model discussion Model output discussion 11th July onwards

[mountain shadow]

31 minutes ago, sheikhy said:

And the 00zs continue with the very dry high pressure them all the way to the end of their runs!!!astonishing!!!!

Sure is. The Atlantic is as dead as a dodo. Will it last into Winter though?

[Methuselah]

9 minutes ago, mountain shadow said:

Sure is. The Atlantic is as dead as a dodo. Will it last into Winter though?

I suspect not, MS:

Although the GFS 06Z is a stonker, by the time we get to Day 16, the tPV looks like finally getting established, and quite a bit farther west than earlier runs may have suggested? Meanwhile, enjoy the Indian Summer!

    

    

    

And there's plenty of scatter within the GEFS temperature ensembles:

    

 

[mb018538]

1 hour ago, Ed Stone said:

I suspect not, MS:

Although the GFS 06Z is a stonker, by the time we get to Day 16, the tPV looks like finally getting established, and quite a bit farther west than earlier runs may have suggested? Meanwhile, enjoy the Indian Summer!

    

    

    

And there's plenty of scatter within the GEFS temperature ensembles:

    

 

It's not getting established at all. It's taking a battering and is going to be at or below record low speeds in the next couple of weeks. 

[Methuselah]

6 minutes ago, mb018538 said:

It's not getting established at all. It's taking a battering and is going to be at or below record low speeds in the next couple of weeks. 

Of course it is, it's what it does at this time of year, it's what it does every year. In some years, though, it's slower than in others?

[Methuselah]

And, blow me down, the GFS pulls another stonker from the hat!

   

    

    

And, before anyone berates me for my enthusiasm, I love snow; snow is what make wintertime worthwhile! But, when none is on offer, it's warmth I yearn for. Cold rain? Yuck!

[Frosty.]

Yay, this would be more seasonal from the 6z op!..fingers crossed. ..let’s just fast forward to winter.. ..and roll on winter ASAP !!!!..battle speed.. ramming speed!!!!..I’m bored with autumn already..pffffft  

Edited October 7, 2021 by jon snow

[Methuselah]

7 minutes ago, jon snow said:

Yay, this would be more seasonal from the 6z op!..fingers crossed. ..and roll on winter..battle speed…attack speed.. ramming speed,!  

Yuck!

[Frosty.]

For sure, there are signs of change towards more unsettled and possibly colder later in the GEFS 6z..wow, I’m turning into a coldie again… I think therefore i am.. !!!

 

Edited October 7, 2021 by jon snow

[Frosty.]

Ok it’s pretty dead in here..Serious question..are there any coldies in da house? …the seasons are changing..doh… …there’s increasing cold in da arctic…doh… … it’s only a matter of time before we see something colder.. doh!.. maybe the 6z is on to something..or perhaps on something.. ?.. just my feeble attempt to liven up the discussion..I failed!   !   

Edited October 7, 2021 by jon snow

[Methuselah]

27 minutes ago, jon snow said:

Ok it’s pretty dead in here..Serious question..are there any coldies in da house? …the seasons are changing..doh… …there’s increasing cold in da arctic…doh… … it’s only a matter of time before we see something colder.. doh!.. maybe the 6z is on to something..or perhaps on something.. ?.. just my feeble attempt to liven up the discussion..I failed!   !   

I reckon they must all be burned to a crisp (a la The Devil in The Dark) Frosty!

Edited October 7, 2021 by Ed Stone

[Allseasons-Si]

I am here @jon snow,Frosty,Karl

on a serious note,...i like the day ten EPS though with a ridge of high pressure over the UK, there looks to be a cool pool of air developing in central Europe though,..keep it there for now then blow it this way come winter

Edited October 7, 2021 by Allseasons-si
added info

[Climate Man]

25 minutes ago, jon snow said:

Ok it’s pretty dead in here..Serious question..are there any coldies in da house? …the seasons are changing..doh… …there’s increasing cold in da arctic…doh… … it’s only a matter of time before we see something colder.. doh!.. maybe the 6z is on to something..or perhaps on something.. ?.. just my feeble attempt to liven up the discussion..I failed!   !   

Give it a couple of weeks Karl. If we are still getting output like that it will have some meaning and an early chase can begin. Need some further cooling down first.

