Model Output Discussion - Mid Summer Onwards

[Aiden2012]

Now this is what I’m looking for

[Mark wheeler]

3 minutes ago, Aiden2012 said:

Now this is what I’m looking for

Well that would certainly be a shock to the system. I wouldn't say no , although would prefer it in December .

[Cheshire Freeze]

51 minutes ago, Don said:

I hope I haven't gone too low (13C) with my October guess already?! 

Perhaps not-

[legion_quest]

To go from unseasonable warmth to unseasonable cold in the span of a week would be extraordinary.

Almost expecting it given the way the weather has been in the last few mths

[Kirkcaldy Weather]

On 19/09/2023 at 21:25, Kirkcaldy Weather said:

What could unfold as we go into October?

These are the biggest development dynamical situations I'd be expectant to be occuring. Hazarding a date keep eyes around later of October Week 2 sometime around 10th - 13th

1. Elongation of European Heights start a gradual movement evolving to Scandinavia---Greenland 
2. New trough emerging close by most probably a smidge to the East then drifting to the UK 
3. I'm noticing that trend of low pressures through the United States trends show that eastern coastal Noreaster style as a possible setup

As the calendar moves forward into October how have things developed since the above?

The major driving contributions continue to be the MJO as is always the case however as covered through my previous post. 

 

The PNA will be having major say in the evolution of 500hpa setups progressing through October

Beginning with the ensemble outlook in the post above 

And a mere 4 days on 

As is easy to spot there has been a MAJOR switch in the state of the upcoming PNA which I have to say is one of the biggest flips i've noticed in my 14 years viewing the model and teleconections outputs.  I believe one of the main reasons contributing to this is given how the current PNA progression has materialised into a significant Rossby Wave Break Event as I covered here 

The quicker trend to a strengthening positive PNA does make sense as if we connect the timing and associated 500hpa evolutions into recent 3-4-3-4-5 this strange MJO backward dynamics also playing a big role in this PNA behaviour IMO

 

 

W Ninò

 

 

Covers our conditions which occurred through September with multiple plume type scenario in the UK with accompanying severe thunderstorm activities, severe impacts originating as a result of MULTIPLE RWB Events with the cut off low composites being beautifully represented certainly from a meteorological lover view as said lows / cyclones developed into the Mediterranean and the great bullseye where hurricanes tracked through that Northeast corridor up into the Maritimes such as Lee -- Nova Scotia particularly noted that corresponding with phase 3 especially. Next and into as we are currently we've watched the European High extend westwards influences beginning for SE parts of the UK then the ridge build for today which then begins transitioning to a classic TRT trough--ridge--trough scenario.

What effects does a positive PNA see coming to the fore?

Starting with our configuration of the Jet as we sit ATM 

The PNA going to + connects with a strengthening of the Jet through Asia particularly East Asia which leads to a strong elongating trough in the far north of the northern pacific > Alaska as noted 

An additional part of this progression involves the emerging Subtropical Jet which I personally like to call the Nino Style Jet

referring to my previous post I stated 

My eye is drawn to the continuing trough close to the Floridian Coastline plus that increased precip signal from Mexico into the GOM maybe the coast of Texas. These areas need to watch close for the next TS developments.

And

Now watch as the MJO begins to traverse into the Pacific.

Spectacular enhanced cyclone development being outputed at the min heres the GEM but many models are incredibly on a similar scale 

Could see 6 or more simultaneous disturbance zones running along a VERY active tropical wave however clear signal of number 1 becoming the first to bring noteable severe conditions and my eye is looking close at the potential 2 separate disturbance zones at the far east side of the TW

Think of the situation how Hilary got going...

This being shown in the ENS so always looks flatter however a proper signal for a TS to go akin Hilary ... California take 2

Taking the changes and processes through the first half of October at the least.

