pm

If I were a betting man I would be putting money on that front stalling a bit further west than is currently being progged. Its parent low out south of Greenland shows signs that it will probably retreat westwards slightly more, with flow becoming more aligned along the front earlier, causing it to stall. Frontal dynamic parameters from today's 12Z GFS suggest the frontal gradient will be diminishing, hence reducing precipitation on Thursday evening (see Q-vector div. charts for 00Z and 12Z runs below).

Ahead of that front, heights are pumped northwards over us and help set up a southern Scandi high for the weekend, which should keep the colder air further west for then. I think one or two more opportunities over the weekend could turn out to be a little more potent for precipitation, though exactly how snowy it will be remains to be seen, given the fact that we'll be in more of a stagnating airmass by then.

Kermit.de.frog · 08-02-2021 9:27pm

There is a risk of multiple snow events for some.

ECM has no less than 3 potential "events" between Thursday and Monday particularly in the eastern half of the country.

pad199207 · 08-02-2021 9:27pm

Gaoth Laidir wrote: »

If I were a betting man I would be putting money on that front stalling a bit further west than is currently being progged. Its parent low out south of Greenland shows signs that it will probably retreat westwards slightly more, with flow becoming more aligned along the front earlier, causing it to stall. Frontal dynamic parameters from today's 12Z GFS suggest the frontal gradient will be diminishing, hence reducing precipitation on Thursday evening (see Q-vector div. charts for 00Z and 12Z runs below).

Ahead of that front, heights are pumped northwards over us and help set up a southern Scandi high for the weekend, which should keep the colder air further west for then. I think one or two more opportunities over the weekend could turn out to be a little more potent for precipitation, though exactly how snowy it will be remains to be seen, given the fact that we'll be in more of a stagnating airmass by then.

Anything that can go wrong will go wrong

Gaoth Laidir · 08-02-2021 9:40pm

Cork Airport is getting in on the snow depth reports, with <0.5 cm reported in the last couple of hours.

Still snowing hard in southeastern England, with 26 cm now at Andrewsfield (87 m amsl) from that frontal event.

Cork2021 · 08-02-2021 9:40pm

nacho libre wrote: »

Well, you may get a few hours of snow there before it turns to rain- especially the further north you are, but the closer you are to the coast the greater the risk of it being just rain or sleet from the get go.

Near Mallow, not so bad

TheMilkyPirate · 08-02-2021 9:43pm

nacho libre wrote: »

Yes it looks good for you. I have a friend in Wexford who does not like snow. I know, i should unfriend him for this insolence:pac:

Blasphemy!

Gonzo · 08-02-2021 9:50pm

Kermit.de.frog wrote: »

There is a risk of multiple snow events for some.

ECM has no less than 3 potential "events" between Thursday and Monday particularly in the eastern half of the country.

Just took a look at the latest ECM snow charts, unfortunately I cannot post them here, so I'll leave a link instead and everyone can look for themselves.

Shows snow cover through much of the country from Thursday to the following Thursday. I think it's a bit of a stretch that the ECM is showing snow cover for at least a week but that's what it is showing this evening.

https://weather.us/model-charts/euro/ireland/snow-depth-in/20210217-0600z.html

kerrycork13 · 08-02-2021 9:57pm

nacho libre wrote: »

Well, you may get a few hours of snow there before it turns to rain- especially the further north you are, but the closer you are to the coast the greater the risk of it being just rain or sleet from the get go.

As this poster said. Cork is just too big a county to say. It obviously is more likely to be rain all along the coast but as it meets the colder air and higher altitudes 50 to 60 miles inland for example ballydesmond charleville and mitchesltown the chances are much greater. So to summarise the further north in the county you are the better.
In relation to shower activity though for the next day or 2 the opposite would apply if you get me.
Hope that clears things up for you

Oneiric 3 · 08-02-2021 10:26pm

Pattern over the last few days. Note how the air mass streaming out of southern Norway is consistently diluted as it crosses over the North Sea:

Currently hovering just above freezing here. Doesn't really matter how you dress it up, but this is a woeful temperature for a winter easterly.

pad199207 · 08-02-2021 10:28pm

Oneiric 3 wrote: »

Pattern over the last few days. Note how the air mass streaming out of southern Norway is consistently diluted as it crosses over the North Sea:

Currently hovering just above freezing here. Doesn't really matter how you dress it up, but this is a woeful temperature for a winter easterly.

Not all easterlies are going to hit the sweet spot.

Gaoth Laidir · 08-02-2021 10:31pm

Oneiric 3 wrote: »

Pattern over the last few days. Note how the air mass streaming out of southern Norway is consistently diluted as it crosses over the North Sea:

Currently hovering just above freezing here. Doesn't really matter how you dress it up, but this is a woeful temperature for a winter easterly.

