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

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Mod Note

This thread is for posting/discussing/analysing FI CHARTS ONLY i.e. Charts in the unreliable time frame, generally +T120 onwards

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squarecircles

The trend continues on gfs runs for fine summer weather developing over ireland through the last week of june.

Meteorite58

A mixed bag next week I would imagine and rather unsettled . Breezy /windy at times with alternating ridges and LP's so alternating temperatures also. Lp's will bring rain and most of the weather with a SW'ly aspect. The jet keeping the Atlantic mobile out to +240 . Next Weds looks warm but a lot of days will have a wide variation in temperatures from cool on windward coastal counties to milder in Eastern areas.

U5q8YeE.gif?1

sryanbruen

I spy with my little eye, something beginning with h on tonight's ECM 12z at +240 hrs.

Personally, I'm very skeptical of this. My reasons being the fact that the ECM has had a poor record recently in consistency, the model wants to form northern blocking over Greenland and not to mention how fast the pattern goes from anticyclonic to a southeasterly in the space of 24 hours.

There has been a trend this morning and yesterday for this period where the ECM now is showing a warm spell or perhaps even heatwave, for it to be a northerly and bringing down cooler air after a warm interval on Friday 22nd/Saturday 23rd. Look how much change has taken place now on this model.

I have been hinting at a hot end to June for a couple of weeks now but until I see it as a trend on the models, I will hold my skepticism. Until then, some very warm weather to take place on Tuesday next week and then Thursday/Friday again. The latter being similar to the heatwave or warm spell of mid-June 2017.

Don't expect much rain in the south and east for the next week, it will continue to remain very dry but more unsettled in the north and west.

pauldry

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

JCX BXC

pauldry wrote: »

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

Definitely showing sustained heat from 6 days out. Little bit closer to the reliable range so hopefully!

Mobhi1

ECM not too bad either.

sryanbruen

For Ireland, the UKMO 12z is a great run if you like settled and not overly warm weather (in fact quite cool). The reason why the run is quite cool is courtesy of a cold front that pushes southwards on Wednesday after a rather warm day on Tuesday (temperatures up to 22 or 23c in the east and southeast). If the high sticks around for a couple of days afterwards then it will warm up quickly especially in the strong sunshine. This looks cloudy for the UK but (especially out west) it seems to me that close to this high pressure, Ireland would be in for some sunny conditions. Temperatures on Thursday/Friday would likely be in the mid teens if there's a lot of cloud but high teens if the sun is there.

GFS 12z shows very similar to the UKMO with a few dry days for Ireland from Thursday 21st to Sunday 24th. The Atlantic tries to invade into the west then on the Monday but gets pushed away back northwards from another ridge being sent up from the Azores with this time, warmer conditions.

Not much northern blocking if any on these runs so these runs are an upgrade in that case.

The anomalous cooling that has been taking place near Iberia only promotes ridging from the Azores and or high pressure somewhere around our shores.

This chart from the GFS 06z is just for fun at +384 hrs but I'm posting it here to show you what this Summer is capable of if everything goes right in the atmosphere.

If you cannot read the chart, it's showing an Omega blocking pattern sending the jet stream way to the north and high pressure fest all over us.

sryanbruen

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.

sryanbruen

Three words for the Pub Run tonight, high pressure fest. It even ends the run off (in squarecircles' words) with a toasty easterly.

Meteorite58

Positive sign for an increase in temperatures seeing heights improving from next weekend and signs of good temperatures into the following week for however long it will last.

The charts look similar to a couple of weeks ago with an area of LP taking up position off Portugal, will be interesting to see if that holds.

hatrickpatrick

Could I suggest that we make a combined technical discussion thread for the reliable timeframe + FI, or a second thread for the reliable timeframe? The analysis being provided in this thread by Ryan and others is spectacular, it's a shame that as per forum rules it has to cut off at T120+ - and it seems like there's no corresponding thread for this kind of discussion for nearer timeframes, with the discussion threads being used more for general "here's what it's like where I am at the moment" type chat.

Just a thought!

sryanbruen

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.

sryanbruen

Bank the ECM 12z, high pressure firmly in control and getting very warm by +168 hrs. The jet stream has gone a bit mental on this run. I'm impressed.

So the UKMO 12z is all alone on its own..... for now.