Strengthening Asian and Pacific Jet Streak

Emerging Nino Style Jet

Awesome evolution into strong positive PNA 

Great watching this come into fruition here its easy seeing the flip 

Weve started generating a dominant setup which is coming through winter 23>>24

   

On 19/09/2023 at 21:25, Kirkcaldy Weather said:

What could unfold as we go into October?

These are the biggest development dynamical situations I'd be expectant to be occuring. Hazarding a date keep eyes around later of October Week 2 sometime around 10th - 13th

1. Elongation of European Heights start a gradual movement evolving to Scandinavia---Greenland 
2. New trough emerging close by most probably a smidge to the East then drifting to the UK 
3. I'm noticing that trend of low pressures through the United States trends show that eastern coastal Noreaster style as a possible setup

 

Phase 5 be coming 

 

 

Perfect showing which encapsulates the cycling from phase 3 to 4 too

 

 

[Addicks Fan 1981]

1 hour ago, legion_quest said:

Interesting to see all the models now lining up after their little disagreement.

Not the outcome I was hoping for, worrying heat levels for this time of year, but makes sense really given just how much there is to our South.

It has to go somewhere, and as it gets hotter and hotter in summer in the Med and Africa, heat is just going to be there for us longer and longer every year.  

I think we need to have the same approach with looking at weather charts as mushy does, he looks mainly at anomoly charts and ensembles, quite a lot of the time he is proven right ️  as well.     Hope he comes back online as well because his contributions are brilliant.    

[Metwatch]

41 minutes ago, legion_quest said:

To go from unseasonable warmth to unseasonable cold in the span of a week would be extraordinary.

October 2018 did just that! An overlooked month for its temperature swings.

[Frigid]

GFS 12z is a wild rollercoaster..

From this

To this, a week later 

Fascinating stuff, October just like March can have wild swings in temperature. 

[MattStoke]

ECM  

[Frosty.]

There’s good support from the GEFS 12z mean for…dare I say it, another burst of summery warmth, indeed, looking further ahead, out to almost mid October, high pressure influence is projected to be significant, at least across southern u k??..but now I’m overreaching!…or am I ?, ….however, summer warmth is reluctant to let go across the s / se…eventually, it will of course!…roll on winter I say! .. well, I am Frosty innit!

 

 

[Mark wheeler]

20 minutes ago, MattStoke said:

ECM  

Yes a home run for the ECM regarding the southerly it seems . All models tonight have this as I have recently posted. 

 

So @ANYWEATHERare you ready to accept here that you was wrong on this occasion? Ecm has had a success here and yes it is extreme for the time of year. 

 

 

 

Interestingly ECM now clears the heat quicker , whats to say it is not right this time too ?

Edited October 1, 2023 by Mark wheeler

[MattStoke]

1 minute ago, Mark wheeler said:

Yes a home run for the ECM regarding the southerly it seems . All models tonight have this as I have recently posted. 

It does though clear the heat away eastwards a bit more quickly at the end of the weekend. A short very warm spell looking most likely.

[Neil Harris]

2 hours ago, I remember Atlantic 252 said:

If I remember though, wasn't GFS, and maybe other models showing similar for today last Sunday? was definitely expecting 25C and sunny today this time last week, GFS underestimated the Atlantic

Yes this time last week, Today was looking very nice. We had outdoor plans.

In the Midlands this afternoon has been very wet

[I remember Atlantic 252]

10 minutes ago, Neil Harris said:

Yes this time last week, Today was looking very nice. We had outdoor plans.

In the Midlands this afternoon has been very wet

Hope not same again, models had everything too far west, already a step backwards on the EC 12Z, another windy unsettled Sunday, with now just Saturday, maybe Friday looking good, will everything be moved east and cancel the warm Fri/Sat?

Edited October 1, 2023 by I remember Atlantic 252

[Mark wheeler]

41 minutes ago, MattStoke said:

It does though clear the heat away eastwards a bit more quickly at the end of the weekend. A short very warm spell looking most likely.

