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

Farmer2017 wrote: »

How far out is Spanish plume from happening ? Does Spanish plume bring much rain

The Spanish Plume is still in the realms of chance and may or may not reach as far West as Ireland. It's more likely to drift up over France and the U.K than move over Ireland.

Even if it did arrive, it might only give us a few thundery downpours at best, and maybe nothing.

The chart below is two days old and it gives July 11th to be approaching the South coast of Ireland. I wouldn't be betting on any significant rainfall from it at this stage though

GFS 12z shows no thundery breakdown and keeps it settled until the third week of July.

Dare I say it: Downgrade.

Last frame of the 12Z ECM (+10 days) is a full on Europe-Wide Heatwave. Whole countries at >30°

What breakdown?

Just look how far north the Jet Stream is at +120!


Also ECMWF 0z shows no real breakdown, it just keeps going and going!

KingdomRushed wrote: »

Am I looking at the same charts as everyone else?

Both GFS and ECM op runs are now clearly signaling a decline in pressure over Ireland from around July 9th onward. The ridge for next week is weaker on every run. The northern hemispheric view is better to assess this trend than the Europe only charts.

Looks OK to me. You seem quite desperate for a return to bad weather?

KingdomRushed wrote: »

No I’m only pointing out what is showing on the model output. 48 hours ago it looked like genuine heat wave conditions were returning from this weekend. This trend is dissolving on the models. And moreover the much vaunted Spanish plume has not just eroded but disappeared. There’s a change coming in my opinion, whether that’s good news (for some) or bad news (for others).

Great that the Plume is gone, better for longevity. Of course the change always comes eventually. Whether cold in winter or hot in summer the end game is always the Atlantic.

KingdomRushed wrote: »

I said the pressure begins to decline I didn’t say there wasn’t still high pressure over us, but it’s the same declining trend that is evident in later frames of GFS which runs longer. That is certainly not heatwave conditions at 216, and 240 is even less promising looking.

I never suggested heatwave conditions ever either........ all I've been saying is settled. This Summer is more about persistence of warm and dry weather rather than extreme side of heat (besides 27th-29th June for Ireland).

For what it's worth of your description, the GFS has forwarded the cool, unsettled phase this morning by a day or two compared to its backdating that it was doing yesterday. It also suggests a trade burst well into FI which it tends to overdo but going by outlooks, this heralds a change into August if you ask me. August, I can definitely see a change coming to something much more unsettled.

Mid-June brought a cool and brief unsettled blip with the jet stream going on a bit of a southerly track similar to how the GFS is showing for the third week of July which was then followed by the heatwave or warm spell. In fact, looking at it now, maybe we're seeing something similar going on here? For sure, we weren't seeing a Spanish plume in early June on the model outlook but the way the ECM has the high pressure aligned (besides the Scandi High) is similar to that of how the models showed for Wednesday 13th June for a couple of days then was followed by storm Hector.

Not doubting the weakening of the high or ridge at all by the way, the long range models such as the CFSv2 also show this for the third week of July but they then restrengthen it for week 4.

Yeah, GFS 12z turns unsettled for Sunday 15th again but far from a washout and relatively cool temperatures at worst, staying mostly average to warm. Pressure just seems average after that initial turn to unsettled weather in FI in a flat westerly.

UKMO out as far as it goes, just anticyclonic and bags of sunshine besides possible morning mist or low cloud.

GEM is just high pressure fest throughout with no loss of strength in the high.

hatrickpatrick wrote: »

Briefly, what are the known biases and caveats of the GEM model? For instance, I do know that where the Atlantic tropics are concerned, it has a reputation for being far more generous in upgrading non-tropical lows to tropical cyclones, which other models don't develop and which ultimately don't end up developing. As in, you can look at a CMC/GEM chart of vorticity in the Atlantic tropics and see two or three tropical storms or hurricanes forming throughout a run, where the GFS and ECM don't see any - and more often than not, the GEM does not verify in these circumstances.

Are there any other known biases with this model which we should look out for in the context of our own part of the world?

I don't know of biases with the GEM but I know that it doesn't have a great verification record.

ECM 12z is a flat zonal westerly and perhaps getting very cool quite quick with the air coming off the cold north Atlantic.

Villain wrote: »

Jesus FI really is all over the place! ECM flipping and flopping too.

I wouldn’t like to try call beyond +120 which makes The Eagles comments too very strange!

I suspect that at least some of the current model uncertainty is related to invest 96-L, a disturbance currently off the US coast which is now formally designated by the nhc to become a tropical depression within the next couple of hours. Models seem to have difficulty with our weather when there's a northward moving subtropical disturbance which is not yet classified as a tropical cyclone and will interact with the jet stream at some stage, so I'd expect them to settle a bit once this system fully develops into a tropical cyclone this evening.

