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

Gonzo

After a very wet and mild Autumn, the season turned cold right at the very end and now it's the all important winter season. Will the current cold conditions persist or will the Atlantic come back and stay here for the rest of winter like it usually does?.

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Mod Note:

This thread is for posting/discussing/analyzing FI CHARTS ONLY i.e. Charts in the unreliable time frame, generally +T120 onward for Winter 2023/2024.

If your post does not specifically relate to an FI chart then it doesn't belong here - Off topic posts will be moved

Thanks

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Remaining chilly over this weekend but we have a warming trend showing that things will become milder during the first week of winter 2023/2024. Current GFS 6z has the Atlantic back in business from this week with low pressures and possibly some windy conditions during the week.

Temperatures next weekend back into double figures widely across the country with plenty of spells of wind and rain.

It continues very unsettled into the following week with low pressures from the Atlantic making it to Ireland with ease.

Week 2 of December starts on a mild note but may cool down as we get a north-east to south-east alignment of the jetstream.

by the end of the run we have warm air trying to move northwards up to the UK and Ireland from the south while at the same time some type of high is trying to form over western Russia and Scandinavian regions.

We finish up on a relatively mild note with the Atlantic still trying to control our weather.

Overall the trend is a warming one but it never gets particularly mild at any stage with temperatures after the recovery from this week close to average or slightly below at times. We are also likely going into a much wetter pattern especially from this weekend onwards.

The next 2 weeks starts off relatively dry over the next few days but becomes increasingly very wet, especially in the western half of the country with large rainfall totals possible by mid month.

There are a few ensemble members that want to bring proper wintry weather back by mid month but for now these are very much an minority option. Hopefully this thread will get alot more exciting soon enough with wintry potential!

Gonzo

Just like the short range models alot of uncertainty with the NAO/AO predictions over the coming 10 to 14 days. Alot of scatter is involved and now we are looking at an NAO forecast which has slowed down the quick return to neutral or slightly positive. Instead quite a few want to keep the NAO negative or quickly go back from temporary neutral to deeply negative yet again, so alot of question marks over the coming 2 weeks in how mild it will become, blocking looks like it will remain but probably not as intense as it is right now.

Definitely signs here that another cold spell could happen mid month if we get blocking in the right position for us.

AO stays largely negative so definitely signs here that blocking may well last longer than we originally thought.

Back to the GFS12z which is rolling out and next Thursday is currently looking very nasty indeed.

and in other news Mark Vogan has released his winter forecast and if you like cold spells in January and February it's well worth a watch. Fingers crossed his winter forecast verifies because it's probably the coldest winter forecast I have seen since I first started watching his videos.

WolfeEire

GFS showing up some nasty looking systems barreling into us. I wonder if the ECM will follow the ICON 12z (below) with the Atlantic coming up against this powerful scandi/Russ block. Unfortunately, we are on the wet/milder side of it i.e. in the mixer.

At 180hrs, NW Europe (including Iceland) the exception at our latitude in northern Hemisphere which is experiencing a fairly intense outbreak of cold. I saw somewhere today that 60% of Europe is currently under snow cover.

adocholiday

I know it's all eyes on the mild vs cold at the moment but that storm for next Thursday is showing in some form on most models now, and GFS is intensifying it from before with the 12z showing a 948hPa landfall. Before this Autumn I'd have said that will likely temper a little bit as we get closer to the day, but the GFS has been surprisingly accurate with some of its 7 day forecasts for storms this year. It had the rainfall totals for Midleton pretty spot on a week out, it was showing storm Ciaran well in advance too, and if I remember right it was showing Debi a week out, although that may have been the ECM.

ECM 12z just out however is showing it way off into the Atlantic bringing some strong gales to the coasts but nothing much overland.

GEM 12z showing it filling as it approaches our SW and by the time it reaches us it's well broken down. ICON 12z has it filling as it northwards well off our West coast bringing some wind to the W/NW but nothing unusual. UKMO 12z has a very small low well off into the Atlantic with zero impact on Ireland.

One to keep an eye on for the moment.

