Model output discussion - summer rolls on

[summer blizzard]

Differences in modelling at the moment are being caused by a small shortwave exiting Newfoundland at day 5 and the degree to which interaction with the primary Jet Stream occurs.

So here at day 5 we see the feature best on GFS (literally that small circle)..

Now the GFS over the next 48 hours has this interact with the jetstream but sufficiently little that it gets cut-off..

While the Euro develops the low somewhat but phases it completely..

..

In essence both models agree that the jet stream will weaken sufficiently for a pressure build but the GFS builds a proper ridge while the Euro moves a bog standard secondary low through.

[damianslaw]

32 minutes ago, summer blizzard said:

Differences in modelling at the moment are being caused by a small shortwave exiting Newfoundland at day 5 and the degree to which interaction with the primary Jet Stream occurs.

So here at day 5 we see the feature best on GFS (literally that small circle)..

Now the GFS over the next 48 hours has this interact with the jetstream but sufficiently little that it gets cut-off..

While the Euro develops the low somewhat but phases it completely..

..

In essence both models agree that the jet stream will weaken sufficiently for a pressure build but the GFS builds a proper ridge while the Euro moves a bog standard secondary low through.

I mentioned a few days ago, keep an eye on developments to our NW, some early cold pooling over NE Canada/Greenland will create a recipe for sudden cyclogenesis over NW atlantic, and allow for shortwave/low development features which could interact and phase with the jetstream invigorating it, and pushing large pressure on any ridge development that does occur over the UK. 

I also said keep an eye on position of core central heights building out of N Russia, further north and east and this would allow the trough invade the UK markedly.

Despite the bullish Met Office long range forecasts for mainly settled dry warm weather - unlike much of the April-July period, I suspect sudden short term developments will unfold, and create much more uncertainty beyond the reliable in the days ahead, with the bias towards unsettled rather than settled..

[Frosty.]

The Ecm 00z ensemble mean looks increasingly fine and warm, at least for most of england and wales as a strong azores ridge extends across the south next weekend, hopefully a sign of things to come throughout september!☺

Edited August 26, 2018 by Frosty.

[Frosty.]

There's a lot to like about the Gfs 6z operational if you like warm settled anticyclonic weather, at least across england and wales with plenty of warm, indeed very warm at times with lots of sunshine..more like summer through early september for many..azores high starts ridging in again at the end!☺

Edited August 26, 2018 by Frosty.

[Man With Beard]

The ECM op run cluster was a. quite small (8 out of 51) and b. the weakest for height rises next weekend. Which gives reason to hope for a more summery outcome than the op run suggests

[Frosty.]

The GEFS 6z mean indicates a BIG improvement during the outlook period, longer term it's all about high pressure and warmth, the warmth mainly across england and wales but plenty of settled weather for all..there is also potential for september very warm / hot weather if we can tap into continental heat as a few of the 6z postage stamps show.☺

[Turnedoutniceagain]

1 hour ago, Frosty. said:

The GEFS 6z mean indicates a BIG improvement during the outlook period, longer term it's all about high pressure and warmth, the warmth mainly across england and wales but plenty of settled weather for all..there is also potential for september very warm / hot weather if we can tap into continental heat as a few of the 6z postage stamps show.☺

How utterly depressing. *sniffs the air for a frost*

[Mike Poole]

So to the 12s then, first out ICON here T180:

run was settled since about Wednesday too.  I think we might start to see some consistency tonight, I should note earlier runs from the FV3 were very encouraging, both 0z and 6z heading warm and settled, the 0z having +16 uppers towards the end. Let's see what the rest of this afternoons runs bring...

[Mike Poole]

UKMO heading settled from T96, really coming into the reliable now. Here at T96, T120:

Edit T144 out now:

Edited August 26, 2018 by Mike Poole

[Mike Poole]

Well any model you look at has a similar if slightly different story, GFS at T264:

heading for home grown warmth, and sunshine here, but hen there is the GEM which builds a high into Scandi and lands like this at T240:

I can certainly see why the MO updates mention very warm weather!

