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FI Charts ( T120+ onwards) Winter 2022/2023 **READ MOD NOTE IN FIRST POST**

  • 22-11-2022 6:31pm
    #1
    Moderators, Science, Health & Environment Moderators Posts: 17,068 Mod ✭✭✭✭


    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 2022/2023.


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


    Thanks


    ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

    Ok, I've had enough of this Autumn and with a week of it still to go, I thought it would be a good idea to open the Winter FI thread extra early, as the GFS short range models are already showing us an insight into the first week of December at this stage.

    After what seemed like over a year of relatively dry and high pressure dominated weather, the autumn brought a significant pattern change to something much wetter since September 2nd. We are still currently in this very unsettled Atlantic dominated pattern but it does look like a change could possibly be happening just in time for the gates of winter of swing open!

    The models are currently playing around with high pressure for the 1st week of December but what they are not sure of is the high pressures position. The positioning of the high pressure at this time of the year is critical to how cold or mild it could be. If the high sits right over us expect plenty of frost and maybe fog. If the high sits to our east, expect mild southerlies or south-westerlies. If the high is just off our west expect a cool north-westerly flow from the Atlantic. If the high pulls out to the mid Atlantic expect maybe a cold northerly shot. If the high positions itself between Iceland and Scandinavia, expect some sort of very cold north easterly etc.

    The GFS 12z just rolled out and is showing a rather chilly 1st week to December as heights try to rise towards Greenland. We begin winter December 1st with a rather chilly easterly wind from the Irish/North Sea. This should be a much dryer scenario than what we are currently in. There maybe some showers on Irish sea coasts but at this stage unlikely to be wintry.

    We generally keep this easterly going through the 1st week of December but it is not a proper cold easterly, a rather cool and slightly unsettled easterly so eastern and northern areas would expect showery outbreaks of rain at times, It would feel very raw in this setup but unlikely to be cold enough for snow away from high ground as we are not drawing in a properly cold easterly.

    We finish up with heights trying to rise over Greenland and Iceland.

    This particular run doesn't really get high pressure sitting over us, so less in the way of frost and fog with this one compared to some of the earlier GFS runs I seen over the past few days. There is an overall cooling trend for the first week of December but nothing properly cold either. Overall it looks like we should get a respite from the Atlantic for at least a week, although it may not be completely dry. There is alot of uncertainty to the first week of December as the positioning of the high and the overall strength of it will be key to how dry we get, if it will become chilly and frosty or could we potentially open the doors to something colder from the north or the east. Alot to play for but it does look like we will begin winter on a slightly more seasonal note than usual.

    Once we get the next week out of the way, things should start to become a bit dryer, but not completely dry either. Expect this outlook to change quite a bit over the coming week especially with the positioning of the high pressure. After a very mild to warm and highly unsettled November, these charts make a welcome change and I wouldn't be surprised if the first week to 10 days of December end up fairly chilly and more seasonal.

    Post edited by Gonzo on


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Comments

  • Registered Users, Registered Users 2 Posts: 8,913 ✭✭✭Danno


    Now...


    Wednesday December 7th:


    and finally, 39hrs later:

    SSW incoming?



  • Registered Users, Registered Users 2 Posts: 91 ✭✭Brendan offaly


    A lot of flip flop with the long range models.

    I see the latest GFS run showing a nice easterly developing.

    There are signs of blocking setting up in December so hopefully the High pressure sits favourable for some wintry weather.



  • Moderators, Science, Health & Environment Moderators Posts: 17,068 Mod ✭✭✭✭Gonzo


    The models are definitely struggling a bit with the first week of December, it's still a week out and the Atlantic will be tough to shift especially for us. If we do get a break from the Atlantic onslaught it may only be for a few days to a week before it's back again.



  • Registered Users, Registered Users 2 Posts: 8,913 ✭✭✭Danno


    The 12z run continues with that theme:

    Note, the GFS isn't wonderful with Irish temperature predictions, so I'd shave a degree or so off those daytime maxes shown - especially away from coasts.


    Also, the SSW over East Russia continues to show up on the charts!



