FI Charts ( T120+ onwards) Winter 2020 **READ MOD NOTE IN FIRST POST**

hatrickpatrick

lucernarian wrote: »

Love the effort man! Just wanted to mention that one of your diagrams appears to have air circulating anticlockwise around the Greenland High? But good stuff otherwise

Ah God dammit This is why you don't try to make graphics before you've had your coffee I'll edit it this evening, thanks for catching that!

Oneiric 3

nacho libre wrote: »

Indeed it was much more straightforward back in 2018, also 2010 if i am not mistaken.

We seem to be seeing a struggle for the Arctic to unleash its cold this season, or should I say, what little cold it contains at this point. For the sort of northerly thee and me would be looking for, we'll have to hope that any severe cold building up over the NE of Europe will return back into the Arctic and and then make its way down to us. I think if there were to happen, it'd be more likely towards the end of this month or into Feb... which isn't to say that it will happen but just more likely.

JanuarySnowstor

Yes would agree it's all a bit underwhelming
2010 the high waxed and waned between Greenland and Iceland.
Still time for upgrades and one important thing to note is even the worst case scenario gives snow chances to hills.
So a wintry spell for highground looks a banker but a substantial cold spell looks 50/50 at best

TheMilkyPirate

nacho libre wrote: »

Indeed it was much more straightforward back in 2018, also 2010 if i am not mistaken.

It surely was more straightforward. Oh to have charts like these 7 days out and then 6hrs out again.


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John.Icy

I'm reluctant to get too excited myself. The Greenland high is so far to our NW on some runs we just don't end up with big cold, lows free to move up over us or to our North. Need that high to push SE or else the cold is going to batter Iceland and we are left praying low pressures play ball and give a chance at frontal snow.

Charts visually look great but we are taking steps away from a severe cold spell currently IMO. We'd be relying on hitting the jackpot with a low pressure just to the south and having a large snowfall from that and I rather not be putting my eggs in that basket. If that happens, fantastic of course. But I am very on the fence about the overall scheme of things currently.

EDIT: The GFS 0z this morning was a more ideal scenario. The high was better positioned and we got a good stab at a severe cold spell. So we still have a chance. Lots to happen with those lows before worrying about where the blocking ends up and what sort of cold we tap into.

CirrusBusiness

Ecm 12z looks good from the 18th onwards!

Oneiric 3

Oneiric 3 wrote: »

We seem to be seeing a struggle for the Arctic to unleash its cold this season, or should I say, what little cold it contains at this point. For the sort of northerly thee and me would be looking for, we'll have to hope that any severe cold building up over the NE of Europe will return back into the Arctic and and then make its way down to us. I think if there were to happen, it'd be more likely towards the end of this month or into Feb... which isn't to say that it will happen but just more likely.

Against that though is a lot of uncertainty, an early FI
Looking at the northern hemphisphere profile, there is deep cold in Scandinavia, Siberia and Moscow
A few days advection from those sources and there's no marginality,not beyond the realms of possibility
We'll see as the fellah says

nacho libre

The issue for so long this winter was that we could not get a high to Greenland, but now we finally can it seems too far north and west - sod's law. This seems a growing signal now. I think the problem is the SSW heightened expectations of what could be- this time last year we would have gladly taken the last frames of the ECM output. Its just all a timely reminder that while the broadscale pattern can look fantastic for deep cold prospects, what weather we actually get is a different matter. Having said that I think we could still get some decent snowfall out of this at times before February, but i don't see ice days with snow on the ground for several days unfortunately.

sryanbruen

Not great to compare 850hPa temperatures with the last cold spell because we seen plenty of times the models underestimated the cold nature of the 850s with the last cold spell (outside of some extreme 18z runs that have been screamed to the heavens of course ).

With a slack airflow and cooler parameters overall like SSTs as compared to where we were in late December, the threshold required for delivering something more significant in terms of sneachta is lower to some extent I would have thought although talking relatively speaking here rather than saying a massive whiteout be on the way.

There definitely has been a trend to a more returned polar maritime airflow though (similar to the start of the previous cold spell) as some have mentioned with the cold air displaced towards Iceland than a direct feed to us from the northeast. This is likely down to a number of factors including the low pressure being overall deeper and not going as far east as some prior runs have shown (including some earlier GFS runs today). Another being the western distribution of a Greenland high although this is more towards deeper end of FI rather than immediate future when the first factor mentioned is likely more telling. The other reason is.. well models just haven't the slightest clue.

I think the UK/Ireland battleground scenario that the UK Met have been hinting at certainly has some credit especially if the NAO becomes more western based later in the period as depressions form in the Atlantic but blocking displaces the jet southward.

esposito

I think we need a scandi high to deliver proper cold from the east. What's coming from north is mixed with atlantic air.

Scandi high to deliver the goods into late Jan and early Feb please:D

CirrusBusiness

Get the high into Greenland first and let things follow after that. That arctic high may come down towards Scandinavia. Lots of possibilities but let's get the Greenland high in situ first and hope things move favourably following after that. ECM has a decent pattern setup from the 18th. Hopefully deeper uppers to follow and more upgrades to come. Still plenty of time..

Oneiric 3

esposito wrote: »

I think we need a scandi high to deliver proper cold from the east. What's coming from north is mixed with atlantic air.

Scandi high to deliver the goods into late Jan and early Feb please:D

Cold easterlies rarely bring severely cold temps though. If we are looking for sub -10s, then a northerly is the only way to go!

nacho libre

sryanbruen wrote: »

I think the UK/Ireland battleground scenario that the UK Met have been hinting at certainly has some credit especially if the NAO becomes more western based later in the period as depressions form in the Atlantic but blocking displaces the jet southward.

