Model Output Discussion 01/09/17

[Frosty.]

A wintry end to October according to the Gfs 12z, synoptically great for opening the arctic floodgates / icegates and locking in an increasingly cold outbreak with strong height rises to the west / northwest..the forum will be buzzing if we see charts like these verify later this month and into early November!..whet's the appetite for the long winter ahead!

Edited October 12, 2017 by Frosty.

[Frosty.]

Sensational mid october plume on the Ecm 12z with temps shooting up through the weekend, especially sunday with monday being the peak with potentially mid 20's celsius for parts of the s / e and 80f could be reached or even a notch higher. The reason I say that is there is likely to be increasing amounts of sunshine breaking through by sun / mon. 

Next week shows predominantly high pressure across southern uk with just a brief blip and an increasingly warm trend again later in the run..for those who enjoy unseasonable warmth, the Ecm 12z is definitely for you! 

 

Edited October 12, 2017 by Frosty.

[ANYWEATHER]

2 hours ago, booferking said:

First hopefully of many northerly,s consistently appearing at the end of the runs now just to get it in the more reliable time frame winter hunt begins .

Hi it will happen sooner or later let's just get this tropical storm out of the way first 

[Singularity]

   

A shallow trough dangling down west of ex-Ophelia interacts with it enough to keep its core west of most of the UK on the GFS 12z, but the 12z UKMO sees less interaction with the core moving through Scotland, while ECM has less still and takes it through the heart of the UK. Thankfully, the system is weakening rapidly during this translation across our lands, but it still delivers a heavy blow to Ireland and a strong one to SW UK (ECM) or W. Wales (UKMO), along with some heavy rain.

  

The Euro High soon shrugs this off in the ECM 12z though. What is it with this resilient ridge I wonder - could all that warm air that keeps getting thrown across at the upper levels and then slowing down be tending to sink and support increased SLP over the region? I'm not entirely sure of thermodynamics permits such a mechanism.

[Sperrin]

The 12z ECM looks to be sending Orphelia right up the centre of Ireland and more potent compared to the GFS. Would this be a fair assessment? 

[Ice Man 85]

Just now, Sperrin said:

The 12z ECM looks to be sending Orphelia right up the centre of Ireland and more potent compared to the GFS. Would this be a fair assessment? 

If the wind charts are anything to go by, then yes.

[damianslaw]

Models possibly struggling a bit today - uncertainty still abounds with regard to the track of tropical storm early next week. With this in mind take anything shown beyond 96 hrs with large margin for error, the differences between ECm output today compared to yesterday at the 120-144 hr timeframe is symptomatic of this..

Whilst GFS is holding its position on the atlantic gaining the upper hand against the ridge and southerly feed. My reckoning is GFS has this one right.

[Pembroke Dangler]

Latest noaa predictions show Ophelia is still a hurricane or extra tropical hurricane just to the sw of Ireland at 8am Monday, I think the folk of cork and surrounding areas could have a pretty big Monday wake up call. Batten down the hatches my fellow Celtic friends across the Irish Sea. 

[Allseasons-Si]

21 minutes ago, damianslaw said:

Models possibly struggling a bit today - uncertainty still abounds with regard to the track of tropical storm early next week. With this in mind take anything shown beyond 96 hrs with large margin for error, the differences between ECm output today compared to yesterday at the 120-144 hr timeframe is symptomatic of this..

Whilst GFS is holding its position on the atlantic gaining the upper hand against the ridge and southerly feed. My reckoning is GFS has this one right.

You are not wrong there

the models of late are all over the place,until we get this ex-tropical storm out of the way then forget it,shannon entrophy big style.

[DR(S)NO]

Early days still but Arpege has gusts of 112 mph+  early Monday south of Ireland...... Gonna be pretty breezy Irish Sea later in the day.... Interesting times ...

 

[Summer Sun]

ECM again shows Ophelia approaching County Cork on Monday afternoon at 962mb at this stage the centre remains at sea

She then continues to push north with pressure at 7pm still 964mb

The centre then makes landfall in County Galway around 10pm at 970mb

Through the night she continues to track towards western Scotland and by 7am Tuesday pressure is at 984mb

[ACCOUNT DELETED]

A decent enough half term week is on the cards if this GFS 6z is correct. 

[Ross Andrew Hemphill]

14 minutes ago, DJ RY said:

A decent enough half term week is on the cards if this GFS 6z is correct. 

Is that retrogression I see?? 

[karlos1983]

Technically this is model related, but moreover well worth a read for anyone interested in Ophelia’s movements. Top post 

 

[feb1991blizzard]

Not a million miles away from a powerhouse Northerly on the GFS 12z.

[Frosty.]

35 minutes ago, feb1991blizzard said:

Not a million miles away from a powerhouse Northerly on the GFS 12z.

Yes this would whet the appetite for winter..it would for me anyway!..the Gfs 12z yesterday was building up to something like this at the end of the run..this one  shows the snow..yeah I know its deep FI but I could really get used to seeing charts like these as we head towards winter!