Meteorite58

hatrickpatrick wrote: »

Could I suggest that we make a combined technical discussion thread for the reliable timeframe + FI, or a second thread for the reliable timeframe? The analysis being provided in this thread by Ryan and others is spectacular, it's a shame that as per forum rules it has to cut off at T120+ - and it seems like there's no corresponding thread for this kind of discussion for nearer timeframes, with the discussion threads being used more for general "here's what it's like where I am at the moment" type chat.

Just a thought!

Sounds like a good idea . I will discuss with the other Moderators and get back to ye.

sryanbruen

The GFS 18z is a high pressure fest again even out to as far as early July though by then becoming more slack and the atmosphere being that bit more unstable. No heatwave being signalled at but again lots and lots of dry and relatively warm weather after Thursday/Friday's cool blip.

The cool blip on Thursday/Friday will be very noticeable especially to southern and eastern regions with nightime temperatures getting well into the single figures whilst daytime temperatures in the mid to high teens but if you get the sunshine, it won't feel bad especially given the high is just centred over Ireland and to the west. The northerly wind will be felt more over the UK than us.

Going by all these charts, it seems Ireland is getting the better end of the deal, not the UK after this early part of the week is out of the way.

sryanbruen

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!

squarecircles

JCX BXC

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

kilkenny31

I'm going to go out on a limb here and predict that the hottest temperature in decades will be recorded this summer. We had one of the heaviest snowfalls recorded as well as one of the strongest storms recorded (not in 2018 but still not over a year ago). So it makes sense now for the summer to give us some sort of heat record. Then to top it off we'll have heavy rainfall before October to make it a year of extreme weather.

Donegal Storm

High pressure all the way this morning with a violent thundery breakdown to kick off July, I'd certainly take that

For any records to fall we'd likely need a week or two of very warm airmass in situ and a tongue of even hotter air to extend north. Happened in the UK a few years back when the July record was broken on a largely cloudy day, think the 20C 850hPa isotherm reached London that day.

At the moment it's looking like more a of a typical high 20's heatwave but that'd do me

PukkaStukka

Donegal Storm wrote: »

High pressure all the way this morning with a violent thundery breakdown to kick off July, I'd certainly take that

Bring it on

Meteorite58

GFS 18Z rolling out and it just wants to keep on going with the warm weather bringing ridging up from the Azores over next weekend and it looks like HP becomes reestablished and it wants to keep it going out to +384 hrs . It must be tempered with the fact that the ECM is showing a different set up to the GFS , still warm but with slack areas of LP in the vicinity producing maybe cloudy weather and some weak frontal or weak trough activity? Either way this is a long way off more normally in FI but still very much linked to this hot spell coming up. The Authorities might have to act quickly on managing the water supply.

Kermit.de.frog

Big shift in the GFS ensemble suite as well looking to keep things going.

The temperatures are also creeping up on the GFS for next week and the weekend.

hatrickpatrick

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:

gfs-0-198.png?6

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?

sryanbruen

The GFS is known for wanting us to go back into a normal pattern. During the previous warm spell, it was unusually consistent with showing no breakdown in a pattern for a long while. I started giving the GFS more credit than I normally did but as soon as the return of the westerlies started to appear, I figured that the GFS was back in its normal state of chopping and changing a lot. Remember the Friday 15th June deluge it was showing? I bet many of you wish that came true by now.

I remember for a few days that the GFS was also showing us going into a westerly phase by next Saturday, now that looks to have been delayed. The UKMO shows us in a very humid and thundery easterly scenario for next weekend which would make westerlies not likely to return for a while as shown from the previous warm spell which had a few thundery interludes around each of the weekends of the period.

CFSv2 has now significantly re-strengthened the above average heights for July with a large anticyclone just centred to the north of the country drawing in warm easterly winds. It's very similar in ways to July 1955 how this pattern is setup on the model. If you did not know, July 1955 was Ireland's sunniest month on record. Bar weakening the heights for a time to average for July 2018, the CFSv2 has remained consistent on an anticyclonic July (as shown by its precipitation anomalies) throughout.

I had two ways July 2018 could go in my Summer forecast:

1. Deteriorate into a very cool and relatively wet month.
2. Continue the Summer on from a warm and dry June with a huge anticyclonic again over us.

Looks like the latter is continuing to be favoured.

My word of advice would be to focus on the weather up to Friday or Saturday for now because you'll find just too many chopping and changes afterwards.

Kermit.de.frog

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

Ensemble average

Stick with the Euros to be honest.

Kermit.de.frog

18z GFS

Some decent storms possible.

hatrickpatrick

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

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

Also should stay very warm until at least Monday.

Cantona's Collars

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.