  • Registered Users, Registered Users 2 Posts: 1,987 ✭✭✭BLIZZARD7


    PV is decimated at the latter stages of the GFS 12z and Para - the GEM splits the PV over the pole by day 10. UKMO looks good too.

    A cold easterly coming in over above average SST’s in the Irish Sea at this early point in the season (early December) is the holy grail of wintery setups for the east coast, as we all know from 2010. Im watching this closely and I do hope that’s the discussion we are having this time next week. For now, it’s developing nicely, but plenty of time for it to all to go wrong still.



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  • Registered Users, Registered Users 2 Posts: 8,913 ✭✭✭Danno


    Indeed there is an interesting trend developing...



  • Registered Users, Registered Users 2 Posts: 363 ✭✭YanSno


    Something very interesting is brewing. NA0 going negative in day 10. Highly likely an easterly , northeasterly in week 2 of Dec but the question is from what source. We'll have to wait until next week to get a clearer picture



  • Registered Users, Registered Users 2 Posts: 4,541 ✭✭✭PokeHerKing


    Yous had to go and jinx us didn't yis!

    Hopefully the pub run just got some bad gear!



  • Registered Users, Registered Users 2 Posts: 157 ✭✭Niall145


    Don't worry it's upgraded again.....for now



  • Registered Users, Registered Users 2 Posts: 1,011 ✭✭✭icesnowfrost


    right at the end of the run but still nice to see




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  • Moderators, Science, Health & Environment Moderators Posts: 17,068 Mod ✭✭✭✭Gonzo


    We still have a long way to go on this one. Every GFS run is completely different to the last and there is alot of scatter with an almost equal number of mild vs cool to cold runs.

    The 6z builds a strong area of high pressure over us which would lead to several days of seasonal frost and fog and rather chilly daytime temperatures. This then pulls out into the Atlantic and at the very end of the run tries to pull down a direct Arctic Express which just about reaches north-eastern Scotland. We can't go any further than this but would like to see this high go further north and slightly more to the west.




  • Registered Users, Registered Users 2 Posts: 240 ✭✭konman


    The parralel run (which becomes the operational in 5 days) looks a bit better.



  • Moderators, Science, Health & Environment Moderators Posts: 12,335 Mod ✭✭✭✭Meteorite58




    Nice charts from the ECM tonight. For snow at lower levels surface temperatures still a bit high as are sea temperatures but promising to see cooler weather coming from an Easterly direction, also nice to see on tonight's run much less rainfall accumulations ( most of the projected rainfall to fall by next Weds ). Could see some dustings on mountain tops at the end of the run with a set up like that especially the likes of Wicklow.

    Interesting to see the Jet coming from the NE.

    Chance even colder weather may come from the East ??







    Post edited by Meteorite58 on


  • Registered Users, Registered Users 2 Posts: 8,913 ✭✭✭Danno


    Tonights 18z GFS continues the cold easterly theme as we get into December.



  • Registered Users, Registered Users 2 Posts: 717 ✭✭✭bazlers


    Probably not the correct place for this but anyhow.

    Back in December 2010 where did the source of the cold originate and what was the temperature there at the time?

    Also in late February 2018 the east midlands seemed to get most of the snow from streamers before Emma moved up along the east of the country. Just wondering did the source of the cold originate from the same area as 2010 and what was the temperature from its origins? Thanks.



  • Moderators, Science, Health & Environment Moderators Posts: 17,068 Mod ✭✭✭✭Gonzo


    GFS 6z isn't up to much for cold lovers but the overall majority of ensemble runs is now shifting more towards colder than average for the first 10 days of December.



  • Registered Users, Registered Users 2 Posts: 2,441 ✭✭✭.Donegal.




  • Registered Users, Registered Users 2 Posts: 4,541 ✭✭✭PokeHerKing




  • Registered Users, Registered Users 2 Posts: 2,078 ✭✭✭John.Icy


    Some substantial blocking on several runs, cross model and especially within the ensembles.

