FI Charts ( T120+ onwards) Autumn 2023 **READ MOD NOTE IN FIRST

Kermit.de.frog

Tonights ICON is probably the best evolution by day 4. Pretty good for coldies. We are still in the more uncertain stage but we should get out of it soon as the evolution is pretty much within 120 hrs now.

Some good runs but we are not there just yet.

Billcarson

Great to see these type of charts. For many months I thought this Dec would be Atlantic dominated rubbish , considering El Niño. Of course still to be resolved exactly what happens but much better then seeing a raging pv over Greenland etc

nacho libre

ECM doing its best to prolong the cold spell, GFS has it getting milder quicker. The one good thing is the pv is still on holidays from its usual abode in fi. So let's hope any milder incursion is temporary and we go back to cold just before Christmas.

PokeHerKing

https://www.boards.ie/discussion/comment/121419542#Comment_121419542

6z looking much better, more like UKMO/ICON etc

nacho libre

https://www.boards.ie/discussion/comment/121419668#Comment_121419668

Yes, indeed the 6z has flipped towards the ECM. It prolongs the cold spell, and in deep FI it isn't the worse outcome, at least it would be dry. Also who know where this high could go eventually :)

squarecircles

Not sure why people are excited by cold rain in a chilly wind,a handful of frosty nights,with temperatures around the coast well above freezing both by day and by night, before the atlantic barrels through again in early december, the way people were talking earlier in the week youd swear there was something epic unfolding.

BLIZZARD7

https://www.boards.ie/discussion/comment/121420258#Comment_121420258

You just posted a chart for 13 days away… we barely have agreement at day 4/5 🤨 🙄

It looks like a spell somewhat similar to last December / with the setup next Thursday/Friday showing similarities to Dec 2017 but that’s too far out to have a proper idea of how it will play out.

Early December cold spells and setups like this are rare in these parts - and we know it’s coming, we just don’t know how cold it will get or how long it will last. The NH pattern is as good as last December if not better, and we also have the Canadian warming amongst other things going in our favour over coming weeks - a far better position than we are in at the start of the vast majority of winters, if you like cold weather.

In the coming two weeks I would be confident some will see snow, probably cold rain first too - but some will see snow.

For what it’s worth - UK Met office are talking about a two week cold spell.

Hard to be negative when we have this setup on the 1st of December…

pureza

You'd need to be advecting directly, 5 or 6 degrees sub zero surface air in the flows on the above charts to have much more than a cold rain mountain snow scenario in Ireland

And it's just not there

You need that cold a source to survive the sea surface temperature modification

There's little point in not being realistic here

A beautiful chart like the above is useless without beautiful advection

And that's just not there yet but it might be by round 2 and and I see it East and North east of here may stay cold and getting colder and available for those later tap ins

WolfeEire

Snow risk for southern and southeastern counties, on high ground especially, around midweek. England in the firing line for Snowfall in the same period. Subtle differences in the track of the low system will place/remove regions in.or from the risk area. For example, the GFS 12z mean has the low system further south again so it may just skirt our south and east coast allowing for a colder pool of air to be pulled in across Ireland more readily. Where this low tracks will influence what happens thereafter in terms of the nature and length of this cold spell as the other shortwave features popping up in the medium range will consequently also change course if the midweek system tracks further south.

Gem the pick of the bunch so far. Nothing overly severe but perfectly seasonal to kick off December. Edging closer to opening a cold spell thread perhaps or at least a winter 1-120hrs thread?

Cork2021

https://www.boards.ie/discussion/comment/121420960#Comment_121420960

👀👀👀👀👀

Gonzo

At the moment the upcoming cold spell doesn't look disruptive for us, more low level cold with daytime and night time temperatures not that far apart so there may not be much in the way of frost as there will be a lot of cloud around over the coming week. We may get some cold rain or wintriness later in the week but at the moment the snow looks mostly confined to highground here and some low ground in the UK and the European continent.

