FI Charts ( T120+ onwards) Winter 2023/2024 **READ MOD NOTE IN FIRST

WolfeEire

Gfs 06z has cold conditions in store for all of Ireland on the 23rd and on Christmas Eve. It doesn't look like it has huge support in the ensembles but is an example of how the slightest shift in the positioning of that Atlantic high could mean mild/cold. I also would never place much faith in the low Res 06z op run. It would be nice if people could, perhaps, leave the hysterics and winter epitaphs to the general winter thread. The forecast will continue to chop and change over the next few days. Christmas is 10 days away!

almostthere12

https://www.boards.ie/discussion/comment/121498430#Comment_121498430

Those 850s are actually colder than what the GFS was showing earlier in the week, however it was modelling the cold spell for 3 or 4 days at that stage with the vortex dropping down on top of us, now it is just a glancing blow.

pauldry

https://www.boards.ie/discussion/comment/121498359#Comment_121498359

Ya I think all thats certain and even if that is, is that there will be a NW airflow.

WolfeEire

https://www.boards.ie/discussion/comment/121498528#Comment_121498528

That's correct. My point is that talk of a mild or very mild Christmas being all but guaranteed is premature as the latest GEFS panel for Christmas Day shows.

Blocking highs in the Atlantic immediately before and after Christmas is a highly unlikely outcome but a slight shift in position of the heights to our southwest / northwest will deliver dramatically different outcomes for Ireland in this time period. The low pressure that is currently set to rapidly develop out of Newfoundland and wipe away a 1070hpa high centred over Greenland in 24hours is a key element of the forecast one week from now. How it interacts with the Greenland and Atlantic High will have a bearing on where heights eventually settle and whether that position will result in a W/SW or a NW/ N airflow.

Gonzo

The chances of a 24 to 48 hour cold spell is still there on the GFS ensembles but it's a minority option with the overall majority of ensemble members keeping it mild or average in terms of temperature.

Very little rainfall over the next 4 to 5 days then possibly a very wet day around 19th of December. After that we look dryish for another few days. This is the period December 20th to 23th where we might get a glancing blow of cool weather. From Christmas Eve we look increasingly wet and mild once again.

Northern blocking looks completely off the table over the coming 2 weeks, we will have to wait for January for that to make a possible reappearance.

The AO is set to become very strongly positive, potentially near record breaking values for a short while before falling back more towards neutral just after Christmas.

The NAO also set to remain positive over the coming 2 weeks but it does show signs of sliding back towards weakly positive just after Christmas.

Perhaps this is a start of things trending in the right direction for January. I would like to see both the AO and NAO go deeply negative at some stage in January but it looks like we have a bit of a wait for this to happen.

bazlers

https://www.boards.ie/discussion/comment/121498606#Comment_121498606

"The low pressure that is currently set to rapidly develop out of Newfoundland and wipe away a 1070hpa high centred over Greenland in 24hours"

This sentence alone makes me think there is opportunities over Christmas. I cant see a 1070hpa high been wiped away that quickly.

WolfeEire

The seven models covering Christmas morning (1am) are below. The 'Azores' high, a familiar cold killer for Ireland and Britain, has a presence in some shape or form in all as does low pressure spilling out of Newfoundland in the direction of somewhere between southern Greenland and Iceland. The latter interacts differently with the Greenland heights in each model. Might be useful to revist an updated collage of below later or tomorrow to see what subsequent runs produce.

torres9kop

I’m in need for some Xmas cheer. Someone say “upgrade” soon :)

SpitfireIV

https://www.boards.ie/discussion/comment/121499514#Comment_121499514

Upgrade.

How's that? 🤣

Gonzo

Just looking at the long term models and they are all singing from the same hymn sheet about the coming 4 weeks. High and dry for this week, followed by the return of very unsettled Atlantic zonal pattern with mild or very mild conditions persisting right into the 1st week of January. There are weak signs that things may become less unsettled by the second week of January with high pressure possibly getting going over Greenland by mid January. If we are going to get some properly cold weather this winter looks like it will be second half of January or sometime in February. Right now we are along way from setting up anything decent, blocking is absent over the next 2 to 3 weeks and the Atlantic will be back in business from around the 20th of December. A possible SSW is unlikely to happen until sometime in January and the possible affects of that take another few weeks after it's occurred so we're going to need patience.

giveitholly

https://www.boards.ie/discussion/comment/121499953#Comment_121499953

But all that could change in a couple of days? Not saying it will but you seem to jump the gun a bit too quickly at times and write off big chunks of winter at a time

WolfeEire

GEM and GFS showing Christmas Eve cold

almostthere12

https://www.boards.ie/discussion/comment/121500000#Comment_121500000

As you flagged earlier how they deal with the low pressure is very important. The GFS 12 deals with it quite differently from the GFS 06 and keeps it separate to the vortex and not as powerful, hopefully this is now what continues to show on the models.

