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

The M is for metres now,not miles 🤣

So basically the 850hpa level is about 600 metres above Lugnaquilla,or the mcgillycuddy reeks

Maybe they do in fact have access to this information long before we do hence the update. I know things can still change, but once there is a trend for things to go pear shaped its not often they switch back to a colder outlook. I think I will join Gonzo on the bench. What's most disappointing is if we are back to wet weather again by next weekend when previously it looked like we may have a more prolonged dry spell.

I know I poke fun at Gerry Murphy, but for the sake of balance and to give pros like him their due, when they see model output showing a Greenland high they probably use their intuition that a shortwave that wasn't initially picked up by the models will come along to scupper a cold spell. That's what happens time and time again, but I suppose the odd time it doesn't is what makes it so satisfying for us

Met É don't predict beyond 5 days ever.

And they're absolutely right.

I always wondered if Met E viewed the ECM at same time as us but I think I have my answer now. They get it earlier hence the update few hours ago re possibly turning milder next weekend.

Be interesting to see if ECM improves and builds those heights over Greenland over next couple of days. And if it does, will the other models still be showing it!

Better heights to GL from ECM mean.

@nacho libre @Gonzo You bought a non-refundable ticket for that rollercoaster. On you get!

Met Eireann said "Current indications suggest that next weekend, there may be a change with our weather becoming milder and with rain developing" and because they base their forecasts primarily off the ECMWF with observation of the UKMO, they would be somewhat correct with this wording, particularly for Friday eve into Saturday when it does got somewhat milder. The EPS runs off the 0Z and considering that was milder than the 12z, they may have based their forecast for next weekend off that.

MTC this morning referred to a 'weak signal' regarding a slow return to seasonable weather.

UKMO favours cold over mild, but has hinted at a potential battleground scenario.

RECENT FORECASTS: MTC called the Christmas weather at least 10 days in advance and was absolutely spot on with his mention of wind and rain. Met Eireann said the Christmas weather would be 'bland' about a week in advance but I wouldn't have thought over a week of strong winds and heavy rain would be 'bland'. That said, they rowed against 'forum' chatter of a cold Christmas. The UKMO never really fancied the idea of cold at Christmas although they did suggest a possible turn at the begging of the New Year.

NEXT WEEKEND AND MODEL OUTPUT: I would say we are in 50/50 territory regarding next weekend. It is not looking mild when you review all output, nor is it looking extremely cold. I do think that the trend towards a more westerly -NAO outlook (Atlantic driven weather patterns) from about 10-12 days time is becoming more likely based on output of the past 24-36 hours but the same output also indicates that a cold blast next weekend remains the form horse.

First of all, this evening's GEM goes cold for the first time in days. It was always the odd one out. I highlighted the 0c and -5c 850 and 2m lines. The 2m temps in particular are much lower in the daytime next weekend and into the following week.

The GEFS shows overall 850s and 2ms to be a tad milder next weekend in the 12z compared to the 00z but it is far from mild nor is there much precip on the cards as Met Éireann suggested.

The ECMWF 12z is a tad cooler, particularly re: 2m temps, for next weekend.

The UKMO 12z is colder than the 0z for next weekend.

The remainder of the models (NASA GEOS, KMA, CMA, ICON, CFS, NAVGEM, JMA) all show an incoming/in place northeasterly or northerly at the same timestamp of 1am next Sunday.

Finally, the NOAA CPC doesn't suggest a strong westerly influence for next weekend. This chart was produced today and is valid for next Sunday (14th) to the 20th.

For there to be a mild outcome next week, there will be an utter collapse of output over the next 24-48 hours. If that happens, then I am going to put in a FOI to the Department of Communications to find out what magnificent modelling system (other than Gerry Murphy) Met Éireann has at its disposal. By the way, ME are the pros and I place great faith in their forecasting so none of of any of this post is aimed at undermining that. It is purely a discussion piece and an attempt to get Gonzo and Nacho back on the rollercoaster!!!

In the meantime, we have the most fantastic dry, cold and clear winter weather to look forward to.

The GFS is much cleaner in its evolution up to 144hrs regarding next weekend's potential cold blast. The high tracks north and west toward Greenland and sort of gets boxed in between the Greenland high and lower pressure in the Atlantic allowing for a sweep of colder air from the northeast. This cold air hits Scotland by lunchtime Saturday which is a good 6-13hrs earlier than the 12z run. It reaches the north coast of Ulster around midnight.

Post 144hrs things get a little stickier. Low pressure to our southwest (most NNW of the Azores) is a little further north on this run which serves to amplify heights over the Iberian Peninsula meaning cold does reach all the way to our southern shores by Sunday night but holds there as it meets that shortwave to our southwest. At this point, the setup would be conducive to some streamer activity along the north and east coasts pushing further inland.

By Tuesday, there is enough of a punch in the colder airmass to eventually allow a further SSW push. We end up with a ENE or Easterly at that point. Beyond this, there is no point in analysing the output as even what precedes this point will chop and change in the coming days.

In simple terms, it turns much colder and potentially wintry next weekend into the beginning of the following week. I would argue it's the wintriest GFS op run to date. That is the op run. Ensembles will tell us where it sits in the overall scheme of things.

For posterity, I will leave this image of part of the PV on holiday in Europe