model discussion Model output discussion 11th July onwards

[ANYWEATHER]

Not surprising given the way the jet stream is there is a huge uncertainty in the longer range forecasts

[damianslaw]

1 hour ago, ANYWEATHER said:

Not surprising given the way the jet stream is there is a huge uncertainty in the longer range forecasts

The cut off low southern arm of the jet to our SW has been an omni-present permanent feature since December. Quite abnormal for it to remain the case for so long...

[mb018538]

Let's have a quick look at the morning offerings..

Looks like a muggy and unsettled picture on the UKMO run as warm air is wrapped around a shallow low pressure system



GEM is starting to look quite wet in the NW especially, as low pressure starts to have more influence. Drier the further SE you head:



GFS is also pretty unsettled out to day 10:



Are we finally seeing the much delayed transition to something more unsettled taking hold? Still hard to say for sure...


 

[Methuselah]

A bit of a mixed, uncertain bag, if today's GEFS 00Z temperature ensembles are anything to go by:

    

 

[Methuselah]

GFS 06Z at T+120 looks mighty encouraging!

    

[Methuselah]

It's a bit like a mausoleum in here today? But anyway, the GFS 12Z is suggesting some quite high uppers, for the last week in September:

    

It might snow in Svalbard!

[MATTWOLVES 3]

1 hour ago, Ed Stone said:

It's a bit like a mausoleum in here today? But anyway, the GFS 12Z is suggesting some quite high uppers, for the last week in September:

    

It might snow in Svalbard!

Don't worry Pete I'm here to give you a big group hug mate

To sum up ECM...well next week looks largely benign,and decent overall...Lower pressure towards the NW perhaps turns things more unsettled later next week...and more so further North! Beyond that...perhaps settling down again towards the South...all in all,not to bad.

Peace out...have a large one.

[Mike Poole]

ECM clusters early set T72-T96:

Well there are 6 so that doesn’t instill confidence in anything at the moment!  Enough said!

Later, T192-T240, trends becoming clearer:

So it is high-latitude blocking (-NAO cluster 1) or mid latitude blocking (clusters 2 and 3).  What looks clear cut is the Atlantic isn’t going to come barrelling in anytime soon (or anytime until late January, if you want a random long range punt ), but the question is whether the high is close enough to give the UK some really decent September weather, and I’m not so sure about that….we will see!

 

[damianslaw]

55 minutes ago, Mike Poole said:

ECM clusters early set T72-T96:

Well there are 6 so that doesn’t instill confidence in anything at the moment!  Enough said!

Later, T192-T240, trends becoming clearer:

So it is high-latitude blocking (-NAO cluster 1) or mid latitude blocking (clusters 2 and 3).  What looks clear cut is the Atlantic isn’t going to come barrelling in anytime soon (or anytime until late January, if you want a random long range punt ), but the question is whether the high is close enough to give the UK some really decent September weather, and I’m not so sure about that….we will see!

 

Yes lots of uncertainty, models do hint at more of an atlantic influence next week, with the high to the NE not having enough power to exert greatest power, however, as I said yesterday much depends on the position of the jet, and where energy is exerted, we could see another cut off low scenario developing to our SW and move in over the UK, holding the main atlantic trough at bay, and instead we end up where we are today.. cyclonic which means unsettled but not atlantic unsettled. We are due a switch to much wetter again after a lengthy dry spell, as has been the theme of the year, dry and settled/blocked, wetter and weak trough/cyclonic - not zonal..

[Cambrian]

The ECM and GFS op at 12z in loose agreement regarding a return to something a bit more zonal by 168h, the ECM is slightly more definite but there’s no zip in either of them, the flow is all rather weak with the main thrust being successively pushed off to the northwest, and an easy tendency for high pressure to reassert from the south. 

ECM  / GFS

 

 

More normal temperatures and fresher, but real autumn toying with us for now. 

[damianslaw]

6 minutes ago, Cambrian said:

The ECM and GFS op at 12z in loose agreement regarding a return to something a bit more zonal by 168h, the ECM is slightly more definite but there’s no zip in either of them, the flow is all rather weak with the main thrust being successively pushed off to the northwest, and an easy tendency for high pressure to reassert from the south. 

ECM  / GFS

 

 

More normal temperatures and fresher, but real autumn toying with us for now. 

As is often the case until the equinox..  Atlantic stutters and Autumn rarely shows it's true hand until end of the month. 

[Frosty.]

