FI Charts (T120+ onwards) Summer/ Autumn 2018 **READ MOD NOTE IN FIRST POST**

sryanbruen

The models have certainly trended warm and dry this morning, more especially for the south of the UK. They're still coming to terms on how early September is gonna fare for Ireland though like how warm it's going to get, how anticyclonic it will be and how much sunshine there is likely to occur. If it's anything like the GFS chart I showed yesterday then we'd be getting ourselves into a very blocked, settled pattern with two areas of high pressure conjoining to form one Omega block. You've seen from June into July how persistent an Omega block can be. The ECM chart I showed yesterday wouldn't be as persistent because there's a little meander in the jet stream (instead of a straightforward west to east up to the north of Scotland) that would disallow the two highs to conjoin. However, it would still be settled for a few days with some very warm conditions possible.

This is the GFS 0z ensembles this morning for Dublin and they have trended warmer and drier. Cork has a similar ensemble diagram.

sryanbruen

12z runs show a real split with the GFS still going for settled conditions whilst the ECM shows a zonal westerly, for early September.

Artane2002

sryanbruen wrote: »

12z runs show a real split with the GFS still going for settled conditions whilst the ECM shows a zonal westerly, for early September.

To add to that, the UKMO and GEM side with the ECM (ie. generally unsettled). The GFS FV3 brings dry weather into the south and east later next week but more unsettled further northwest thanks to the jet stream remaining close to the north. Still much to be resolved.

Meteorite58

A mix of weather for next week. The HP building around Weds / Thurs at the moment looks like getting swept away by a LP barrelling through around Fri , on the latest ECM 12Z, which presently looks wet and very windy but a long way off so changes are possible. After that a brief ridge followed by frontal weather and a neat wave depression showing up forming off a front at the end of the run but that is to far away and could look very different over the next few runs. Overall could be some very wet and windy weather at he the end of the week if those charts hold up.

sryanbruen

GFS 18z is absolutely stunning for around next Sunday with a southeasterly flow of air from the continent. The air would be dry, very warm and likely sunny. Would be an excellent start to September if it were to verify. Even better than the GFS 06z chart BliainanAir showed in terms of warmth potential.

If this chart were in the middle of Summer, we'd be talking 30c but this is the start of September so more like mid-20s (the Irish September record is 29.1c).

sryanbruen

GFS sticking to its guns this morning on a settled start to September but this time, it now shows blocking over Greenland beginning to occur.



ECM 0z is westerly but relatively high pressure to the south and east bringing the wind from a southwesterly. It'd be mostly cloudy and humid with some drizzle to the north and west. Far from a washout but very boring conditions if this were to verify.



Changes continue.

hatrickpatrick

The divergence between the two really is striking - hope the GFS pulls a rare victory over the ECM

Meteorite58

No big Lp at the end of the week( big outlier by the ECM a couple of days ago that I fell for ) instead rain at times, timing and track not certain yet but around Fri ( maybe mostly skimming Southern coasts) and Sun with frontal rain, breezy on coasts but nothing of note at this time. Rain at times over the weekend and then becoming settled according to the ECM with ridging up over Ireland and the centre of the HP passing over the country leading to calm and maybe foggy conditions for a few days next week if this was to verify. No great temps showing up at this stage, probably around high teens, low twentys at best with cool nights .


ECM and GFS similar trend up until + 240h

squarecircles

sryanbruen

Classic chart (from the GFS 12z) for Monday, September 3rd next week with a real easterly flow which will still be very warm in early September. Massive area of high pressure extending from America to Russia.

Summer lovers would look at this in real frustration and wish it happened at the start of August than the beginning of September.

Still a lot of uncertainty though on exact details like temperature. ECM not really showing enthusiasm for warmth on its 0z run, will see what the 12z has to say.

Imgur acting up on me so here's my tweet instead showing the chart.

https://twitter.com/BruenSryan/status/1034486043247095809

Harry Palmr

Better in September than August for my money - pushes that first Autumn storm, whenever it might happen, further out and we get some warm but not hot dry sun.

sryanbruen

ECM 12z is very similar to the GFS actually but not as warm as that. Extensive area of high pressure from America to Russia and this time no Biscay low.

sryanbruen

Hallelujah, the UKMO is also showing the very blocked and settled setup to start September. Have we got some certainty for a change!?

hatrickpatrick

@Ryan, one thing to keep an eye on is a tropical wave which is just about to emerge from the African coast into the Atlantic - for some reason it's not an invest yet, but it's being given a 50% chance of development within five days, and the models currently have it tracking around the Azores High and coming alarmingly close to our shores. Currently, the GFS shows it slipping by us (grazing the northwest with a rain belt, but very short lived) and allowing the high to slip into its wake - but if recent tropical cyclones in our neck of the woods are anything to go by, it would only take a small nudge for it to make a direct hit on our shores.

Of course, until the last second Ernesto was supposed to do just that and ended up largely passing us by - so unfortunately it has to be said that the reverse is also possible.

Here's a gif with the disturbance starting off in the central Atlantic and tracking North us us:



It does appear on the final, 240h frame of the ECM as well:

sryanbruen

hatrickpatrick wrote: »

@Ryan, one thing to keep an eye on is a tropical wave which is just about to emerge from the African coast into the Atlantic - for some reason it's not an invest yet, but it's being given a 50% chance of development within five days, and the models currently have it tracking around the Azores High and coming alarmingly close to our shores. Currently, the GFS shows it slipping by us (grazing the northwest with a rain belt, but very short lived) and allowing the high to slip into its wake - but if recent tropical cyclones in our neck of the woods are anything to go by, it would only take a small nudge for it to make a direct hit on our shores.

