model discussion Model output discussion 11th July onwards

[Mike Poole]

3 minutes ago, blizzard81 said:

Of course we are comparing an 'actual' chart with a predicted chart at day 10 so the usual caveats apply. Always wanted to use that phrase

For sure, but the mean which I’ve added to my post above, backs up the view there is very little coming our way from the upstream pattern.  It is different to last year, whether that is good news or not come winter I can’t say yet, to be honest!  Let’s hope…

[bluearmy]

7 minutes ago, blizzard81 said:

At first glance looks similar. I'll give you that. One big difference is the big Aleutian low. Present in this years chart. Absent in last year's. 

 

2 minutes ago, Mike Poole said:

Thanks, yes that is one spot the difference!  The other is the low heights over the USA on last years charts, completely absent on this year’s - it is for me about what is upstream!  And my answer is nothing, this year!  

My point was that the NH charts at the moment look very ‘un autumnal’ ……..and yet what happened last year after those ‘un autumnal’ charts ….. I wasn’t finding similarities…… I didn’t think there were many ….

[blizzard81]

1 minute ago, Mike Poole said:

For sure, but the mean which I’ve added to my post above, backs up the view there is very little coming our way from the upstream pattern.  It is different to last year, whether that is good news or not come winter I can’t say yet, to be honest!  Let’s hope…

Yep indeed, just seen the mean chart you posted. We always live in hope.... 

[blizzard81]

1 minute ago, bluearmy said:

 

My point was that the NH charts at the moment look very ‘un autumnal’ ……..and yet what happened last year after those ‘un autumnal’ charts ….. I wasn’t finding similarities…… I didn’t think there were many ….

I think at first glance there are quite a few similarities 

[blizzard81]

5 minutes ago, bluearmy said:

 

My point was that the NH charts at the moment look very ‘un autumnal’ ……..and yet what happened last year after those ‘un autumnal’ charts ….. I wasn’t finding similarities…… I didn’t think there were many ….

Now if you had posted this chart, I would have understood your point about not many similarities. 

[Mike Poole]

Pub run, and you can see the 5 wave pattern T96:

In my view that cannot develop into an Atlantic autumn onslaught pattern, it is too meridional…and before we get to winter, one or more  of those ridges is going to have to go - will be interesting to see which!

[bluearmy]

8 hours ago, Mike Poole said:

Pub run, and you can see the 5 wave pattern T96:

In my view that cannot develop into an Atlantic autumn onslaught pattern, it is too meridional…and before we get to winter, one or more  of those ridges is going to have to go - will be interesting to see which!

Week 2 looks to have a mainly +NAO developing with a NW/SE split ……those in the north of the U.K. will certainly feel that the Atlantic is bossing their weather later in October. Remains to be seen if it can be described as an ‘onslaught’.  Currently doubtful. 

[mb018538]

These charts on the 00z UKV has caught my eye today...

 

Temperatures at 17/18c at 3am in the morning in mid to late October?! Very tropical airmass with 850 temps at 13/14c and humidity close to 100%

Would that be some sort of record??

[joggs]

8 hours ago, Mike Poole said:

Pub run, and you can see the 5 wave pattern T96:

In my view that cannot develop into an Atlantic autumn onslaught pattern, it is too meridional…and before we get to winter, one or more  of those ridges is going to have to go - will be interesting to see which!

Probably 2  and 3 knowing our luck.

[Frosty.]

There’s still plenty of support for a cold incursion from the north in the GEFS 0z later next week, timings and duration vary, as does the depth of cold but as previously, some members don’t support it at all and the ECM 0z operational isn’t interested either…but it’s probably too early to start getting excited by cold potential unless something freakish was to verify…it’s only mid autumn!   
 

Edit..I forgot to mention it’s turning very unsettled next week with rain and strong winds….. doh, doh, how silly of me!  ?  

