model discussion Model output discussion 11th July onwards

[mb018538]

Time to head off to Siberia again then. Temps into the high 20s/low 30s again for the umpteenth time this summer.

[Eagle Eye]

@Zak MGood to hear from you again, here's my breakdown of a lot of models. 

GFS has a brief spell of warmth before more low pressures move through and then a good chance for more warmth on the cards although it is further out. 

ECM is good in bringing a more prolonged spell of heat but only for the luckier areas although it looks mostly the same for the future, perhaps we're having some agreement further out on what's on the cards. 

GEM yet again doing mostly the same things as the other models which is interesting this far out, perhaps to a leer extent though than the other models within this short comment on here. 

Xander

 

 

[MATTWOLVES 3]

Ecm mean and the op are pretty much in agreement this evening,bar the odd bump in the road regarding temps later in the period.

Definitely last one from me as a fistful of dollars as just started..

[Frosty.]

I would settle for perturbation 2...although p3 ain’t bad..but I don’t fancy p4..  

p2 would make august for me...  

 

[Guest]

1 hour ago, stodge said:

What happens is a plume of air from the Azores HP is carried north and gets cut off as LP develops behind it. 

I've never seen anything like that on a chart - just thought it was worth a mention.

Utterly bizarre, but in a year where Canada reached nearly 50C, we’ve had basically no summer, Finland through Lithuania have had warmest months on records who knows  what’s possible. 

[damianslaw]

Immediate outlook, abysmal.. low pressure stuck on spin cycle it seems, going nowhere for 5 days..

[Frosty.]

Friday the 13th is considered unlucky, but if the Gfs 0z operational is right, we would be very lucky! ...and beyond mid month we become even luckier! ? ? ...summer ain’t over!!!! 

Edited August 5, 2021 by jon snow

[bluearmy]

gefs now on the same page as the geps and eps re next weeks upper trough ……the poor geps outlook for week 2 coming to fruition for week 1. certainly the envelope has settled on the geps/eps side. 

[Guest]

40 minutes ago, jon snow said:

Friday the 13th is considered unlucky, but if the Gfs 0z operational is right, we would be very lucky! ...and beyond mid month we become even luckier! ? ? ...summer ain’t over!!!! 

This is a sarcy response but this has zero chance of coming off as I have friends coming down Friday the 13th, 8 of us playing golf locally. Rain 100% guaranteed

[Methuselah]

A rather spiky-looking GEFS 00Z ensemble this morning; T850s between 5 and 15C will do me okay, though:

      

 

[Frosty.]

1 hour ago, Alderc said:

This is a sarcy response

I expected nothing less! ..just kidding.. ...anyway, it’s a good Gfs 0z op under the circumstances, even if it has zero chance!  

[Scorcher]

2 hours ago, jon snow said:

Friday the 13th is considered unlucky, but if the Gfs 0z operational is right, we would be very lucky! ...and beyond mid month we become even luckier! ? ? ...summer ain’t over!!!! 

August 13th was hot last year as well- let's hope it is lucky for us again.

[northwestsnow]

EC intent on the bringing the trough into play so was probably right with its general progression ...

With Sept 3 weeks away my thoughts are already turning to Autumn and dare I say Winter.

Early news Marco Petanga suggesting eQBO......     a weakish ENSO( nina) might be an interesting combination.

ENSO / Strat thread may be interesting over the next 6 to 8 weeks ..

[Methuselah]

GFS 00Z at T+360 . . . Very unlikely to materialise? Yes, of course -- but 'impossible'? Of course not!?

    

Edited August 5, 2021 by Ed Stone

[Uncle_Barty]

On 04/08/2021 at 17:15, Tamara said:

The very few cloudier days get a discussion going down here!  The last rain that fell was about five or six weeks back, and with a few thundery showers before that earlier in June, so close enough to the theme of a Mediterranean summer even though there has not been any true sustained heatwaves of 35 to 40C (and upwards) beyond a couple of brief spells in July.

Its no guesswork involved that the two periods, so far, of this summer, that have seen a departure from the changeable cooler and sometimes very wet pattern that UK and other parts of NW and central europe have seen have coincided with momentum shifts upwards between the tropics and extra tropics. The first being in the opening ten days to fortnight of June and more recently the mid to latter part of July. The downturn from mid June to the first part of July, and the latest one on-going, being a result of the high frequency tropical cycle returning to mirroring an underlying increasingly Nina-esque standing wave once again and associated generally rather lower than average atmospheric angular momentum tendency.

The Global Wind Oscillation phase plot, (a depiction of wind-flow inertia within the atmospheric circulation which gives a  useful diagnostic guide to jet stream behaviour) and also the angular momentum anomalies themselves (that the GWO mirrors in its orbits) both illustrate those two relatively short upward cycles within otherwise supressed tendency.  Its a deliberately simplified illustration (with rather pedestrian hand-work) but it does provide a mirror for correlation purposes.

 

In synoptic terms (for summer wavelengths) this ebb and flow pattern revolves around the movements of a stronger than average Azores high sub tropical ridge (the one that gives the stable sunny and very warm/hot conditions to southern europe). However, with tendencies for this to retrogress its influence across more northern parts of europe due to upstream wind-flow inertia decelerating c/o rossby waves amplification occurring across the Pacific when tropical connection suppression takes hold across this section of the tropics and sub tropics.