WolfeEire

https://www.boards.ie/discussion/comment/121442972#Comment_121442972

Ecm is imilar in last frame to ICON with the Scandi high pushing west. Heights greater to our south

Meteorite58

https://www.boards.ie/discussion/comment/121443298#Comment_121443298

Yeah adocholiday looks like something brewing. ECM windy overland but nothing exceptioanl on the 12Z, ACCESS-G not a bad model to have in the suite showing very windy windy to stormy by the coasts on Weds and stormy Thurs. GFS has the storm moving relatively slow so giving very strong winds for quite a number of hours on Thurs.

Weds strong winds just on the 120hrs but a lot of uncertainty, maybe a bit clearer tomorrow. You would think that we could well get some strong winds at some stage Weds or Thurs or both.

Looks very wet also, Southern counties showing up the wettest, ECM showing 50mm in 24hrs in places and 35-30 over a wide area, GFS also quite wet, ECM showing 50 to 60 mm along the South over 2 days and higher in mountainous terrain in the SW.

Gonzo

GFS 12z set of ensembles overall increases the chance of having another cold spell between the 11th and 16th of December. The main trend from the GFS is that we are most likely entering another few very wet weeks with deluges possibly coming back.

Alot of scatter from the 7th of December with quite a few very mild runs but also an increasing number of very cold runs towards mid month. Overall a very wet ensemble, most of this is rain but some of it is also wintry potential. The mild turn mid week looks nailed on but what isn't nailed is how long it will last, could only be a few mild days before we turn cold again.

adocholiday

https://www.boards.ie/discussion/comment/121443490#Comment_121443490

2 years to the day since Storm Barra, a 956hPa Storm that made landfall in Galway but that went through rapid deepening on approach. That storm left us with no power for 4 days, it went Tuesday morning and came back Friday night at 10pm so hopefully won't be a repeat of that!

icesnowfrost

All eyes on the 17th 🤤🥶🥶❄️❄️❄️

Gonzo

https://www.boards.ie/discussion/comment/121444483#Comment_121444483

The 18z operational run is very much an outlier at the end, on it's own. As for the rest of the ensembles it's weakening on the potential colder weather mid month and keeping things relatively close to neutral and still plenty of precipitation. We will probably see more changes tomorrow as the outlook is very uncertain past the mild turn towards the end of this working week.

nacho libre

A few of the models have suggested a Scandi high at different times with the the Atlantic hitting the buffer. The UKMO long range also mentioned a chance of a longer cold spell towards the end of December.

i think there are three possible outcomes to this

1: we stay on the mild side of the boundary, with frigid air over or close to the UK. We would have slow moving fronts dumping lots of cold rain in this scenario as they stall and eventually fill

2: A full on return to zonal

3: We get an epic cold spell after mid month

Unfortunately, I think 1 might be the outcome because Russian Highs rarely back far enough west in the end to deliver directly for us, but indirectly a strong Ural High could deliver come January:)

PokeHerKing

All hope gone on this morning runs anyway 😭

Gonzo

The GFS ensembles definitely shifted more towards a relatively average to mild few weeks to come, the potential cold spell around mid month that's been in the GFS for a few days now is more or less gone this morning and replaced by mild or very mild ensemble members. Ah well we knew much of this month would end up average to mild anyway as that is always the way in the lead up to Christmas with 2010 being an obvious exception.

I've read 2 winter forecasts and both have mild for December and much colder potential for January and February. Hopefully by Christmas we'll be starting to see the stuff that dreams are made of in all the models. Gavswinter forecast will be released tomorrow so looking forward to that one.

Hooter23

Expect the charts for next thursday onwards to change alot...storms before or during the weekend could be upgraded...storms could continue into the following week but also a chance of colder weather instead...jetstream could bring them south too...but it does look like our usual storms we always get around christmas for a few days anyway

WolfeEire

https://www.boards.ie/discussion/comment/121446048#Comment_121446048

Spot on. Difficult to read much into our weather beyond Thursday as the track and depth of that depression is chopping and changing all the time. The ECM 12z is very different from 00z for the period thereafter. With continue blocking to our north and northeast, I feel we will see a colder turn before Christmas. As things stand this might come from north or northwest on the backend of low pressure system initially. Very often at this time of year you would look at the long range charts and you would see little, if any, potential for a break in the Atlantic driven pattern but it's different this year. Plenty of potential for cold weather. A stretched polar vortex come.mid December is one thing to look out for.