However a lot can change very quickly and we could be looking at a much more exciting prospect in a weeks time as there is a lot of uncertainty in the models past a few days at the moment.

It's fairly obvious blocking is going to dominate over the coming 7 to 10 days with the AO collapsing over the next 48 hours and remaining deeply negative into the first week of December.

NAO also taking a nosedive tomorrow but it may make a quick recovery back to neutral.

Latest GFS 12z looks fairly mild and could be an outlier, it wants to turn it milder into next weekend with the Atlantic back in action after that but that is in the very unreliable timeframe.

esposito

As nacho mentioned earlier, we could see a brief recovery in temperatures next weekend before things turn colder again. However a lot of uncertainty beyond 96hrs and we could easily see more lows "sliding" with blocking in place. How strong the block is is the big question. Very interesting model watching at the moment. What gives me increased confidence about the winter ahead is the amount of deep cold that's building in Scandinavia and eastern Europe so if we do get more blocking down the line we could get deep cold uppers (at least -8c) reaching us. I'm a hell of a lot more optimistic now than I was a few weeks ago for winter 2023/24. Maybe Christmas Day won't be as mild as I thought now :)

PokeHerKing

https://www.boards.ie/discussion/comment/121420258#Comment_121420258

Stronge take. Don't think anyones mentioned epic (apart from one poster mentioning 2010 which I presume nobody paid attention to as they're not a reg).

Anyway, -8 uppers over and around the island is cause for excitement. Its not that often we get them and they of course have to be near/in situ if we're to have a chance of -10/12 snowmakers.

WolfeEire

ECM keen to get a milder airflow in over Ireland by around day 7-8. Drastically different run from the 00z.

Also, the low pressure area on the Sunday chart disappears come 24 hours later. Strange run but the op is keen to bring in milder air.

Gonzo

A fairly big shift to mild also on the GFS from next weekend with the following week looking very wet once again and mild. Hopefully we can keep a decent depth of cold to our north and east so a few weeks into winter, if we can tap into another round of northern blocking that we can lock into much colder air than what is predicted for this week. My hopes are on for what happens after Christmas.

Best chance of getting some wintry precipitation seems to be around December 1st to 2nd on latest models.

sryanbruen

https://www.boards.ie/discussion/comment/121421608#Comment_121421608

ECM 12z is the best run I've seen this season so far. It ends on the ultimate tease - wave breaking occurs in the North Atlantic with strong warm air advection wafting up from the Atlantic to the pole. On the eastern side this inflates the ridge and winds would go easterly thereafter. Lots of cold air supply too. Absolutely classic stuff but pure fantasy.

WolfeEire

https://www.boards.ie/discussion/comment/121421646#Comment_121421646

Looking at this run in isolation, it's how it gets to the chart you posted and how it handles the various shortwaves after midweek that doesn't look right to me. Collectively, this afternoon's output does shift the midweek low a little further south allowing colder air to be pulled in for the remainder of the week but after that the results are different on the various models other than each trending towards less colder air in about 7-8 days from now. You will probably get a bit of scatter on the ECM ensembles based on the 12z. The 00z had a 7-8c top to bottom scatter by day 10. At least, models are interesting and we are not staring at the Atlantic conveyor belt with no sign of a reprieve.

sryanbruen

https://www.boards.ie/discussion/comment/121421684#Comment_121421684

Yeah I'm only posting it for the eye candy aspect, I have no doubt it would produce a prolonged severe cold spell after as that high inflated and would retrogress after. It has a very 2009 look to it but that's pure fantasy as I mention.

The way it treated Thursday's low being way way south and barely develops it through the English Channel is a bit dubious alright, being very different to all the other deterministic runs despite the southward trend which normally happens with these kinds of lows anyway. I note the ECM verification stats haven't been the best of late either. UKMO seems to be doing the best followed by the GFS.