[Midlands Ice Age]

51 minutes ago, jon snow said:

Ok it’s pretty dead in here..Serious question..are there any coldies in da house? …the seasons are changing..doh… …there’s increasing cold in da arctic…doh… … it’s only a matter of time before we see something colder.. doh!.. maybe the 6z is on to something..or perhaps on something.. ?.. just my feeble attempt to liven up the discussion..I failed!   !   

I'm a with you my man. Keep dem a comin.

 Just about to do an Arctic forecast for the snow and ice thread to add a bit of spite for the iced Tonic water (Oh alright then a G&T if you insist).

Those two big dollops of blue either side of the Bering Strait on SI's maps interest me more at this time of year.

MIA

 

Edited October 7, 2021 by Midlands Ice Age

[Kirkcaldy Weather]

4 hours ago, Ed Stone said:

Of course it is, it's what it does at this time of year, it's what it does every year. In some years, though, it's slower than in others?

starting on the PV side of things toward the end of the runs currently signs of displacement I'm definitely no stratospheric expert but warming in October I believe is a rare beast 

   any impact on our weather from that remains to be seen but a possibility, onto the main part of my post. MJO phases 4 + 5 in October also raises some interest  that's the route I'd expect to start appearing in the charts through the next few weeks or so, possibly around three - four weeks early for my personal snow hunt beginning but should the blocking manifest like that the move into winter might begin on a fascinating setup. 

[Tamara]

Fairing infinitely better than the folk have had to endure across the other side of the Mediterranean in Italy, It continues glorious in this SW part of the Mediterranean with a cool down to about 20C on Sunday with some rain a.m -  warming back up through this week to 28C yesterday and already 30C this afternoon with stunning deep blue skies helping to ripen the new citrus loads on the trees. Each evening here at this farm with its chickens and various semi-rural wildlife is velvet warm with starlit skies. The outlook continues the same

In the bigger picture, the continued warmth in my part of the world is further helped c/o the strength of sub tropical ridging augmented by the warm air advection processes of the remnants of Hurricane Sam. Equally it is helping the UK recover from the drab wetness of recent days and typically underwhelming temperatures. The persistent African waves across the Equatorial Atlantic, based on the alignment of the low frequency tropical convection standing wave across the Western Hemisphere, Africa/Indian Ocean - often favourably create a strong anticyclonic downstream ridge extending from sub tropical ridges at this time of year when such tropical storm  activity recurves sufficiently to interrupt the Atlantic ridge dominance of the entrenched low angular momentum La Nina state.

The GSDM plots clearly depict the low angular momentum Nina state, with the GWO endorsing the upstream amplification momentum transport processes at work with no orbit for quite some time out of the Nina phases 1,2 and 3. A sustained deficit of -2SD (standard deviations) is very firmly indicative of La Nina

 

The described upper air and surface pattern changes as the tropical activity season comes to its close and the more commonly seasonal La Nina default resumes. Though unlike a fair amount of commentary to the effect on this thread, it means little or nothing for the following season on its own to sate the very strong bias preferences of the majority of the UK audience.

The high frequency MJO is tracking eastwards through the Maritime continent towards the Pacific .....

 

....and this will act (temporarily) to quieten the African wave process but at the same time provide some extra holding to the downstream ridging as momentum across the Pacific (temporarily) increases c/o westerly winds (shaded red) west of the dateline trying to push up against a wall of easterly trade winds (shaded blue) at, and to the east of the dateline.

As wind shear c/o the wall of La Nina trade winds weakens the MJO thunderstorm development attempting to encroach the Equatorial Pacific, then tropical convection suppression occurs and the advancing westerly wind burst gets stopped in its tracks. The low frequency walker cell signal re-emerges and its then a case of seeing how the Atlantic ridge evolves to take over the downstream pattern as the wavelength is re-set from renewed amplification in the Pacific.

In broad weather terms this translates to a pleasant fairly warm (by UK standards) spell of weather and continued very balmy summerlike weather down here in SW Europe with more days of circa 28C to 30C to come. Thereafter, a signal for the downstream ridge to break down and some kind of amplified longwave trough crossing west to east across N Europe and Atlantic ridging behind it with wet and windy weather followed by chillier showery conditions with NW winds. Further south west in europe, a good chance that this trough will repeat the recent sequence and provide a day or two of (relatively) cooler weather with some rain before renewed ridging from the nearby Azores settles things down again.

