Model Output Discussion - 31/8/14 Onwards.

[damianslaw]

ECM looking the least unsettled as we head into week 2

In fact the south probably would receive no rain at all with high pressure drifting west to east across southern Europe and the south of the UK. Is the ECM overdoing this or are the other models over-egging the strength of the jet coming off the eastern seaboard?

 

There are strong signals the Jetstream will intensify markedly next week - very much a response to the steeping temperature gradients developing over NW Atlantic - the slumber of recent weeks can't hold steadfast for much longer..

[shaky]

Just when you thought all the models were agreed on a breakdown out comes the rcm 12z with high pressure right throughout!!!

[Polar Maritime]

Just when you thought all the models were agreed on a breakdown out comes the rcm 12z with high pressure right throughout!!!

 

They are, Remember it's 1 run & the ECMWF only runs until 25th/26th. A few more frames the right way from there, Look at the angle of the Jet tilted S/E out in the mid-Atlantic, And the block being pushed East with the PV over Greenland setting us up for a classic Zonal flow.

 

Edited September 16, 2014 by Polar Maritime

[knocker]

Running it a bit further PM. And perhaps not dissimilsr

 

Edited September 16, 2014 by knocker

[Frosty.]

I agree with polar maritime and firmly believe that a pattern change to cooler and unsettled atlantic weather is coming later next week.

[Polar Maritime]

The Atlantic Low's push even further South on tonight's run by the 24th.. Bringing much cooler/unsettled conditions as warm air gets pushed up into the Poles spreading the PV for the turn of the Month This would be a real shock to the system after the dry/calm pattern we have been stuck in.

 

Edited September 16, 2014 by Polar Maritime

[knocker]

Supporting the above. I was doing a quick check on Edouard, nothing new there, but it did continue with the Atlantic breakthrough regarding the UK. No doubt this won't load in sequence. It didn't.

Edited September 17, 2014 by knocker

[knocker]

Confirmation of the above.

 

[IDO]

GEM keeps the south relatively settled till D10 this morning, then looking wet: 

 

GFS more progressive with the Atlantic and around D8 it has the washout incoming: 

 

Though the spread between D8-9 suggests uncertainty and that looks like timing issues between the GEFS with many members delaying the zonal train more in line with GEM:

 

 

The ECM mean from last night also suggests from around D8-10 we see the more unsettled weather move in: D10 mean

 

At this time range possible adjustments as too how far the jet sinks south but the return of the westerly flow looks inevitable by the end of September. Hopefully it won't herald months of insipid zonality; the last two CFS runs suggest it will be transient:

 

 

 

In the interim we have around 4 warms days coming for the south, likely our last warm spell. This likely to spark off a few downpours on Friday/Saturday:

 

 

 

The London temp graph suggests average-below av. temps upcoming from Sunday:  

 

Next week looks like a continuation of the slack setup as we await the change, so relatively dry and feeling pleasant enough.

 

 

[Polar Maritime]

Low Pressure pushing much further South by the 24th on this mornings ECM.

 

Edited September 17, 2014 by Polar Maritime

[Frosty.]

The Gfs 00z op run from T+192 hours looks generally cooler (average) and unsettled with atlantic systems tracking across the uk, temperatures well down compared to currently but the southeast still feeling pleasantly warm at times, but all areas have spells of strong winds & persistent rain interspersed with brighter, showery days..it will finally feel like autumn has arrived beyond the middle of next week.

ps..I agree with polar maritime, one of the most respected posters on here..and please will someone sort these charts out because they are always loading in the wrong order..I thank you

Edit: @Frosty - Mission completed! Charts in order. - DiagonalRedLine -

Edited September 17, 2014 by DiagonalRedLine
Re-ordering the attached charts. :)

[IDO]

Low Pressure pushing much further South by the 24th on this mornings ECM.

 

 

 

Yes but by D9 and 10 the south back under better conditions including +12c uppers:  

 

I don't believe that either. ECM have surpassed themselves of late and set flip flopping records for D8-10 charts.

 

Last night at D9:    This morning at D8: 

Edited September 17, 2014 by i'm dreaming of...

[ANYWEATHER]

Yes but by D9 and 10 the south back under better conditions including +12c uppers: ECM1-240-15.GIF ECM0-240-6.GIF

 

I don't believe that either. ECM have surpassed themselves of late and set flip flopping records for D8-10 charts.

 

Last night at D9:  ECM1-216-12.GIF  This morning at D8: ECM1-192-13.GIF

To be honest. you would be hard pressed to believe any model output past five days in the current time!!! but perhaps a signal now of Atlantic weather pushing in....

Edited September 17, 2014 by ANYWEATHER

[Polar Maritime]

To be honest. you would be hard pressed to believe any model output past five days in the current time!!!

 

Yes the Models this morning are just showing another variance after D5/6. Lot's of erratic outputs to continue I would think over the next few days, As always when a pattern change is evolving. Very interesting Model watching..  

