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

Danno

GFS 06Z Gives us cool/cold from the northwest mostly from Saturday to next Wednesday, then a fairly mild southwesterly for ten days thereafter. Hints of a cold push from the northeast right at the end of the run.

GEM 00Z keeps us cool/cold from Saturday until next Friday, but a straight line westerly with +5c uppers back to Newfoundland looks like establishing from next Friday and over the following weekend.

ECM 00Z a little different. Looks to set up a huge low pressure system west of Norway and keeps us in the cool/cold.

Overall the three big guns have us under low pressure driven weather with us on the cool side for the next week. Chances of transient wet snow showers and I'd say any accumulations really for hills and mountains. Anything at low levels will be slight coverings and short lived.

pauldry

Yes there will be a cold snap next week for a day or two with widespread wintry showers but after that back to what we have had but perhaps not this wet.

Gonzo

I don't think this cold snap is going to do much in terms of snow away from high ground. Southern and eastern areas could get a dry day or 2 out of it which was probably the best case scenario rather than sleety showers keeping everything very wet. It's typical toppler stuff and then back to relatively mild conditions. Everything about this is from the Atlantic too many mild sectors etc etc.

squarecircles

Yeah unfortunately the cold snap wont have much impact in Meath.

By TUESDAY it seems likely to be cold enough for snow or sleet, and a "polar low" is indicated for western counties, dropping south in the upper level northerly flow. This will lead to an interval of wet snow and less windy conditions until the polar low has passed south. We'll have to keep an eye on this, sometimes this scenario at seven days can change into a track further west which leads to a more variable precipitation outcome; there are also concerns the polar low could strengthen and become a locally disruptive event. At this rather distant time range, temperatures are likely to be in the range of -1 to +3 C.

nacho libre

It probably won't have much adverse impact on lower ground. Provided there are no further downgrades, I still think that transient lowly lying snow is possible, and having not seen a flake of snow so far this winter that will do me. I would love ice days and significant accumulations of dry snow as much as anyone, but that is not going to happen anytime soon, unfortunately.

.Donegal.

Lower ground snow possible on the UKMO. -8 uppers touching north coast day 5. -6 NW Connacht to a line just south of Dublin.

UKMO is an improvement on the previous run. Day 6 and 7 below. I wouldn’t rule anything out yet

WolfeEire

The UKMO is looking very wintry at times

The GEFS ensembles are an upgrade on this morning's run with the milder air holding off for longer. The GEM and ICON both rather marginal. The JMA showing potential for a rain/sleet to snow event early Tuesday.

Arguably, the potential for snowfall is currently greater within the 5-7 day period than anything that has come before this winter. Fast moving showers in an unstable cold airmass is the stuff of nightmares for forecasters.

The NAO index showing readings as close to neutral for the first time since the end of the cold spell one week before Christmas.

The UK Met Office has changed its tune from milder SW conditions for next week to something more seasonal. I live the line in bold. It's usually brief colder incursions.

On Monday, with cold air in place, showers are likely to be wintry across the north, even to low levels, with some wintriness in showers further south too, but equally there will be some sunny spells. For the following few days, the most likely scenario is one of generally colder conditions, compared to recently, to dominate, with potential for brief incursions of milder air tied with Atlantic frontal systems.

Neddyusa

https://www.boards.ie/discussion/comment/120094625#Comment_120094625

Well done SC!

I believe that's the first time the words Polar and Low have been mentioned together on this forum for a few years!

Have a feeling this could throw something similar to the late December 2001 PL at us. We got 8 inches from that one, and it stuck around for the week.

Edit: maybe it was Dec 2000?

WolfeEire

https://www.boards.ie/discussion/comment/120095521#Comment_120095521

Uppers of minus 5 or a shade lower, an unstable airmass and a wicked breeze will negate mariginality in some places. Latest ECM.

"Ticket for one please" 🚇️

Gizit

Yes please ECM. Will no doubt change but you never know ....

sryanbruen

That ECM is something else.

(Granted it would be lot more of a rain mix than this shows)

sicknotexi

I'd take that ECM. Only 5 days away too.

nacho libre

https://www.boards.ie/discussion/comment/120095556#Comment_120095556

Will that low intensify like that as it moves South East? I just have a feeling that low could be shallower in the end . The cold spell might not last long as per the latest ECM , but heavy snow in a strong driving wind would be fantastic to see.

Gonzo

IF it plays like the ECM in reality I feel what will happen is more of a wet wintry mix near the coasts, particular the east coast with cold rain maybe 30 to 40km inland from the coast, Best chance of actual snow would be midlands and inland parts of the north-west.