    Interesting times ahead. Plenty of runs still look a bit boring with high pressure just too close, but becoming more seasonal regardless. I suppose you will put up with some days of high pressure being too close to us for any action to kick off *IF* the high eventually goes walkabouts to a more favourable orientation and position. No major cold pool lurking so we either need something prolonged to give the cold a chance to start spilling into Europe or else we'd need to look at two bites of the cherry and the first spell will set the scene for a reload that will get going much quicker. Cold spells at the start of real Winter can be a real pain when the cold is far away, not often on this island we get the perfect synoptics lasting 7+ days so all the pieces of the puzzle fall into place. 2010 is a great example. Blocking and wind from the East started ~20th November but the peak of the snow that period was what, the 28th Nov - 3rd Dec?

    GEM a very nice evolution in FI. Substantial blocking to our North.

    By +240 you finally have the deep cold starting to spread from Russia/Eastern Europe. Patience needed.

    Considering it's Day 8, the GEM and GFS are really quite similar, though the GFS does not play out anywhere near as favourably owing to better setup on the GEM. Still, a trend you say? My interest is growing but I feel like we had a phantom cold spell only last December (IIRC?) so staying firmly grounded for now.




  • Registered Users, Registered Users 2 Posts: 2,078 ✭✭✭John.Icy


    ECM at Day 10 another variation of huge blocking to our North. Cold pooling to our East is better here than the GEM, closer...just need things to go our way at that stage with alignment to unleash the beast.

    Let's see where we are Sunday evening when todays Day 8-10 charts become Day 6-8.



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  • Registered Users, Registered Users 2 Posts: 717 ✭✭✭bazlers


    Cheers, but it doesnt really give the source of the cold or the depth of cold from that source. Just that it was arctic air. Was trying to work out the temperature differential between the Irish sea and air temp of that cold air to produce such convection in 2010 and 2018.



  • Registered Users, Registered Users 2 Posts: 4,541 ✭✭✭PokeHerKing


    Needs to be around a 14 degree difference between airmass and sea temps to produce lake/sea snow.



  • Registered Users, Registered Users 2 Posts: 2,078 ✭✭✭John.Icy


    https://www.meteociel.fr/modeles/archives/archives.php?day=24&month=11&hour=0&year=2010&map=7&region=&mode=2&type=ncep

    I believe this should link you to the 24th of November 2010 as the cold starts approaching from the East, 850s shown on this set of charts so you can see depth of cold and also where it's coming from, northern hemisphere view. The next 15 days are loaded on that link but you're free to change them around. The second bout of cold from mid-December came from the north then.



  • Registered Users, Registered Users 2 Posts: 13,738 ✭✭✭✭sryanbruen


    Personally I don't know what to make of it all. There's been a clear signal for a decent number of days now for ridging over Scandinavia to start influencing our weather by early December and give relief from the zonal Atlantic flow which has dominated this autumn since the pattern of the late summer broke on September 2nd. There's a lack of cold residue aloft over the continent to advect westward in an easterly flow. This has been common for many easterly attempts we've seen especially of late it seems - most notably February 2017 and January 2021. This has resulted in retrogression of the anticyclone to Greenland being more vital than ever to allow a trigger low to drop into Scandinavia and give the sufficient cold airmasses that would be required to guarantee sea level snow to an island like Ireland. However, would the blocking pattern be able to sustain itself for that long to feed in these airmasses?

    Sea surface temperatures (SSTs) around Ireland are currently 11-13C with warmest being in the deeper waters of the Irish Sea. These values are around 1-3 degrees above average for this point in the year, particularly in the Irish Sea. Warm SSTs are like a double edged sword. They can enhance instability and lead to higher lake effect rates, therefore more showers. However, if the sufficiently cold airmass is not able to be advected in the first place, then these showers, unless necessary cooling takes place from intense showers, will generally be of cold rain.