Of course, until the last second Ernesto was supposed to do just that and ended up largely passing us by - so unfortunately it has to be said that the reverse is also possible.

Here's a gif with the disturbance starting off in the central Atlantic and tracking North us us:

It does appear on the final, 240h frame of the ECM as well:

I have been keeping an eye on tropical developments as I've been explaining in the Winter discussion thread in relation to active hurricane seasons. They're a reason also why I see September being a more unsettled month after a dry opening (see the Autumn discussion thread). They're not likely to affect us for at least next week as shown by the model agreement.

Looks like the GFS ensembles show the massive anticyclone too.



Talk about reoccurring patterns.....

Meteorite58

ECM 12Z keeps the ridging developing and HP building over Ireland as we move into next week . Not a scorcher but seeing temps into the high teens, signs that warmer air might be drawn in from Europe towards the end of the week.

Harry Palmr

The mellow fruitfulness keeps building, right through to mid September it's settled in F1 land.

Meteorite58

The Blocking High not doing a good job of blocking going by the latest runs. Ridging up over us but the HP never gets fully established next week instead areas of LP take over from around Thurs and become more under their influence by the weekend. A very big change by the main two: ECM and GFS. Will it stick. Are we going to see a range of outcomes over the coming runs as the models try to factor in the remnants of Florence ( which has a different track with every run, yesterday into Portugal / Spain, heading towards Iceland/ Greenland on previous runs and today's GFS 6Z heading towards Ireland, expect plenty more tracks ) or does it have much of a bearing at all on the models at this stage? Into FI looks like back to more zonal weather with the Atlantic bringing in the LP's.

MJohnston

Is that Florence making a beeline for us in the GFS?

Meteorite58

MJohnston wrote: »

Is that Florence making a beeline for us in the GFS?

Yes on this run but loads of different tracks already , more or less different on each run and model. Could meander for a couple of weeks out in the Atlantic yet and end up anywhere but interesting nonetheless. I am most interested on how and if it is going to affect forecasting for us in the coming weeks.


https://twitter.com/WeatherdotUS/status/1036238805865521152

SleetAndSnow

If it were to hit, it wouldn't be as strong as Ophelia correct and would most likely be tropical storm remnants?

Meteorite58

SleetAndSnow wrote: »

If it were to hit, it wouldn't be as strong as Ophelia correct and would most likely be tropical storm remnants?

Impossible to know at this stage I would think. The models are struggling with its track 7 days out not to mind over 2 weeks away.

Artane2002

Jeez, look at that nasty low (to the SW) making a beeline for England on the ECM. It was shown on the 0Z too. Widespread gusts of over 60mph in the south of England. Nothing too bad for Ireland, between 20 and 40mph, windiest in the south. No need to worry, still at day 8-9.

sdanseo

That "nasty low" could potentially be either Hurricane Helene or further development of another potential subtropical cyclone.

Eyes open for the next while.

Artane2002

I believe it is ex-Helene

sdanseo

Artane2002 wrote: »

I believe it is ex-Helene

That drove me mad. Normally a glutton for technicalities but it gives the impression that it isn't serious and is while scientifically correct a horrendous public safety message.

Artane2002

sdanseo wrote: »

That drove me mad. Normally a glutton for technicalities but it gives the impression that it isn't serious and is while scientifically correct a horrendous public safety message.

For arguments sake, if this was to deliver cat 1 hurricane speeds, would "Ex-hurricane Helene but with category 1 hurricane winds" sound better :P?

sdanseo

Artane2002 wrote: »

For arguments sake, if this was to deliver cat 1 hurricane speeds, would "Ex-hurricane Helene but with category 1 hurricane winds" sound better :P?

As long as Joanna does the forecast, I'll accept that. :pac:

Meteorite58

sdanseo wrote: »

That "nasty low" could potentially be either Hurricane Helena or further development of another potential subtropical cyclone.

Eyes open for the next while.

All of a sudden turned stormy out in FI. On this run remnants of Helene and another huge area of LP coming in from our NW. In this present climate with so much energy being released into the atmosphere from the Tropics you would expect our weather to become very unsettled at some stage. Our latitudes though have been very very difficult to have any sort of accurate forecasting past +120 in recent weeks with many wild swings in trends. Helene looked to have stalled in the Azores the last few runs now it is hurtling towards us at +240 albeit in a diminished state. An Outlier ? To be monitored.

sdanseo

Meteorite58 wrote: »

All of a sudden turned stormy out in FI. On this run remnants of Helene and another huge area of LP coming in from our NW. In this present climate with so much energy being released into the atmosphere from the Tropics you would expect our weather to become very unsettled at some stage. Our latitudes though have been very very difficult to have any sort of accurate forecasting past +120 in recent weeks with many wild swings in trends. Helene looked to have stalled in the Azores the last few runs now it is hurtling towards us at +240 albeit in a diminished state. An Outlier ? To be monitored.

I poked a lot of fun at the GFS last night for showing Florence re-intensifying into a 957mb low between us and Greenland.

Now the ECM - which picked up Florence's current position and intensity pretty well nearly a week ago - is showing it as well, and of course also Helene bouncing back in our direction again. Interesting times ahead for sure.