Nice animation. We (especially you) were always going to be on the extreme periphery of the coldest air. Last in the soup queue, so to speak.

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

Gonzo · 08-02-2021 10:39pm

pad199207 wrote: »

Not all easterlies are going to hit the sweet spot.

This easterly is close to a bust. We've seen colder temperatures and better snow showers from the Atlantic and that's saying something.

We still have Thursday to Sunday to hopefully deliver something of note.

Oneiric 3 · 08-02-2021 10:44pm

Periphery or not, these temperatures are extremely poor.

nacho libre · 08-02-2021 10:55pm

It's a timely reminder that easterlies often times are not what they are cracked up to be either. They are very much hit and miss, just like Northerlies.

nacho libre · 08-02-2021 10:58pm

Gonzo wrote: »

Just took a look at the latest ECM snow charts, unfortunately I cannot post them here, so I'll leave a link instead and everyone can look for themselves.

Shows snow cover through much of the country from Thursday to the following Thursday. I think it's a bit of a stretch that the ECM is showing snow cover for at least a week but that's what it is showing this evening.

https://weather.us/model-charts/euro/ireland/snow-depth-in/20210217-0600z.html

I'll believe that chart when i see it!

Oneiric 3 · 08-02-2021 11:01pm

nacho libre wrote: »

It's a timely reminder that easterlies often times are not what they are cracked up to be either. They are very much hit and miss, just like Northerlies.

If there is one benefit to this easterly, it is how dry it is. Nearly blinded by the roads around around the streets here, they look almost white with dryness. Something that has not been seen since about October. Badly needed, yet, I still don't recall any heavy rain this year, just miserable light cold crap pretty much 80% of the time.

nacho libre · 08-02-2021 11:09pm

Gonzo wrote: »

This easterly is close to a bust. We've seen colder temperatures and better snow showers from the Atlantic and that's saying something.

We still have Thursday to Sunday to hopefully deliver something of note.

Just to add, if Thursday to Sunday does not deliver, it will prove that this winter has been one big tease. I know i come across as negative, but it's only because this winter could have been a classic one in terms of snowfall and cold with the nh profile we've have since late December, yet it has led to poor surface conditions overall. The real kicker is that in some winters, where we have endured our default winter pattern, we've actually had more snowfall than we've had so far this winter.

Nqp15hhu · 08-02-2021 11:11pm

The only issue I have is the wind and cloud. It’s quite difficult to sustain subzero temps in sunshine without snow cover.

Here today we struggled to get above 2c despite the sunshine, I think that is relatively cold. Yes the minimums could be better, that is down to the wind rather than the airmass intensity.

An easterly, however, is never going to meet the standards of a good northerly here.

JanuarySnowstor · 08-02-2021 11:15pm

Starting to look incredible for the East Thursday to Sunday
Heavy snow almost a certain red warning for the East and Northeast
Those who are saying this Easterly is a sham compared to years gone by. Em sorry I've lived through them and if the snow delivers this weekend it will be on the top 5 over the last 40 years!!

Cluedo Monopoly · 08-02-2021 11:17pm

Oneiric 3 wrote: »

If there is one benefit to this easterly, it is how dry it is. Nearly blinded by the roads around around the streets here, they look almost white with dryness. Something that has not been seen since about October. Badly needed, yet, I still don't recall any heavy rain this year, just miserable light cold crap pretty much 80% of the time.

I said the same yesterday. This dry period was needed. We were approaching median flood levels.

He is the station at Dangan. The water levels have already fallen significantly since the 4th Jan.

https://waterlevel.ie/0000030098/0001/

Nqp15hhu · 08-02-2021 11:18pm

JanuarySnowstor wrote: »

Starting to look incredible for the East Thursday to Sunday
Heavy snow almost a certain red warning for the East and Northeast
Those who are saying this Easterly is a sham compared to years gone by. Em sorry I've lived through them and if the snow delivers this weekend it will be on the top 5 over the last 40 years!!

Well the snow is very localised. A good system would deliver widespread snow, or provide plenty of opportunities for deep snow.

This one is just rather dry.

nacho libre · 08-02-2021 11:19pm

JanuarySnowstor wrote: »

Starting to look incredible for the East Thursday to Sunday
Heavy snow almost a certain red warning for the East and Northeast
Those who are saying this Easterly is a sham compared to years gone by. Em sorry I've lived through them and if the snow delivers this weekend it will be on the top 5 over the last 40 years!!

If is the keyword. Also be careful JS, everytime you ramp it usually all goes to pot:p

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

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