    The other thing I am wary about is the state of the stratosphere. The upper stratosphere has had a temporary displacement of the stratospheric polar vortex (SPV) towards Siberia. This in theory would allow for some height rises towards Greenland albeit unlikely a massive omega block that would deliver a severe cold period. Then the upper stratosphere is set to go very cold again over the North Pole with the SPV returning to its home, remember the stratospheric polar vortex naturally is still strengthening until the New Year period when climatologically it peaks in a typical winter. At the same time, we have a very blocked troposphere - at least according to all the modelling of the past week - which leads to a bottom up split of the polar vortex in the lower stratosphere closer to the trop. Apparently, this last happened in the famous late 2010 period to this extent that's been projected by some runs (KEY WORDS being SOME, not all or most!). It must be stressed that is merely a reflection of how lacking such wave reflection from the trop to the lower strat has been since then and blocking highs won't just magically develop in the same way and end up in the same places ideal for cold air advection. If the blocked troposphere disappears, so does any hope realistically speaking for cold lovers of returning to a blocked setup as the strong stratospheric polar vortex aloft higher up would link with the troposphere and give a very zonal pattern which would be difficult to get out of. This is what happened in February 2011.

    Earlier this week, I did this very crude set of diagrams to show the classic evolution of a cold spell that is featured in many past winters. We start off with what we have now basically - higher pressure to our E/NE whilst the Atlantic low gets blocked off to our west. Warm air advection between the two weather systems takes place from Iberia or Africa to the Arctic. This inflates the ridge of high pressure on the eastern side and forces the area of low pressure to our west to undercut. At this stage, airmasses being advected westward via easterly winds and the Scandinavian anticyclone are not typically all that cold - to differing degrees from year to year - though rather chilly in nature as it is a continental flow. However, as the high retrogrades to Greenland, it allows colder air to feed into Scandinavia and northeast Europe. Favourable positioning of low pressure systems to our SE will allow cold air advection towards Ireland. A classic negative North Atlantic Oscillation (NAO) signature. This is what happened in both winter 2009-10 and November 2010. In the case of November 2010, the air was sourced straight from the Urals from an extreme northeast direction that is highly rare.

    We have been taunted time and time again with "potential" from blocked patterns in so many years. Let's not kid ourselves. I would probably have to use more than two hands to count the many times alone. The whole "short term pain, long term gain" has been said to death as of this point and I expect to see it used more again with the lack of cold residue over the continent and waiting for the block to retrogress westward to allow the cold air to feed in from either the Arctic or Siberia. I don't like the sound of putting up with these raw chilly, cloudy easterlies. I will leave model commentary to other posters and will not be much word from me on the matter until a clearer picture is being painted by everything coming together.

    To end this post on a positive note, least we have something to discuss rather than just the rain, rain, rain which this autumn has overstayed its welcome on.

    Enjoy the rest of your weekend and thank you for reading my waffle as always.


    Post edited by sryanbruen on

    Photography site - https://sryanbruenphoto.com/



  • Posts: 0 [Deleted User]


    850 temp ensembles from 0Z run. Trending downwards, but theres still a fair degree of uncertainty it has to be said. One mad outlier suggesting nearly minus 15C! Must have been out on the beer last night.......




  • Moderators, Science, Health & Environment Moderators Posts: 17,068 Mod ✭✭✭✭Gonzo


    GFS 12z has dropped the northerly idea from this morning and going for an easterly instead through the 2nd week of December.

    Showers of a wintry nature blowing up over the Irish Sea and peppering much of Leinster. Donegal and parts of the south coast getting in on the action too perhaps.

    By this stage inland parts of the country struggling to get much above -1C during the afternoon with bitterly cold long fetch easterlies screeching in from a long distance into Russia via the Siberian Express. The east coast is the warmest part of the country in this setup with the warmer than average sea surface temperatures keeping coastal parts of Leinster up to around 3 or 4C.

    This is indeed a Beast from the East for the middle portion of December. Try not to get too excited because this is along way off and the next run could be more like earlier runs where we don't get properly cold or unsettled. If we are seeing charts like this maintained a week from now i'll start to get excited.

    Post edited by Gonzo on


  • Registered Users, Registered Users 2 Posts: 91 ✭✭Brendan offaly


    Perfect time of the winter season for this to happen, ( if it does at all).

    All we need is a little luck.

    Ireland is due a decent cold spell.