96L denoted by a red X on the left hand side of this image:



Special Message from NHC Issued 6 Jul 2018 20:10 UTC
NHC will initiate advisories at 5 PM EDT on Tropical Depression Three located a couple hundred miles southeast of the North Carolina coast.

Cork Boy 53 wrote: »

What did he say?

Well he nearly guaranteed good weather for the next 10 days and to be little in the way of rain for remainder of the month..he sounded fairly certain of it ...

The air between the Eastern Seaboard of the US and us is stupidly warm as compared to averages, and without looking, you'd imagine SSTs would be slightly above normal.

Warmer water fuels hurricanes and other cyclones and will contribute to their remnants as well.

(Note: this is not and cannot be an Ophelia when it reaches us. Forecast to track thousands of km too far north for that)

That's all I'll say for now other than that the last few months have thrown the rulebook away - and the fact that we're openly discussing an Atlantic Hurricane before it has even been named in terms of its impact on Ireland is quite extraordinary.

GFS 12z is cool, unsettled and cyclonic.

GEM 12z = Summer 2018 lives on.

UKMO starts to turn unsettled at the very end.

Yeah, I definitely think Tropical Depression 3 and Beryl are causing a ruckus in the model output. This is just silly at this stage.

If ECM 12z follows history of previous days, it will be an unsettled run. The ECM 12z runs have had a tendency to be unsettled recently even though the 0z runs tended to be settled.

sryanbruen wrote: »

It does not follow history, staying settled and warm.

Well then obviously this is the correct model and all the others are just worthless pieces of junk which we can safely ignore

Have not done one of these kinds of posts in quite a while now but this is my update on everything and my thoughts on the outlook which in fairness has proved to be a big headache.

To start off, let's have a look at the latest run of the GFS model. What can I say? Well, it's a very different run compared to pretty much every other GFS run we've seen in the past few days. It keeps high pressure going up to and including Sunday 15th (St. Swithin's Day) with further settled and dry weather although some showers possible Thursday/Friday generated by the heat and slacker gradients for a time in the atmosphere. After Sunday 15th, everything goes slack again with average pressure for the third week of July with nothing definitively unsettled or a washout being indicated on this run, just some light rain bands or showers and sunny spells. Temperatures would be going back down towards average over Ireland but as you can see from Tuesday 17th on this run, the cool 850hPa temperatures over the North Atlantic just don't quite get in to Ireland thanks to a continuously anomalous area of above average heights to the east and over the Azores as well as the jet stream splitting into two.

This is a very different run as I said to what we've seen from the GFS these past few days so it's to be taken in isolation as the overall consensus is for a brief unsettled and cooler period - until we start seeing similar runs to this GFS 12z of course.







UKMO keeps things settled and at the end of its run, the high starts to go to the east pulling in a south to southeasterly flow. On this run, this flow looks stable and high pressure dominated so don't expect convection really if the UKMO 12z were to come off. This is different to yesterday's UKMO 12z which wanted things to turn unsettled by that time frame so again like the GFS 12z to be taken in isolation and not very serious until we see trends of it appear.



What is causing all the ruckus? Simply, Tropical Storm Chris. This is the current expected track of Chris up to Friday. It is expected to become extratropical by either Saturday 14th or Sunday 15th as it comes closer to our shores. The exact track of Chris is uncertain. Previous runs showed it coming through us and bringing us a bout of wet and windy weather but today's UKMO and GFS show it well to the north of us barely having an impact on Ireland.

Chris could be the start of an unsettled spell OR it could even prolong the settled weather again! Let's take a trip back to August 2014 and also April this year.

Both lows; ex-hurricane Cristobal on 31 August 2014 and "Irene" on 16 April 2018; promoted ridging over us. The first one, Cristobal, gave away to one of the driest Septembers on record in our countries with barely any rainfall for a lot of places for much of the month following a very wet end to Summer 2014. Meanwhile, Irene gave away to an exceptional warm spell for the time of year (at least in the UK) and later, a very dry May along with a very dry June with lots and lots of high pressure being the dominant influence. Same could happen with Chris this time in prolonging the settled weather again with it helping to ascend more high pressure from the south (which will be bad news). The Azores High is still very strong and ridgey. Add the fact that the GFS was "toying" onto this idea too yesterday well in FI on some runs. I would not be surprised whatsoever if this was to actually happen given how the Summer has turned out so far and with reasons above given light. You could also consider Hector of mid-June.







GFS ensembles seem to have upgraded the warmer than average temperatures too out to Tuesday 17th but we'll see the whole suite soon.

Uncertainty is a big issue out as early as later this week so taking anything serious beyond that time is a bit pointless.