Yes, for all the criticism of long range forecasts, you have to hand it to the UKMO if it pans out like this. For all the talk of model volatility before and during a ssw, it would indicate their in house model had a good handle on what would transpire

Oneiric 3

nacho libre wrote: »

The issue for so long this winter was that we could not get a high to Greenland, but now we finally can it seems too far north and west - sod's law..

There isn't sufficient cold to allow cold air advection to take place in order for a Greenland high build in the first place.

bazlers

Lads ye would have given your right arm for this most other years. Personally i dont think things are too bad at all when we are discussion what direction we want the cold to come from. See what the next run brings ; )

nacho libre

Oneiric 3 wrote: »

There isn't sufficient cold to allow cold air advection to take place in order for a Greenland high build in the first place.

There is a Greenland high on the later stages of the ECM.

Oneiric 3

The way things are looking at this point, it does look like we'll finish with a colder than average January, yet, a cold January that will go down as being memorable unmemorable.

Oneiric 3

nacho libre wrote: »

There is a Greenland high on the later stages of the ECM.

Because of a bank of frigid air moving into the Arctic from northern Canada has allowed it. That is my point.

Oneiric 3

Oneiric 3 wrote: »

Cold easterlies rarely bring severely cold temps though. If we are looking for sub -10s, then a northerly is the only way to go!

Well actually for obvious reasons I'd say a long northeasterly is better
No Atlantic modification
Hens teeth
But I'm expecting one soon
Don't let me down PV

Oneiric 3

AuntySnow wrote: »

Well actually for obvious reasons I'd say a long northeasterly is better
No Atlantic modification
Hens teeth
But I'm expecting one soon
Don't let me down PV

Of course, but an Arctic sourced NE'ly is still a 'northerly', just as a continental NE'ly is still an easterly.. in my opinion. Subjective reasoning, but valid.

Donegal Storm

AuntySnow wrote: »

Well actually for obvious reasons I'd say a long northeasterly is better
No Atlantic modification
Hens teeth
But I'm expecting one soon
Don't let me down PV

North easterlies are definitely best. Easterlies, for all their hype on here typically only deliver any snow to the immediate east coast counties with clear skies elsewhere. With a north easterly Ulster gets in on the action and there's a higher chance of disturbances in the flow for some more widespread events

nacho libre

Oneiric 3 wrote: »

Because of a bank of frigid air moving into the Arctic from northern Canada has allowed it. That is my point.

I'm a bit confused here

So is your issue that the origin of this high is much different to what we saw for example in 2010. That was a classic scenario of retrogression that locked in cold.

bazlers

Donegal Storm wrote: »

North easterlies are definitely best. Easterlies, for all their hype on here typically only deliver any snow to the immediate east coast counties with clear skies elsewhere. With a north easterly Ulster gets in on the action and there's a higher chance of disturbances in the flow for some more widespread events

I live in offaly. I had a foot of snow from streamers in Feb 2018 the day before storm Emma arrived.

Oneiric 3

Donegal Storm wrote: »

North easterlies are definitely best. Easterlies, for all their hype on here typically only deliver any snow to the immediate east coast counties with clear skies elsewhere. With a north easterly Ulster gets in on the action and there's a higher chance of disturbances in the flow for some more widespread events

Same source but it's all about the angle of attack. Here in Connacht, and particular here in the south, we need either a direct northerly or even NW'ly to be in with a chance of a decent covering. The heaviest snows during the winters of 2010 and 2000, for example, came from the NW or N.

Tyrone212

Directly Northerly's are best IMO.

Humberto Salazar

Pity about the uppers. They're OK, but not quite good enough. Methinks we may be frustrated until February. I could be wrong.

ninebeanrows

ECM ensembles are out, whilst there is now growing support for a cold spell, few if any members bringing 850hPa temps below -8 to day 10, mean is around -4 from day 8-10.

Oneiric 3

nacho libre wrote: »

I'm a bit confused here

So is your issue that the origin of this high is much different to what we saw for example in 2010. That was a classic scenario of retrogression that locked in cold.

Which came first, CAA or the Greenland high?

Tyrone212

Donegal Storm wrote: »

North easterlies are definitely best. Easterlies, for all their hype on here typically only deliver any snow to the immediate east coast counties with clear skies elsewhere. With a north easterly Ulster gets in on the action and there's a higher chance of disturbances in the flow for some more widespread events

Easterlys are terrible for me. I think North Donegal does well from them, the only place really in Ulster from 2018 that I can remember that did(Monaghan,Cavan did alright i think). My Brother lives near buncrana he was under streamers for days, his car was buried and I had none. Interestingly Shrove in Donegal is further East than Waterford Kilkenny and pretty much identical to Kildare Town. That area of Donegal is exposed to an Easterly.

Oneiric 3

Tyrone212 wrote: »

Easterlys are terrible for me. I think North Donegal does well from them, the only place really in Ulster from 2018 that I can remember that did(Monaghan,Cavan did alright i think). My Brother lives near buncrana he was under streamers for days, his car was buried and I had none. Interestingly Shrove in Donegal is further East than Waterford Kilkenny and pretty much identical to Kildare Town. That area of Donegal is exposed to an Easterly.

It's interesting to note that temps the other night, that came C/O of not a very potent northerly source, reached lower levels than they did at any time during the 'Beast from the East' back in 2018.

2018 Beast min: -7.0c in Cork
2021 so far: -8.2 in Dunsany and Caement.