I would give an overview that would favour a return to milder, Atlantic zonality through the latter part of the first week of December but teleconnections were not very helpful in seeing this "cold" spell (if very meh parameters as has always been the case going into it). The interest purely lies more on if we retain some kind of high latitude blocking even when we go milder then re-develop the blocking through the latter part of December.

nacho libre

I hope the ECM is correct but the way it gets there doesn't look feasible the way the high manages to get through a narrow gap like that. I think the next run won't have it. Though It will be interesting to see the ECM Control run tonight. The GFS was the first to pick out this blocking potential, so perhaps it's right about about a return of the Altantic?

The problem is, as we saw last year, once the Atlantic gets back in it could be there for weeks and no teleconnections may shift the pattern- which would be funny given the current situations shouldn't be happening with AAM being on the floor and the MJO being in phase 2 . It's good there is such extensive cold to the north east, but sod all use if we can't tap into it. Unless you are going on holidays to Scandinavia:)

Jizique

Big change in German long range forecast on wetter.de which was keeping it baltic up to Christmas on friday but is now talking about "absurdly warm" even in Munich in the run up to Christmas

mcburns07

https://www.boards.ie/discussion/comment/121422088#Comment_121422088

4 weeks away, irrelevant

Widdensushi

https://www.boards.ie/discussion/comment/121422128#Comment_121422128

Relevant to this thread. surely, specifically what it's for ,not discussion of previous weather, thanks to all that post forecasts here, much appreciated, obviously the further in the future the less likely to occur but interesting to follow either way ,I presume this will be deleted and rightly so as this is a thread for 120+ model discussion only!!!!

WolfeEire

Gfs nudges the midweek low further south where it only skirts past southern England and heads into France allowing colder air to be pulled in over Ireland. A colder run with daytime temps in low single figures away from the coast on Thursday into Friday.

PokeHerKing

White gold for east coast Thursday night on the pub run

sicknotexi

https://www.boards.ie/discussion/comment/121422242#Comment_121422242

Any snow about though?

pureza

https://www.boards.ie/discussion/comment/121422536#Comment_121422536

Forecasting concensus at this stage away from the highest ground would be a No

WolfeEire

Cooler 06z GFS

2M TEMPS

Gonzo

https://www.boards.ie/discussion/comment/121422536#Comment_121422536

Snow is unlikely away from high ground. Precipitation isn't going to be much anyway and it will be cold rain/drizzle or a sleety mix for most of us.

the main point about this weeks weather is that it's a very welcome break from the deluge pattern we've had for months on end and we are not in the typical Atlantic conveyer belt mild setup that usually dominates winter from start to finish. Model watching is the main interest in this spell of weather to see where we go over the next 6 weeks. Mild weather will likely make a return from week 2 of December but how long it lasts and what happens after Christmas is what interests me the most. I am hoping we can have another go at tapping into proper cold after Christmas. By then we should be able to pull in much colder upper air temperatures combined with cooler sea surface temperatures if get lucky and should be in a better position for low ground snow.

This current spell is taking place final days of November, opening days of December, the seas around us are much warmer now than they would be in January or early February and cold air gets moderated very quickly. We would need something exceptional like December 2010 to get snow end of November/beginning of December. The current spell will have uppers in the -3 to -6 range generally which does not support low level snow with warm seas around us moderating the cold further.

Billcarson

While this upcoming cold spell is unlikely to be as cold as last December's , at least we might have further chances going forward unlike last yr when that was it.

Gonzo

https://www.boards.ie/discussion/comment/121423748#Comment_121423748

the opening week of December last year was a great start to the winter with very penetrating frosts which looked like a covering of snow but yeah once the mild swept in that was winter over and done with well before Christmas. I feel this winter will be a bit different, hopefully we will get several chances from the northeast and east. The past few cold spells we've had in recent winters have been mostly dry affairs, about time we get something very cold and unstable, we are due it by this stage.