    😀



  • Registered Users, Registered Users 2 Posts: 1,628 ✭✭✭Billcarson


    Difficult to know what will happen. We've been here before over the yrs where things look like having potential but doesn't deliver much. At least its something to hang out hats on though. Chilly often dry seasonal weather looks most likely atm for the first half of December. May lead onto something better, may not. But I would take a Seasonal December anyday.



  • Moderators, Science, Health & Environment Moderators Posts: 17,068 Mod ✭✭✭✭Gonzo


    A further swing to the cold side from the GFS with the milder runs becoming less and less for now. We need alot of luck for this to be maintained as this is over 2 weeks away. Everything has to fall into place perfectly and even if it does all it takes is one low pressure from the Atlantic to spoil the fun much like it did in the build up to Christmas last winter. At the same time this is the first time we've had any sort of wintry charts to look at since things went horribly wrong just before Christmas last year.




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  • Moderators, Science, Health & Environment Moderators Posts: 12,335 Mod ✭✭✭✭Meteorite58


    After a few wobbles in the charts ECM showing Lots of cold nights showing up now with frost in places, low rainfall totals, daytime temperatures towards next weekend in low single digits, light winds in general look to back from SE to E to NE to N from about Weds onwards becoming more N'ly towards the end of the run. Looks promising to settle and cool down for a bit. Will see how long the the Russian High keeps the cold aimed at us and helps to block out the Atlantic.







  • Registered Users, Registered Users 2 Posts: 24,409 ✭✭✭✭Kermit.de.frog


    It's looking ever more interesting. Long way to go but this has the feel of something that could evolve in to something special at short notice. Exciting! 😎



  • Registered Users, Registered Users 2 Posts: 3,624 ✭✭✭Working class heroes


    Racism is now hiding behind the cloak of Community activism.



  • Moderators, Science, Health & Environment Moderators Posts: 17,068 Mod ✭✭✭✭Gonzo


    We're back to the more sensible runs that are not all that exciting. Still anything is possible but the most likely scenario is we will get a spell of much dryer conditions with frost and fog possible. After a 3 month deluge this spell of weather will be most welcome and it will still feel alot more seasonal than how the majority of our winters start off with.



  • Registered Users, Registered Users 2 Posts: 91 ✭✭Brendan offaly


    Keep the faith. Charts are all indicating easterly flows.

    Anything is possible.



  • Registered Users, Registered Users 2 Posts: 933 ✭✭✭snowstorm445


    As much as it'd be great to see something evolve I seem to recall a lot of times over the past few years where we've gotten amazing synoptics in the run up to December/Christmas. Whereas the last time they ever panned out was maybe December 2010 (or early December 2017 at a push). We had a very infamous example back in December 2012 which sent us straight into the freezer within a week, the whole Jet Stream across Russia was basically reversed. It got watered down pretty quickly as 95+% of them do.

    It seems to be a running theme at this time of year. We also seem to get amazing runs in the run up to New Year as well. Best not to get drawn in to be honest. Although I suppose it's good that something chilly is on the cards, that's never a guarantee in winter anymore.



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  • Registered Users, Registered Users 2 Posts: 1,441 ✭✭✭esposito


    @snowstorm445 V true. It just amazes me how often a low in the Atlantic suddenly appears out of nowhere on the models and then powers through or to the north of Ireland and it all then goes t**s up.

    As always, it will never be plain sailing for us. The models will chop n change etc. Best not to get too excited at this early stage.



  • Registered Users, Registered Users 2 Posts: 58 ✭✭booferking


    Lock and loaded winter incoming 12z Icon.



  • Registered Users, Registered Users 2 Posts: 4,541 ✭✭✭PokeHerKing


    The gfs has been counting down an easterly feed of some description for over a week now.

    Anything really epic is still way out in FI but I think it's fairly nailed on now that the start of winter will be quite seasonable for a change.



  • Registered Users, Registered Users 2 Posts: 1,987 ✭✭✭BLIZZARD7


    Everything moving up a notch on this afternoons runs - UKMO, GFS + GFSp, GEM and ICON are all stunning. Major northern blocking and an easterly flow of some sort is looking more and more likely for Ireland by next weekend.