An alternative scenario is a cut-off low heading down towards the Azores/Madeira providing some humid thundery weather with the Atlantic ridge overlaying the cut off feature. At the same time, this would probably give chilly anticyclonic conditions for the UK and other parts of NW Europe.

Either way, it would suit me fine and don't miss the UK descent through autumn one bit

[Frosty.]

das ICON 12z ist ziemlich antizyklonisch! …Nein..Nein..Nein..Ich will Kalte und Schnee!!!  

 

[Allseasons-Si]

 At this from the gefs 12z control run,...could there be snaw towards the end of the month!!!,certainly a possibility the further north you are...

a look at the gefs ens and there does appear to be a steep decline towards the end

 

[Mike Poole]

4 hours ago, Kirkcaldy Weather said:

starting on the PV side of things toward the end of the runs currently signs of displacement I'm definitely no stratospheric expert but warming in October I believe is a rare beast

Yes, this definitely of interest, and there are I think 2 things at play at the extended timescale.  First, ECM 12z T240 illustrates a pattern that will put pretty much maximum pressure on the strat vortex, Aleutian low and Siberian high:

The second is the trop has been prone to blocking for 10 months now, and there is no obvious sign of that changing in our neck of the woods anytime soon.  Hence the prolonged upcoming October settled spell.  

Longer term, probably for the strat thread, but briefly, if the trop early cold season pattern is primed for blocking, then a timer starts for this to be overrun by the strat vortex, if the strat vortex gets off to the kind of start suggested at the moment, that timer has at least a couple of months on it…

Edited October 7, 2021 by Mike Poole

[Mike Poole]

Just drop this in here, JMA T264 chart, and the NH weather patterns are in a right mess on this one, extraordinary chart:

Same pressure on the strat vortex as ECM, and nothing in the Atlantic.  Weather here may be boring autumn settled weather but the run up to winter should be very interesting indeed.  

[damianslaw]

Seeing a path to an eventual cooler pattern with NW airstream, in the near term we have signs this is the general direction of travel, glancing NW feed early next week and scandi trough developing, ridge then comes back, but the trough holds firm and deepens, and it is this feature that will give the ridge/high a kick further west more forcefully in time and we remain exposed to cooler feed.. 

[Ali1977]

A bit early to get too excited about a 500s mean being like this towards mid Autumn, but with the standard zonel winds and standard NH set up failing to materialise (so far) it seems to be a pretty good start.  There also seems to be plenty to be positive about atmospherically later into Oct and on into Nov for us cold lovers, so fingers crossed that gathers pace and we start with a November to remember  

Edited October 8, 2021 by Ali1977

[mb018538]

Morning all!

Looking settled out to mid month....but are there now hints that the high pressure may begin to break down after?

The GFS ensembles are starting to pick up on a lot more rainfall spikes, as well as a drop in pressure:


 

ECM doesn't seem quite so interested though, still keeping an Azores ridge nosing in.



GEM has a shallow trough moving in and the high breaking down:

Looking like a bit of a crunch point in around 10 days time as to what the rest of October looks like.
 

[Frosty.]

A better 6z op compared to the 0z, pretty impressive warm / anticyclonic conditions, especially  at the end of this Gfs run just a week or so from November…this ain’t normal standard conditions on the cusp of nov whatever some May say!!  
 

 

Edited October 8, 2021 by jon snow

[Methuselah]

6 minutes ago, jon snow said:

A better 6z op compared to the 0z, pretty impressive warm / anticyclonic conditions, especially  at the end of this Gfs run just a week or so from November…this ain’t normal standard conditions on the cusp of nov whatever some May say!!
 

 

An intense bout of model-fatigue has broken here in Chez Ed, Karl. And the murky weather isn't helping. And, now the DWP has called me to one of their charades about reassessing my autism AGAIN!

[lassie23]

22 hours ago, jon snow said:

Ok it’s pretty dead in here..Serious question..are there any coldies in da house? …the seasons are changing..doh… …there’s increasing cold in da arctic…doh… … it’s only a matter of time before we see something colder.. doh!.. maybe the 6z is on to something..or perhaps on something.. ?.. just my feeble attempt to liven up the discussion..I failed!   !   

I think the 6z has smelt the coffee and drank it all