Possible chance to see some white stuff on Christmas Eve evening if this comes off.

Billcarson

Xmas day looks seasonal on gfs. The models don't know if they are coming r going atm lol.

Gonzo

https://www.boards.ie/discussion/comment/121499998#Comment_121499998

Not jumping the gun, yes we could get some low level cold between now and New Years but without proper Northern blocking a noteworthy cold spell is looking highly unlikely any time soon. We need northern blocking and we need the heights over Spain and Portugal to be gone. Once this happens this greatly increases our chances of pulling in some proper cold from the north or the east but neither of these things are going to suddenly happen in the next few days. Maybe early to mid January we will see this situation unfold.

almostthere12

Looking at the UKMO it doesn't seem to believe that the low really even exists out by Canada:

mcburns07

https://www.boards.ie/discussion/comment/121499953#Comment_121499953

Notoriously accurate 4 weeks out and all

You do love to torment yourself by painting as bleak a picture as possible Gonzo. Reverse psychology perhaps.

WolfeEire

GEM 12z ensembles (bottom) showing that cold snap with a considerable cool-down from the 00z run (top). UKMO at 144-168hrs looks similar to GEM. ECM at 72 hours has the western Atlantic high a tad further south.

Gonzo

https://www.boards.ie/discussion/comment/121500234#Comment_121500234

Reverse pshchology and the fact that the rug has been pulled from under us countless number of times over the past 15 winters with 2009,2010 and 2018 obvious exceptions, oh the joys of being a winter snow lover living in the most north-western country in Europe beside that huge radiator! I am hopeful more than usual about this winter but it's all on the second half of winter.

WolfeEire

https://www.boards.ie/discussion/comment/121500423#Comment_121500423

JMA follows GEM and GFS. JMA showing an unstable airflow on Christmas Eve.

ECM doesn't quite get there even though the high does track further south. A rogue shortwave out of Bermuda deepens and rapidly moves north and west of Newfoundland. Cold air lurks just to the north of the island of Ireland. As I said earlier, subtle changes (of which there will be many more over the next few days) will throw up vastly different outcomes.

2-4 cold spell around 23-26th very much on the cards as it was even before the cold upgrades on other models.

Hooter23

One chart says we are going to freeze another says were off to the beach 🙃 ....id say we'd be better off going with the forecast methods they had hundreds of years ago than looking at these charts

InAtFullBack

It's a very inconsistent output either way from the models which suggests that wholesale pattern changes are going on in the background.

Robwindstorm

https://www.boards.ie/discussion/comment/121500928#Comment_121500928

This is one of the funniest comments I've read in a long time and everyone posting ensembles charts etc . 🤣

WolfeEire

The 18Z (bottom) mean showing increased support for cold from 23rd to Christmas Day than the 12z (top) with more of a NW tilt to the airflow and more troughing over Scandi. The Bermudan Bugger shortwave showing up on the ECM doesn't appear on the op run either. The ensembles will be colder than the 12z.

pauldry

GFS Xmas Party pub run not as cold as I thought it would be. That cold plunge will be gone in the morning run but likely back by the evening one.

Meteorite58

In general I think at this stage we are starting to see a meridional Jet stream possibly giving fairly active weather over Christmas at times. GFS showing some very sharp thermal gradients along with very fast jet , it is churning out lots of unsettled to stormy charts over Christmas including Christmas day , ECM not as severe, some breezy to windy charts but nothing extreme. GEM windy to very windy at times, ICON windy at times, ACCESS- G windy to very windy at times, UKMO run only up to Fri and looking quite windy Thurs/ FRi as are most of the models.

So perhaps we are looking at quick moving systems, alternating between relatively mild to cold at times as the weather comes in waves. Bit of a spread on rainfall predictions but in general looks like fairly wet at times in the Western half of the country especially Atlantic coastal counites. Some models going for a bit of wintry weather leading up to Christmas day but quickly washed away as milder more active weather sweeps over us. Not seeing any major cold spell develop as the patterns look a bit too volatile, but who knows if you get some system coming up against colder airmass leading to a dump at some stage. Thinking the bland benign weather might be coming to an end soon.

pauldry

Climate reanalyzer gives us temperatures 2 to 3c above normal until next Thursday then I assume 2 to 3c below normal after that until Christmas . So probably 3 to 6c or 7c.

squarecircles

6pm christmas evening, heavy snow falling across the country,

what a magical chart.

highdef

https://www.boards.ie/discussion/comment/121502290#Comment_121502290

Fear not, the same chart on the latest run is quite different.

The latest run does still show wintry showers, mainly in northern and western parts, some getting into the north Midlands but it's all very marginal stuff. Inland and high ground would be key requirements to be in with a decent chance of a covering of snow, based on the current GFS run alone.