    How long we can sustain that and thus how cold it gets is very uncertain still, but I’m starting to get excited now. This has the hallmarks of a vintage winter spell.

    Hopefully the ECM is on the same Siberian express that the other models are on this evening.



  • Registered Users, Registered Users 2 Posts: 157 ✭✭Niall145


    GFS and ECM this morning both showing snow for Ireland next week



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  • Moderators, Science, Health & Environment Moderators Posts: 17,068 Mod ✭✭✭✭Gonzo


    The snow risk has increased a good bit on the 00z, lets see what the 6z brings. Alot of interest across the UK and Ireland is causing Wetterzentrale to be painfully slow or non responsive at the moment.

    edit: 6z milder than the 00z, still has an easterly but more south-easterly so it's drawing up much milder air from the south. However it does look like we will end in a much colder theme towards the end of the run.

    Post edited by Gonzo on


  • Moderators, Science, Health & Environment Moderators Posts: 17,068 Mod ✭✭✭✭Gonzo


    GFS 6z requires much patience to get the cold in but we get there in the end.




  • Registered Users, Registered Users 2 Posts: 15,956 ✭✭✭✭Villain


    That +342 needs to be hidden, poor Kermit will have a heart attack :D

    Great to see a pattern change coming and a chance of something cold and settled, NAO going negative and some other building blocks moving into place but it will be a slow ride to real cold as it just isn't there yet.



  • Moderators, Science, Health & Environment Moderators Posts: 17,068 Mod ✭✭✭✭Gonzo


    The 6z brings snowcover to the south, however this is far too early to be looking at snow coverage.

    Temperatures by night get to around -6C in central areas.

    A fairly major warming is going on at the same time, this is not an SSW but is still a decent warming for this early in the winter.

    Could this lead to a proper SSW end of December or early to mid January perhaps?

    NAO/AO goes deeply negative in early December for a while before staging a recovery mid month.

    No shortage of model watching over the next 2 weeks.



  • Registered Users, Registered Users 2 Posts: 474 ✭✭KingdomRushed


    With ups and downs each day the models certainly seem to be gripping on to the prospect of high pressure developing over Scandinavia in the short term and migrating toward greenland in the medium to long-term. These are the synoptics that bring cold and snow to Ireland in mid winter, so regardless of the final details at the moment it certainly looks healthy and promising for a taste of winter weather for the first time in many years for the December period.

    The GFS ensembles are coming out at the moment for 6z and show a significant upgrade in that pressure signal over greenland in the medium term.

    Still on the right road anyway whether it manifests or not. Looks like a good shot in my opinion without getting the anti-freeze and sleds ready...(yet)



  • Registered Users, Registered Users 2 Posts: 1,628 ✭✭✭Billcarson


    Definitely the most interesting model watching for cold fans in a long while. Lp to the south sends milder air over us for a day or 2 next week then the cold air returns with a vengeance. All subject to change of course. How cold it gets initially depends on that lp. If it ends up further south it should get colder quicker.



  • Moderators, Science, Health & Environment Moderators Posts: 17,068 Mod ✭✭✭✭Gonzo


    ECM 00z not looking bad either, just more of a northerly component to it compared to the GFS.

    We are all going to need much patience over the next week to 10 days to see where do we end up with all this. This is a bit of a slow burner that may or maynot pay off. We shall see. At the same time this is probably the most promising charts we have seen for cold since 2018.



  • Registered Users, Registered Users 2 Posts: 2,329 ✭✭✭Cork2021


    Right I’m going buying a flexi ticket for the snow train!!!



  • Registered Users, Registered Users 2 Posts: 8,913 ✭✭✭Danno


    Make sure it's a one-way ticket tho! 😜

    That was quite a 6Z GFS run and no shortage of cold in it.

    Much of the continent in the -5c to -10c minima range and lower further east. Daytime maxes widely sub-0c too.

    It's gonna be a damn cold wind coming off that towards us.



  • Registered Users, Registered Users 2 Posts: 389 ✭✭torres9kop


    Does that above chart say large volumes of snow for Dublin? Please say yes 👍



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