A turn to milder (not much above IMT for time of year), wetter and windier conditions from Tuesday through to the weekend. After that, who knows.

bazlers

Mr,wolfeEire,

Your dedication to this thread and your knowledge to weather matters in general is certainly in a different league to mine by a long way.

Is a stretched polar vortex not indicate a milder set up for Europe to come? Most of what i have read seems to stress this.

Thanks

WolfeEire

https://www.boards.ie/discussion/comment/121446680#Comment_121446680

Hi Bazlers. It would/could lead to the opposite.

The Polar Vortex is a band of Westerly winds circulating in the stratosphere above the North Pole. The stronger these winds the colder the air in the Polar region. Sometimes these winds can weaken, most often in the winter months. Sometimes, the polar jet stream that hugs its southern flank can also weaken leading to kinks in that super cold airmass. Consequently, a 'stretched" vortex ultimately means a weakened/disrupted vortex that slips off its normal position over the pole and can sometimes precede an a split where this cold pool can also split into two. Cold air gets displaced and floods south. This graphic illustrates this. It can lead to severe cold outbreaks here but as always, it's not always guaranteed as cold can easily flood south instead over North America or eastern Russia etc.

That graphic i posted above is two weeks out so will chop and change. I was only noting what it was showing rather than suggesting it was a strong likelihood.

WolfeEire

Nothing excessively mild on the ECMWF ens for the next 10 days. Heights rising slowly beyond the end of the coming working week. A.lot of spread beyond Wednesday.

bazlers

Hi Wolfe,

Thank you for your reply. Yes i saw that grapic and i would have thought it was suggestive of cold air in to north and NW Europe and then i read Judah Cohens comments and he was stating it could lead to milder conditions in Europe and colder out breaks in N Amrica. Who knows!!!!

The weather will do what it wants and we will just have to keep playing catch up : )

WolfeEire

Gfs has a polar maritime airmass moving in as a slack Atlantic depression tracks east southeast across Ireland into Britain with heights building to our northeast in 9-10 days time.

Will probably be an outlier in the ensembles but it's not an improbable income following a very unsettled preceding week.

Finishes off with an easterly but not one that taps directly into deep cold, rather a modified continental source but cold nonetheless.

WolfeEire

Interesting evolution in GEM. Mild and very unsettled up to next weekend before heights rise in the Atlantic stretching to that seemingly perma-high over Greenland. Gem below. Meanwhile, gfs keeps the Atlantic systems active and demolishes the Greenland heights. Evidence of that predicted stretched vortex showing up on the GFS which will present more interest down the line regarding potential cold in the run up to and over the Christmas period. Ukmo somewhere in between and probably closer to the actual outcome due to a forecast neutral to slight positive NAO and negative AO for the time period. Interesting times ahead. It's not often you can say that in relation to December weather watching

WolfeEire

ECM 12z finishes off with a Scandi high but no real blocking out in the Atlantic, leaving us in a cooler Atlantic flow with the coldest air staying to the north of the island of Ireland. The 12Z is a good bit cooler than the 00z (bottom of 2 images).

WolfeEire

Gfs ens day 7 (as we head into later next weekend) has a few more cooler members and thus follows other model output this evening. 18z top and Oz bottom

The below pressure charts suggests that a polar maritime airmass is most likely i.e. cool and blustery conditions in WSW to NW winds a.k.a. Muck. The weather thereafter alternates between this airmass and less cold westerly or westsouthwesterlies which isn't unusual for the time of year. It would be in keeping with a slight positive NAO. By the end of the run, low pressure systems come barrelling out of northeastern Canada . The days 8-14 ensembles showing a good few colder members than previous runs today with the Jetstream tilting easterly rather than eastnortheasterly which would be in line with MTs thinking this week that low systems will begin to track more to our south as we head toward mid December.

nacho libre

Looking at this morning's output it might be best to take a break from the models for a few days if it's cold weather you are after. Things maybe different on the broader scale in the hemisphere, but we look like having our usual December weather over the next 10 days at least

sryanbruen

Some good points noted by James Peacock or Singularity as he's known on Netweather.

