Model Output Discussion 12z 30/06/13

[Gray-Wolf]

Is it not an insight to how such situations arise Pete? If we can look at ENSO phase, QBO,AMO,PDO as giving a tilt to how patterns will develop then why not the instant impacts of snow/ice loss?

 

Now we are back in a period of negative snow anoms will the heat this allows to our north have no impact on our systems as they develop and travel?

[Gael_Force]

Maybe they weighted their conclusions wrongly and should have looked more to the arctic changes for the driver of the Jet's recent 'excursions' . to me it is no mistake that , post another 18% drop in ice levels, we should see a similar 'switch' to the one we saw with the 07' 22% drop in ice cover?

 

Shift the jet on a cycle and troughs become peaks and peaks become troughs ( sorry Mid europe but it's your turn now!)

 

The movement of the jet stream and shifting cycles of 'up and down' has gone on throughout history; why on earth are you suddenly applying a normal cycling to Arctic ice melt?

[Methuselah]

Maybe yes, maybe no; but we already have a thread for discussing the jet stream's response to melting ice...

 

http://forum.netweather.tv/topic/74403-arctic-ice-will-it-affect-our-weather/

Edited July 2, 2013 by A Boy Named Sue

[johnholmes]

The movement of the jet stream and shifting cycles of 'up and down' has gone on throughout history; why on earth are you suddenly applying a normal cycling to Arctic ice melt?

a good question

[Frosty.]

The GEFS 06z mean is incredibly good in terms of the anticyclonic spell persisting for a couple of weeks, all the way to mid month, from this weekend onwards it looks every bit as good as the Ecm 00z ensemble mean charts I posted earlier, it is likely to become hot in the south as early as this weekend and the hot air then pushing north to the rest of the uk with temperatures nationwide of 25 celsius plus, more like high 20's to low 30's celsius for the south by early next week but even scotland looks like having temps in the high 20's celsius through next week, it's looking like the best heatwave for several years is only 3 days away from commencing.

[Scorcher]

 

 

The return to cooler unsettled conditions later next week has been on a few runs from GFS now over the past few days so its going to be a case of wait and see how things progress over the coming days

 

There was no breakdown to cooler and unsettled conditions at all on the GFS 00Z though, will be interesting to see if the 12Z run goes back to that.

[Summer Sun]

There was no breakdown to cooler and unsettled conditions at all on the GFS 00Z though, will be interesting to see if the 12Z run goes back to that.

 

Yep it seems the 06z runs go for a break down then the 00'z don't the 12z is eagerly awaited

[johnholmes]

another illustration of the roller coaster winter or summer of watching each GFS run.

[DAVID SNOW]

another illustration of the roller coaster winter or summer of watching each GFS run.

 

No harm in that

[Summer Sun]

12z GFS rolling out now

 

 

This run isn't as hot for the north on Sunday (12z left 06z right)

 

Edited July 2, 2013 by Summer Sun

[Weather Boy]

12z GFS rolling out now

 

 

This run isn't as hot for the north on Sunday (12z left 06z right)

 

 

Remarkable consistency of the runs having the hot spot as being Solent towards inland Dorset.

 

Some toning down, to my eye, of the moderation in temperatures in the south-east, away from coasts (still cool in Norfolk and Suffolk though).

[cheese]

12z GFS rolling out now

 

 

This run isn't as hot for the north on Sunday (12z left 06z right)

 

 

See, this is what irritates me about the GFS temperature projection charts - as far as I can tell there is absolutely no reason why the temperature should be significantly lower on this run compared to the 06z when there is no nearby precipitation, it's practically the same as the 06z. So much variation from run to run seriously diminishes the credibility of the GFS.

 

And to make matters worse-  the following day now only has a maximum temperature of 21C at the very best in the bulk of England, with only a very narrow strip of 25C in the far south of England. WTF? All of this under an area of high pressure as high as 1032mb. Sorry GFS, you're rubbish.