Edited October 13, 2017 by Frosty.

[Singularity]

  

So let's get this straight - with a little assumption regarding the uppers not reducing unusually quickly during next Saturday afternoon, the ECM 12z run has the 15*C 850 hPa isotherm visiting the UK on three days out of the week starting Saturday (or Sunday if you like). We've had a hard time getting that to happen in a number of recent Julys (not this year's though, thankfully) so it seems pretty extraordinary to me. 

[ANYWEATHER]

Evening All ! A lot of uncertainity in the next few days regarding tropical storm ophillla . There is a big degree of uncertainty of the east/west movement of this Ireland perhaps having the most powerful influence of this but a little shift eastwards  then Wales and the far West of the uk will feel the storm. After that once the muddy waters clear . the clear cold air takes hold of the the  uk it Will feel like Autumn.....

[Man With Beard]

I'm increasingly seeing a second warm weekend on both ECM/GFS runs (not on every run, but more than not)

  

Edited October 13, 2017 by Man With Beard

[chrisbell-nottheweatherman]

On 10/12/2017 at 21:50, Pembroke Dangler said:

Latest noaa predictions show Ophelia is still a hurricane or extra tropical hurricane just to the sw of Ireland at 8am Monday, I think the folk of cork and surrounding areas could have a pretty big Monday wake up call. Batten down the hatches my fellow Celtic friends across the Irish Sea. 

Apologies Mods for slight O/T post, but isn't it technically correct to state that, but the time it hits Ireland, it will be an extratropical windstorm?

[knocker]

A quick look at last night's anomalies to see if we can get a handle on the outlook post next week's hiatus.

In the medium term still looking unsettled, the usual N/W bias and temps around average,  with a westerly upper flow and the trough to the north west remaining quite influential. But the upstream pattern is shifting with the vortex lobe retreating to Alaska with a ridge in eastern North America.

In the later period no particular agreement but indications that the quite amplified upstream pattern will move east with a trough now in east N. America and height rises in the western Atlantic, the implications of which are not obvious for the UK at the moment but no obvious path to more settled weather

Back to the here and now. Today remaining cloudy in many areas, more particularly in the north and west with a weak front hanging around, with patchy drizzle but where the sun does break through eastern areas could reach around 21C. Later in the day a wave forming on the front to the west tracks north east to bring rain to N. Ireland and western Scotland through tonight and tomorrow. Further south it will remain dry and becoming very warm in places with temps possible in the 25C range.

Which brings us to Monday and Ophelia. Not to dwell too long on this as I'm sure it will be adequately covered elsewhere but at 12 it is south west of Ireland 958mb whilst most of the UK is still dry and basking in the unusual temps excluding N. Ireland and Scotland. It runs NNE into Scotland and then east to be absorbed by the upper trough to the NE.by Weds midnight. People need to keep abreast of updates from the various professional agencies.

All of this has cleared the decks for the Atlantic to make it's move and with a strong westerly upper flow impacting the south of Britain the next deep low has arrived to the NW of Scotland with associated fronts and rain crossing the country on Wednesday.with temps returning to near average.

This merely heralds the start of a period of very unsettled weather (according to the gfs of course) with shortwaves popping up in the circulation of the main low and swinging across Wales and England before the next very intense low pressure arrives on the scene 951mb over the Hebrides by Saturday with fronts crossing the UK and very severe gales to Scotland, N. Ireland and the north of England. Obviously this a long way from being definitive but the potential is around for some nasty weather.

A very mixed bang with marked regional variations as can be seen with a quick glance at the rainfall distribution.

 

Edited October 14, 2017 by knocker

[Polar Maritime]

Great post as always from Knocker above, Yes the GFS certainly shows the Atlantic powering through bringing gales even severe gales for the North next weekend, All aided by a very strong Jet running over the UK. More named storms certainly possible..

 

[knocker]

Although differing a lot vis detail generally unsettled is also the name of the game with the ecm from the middle of next week. Albeit N/Ireland, Scotland and NW England are entitled to say so what's new.

[phil nw.]

Just adding to recent posts by Knocker and Polar M with the latest London ens graph underlining what the latest modelling is showing with unsettled weather extending south east from day 5.

We can see the marked drop in temperatures and a jump in the rainfall totals showing later next week.

So after the balmy warmth brought north by Ophelia over the next  few days it does looks like a change to a more Autumnal westerly type will be spreading to us all.

Day 5 on the latest operational runs

They do show a little variation on detail but the general outlook is certainly pointing to a resurgent Atlantic pattern.

[knocker]

Once Ophelia has strutted it's stuff the ridge will hang on in there over England and Wales on Tuesday giving way to slack area of low pressure on Weds before the Atlantic kicks into action. Along way from being pinned down but next weekend needs a eye kept on it.

Edited October 14, 2017 by knocker