The Gfs 0z operational shows another plume early next week with increasingly humidity and temperatures again into the mid / upper 20’s c across the southern third of the u k, especially further s / se with very warm sunshine sparking some heavy thundery showers with a more general area of thundery rain heralding a change to cooler, fresher conditions from the west by midweek but still on the warm side further s / se with temps into the low 20’s c but much cooler further n / nw…week 2 looks a lot more Atlantic driven with spells of rain and strong winds interspersed with sunshine and showers and generally temperatures much closer to where they should be in mid / late September. ? ⛈ ?  

 

 

 

Edited September 10, 2021 by jon snow

[Methuselah]

Well, today's GEFS 00Z ensembles do suggest that something rather juicy might transpire, during the coming weeks?

    

[mb018538]

Forecasting still a nightmare at the moment!

W/NW'ern areas tending to be wetter as a more westerly zonal flow sets up on the ECM, though high pressure looks poised to nose in at day 10...



GEM has this at day 10 too:



Still the potential for a humid couple of days through the middle of next week, though with surface pressure low it could be thundery:

[Polar Maritime]

GFS showing the Atlantic knocking on our doors by the end of next week, With Low Pressure systems firing across from the West on a strong Jetstream.

 

 

Edited September 10, 2021 by Polar Maritime

[mb018538]

1 hour ago, Polar Maritime said:

GFS showing the Atlantic knocking on our doors by the end of next week, With Low Pressure systems firing across from the West on a strong Jetstream.

 

 

Looks a lot like last nights ECM 500mb update. Atlantic trough getting close, with a ridge just about hanging on tin the east. NW/SE split probably favoured.



Interestingly the ECM is still favouring high pressure to become increasingly dominant as the month progresses towards the last 7-10 days:



A very blocked outlook on the regime frequency plot too:

[MATTWOLVES 3]

Yep as mbo mentions,still looking like a largely settled regime away from the NW as we move further into the month,and this holds firm for the start of October also! 

Anomalies hint at this scenario,keeping in mind this will be the expected general pattern over a set time,but will not necessarily show up odd days here and there that bring more unsettled conditions. So the set up looks similar from last part of the month through till first part of next month.

[Frosty.]

Ironically, although the Gfs 6z op is less plumey regarding early next week (compared to the 0z op)…the general warmth lasts longer, especially further s / se with temps potentially into the mid 20’s c!…as a consequence week 2 isn’t quite as unsettled as the 0z op although there is still some wind and rain at times! ⛈ ?  

Edited September 10, 2021 by jon snow

[Frosty.]

Oooooook, I think.. ..according to the GEFS 6z mean longer term that the Atlantic will break through to some degree..especially further n / nw.. whereas the s / se perhaps will be less unsettled and a tad warmer?.. let’s realise that summer is pretty much over, although we can still get summery weather as late as early October!…I think we could eventually. …. be potentially slipping into a more typical early autumn pattern..for sure, a dose of bells whiskey has helped me reach this conclusion! …cheers  ..  

Edited September 10, 2021 by jon snow

[Methuselah]

Well, today's GEFS 06Z ensembles don't look too bad -- at least it'll be mild!

    

[Frosty.]

13 minutes ago, Ed Stone said:

Well, today's GEFS 06Z ensembles don't look too bad -- at least it'll be mild!

    

Mild is fine, until nov, then I want..nooo.. I demand cold! …anyhoo, I think we can squeeze a bit more of summer according to the GEFS among others..?…yeah and then I’m looking forward to winter..very much.. I really must stop drinking.  …yeah right!!  

 

Edited September 10, 2021 by jon snow

[Methuselah]

10 minutes ago, jon snow said:

Mild is fine, until nov, then I want..nooo.. I demand cold! …anyhoo, I think we can squeeze a bit more of summer according to the GEFS among others..?…yeah and then I’m looking forward to winter..very much.. I really must stop drinking.  …yeah right!!  

 

1978 redux would be fine, Jon: mild-warm (mid-70F temps in mid-October!) until late November and then BOOM! -- a winter of discontent!

[Frosty.]

10 minutes ago, Ed Stone said:

1978 redux would be fine, Jon: mild-warm (mid-70F temps in mid-October!) until late November and then BOOM! -- a winter of discontent!

I’m doing my best Ed..me and you are keeping the model output discussion alive!.. well done mate..as you say, wow, early 1979.. I don’t need to look at the archives.. it was perfection for a coldie..heavy drifting snow and bitterly cold..I just love bitter cold soo much, you can’t imagine.!   

Edited September 10, 2021 by jon snow

[Methuselah]

So, here we go: charts the like of which we'll no' be seeing, come January and February:

    

[Methuselah]

I bet we'll see plenty like these, though!