Meteorite58

A very interesting weather set up indeed for next week. Currently showing with what looks like a wave depression forming rapidly on a strong WNW jet stream. Could even be referred to as a weather bomb or bombogenesis perhaps, looks to deepen rapidly , maybe 30mb in 24 hrs or less.

Tonight's charts show the strongest winds south of Ireland on it's present track and the precipitation over Ireland running into the cold air. Finely balanced as always, will make for some interesting observing. The mid level 850hpa temps may not be very low for normal snow set ups but how deep the system is will help to pull down the the freezing levels.

Slight change in track further N could have a big bearing bringing very strong storm force winds over the South and also push the precipitation further N also. You can see in the latest output how quickly the system deepens as it transits Ireland but this is just one run and it will over the next number of days look some bit different to tonight's run but the potential is there for some significant weather.

The GFS has a very strong jet further N over Ireland keeping the forming area of LPs more over the UK / North Sea so a big difference at this stage .

UKMO not too dissimilar to the ECM, brining stronger into into the SW.

WolfeEire

The ECM op run wasn't an outlier as it turned out. Very much matching the mean up to midweek next week when the mean is actually lower than the op.

Cork2021

https://www.boards.ie/discussion/comment/120096171#Comment_120096171

Booking office open?? 🚂🚂🚂

nacho libre

Another GFS run showing cold air approaching from the North East in Fi. Also looks wintry next Tuesday. The colder air seems to last a bit longer too.

nacho libre

ECM now following the GFS in trying to build heights to our north east by day 10. Unfortunately most of the cold air is gone at that stage, but if the high could be sustained then cold air would eventually come. Before all that we seem to have lost Tuesday's deep low, a slacker flow , but there still should be some snow around before the high moves in. The GFS again is best in terms of prolonging the cold period.

Let's see if tonight's output continues the theme of a pressure build to the North East. Also it's getting rather warm in the strat in fi.

Gizit

Certainly more interesting charts to look at. GFS 6z has now picked up the deep low so still an option. Still time for changes good and bad

SleetAndSnow

Lol GFS, if this comes off then I hope we will be building snowmen!

Given its the GFS though, it could be showing mild southerlies with a massive Azores high in the 12z

WolfeEire

Latest GFS showing lying snow on high ground at least by Tuesday evening. It is the control run so it runs at a lower res, but looking at the ensembles it appears to be well supported. The ensembles take a big move towards colder conditions from Sunday than were shown on the 0z run (the high is positioned a little further southwestward allowing the polar maritime airmass to plunge further south). There is a 'slight' lift in temps on Monday before a secondary plunge of cold air on Tuesday morning with plenty of instability in the airflow meaning that marginal conditions for snow at lower levels may very well be negated in places.

The extent of how wintry it will get remains to be determined. However, it's at this point (120hrs) that snow potential tends to downgrade so confidence in a potential disruptive spell of wintry weather for parts of the country taking place is growing. The GFS also appears to stretch out the cold spell to Friday.

Chris_5339762

The GFS always hilariously overestimates snow, but still interesting to see.

squarecircles

06 Z GFS

esposito

https://www.boards.ie/discussion/comment/120097909#Comment_120097909

Bank! 6z unfortunately can’t be trusted a bit like the 18z but we shall see.

PokeHerKing

https://www.boards.ie/discussion/comment/120097692#Comment_120097692

Below was the GFS last Sunday. Not sure why it gets such hate on here. I think it modeled the early December cold snap extremely well and fingers crossed its doing the same for the upcoming event

SleetAndSnow

https://www.boards.ie/discussion/comment/120098067#Comment_120098067

Since its 'update' the gfs has been very bad at times, often completely flipping from one run to another, usually at the extreme end of its ensembles (extremely mild or extremely cold), so while it might show trends early on, there is a very high chance the next run would be a very mild or very cold run and it would be completely out on its own. E.G At the end of the cold run in December, the gfs was showing a strongish greeny high still being there (in the reliable timeframe), cold over us while the gem, ukmo, ecmwf all had that gone. It kept it up right till the end when it was eventually wrong again. It's verification rate against the other models hasn't been great of late, with even the GEM performing better,

TLDR; It just hasn't been very trustworthy of late with constant flopping from one extreme to the other unfortunately.

PokeHerKing

https://www.boards.ie/discussion/comment/120098092#Comment_120098092

I don't put much stock in any model run to run. Especially GFS given how many it churns out a day. The trend is always what I'm looking at.

SleetAndSnow

https://www.boards.ie/discussion/comment/120098113#Comment_120098113

That's the best way to do it! But for the GFS, it has had many trends recently that have just been totally wrong. Showing them for a number of days and then it slowly falls back in line, sometimes when it hits about 72hrs to go only.

https://www.boards.ie/discussion/comment/120097668#Comment_120097668

Midnight ECM no longer has a deep LP for this timeframe.