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

pauldry wrote: »

surely an outlier syran

id favour the rain in w and n dry in s and e prediction myself with lows sweeping in to the nw of ireland

later in June id see potential for more widespread sunshine

It is an outlier in its ensembles and clusters. It was so different to anything we had previously seen.

The model runs weren't that great this morning. Nothing as totally awful as ECM 12z from last night though.

Latest GFS ensembles for Dublin (other places such as Cork again have very similar ensemble charts) show average temperatures through the 15th to the 21st i.e. daytime maxima here between 16-18c. Out to the north and west, perhaps around 14-17c. Interestingly, a brief spike up of temperatures has appeared now ahead of the rain for later next week bringing temperatures temporarily back up to 20 or 21c perhaps for a short period of time before the rain falls in the east?

In the extended range of the ensembles, it seems the warmth for latter June has been upgraded. The OP run itself shows a warm up for 21st/22nd before a cold front pushes in from the west and cools things back down again but the general ensembles show it warm post-21st. The OP is an outlier in the ensembles again on both the GFS and the ECM continuing the uncertainty of the outlook on exact details.

Rainfall spikes appearing every day after next Wednesday showing you that the outlook is changeable in spite of the temperatures warming up again in the extended range.

Quite high pressure dominated for the majority of the ECM clusters following this unsettled blip. That's two runs of the clusters now showing this. Keep in mind, they were going more towards what the OP run was showing two days or so ago so these are very open to changes as much as the OP.





GFS 0z and 06z both show the high pressure ridging from the Azores early next week and Sunday 17th is of similar evolution to that of the UKMO and GEM last night.

At the end of the 06z run, the GFS brings in a hot easterly. Just for fun.







ECM OP vs ECM ensemble mean. ECM OP is once again, an outlier!





GFS 06z ensemble mean this time next week with the Azores High attempting to ridge up to us though on the mean (not on the OP run) missing the west close to the jet stream.

azores high continues to intensify on the gfs run,building entirely over the country towards the end
of the run,then slipping to scandinavia allowing a nice toasty east wind to blow in.

This mornings GFS is throwing up renewed heat however there seems to be disturbances in the North and West at first

The GFS 12z ensembles agree very much with the OP run with a settled end to next week across the whole country but cool. The high is just a bit further westwards though on the ensemble mean which would probably bring more cloud especially to eastern regions of the country.



GFS ensembles for both Dublin and Cork are very dry (especially Cork) and relatively warm. If the GFS ensembles for Cork are correct, I think we would have to start talking about an absolute drought (minimum 15 consecutive days with 0.1mm of rain or less) down there

Dublin:



Cork:



Always that more unsettled in the northwest (bar the end of next week) but even here, nothing alarmingly wet and relatively warm again.



ECM 12z follows similar suit to both the GFS and UKMO. Have we finally got some agreement?

After this settled end to the week, the model goes into a changeable pattern with transient ridges from the Azores than sustained.

GFS 12z is very settled again and increasingly warm after the cooler blip courtesy of a cold front later this week. Well out into FI, it becomes much more unsettled but the previous few runs of the GFS before this all showed high pressure continuing throughout so don't take that seriously at this stage.

UKMO 12z is quite different to any of the model runs since yesterday afternoon. It shows the high pressure over us for Thursday/Friday but then slips to the south on Saturday at +144 hrs allowing more of an Atlantic influence to the weather with the jet stream very close to the north. The upper air temperature distribution suggests a northerly flow than a westerly but the 500mb heights show a westerly so I'm kind of puzzled on this one. Guess the full agreement didn't last long!

The GFS 12z ensembles are in agreement with the OP run again in settled conditions for the end of the week into the following week. No heatwave or very warm spell being signalled but a lot of dry weather.

ECM is currently rolling so we shall see what it has to say.









The longer range models are still on odds with one another in terms of how July is going to pan out. The ECM and CFSv2 both show a very dry, anticyclonic month but with average to perhaps even slightly cooler than average temperatures. However, I will show you here what the CFSv2 temperature anomalies were showing this time 5 years ago for July 2013. It was showing an average to cool month just like it is now for July 2018.