The net effect of recurring Pacific amplification is to keep re-setting the downstream pattern to a trough/ridge/trough pattern - with the final ridge /trough arrangement being across the west/central atlantic and north western european sectors respectively. As suppression briefly wanes across the pacific, c/o (1) eastward passage of the high frequency tropical cycle increasing wind-flow across the Pacific and sending the (2) amplifying rossby wavelength downstream, then the trough over UK/NW and central europe is replaced by ridging for the temporary period that this interference with the background base state exists.

Its hard to see a break to this pattern cycle rut at present, and with signs that a La Nina-esque hold on the wider hemispheric pattern may strengthen again heading into autumn. This makes it likely that Atlantic ridging will continue to dominate proceedings overall, though as per the previous post, its worth watching out to see how  tropical storm activity intervenes if, following any recurving tropical storm (from within the Equatorial Atlantic) another intra-seasonal kelvin wave crosses the tropics and a further temporary rise in angular momentum occurs. This maybe more likely late this month and perhaps into September. Other than this, any hotter spells and more southerly winds (for UK/NW Europe) seem harder to come by and restricted to breakaway ridging transferring eastward ahead of main troughs and associated advection of  brief plumes. Though again, this sequence could be further amplified or augmented if any tropical activity gets caught up in such a sequence.

Lots more lovely sunshine and customary warmth to come down here ( nothing likely to top up the water bore-hole for some time yet), but a case of making the most of the drier, warmer and more settled spells when they come for the majority interest of the forum in the UK

Thank you once again, Tamara.

Just to aid my understanding here.. from your post above:

(1) Are you referring to the MJO here?

(2) This is a reference to the waving jet-stream?

Is a Kelvin wave (atmosphere) connected to the MJO, or are they different processes?

I am assuming that the La Nina pattern is driving the default Atlantic ridge/ NW Euro trough, with a reasonably strong MJO event (and/or other factors)  temporarily disturbing that pattern? I also read in past years that there may be, at times, a "decoupling" of the atmosphere from the ENSO state.. what drives that?

 

Thanks

[MATTWOLVES 3]

36 minutes ago, DCee said:

See Tamara's post above, not many periods of settled weather ahead.

Early Monday looks OK if you can be in Cornwall by the next day, from then on it's relatively calm...or leave it until Thursday for another window?

The conditions hopefully settling down around Monday for a few days...The conditions in the area your traveling too should be set fair with temps around 22-25c.

The Gem puts us back to square one come later next week,and just in time for the Weekend! Doing my nut in now all of this!

That 2nd low needs watching also could bring some much warmer conditions ahead of it for a time at least.

@emmett garland this post was intended for you

Ps..got room for one more? I'm an excellent sailor

Edited August 5, 2021 by MATTWOLVES

[Methuselah]

A typical summertime mix of sunshine/heavy showers this weekend. However, sea breezes could well keep many coastal districts mainly dry & sunny:

    

[Methuselah]

The situation gets a tad more interesting by Day 10. I wonder when (if) that European heat will come into play. After all, didn't we see 94F a few Septembers' ago?

    

 

[Mapantz]

Off-topic posts moved over to here

Please keep to model discussion. 

Thanks. 

[Dangerous55019]

Hello everyone 
I though I'd throw my two peneth worth into this discussion with the CFS weekly anomaly charts. Yes I know its the CFS, but I find that they can be a reasonable good guide.

Week 1 - 5th - 11th August: This is basically showing low pressure centered over Northern Ireland and Scotland = Unsettled with showers, longer spells of rain/thunderstorms, and I dare say sunnier bit in between.

Week 2 - 12th - 18th August: Low pressure in basically the same position as week one, but it does look weaker... So I'd say the same but with a possible transient ridge of high pressure ????

Week 3 - 19th - 25th August: The UK looks sandwiched in between to large ridges of high pressure, one from the Azores, and a big Scandi high, with a very small area of low pressure over northern France and the South coast... Its possible that this could be a settled(ish) week, but with a risk of thunderstorms moving up from the south.

Week 4 - 26th August - 1st September: High pressure from the Azores joining up with the Scandi righ right over the top of us! Is the the start of 'Old Wives Summers'? when high pressure treks from the Azores toward Siberia? Time will tell. 

As always its the CFS so please take these charts with a gritter full of salt.

 

[Methuselah]

Well, at least the GFS 06Z is not an outlier:      

[Frosty.]

Just a quickie before the 12z gets into full swing..the Gfs 6z operational indicated a changeable outlook, trough / ridge / trough / ridge etc etc but eventually by the last third of august, high pressure gets a foothold, so perhaps if we are patient, the last 10 days or so of summer could be worth waiting for as the longer term signal from the pros is still potentially excellent for summer fans!  

 

Edited August 5, 2021 by jon snow

[MATTWOLVES 3]

Stone the crows the GFS 12z could of been on the Gin this afternoon...now where will this sit amongst the ens? Either way it's very pleasant viewing on a thoroughly wet evening here.

Here's the mean at a similar time frame.

Edited August 5, 2021 by MATTWOLVES

[Zak M]

I'd say the 12z GFS is pretty good this evening. Would be very warm in the SE if this was to verify. 

Interested to see where the OP sits in the ensembles.

   

[Climate Man]

1 hour ago, Zak M said:

I'd say the 12z GFS is pretty good this evening. Would be very warm in the SE if this was to verify. 

Interested to see where the OP sits in the ensembles.

   

But the ECM  which I am sorry, I cannot  post, is horrible.