FI Charts ( T120+ onwards) Winter 2023/2024 **READ MOD NOTE IN FIRST
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01-12-2023 1:03pm#1
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:
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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!
Post edited by Gonzo on16
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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.
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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.
www.x.com/wolfeeire
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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.
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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.
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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!
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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.
www.x.com/wolfeeire
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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.
Post edited by WolfeEire onwww.x.com/wolfeeire
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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.
www.x.com/wolfeeire
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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
www.x.com/wolfeeire
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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).
www.x.com/wolfeeire
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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.
www.x.com/wolfeeire
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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.
www.x.com/wolfeeire
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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.
www.x.com/wolfeeire
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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.
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