[Frosty.]

These Gfs 12z charts would be great in winter..Beast from the East worthy!❄❄❄

[Mike Poole]

The GEFS mean, is screaming settled from the word go:

Here T144, T 252, T360:

Welcome back summer!

[Mike Poole]

ECM gets there too, T240:

Not nailed yet though more runs needed !

[Frosty.]

5 minutes ago, Mike Poole said:

ECM gets there too, T240:

Not nailed yet though more runs needed !

Yes following today's cool, wet / windy washout most of the Ecm 12z looks pleasant with plenty of ridging / high pressure..temps up and down but at least there would be plenty of dry and sunny weather and not much rain to speak of.☺

Edited August 26, 2018 by Frosty.

[Frosty.]

A decent Ecm 12z ensemble mean tonight, essentially the week ahead looks drier and a little warmer with some sunshine at times, a risk of a few showers around but largely fine, best further south and actually becoming even better across southern uk next weekend into the following week with a strong azores ridge extending across southern areas, probably staying more changeable and cooler across northern uk. Beyond that, signs the more changeable less warm weather spreading south but still some azores ridging persisting  further south.☺

Edited August 26, 2018 by Frosty.

[mb018538]

Looking decent in the south perhaps, but the option of a big UK high pressure looks less likely to me for now...jet stream perhaps a bit close, and the cut off low scenario that supported this outcome has gone too. We’ve also gone from tight nicely banded ensembles above average, to scattergun ensembles in 10 days where it could either be a heatwave or below average and chilly. Not helpful!

 

[Frosty.]

The Ecm 00z looks a good run and ends beautifully..the Gfs 00z also looks summery through early september, there's plenty of high pressure and warmth, even some plume potential!☺

[Man With Beard]

Very quiet on here, but in case anyone is interested, the early September "settled spell" ... continues to look short lived. The largest EC cluster now suggesting a break in heights between Scandi and the Atlantic, with the UK somewhere in the middle, this being by 4th September 

Could be OK (and warm) in the SE, looking a bit dodgy elsewhere - cluster 3 allowing some hope of more widespread settled weather but it's only 20% of solutions. 

Further out, 2nd weekend of September 

can't really make a forecast on that, a ridge probably building somewhere further north than usual but not guaranteed to favour the UK with settled weather. 

[Frosty.]

The Gfs 6z operational is a predominantly settled run with lots of high pressure / strong ridging and pleasantly warm, occasionally very warm further s / e..the jet stream stays to  the north, close enough to northern scotland to make the weather cooler and more changeable up there but even those areas are under the influence of high pressure at times with the PFJ well to the north..for the most part, it's a decent end of summer / start of autumn run.☺

Edited August 27, 2018 by Frosty.

[Frosty.]

Really nice GEFS 6z mean from later this week to the end of the run..and beyond!

It suggests high pressure domination and becoming warm, even very warm potential across southern uk.☺

Edited August 27, 2018 by Frosty.

[Mike Poole]

UKMO and GFS at T144:

Pretty similar for next weekend.  High pressure dominated,settled and warm for much of the country.  

GFS through to T240:

I can't see what's not to like if an extension to summer is your thing.

[Mike Poole]

FV3 is also favouring the warm settled spell, of interest at T192, 12C uppers widespread in the south, storm potential there too:

Actually interest in this run. Here at T228:

16C uppers into the SE, and the low encroaching...

Edited August 27, 2018 by Mike Poole

[Mike Poole]

Now even the ECM  has got behind it, the UK high and summer resumed!

T192 and T216:

Wowsers at T240:

Edited August 27, 2018 by Mike Poole

[Man With Beard]

Yes, more encouraging runs for an extended settled period tonight. However the ECM is a good example of how high pressure will not get hotter any more on its own - it now needs a warm feed to get it going. Sunny and 19-23C likely after being a little warmer at the weekend. 

[ANYWEATHER]

Evening ! The Jet stream tells the story