Edited July 2, 2013 by cheese

[Summer Sun]

GFS is certainly downgrading temps for early next week across the UK

 

12z

 

 

06z

 

 

The east coast and the SE still look the cold spots in the UK

Edited July 2, 2013 by Summer Sun

[Gordon Webb]

GFS = giving fluctuating statistics

[Captain Shortwave]

GFS is certainly downgrading temps for early next week across the UK

 

12z

 

 

06z

 

 

The east coast and the SE still look the cold spots in the UK

The uppers are not as good on this run, 12C isotherm is a couple of hundred miles further south. I assume an over reaction in the surface temperature could be possible here.

[Scorcher]

Wow if those temperature predictions are correct from the GFS that will be a massive disappointment- I can't see why they are so much lower though given the orientation of the high hasn't changed from previous runs and the uppers are still warm.

[NUT]

Storm risk for next tuesday although still there, has been toned down (earlier was showing a lot of yellow over scotland for tuesday) more toned down to green

[SizzlingHeat]

Cooler and breezier in the south on this run. 528 thickness along south coast rather than central Britain thus temps of 25-27c for most

[Geordiesnow]

See, this is what irritates me about the GFS temperature projection charts - as far as I can tell there is absolutely no reason why the temperature should be significantly lower on this run compared to the 06z when there is no nearby precipitation, it's practically the same as the 06z. So much variation from run to run seriously diminishes the credibility of the GFS.

 

And to make matters worse-  the following day now only has a maximum temperature of 21C at the very best in the bulk of England, with only a very narrow strip of 25C in the far south of England. WTF? All of this under an area of high pressure as high as 1032mb. Sorry GFS, you're rubbish.

 

Well from what I seen, the reason is simple, the high was slightly further West than the 06Z therefore it allows that front to topple in and thus the air was slightly cooler in northern areas than on the 06Z run so the temp profiles look fairly plausiable too me. 

 

The UKMO run does look better too me but for Saturday pressure is slightly lower than the GFS 12Z run in Northern areas so that front is likely to topple in further in. 

 

At this range, it would be false information in saying the weekend will be warm and sunny because the exception to this rule appears to be in Scotland and Northern Ireland, especially on Saturday. 

[Summer Sun]

Tuesday picks up but the south east remains disappointingly cool

 

12z

 

 

06z

 

[Barry12]

Temperatures will get up to 28C in the SE and 24C in the North on Sunday, GFS is undercooking:

 

http://www.bbc.co.uk/weather/features/23153065

Edited July 2, 2013 by Barry95

[Frosty.]

The ukmo 12z is stellar, turning hot and sunny everywhere, as far as the high pressure is generally concerned, every model run will show variability which will favour different parts of the uk for the hottest weather but I see no point in nit picking between 22 celsius and sunny and 29c, it's going to feel great whether it's warm, very warm or hot since the sunshine totals will be well above average during the upcoming anticyclonic spell, the fact is that some areas will be hot, some very warm and others warm but only the east coast will have cool refreshing sea breezes tempering the warmth.

[PolarWarsaw]

I can't understand why people judge a run by a couple of degrees on a notoriously poor models temperature charts. Seriously, there isn't much difference between 25oc and 27oc, so I'm not sure why people moan about it. Sun is sun, warm weather is warm weather - enjoy it.

[Tamara]

GFS is certainly downgrading temps for early next week across the UK

 

 

 

 

 

The east coast and the SE still look the cold spots in the UK

Slight exaggeration maybe   I think it is highly likely that eastern parts south of, say, the Humber will be that bit cooler with a light easterly breeze (and personally I am not complaining about that, as pleasantly warm is perfect for me) but I think that it is not worth taking much notice of these GFS temperature charts at this distance as they fluctuate so much and need to be taken with a pinch of salt.

 

The UKMO this evening suggests increasingly very warm/hot weather anyway countrywide from later this weekend and into next week, although perhaps again the very highest temperatures in western and central parts of the UK. The High maybe fractionally further south than GFS, although there is little in it

Edited July 2, 2013 by Tamara Road

[johnholmes]

It is a fairly simple explanation if you look a bit more carefully at what GFS has done. On the 06z there was almost no flow off the N Sea for SE'ern coastal areas, there is on the 12z=simple a more definitie flow off the cold sea thus lower temperatures IF it is correct.

Edited July 2, 2013 by johnholmes