I think that's up for grabs still . Mogreps have plenty staying warm for London . Further north and west less so although still some keeping it warm even here .

[damianslaw]

Interesting model viewing at present. Yesterday ECM and GFS were complete opposites at the 144-168 hr timeframe. This evening they are much more in sync.

What have we in store, another very mild week, especially by Thursday, with the ridge to the SE pulling in a warm southerly draw holding the trough to the west. This synoptic is maintained into the weekend. Sat 7 currently projected to see very mild uppers, and widely temps into low 20s I would expect.

Thereafter, the ECm shunts the heat aside quick, the trough moves in and we pull in much cooler air from the NW, trend followed by increasingly cooler air. GFS is the same.

The classic southerly then northerly switcharound often happens in Spring, might be on offer.

[Lukesluckybunch]

ECM bringing in a very warm airmass also..but shortlived.at 240h theres a trough to the northwest ,would it produce a shot of early cold.a day or 2 after?

[Lukesluckybunch]

1 hour ago, Mark wheeler said:

I think that's up for grabs still . Mogreps have plenty staying warm for London . Further north and west less so although still some keeping it warm even here .

hi mark the latest ECM is showing the very warm air..but doesnt last all that long

[Mark wheeler]

12 minutes ago, Lukesluckybunch said:

hi mark the latest ECM is showing the very warm air..but doesnt last all that long

The ens look like they agree broadly with that scenario this evening , however there is a minority but significant cluster that keep it warmer for longer. Lets see what GFS says soon and more so the runs tomorrow, fantastic model watching  as the transition of seasons unfolds.

[WYorksWeather]

UKV high resolution is gradually coming into range. Looking back, this was pretty accurate in nailing temperatures during the September heatwave, whereas GFS and ECM generally came out a little too low.

Only up to Friday afternoon today. The 21C on Friday is noticeably higher than GFS (18C) and ECM (19C).

Main difference is the timing at which the 15C isotherm becomes widespread. UKV gets there for many by 15Z Friday, allowing a significantly warmer afternoon, whereas on ECM and GFS the highest 850s are kept close to the SW coast until Friday evening or early Saturday, with sea breezes therefore limiting maxes on Friday.

Shows how a tiny change in timings, surface conditions etc. can still play havoc with predicting temperatures at this stage. More runs needed!

[SunnyG]

9 hours ago, Addicks Fan 1981 said:

Pretty dry really and little if any sign of any rain whatsoever according to the EPS at 240 hours ahead.    

EPS-fast Model – 500mb Height Anomaly for Northern Hemisphere | Tropical Tidbits

WWW.TROPICALTIDBITS.COM

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EPS-fast model forecast of 500mb Height Anomaly for Northern Hemisphere

 

That's what I like to see. May it continue. We've had more than enough rain in July and August.

[Uncertainty]

4 hours ago, Aiden2012 said:

Now this is what I’m looking for

Hopefully, come late March, we might even be sick of that pattern! 

 

1 hour ago, Lukesluckybunch said:

ECM bringing in a very warm airmass also..but shortlived.at 240h theres a trough to the northwest ,would it produce a shot of early cold.a day or 2 after?

The op looks like it would chuck a big northerly in day 11-13

[alexisj9]

26 minutes ago, SunnyG said:

That's what I like to see. May it continue. We've had more than enough rain in July and August.

As I still have flowering plants somehow, well the weather I expect has something to do with it, will have to start watering them again if it doesn't rain tomorrow, this weather is getting ridiculous.

[Mark wheeler]

1 hour ago, Lukesluckybunch said:

hi mark the latest ECM is showing the very warm air..but doesnt last all that long

 

[WYorksWeather]

Raw maxes from the 18z GFS for F/S/S/M/T (and yes, the heat extends from Fri-Tues for some places) are 21/25/26/24/24.

Summer for many on Sunday:

But for the cold fans, a frosty morning for many at 252 hours by Thursday 11th (not to be taken seriously!)