Edited September 17, 2014 by Polar Maritime

[johnholmes]

The anomaly charts, having been fairly consistent between the 3 I use show a change this morning, links below, with EC-GFS showing quite marked differences between one another and neither is that much like the NOAA 6-10 day issue from last evening. My own well known view is that when they differ then doubt has to be high over any predicted upper air pattern or any emphasis on either a settled or unsettled pattern to the weather. Even less can any credence, in my view, be put on the 2 major synoptic models past 5-6 days ahead.

 

EC-GFS

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

 

NOAA

http://www.cpc.noaa.gov/products/predictions/610day/500mb.php

[Liam J]

An unsettled set of charts to end the ECM 00z compared to yesterday evening, a very flat pattern across the Atlantic with depressions firing west to east - It would feel like Autumn proper has arrived especially further north with the south managing to hold onto to some late season warmth. Just a variation on a theme that's emerging so expect some more chopping and changing over the next few days, it does look like the current extended settled spells days are numbered and it's only a matter of time before we see the true face of Autumn. Make the most of the current late summer weather!

 

The lakes and reservoirs are in need of a top up around here as we haven't had any rainfall so far this month!! How often can you say that in September?!!

 

 

Edited September 17, 2014 by Liam J

[Summer Sun]

High pressure dominates UKMO's 00z update though by Tuesday we maybe seeing the first hints of the Atlantic moving in as pressure begins to fall for NW Scotland, temperatures slightly lower for the south than we'll be seeing over the coming days but still very pleasant for the time of year with mist and fog patches developing at night

 

[phil nw.]

We can see the uncertainty for later next week in the 00z models.

ECM at day 8 has a much sharper Canadian trough upstream compared to the GFS which throws lower heights se towards Iceland and the UK.This is reflected in the means too.

The NOAA forecasters last night commented on the uncertainty over week 2's wave pattern also mentioning the large spread in yesterday's 12z ens members.

http://www.cpc.ncep.noaa.gov/products/predictions/610day/fxus06.html

 

It does look like that lower heights to our north will start to increase the zonal flow from the west around mid next week but then how far south will the real unsettled conditions get remains to be agreed on.

Edited September 17, 2014 by phil nw.

[Frosty.]

 

 

The lakes and reservoirs are in need of a top up around here as we haven't and rainfall so far this month!! How often can you say that in September?!!

 

ecm1.gif

After last winter when it never stopped Bl**dy raining and some parts of the uk were flooded out, I never thought things could be so bad a few months later. I firmly believe changes are afoot next week, we are about to become unblocked

Edited September 17, 2014 by Frosty.

[IDO]

As if to show what we have been saying for the last few days the GFS op keeps the south more settled than recent runs:

 

D8:  D13:  D16: 

 

GEM  has now introduced a totally different setup for D8: 

 

At D10 it is just losing the higher pressure and is now in a slack flow: 

 

So the uncertainty remains...

Edited September 17, 2014 by i'm dreaming of...

[Polar Maritime]

Yes ^, The run's this evening are showing a North/South split with the Atlantic mainly effecting the North of the UK. Many more variances to come over the days ahead with high uncertainty as you say reg detail.  ECMWF has High pressure pushing back in towards the end of the run..

 

But the Atlantic is not far behind.

 

Edited September 17, 2014 by Polar Maritime

[IDO]

All change ECM this evening, so no surprise there.

 

An insurgent Atlantic does not really ingress, certainly not for the Midlands south.

 

D8:   D9:  D10: 

 

JMA going all in for washout for D8: 

 

The trend from the three main models today is to downplay the more unsettled westerly flow as it is kept further to the north than previous runs. Hopefully the models can run with this now. Certainly the NAO and AO indices suggest that the current forecast Atlantic surge may not be long term:

 

 

 

 

 

 

[Polar Maritime]

Yes as always with the GFS the West gets over played with-in it's program bias when picking up the Atlantic signal, Last nights run was a perfect example of this. Far from a done deal yet, But the South does look to hold on to more settled weather for now.

Edited September 17, 2014 by Polar Maritime

[Frosty.]

The Gfs 00z op run from T+192 hours looks generally cooler (average) and unsettled with atlantic systems tracking across the uk, temperatures well down compared to currently but the southeast still feeling pleasantly warm at times, but all areas have spells of strong winds & persistent rain interspersed with brighter, showery days..it will finally feel like autumn has arrived beyond the middle of next week.

ps..I agree with polar maritime, one of the most respected posters on here..and please will someone sort these charts out because they are always loading in the wrong order..I thank you

Edit: @Frosty - Mission completed! Charts in order. - DiagonalRedLine -

h500slp.pngh500slp (1).pngh500slp (2).pngh500slp (3).png

Thanks DRL

[ANYWEATHER]

A Big pattern change looks very likely next week, with our neighbour the Atlantic ,courtesy of a revitalised jet stream heading towards the Uk. Details will be impossible at this stage ,but the slippery slope to normal Autumn weather , looks very likely.      Models will always filp and flop at this stage

Edited September 17, 2014 by ANYWEATHER