I continue to hold skepticism of both the longer range models and the shorter range models. I seriously do think they're undercooking or underestimating the temperatures for July 2018 - if only we could see what they would be showing this time in 1976 and 1995. I will await for further trends on the shorter range model output.

Now this is where it starts to get somewhat complicated but stick with me, I am trying to make it as easy to understand as possible. How we've gotten away with such a blocked pattern since February is down to how the Atlantic Meridional Overturning Circulation (AMOC) has behaved after the Sudden Stratospheric Warming event. You can see how the AMOC has fared (in general) since February in the chart below with the arrows labelled showing the direction.

The winds in the Atlantic have tended to come from the north whilst the anticyclonic block over Scandinavia caused the winds to come from an easterly for us. The way the winds aligned in the Atlantic brought cold air down from the Arctic into the North Atlantic from Greenland down to the eastern side of the North Atlantic and through the tropics. The air is then moderated a lot as it's brought into the middle part of the North Atlantic where it's been warmer than average. When you have an SST profile or AMOC like this, it's a sign of a negative Atlantic Multidecadal Oscillation (AMO) which usually promotes blocking to the east. It just happens though that now this cold pool in the Atlantic is weakening somewhat allowing the warmer SSTs to filter through the cold. When you have this kind of contrast with the warm air battling with the cold air, it tends to blow up the Polar Jet or is commonly known as the jet stream. When you get an intensified jet in Summer, it can be of two things. It can be a sign of great anticyclonic Summer weather that isn't very humid with a blocked ridge from the Azores carrying all the low pressures up to the north of Europe. It can also be a sign of a very wet and cool signal if the Azores High is weak. This is why I have concerns and hold skepticism though this will become far more of a player in the Winter than Summer. With the anomalous cooling still over the Azores and to the west of Iberia, I am more favourable of the Azores High ridging to us in a way like July 2013 did than another easterly spell. July 2013 had a very deep cold pool just to the west of Iberia which is worth nothing this time around. But never say never with our weather.

ECM has impressed me even more with its 0z run, high pressure firmly in control (again) and incredibly warm during the last week of June with upper air temperatures surpassing +12c. The jet stream does lie quite close to the northwest on this particular run for Sunday 24th/Monday 25th mind you. Otherwise, what a cracker of a run (no exaggeration).

The question is, is the ECM an outlier in its ensembles? Most certainly not. Tons of agreement for the high to dominate from the ensembles too.

GFS 0z has a lot more of an Atlantic influence especially up to the north of the country but a few settled days nevertheless before low pressure returns around the last weekend of June though this is then followed by another ridge from the Azores at the end of its run.















These are some of the best ECM clusters I've seen in my model watching years for warm and settled weather!

And remember to always add a few °c to the GFS figures, they consistently underestimate.

The GFS currently rolling out seems to be downgrading the high pressure somewhat - still keeping it high, but slipping a bit:

Here are two charts for the same time - 14:00 on July 3, first from the 6z and then second from the 12z

6z run:



12z run:



The change between the two looks to me to be the Atlantic / Jet Stream trying to fight back and re-establish itself to our North? The downgrade isn't a disaster by any means, should still be very dry and warm, but does it signal the beginning of the blocking pattern's eventual disintegration?

I wouldn't worry about the GFS op run (and certainly not at 192 hrs)

Ensemble average




Stick with the Euros to be honest.

Met Eireann and the GFS predicting very heavy rain for a lot of the country on Sunday - given that the charts continue to show high pressure throughout that period (lower pressure than the surrounding epic highs, but still far higher than a normal Irish low pressure system) does this open the door to some thunderstorm activity? Looking at the charts, and people can correct me if I'm wrong here, it seems that any moist air in that setup would be considerably warm?

Kermit.de.frog wrote: »

Yes, thunderstorms would be very likely moving up from the south. Classic setup for us.

Also should stay very warm until at least Monday.

Anything to point to a reload of the heat after Monday? There seems to be conflict between forecasters as to what might happen. It's as if the charts aren't sure as to what's gonna happen.

Changes again for the weekend. UKMO keeps the very warm continental flow throughout delaying the incursion of thundery LP from the south until the early days of next week.

Sunday, very warm.

ECM quickly changing magazines and reloading next weekend. GEM agreeing

UKMO - high pressure building in from the southwest towards the end of next week.



GFS - more or less the same trend.