"Since yesterday's 12z run, GFS has diverged from its own ensemble mean by dropping a deep low into Scandinavia. Checking MJO composites for the near-term phase 4 activity, it appears GFS has started following a path typical during neutral ENSO, rather than El Niño"

"The same is true looking at MJO phases 5-6. During an El Niño we usually follow a path that's far milder for (N)W. Europe but also a lot more disruptive to the polar vortex, raising odds of cold weather in that region later on."

"This has been the broad expectation formed by many meteorologists lately, such that Dec is anticipated to have a cold-mild-cold shape for (N)W Europe, while being mainly cold in the E. GFS' new path would really mess with that sequence (colder mid-Dec & lower chance cold after)."

"Of the latest ECWMF ensemble set, nearly half follow that pathway, though only about a quarter make so much of the trough into Scandinavia. Seems to me we're yet again seeing questions raised regarding how well connected to the atmosphere the El Niño event will be."

"P.S. Even if we do follow the neutral ENSO style pathway, there would be a good chance of substantial disruption to the polar vortex, but it would be a bit later in time, with any resulting SSW more likely to be early to mid Jan rather than final third Dec... which is to say, the SSW-related chance of a substantial cold spell would be shifted from mainly in Jan to mainly in Feb.

With that in mind, this will be an important week of forecast modelling with respect to what goes on over Scandinavia next week & the subsequent impacts."

WolfeEire

https://www.boards.ie/discussion/comment/121451728#Comment_121451728

It's looking rather zonal for the next 10 days with your typical transitions from SW to NW airmasses. You would need to see hints of changes to this by the end of this week for any Christmas cold prospects to materialise.

Would have thought, with an active Atlantic, that this precip accumulation chart would have been higher for the 16 day GFS period. That said, these totals are not what we want to see with already saturated ground.

WolfeEire

High pressure stretching from Iberia to the mid Pacific in the GEFS mean. I am thinking that would be common in a situation where the vortex is stretched. You also can see how the jetstream is impacted by these heights, becoming less vigourous. Perhaps, a sign that the Atlantic will return to at least a neutral state by the end of the current GFS window.

Gonzo

I feel there is still some scope for a possible cold outbreak in the next 3 weeks. The 12z is a bit of an outlier with a strong area of high pressure over us followed by something of a cold snap right at the end.

Overall looks very wet from Wednesday, through the weekend and into the early part of next week. After that there does appear to be a dryer trend and faint signals of a cooling trend which may or may not lead to a potential cold spell. The next week to 10 days of model watching will be crucial for developments over the Christmas period.

From December 12th to the 20th there is a lot of scatter there with very mild and chilly ensemble members.

nacho libre

The ECM in FI showing the cold coming back to the north east. The outlook after the wet period could be cold and dry. Any high over us, as the GFS shows, at this time of year should lead to cold nights, and cold days due to inversion. You would have to say no signs of any snow yet, but if we do get a high over us, if the mjo does go to phase 7 or 8 in the days ahead, then hopefully that will lead to any high in situ moving north west or north east rather than sinking.

InAtFullBack

Anyone for a 1100hPa anticyclone over Greenland?

InAtFullBack

Just for records sake:

1,084.8 hPa

The highest adjusted-to-sea level barometric pressure ever recorded on Earth (above 750 meters) was 1,084.8 hPa (32.03 inHg) measured in Tosontsengel, Mongolia on 19 December 2001.

igCorcaigh

https://www.boards.ie/discussion/comment/121455633#Comment_121455633

They could do with scaling that measure onto a more interpretable metric, eh?

Compress and logarithm perhaps, but the measure of hPa isn't particularly understandable to plebs like me.

InAtFullBack

Flood gates to the north are open for business!

WolfeEire

The 18z GFS run brings us The Polar Express for Christmas. 🚊❄️

Fantasy Island eye candy (and that's all it is for now). If this isn't an outlier (it is nailed on to be), I am heading to the bookies in the morn.

InAtFullBack

https://www.boards.ie/discussion/comment/121455652#Comment_121455652

Perfect ingredients for a polar low to whip up over the mild north Atlantic waters...

Billcarson

https://www.boards.ie/discussion/comment/121455649#Comment_121455649

A bit like when the floodgates opened for the second cold spell in Dec 2010 around the 17th/18th. We can but dream for now.. ...

Gonzo

Now that's a proper northerly with -9 to -10 uppers cold enough for snow to low levels right down to the beach, no Atlantic mixing, the biggest problem would be precipitation due to our geography, would need some polar lows to bring snow down across the country. As is if it verified it would be much colder than the low level cold and dampness of the current cold spell. I suspect this might be the first tease of what the final third of December could have on offer, most likely back to a mild run for the 00z. Hopefully more interesting charts to come over the coming week with a growing level of confidence in the possibility of an end of December proper cold spell.

WolfeEire

https://www.boards.ie/discussion/comment/121455652#Comment_121455652

As far as outliers go this one will be well out there. Ensembles showing little support.

nacho libre

Crikey what a run. The pv descending on Scandinavia. No marginality here folks!

Too bad the GFS will have sobered up in the morning- or is this like when it picked up on the current cold spell and none of the other models were interested, we can only hope!

Gonzo

The GFS 00z and 6z have well sobered up as expected.

kittyn

https://www.boards.ie/discussion/comment/121457038#Comment_121457038

For now ;) I just have a feeling something is brewing!

pauldry

The CFS promises a cold Xmas day on its ever flipping runs just 480hours away

WolfeEire

GFS 2m temps showing progressively cooling temps from about a week from now. It certainly isn't showing any sign of a significant warm-up leading up to Christmas. Conditions look quite zonal initially but definite signs now of pressure rising near/over Ireland.

InAtFullBack

https://www.boards.ie/discussion/comment/121457038#Comment_121457038

Indeed, though the 06Z does show high pressure from NFL to Azores building up and possibly linking up with heights already over Greenland. A low looks set to track into Scandinavia and bring down an arctic blast in time for Christmas (if the GFS only went on for another 120hrs). Though it must be said that I'm probably over-optimistic in reading into this as a trend back towards last nights 18Z!

Gonzo

At the moment the GFS is suggesting a slight cooling trend which is mostly down to the potential north-west to south-east alignment of the jetstream from a weeks time which is still a relatively mild direction as it is still very much Atlantic driven. I'm fairly certain we shall see a few interesting charts pop up again over the next 2 weeks, maybe complete outliers that will gain extra support over time.

What I would love to see is a proper SSW split around Christmas and not having to wait till end of January or beginning of February when most of the ships have sailed by that point and we'd be looking at March for any possible effects on our weather.

nacho libre

I wonder what the lag effects between the mjo going to phase 7 or 8- assuming it does- and the response we might expect to see in the troposphere arising from it. If( always if) it happens might we then see a high near us eventually going north westwards during Christmas week?

With this in mind lets hope last night's GFS run, albeit an outlier, is the start of a trend we see repeated in some runs over the next few days.

As regards an eventual SSW, I've read a period of zonality beforehand might be better, because if the Northern Hemisphere is similar to what we have now, then an ssw could end up shaking things up for the worst by bringing about a zonal pattern

WolfeEire

500hpa anomalies for Christmas week (Dec 25-31) via ECMWF. The EC42 has a propensity to change but it's.an interesting medium range forecast for cold prospects

WolfeEire

"Zonal swells, zonal swells, zonal all the way" 😥

Models are largely in agreement about a continuation of an Atlantic driven weather pattern up to 21st/22nd. The jetstream is set to shift to further north next week as high pressure builds from the Azores and Iberia, which has been the deathknell of cold prospects in many a December. The latter is subject to change but, as things stand, it will dictate our weather in the run up to Christmas. Slight changes in how this high positions itself will change the forecast so an interesting few days ahead. The CFS is an example of what could happen but...it is the CFS (https://www.meteociel.fr/modeles/cfse_cartes.php?ech=198&carte=0&mode=1&run=0)

WolfeEire

The GEM does something interesting with the area of high pressure toward the end of the run as it regresses further northwest and begins to link up with the Greenland high and direct the colder airmass south toward Ireland

Gonzo

GFS 12z delivers a white Christmas for Greece....

They don't need SSWS, Easterly QBO's, seaface temperatures don't matter either, they just get snowy outbreaks every single winter almost guaranteed at this stage.

WolfeEire

https://www.boards.ie/discussion/comment/121462579#Comment_121462579

The JMA does something broadly similar to the GEM for the same timeframe.