Edited October 14, 2021 by jon snow

[johnholmes]

9 hours ago, Mike Poole said:

Pub run, and you can see the 5 wave pattern T96:

In my view that cannot develop into an Atlantic autumn onslaught pattern, it is too meridional…and before we get to winter, one or more  of those ridges is going to have to go - will be interesting to see which!

Don't bet on that, 4 is a better number for either very slow moving patterns or even stationary in my experience.

[Mike Poole]

20 minutes ago, johnholmes said:

Don't bet on that, 4 is a better number for either very slow moving patterns or even stationary in my experience.

Yes, thanks, John, I agree for stuck patterns in winter.  I have been struck by the very meridional pattern through summer, though, with a higher wave number, which is why I’ve been watching it, and musing on what it might (or might not!) mean if the wave number is forced to reduce further to 4 or 3 as we edge nearer to winter.  

[Ali1977]

Day 6 on the latest GFS shows the WAA  pushing further into Greenland, which may help further down the line. It’s way too early to think about snow and ice but the NH is looking really really different this Autumn. I still think we’ll see U.K. wide frosts before the end of soft which in itself isn’t a regular occurrence 

[mb018538]

Tuesday is looking more and more likely to be unseasonably warm:

 

Strong NW/SE bias for rainfall in the next couple of weeks:

 

[Methuselah]

Oo er missus:     

[Frosty.]

Bring on the cold?..or cool..woteva.. pffft! ..for Scotland at least!  

Wow..that’s yesterday’s 12z..my bad..in my defence..I have slow tinternet.. I blame meteociel..damn frogs.. ! 

Edited October 14, 2021 by jon snow

[Methuselah]

Just now, jon snow said:

Bring on the cold?..or cool..woteva! ..for Scotland at least!  

 

Sod the cold!   

[Cambrian]

The pattern since the beginning of July has been slow, but far from stationary, there’s broadly been 2-3 weeks high pressure / mainly dry, then 1-2 weeks low pressure / often very wet for a few months now. There was a longer period of wet weather in August, but the second half of this wasn’t associated with particularly low pressure. This graph shows the barometric pressure (black line) and precipitation (blue line) since the beginning of July where I am. 

Looking at the 9-day panels of the ECM and GFS 0z operational runs, this same pattern is being maintained currently, with the dry weather breaking around the 19th - the 9 days starting with 3 dry ones, followed by 6 days with a good chance of rain, including a few days with some chillier prospects with plenty more trough lying out west on the both models for another unsettled week at least following that to be reasonably expected, and importantly, the trough getting well over through Scandinavia into Russia. 

ECM / GFS

 

Put it all together over the period of a whole season, it all averages out in terms of pressure and precipitation. If this current pattern was to prevail into winter, we would no doubt get plenty of frosts in the dry periods, plenty of rain as the trough grinds its way in, snow in showers for a few days when the trough gets to our east. The main chances for more general snowfall will probably rest in the formation of secondary lows at the base of the trough when it is over us or to the south, and the increasing chance as the season progresses of cold air digging in over the continent and the trough trying to undercut it from the southwest, the same things we’d look for in any winter. 

I guess what people are saying is that if this pattern slows down further, reducing to a 4 wave pattern, then the chances of both of these scenarios is increased, which I can see. But we could equally get repeatedly stuck on the wrong side of the trough too.

So what I’ll be looking for as much as the hemispheric wave pattern, as rightly pointed out above, is the maintenance of the warm air advection pushing up into Greenland and the impressive southward extension of the troughs in the Atlantic, and over and indeed to the south of the UK and Ireland when they encroach, which has been quite a feature recently.

If that’s maintained, I feel we could get plenty of wintry weather. If it isn’t, we’ll get some frosts, followed by days on end of mild weather, with the trough being held to the west of us by an increasingly belligerent continental high.

(I’m sorry for the lengthy post, but I must admit I’m finding this autumn a particularly intriguing one - back to a shorter post next time!)

[Methuselah]

On the subject of things being 'stationary', the last place I worked had a 'Stationary Cupboard'. It never moved in all my nine-years' working there!

Edited October 14, 2021 by Ed Stone

[damianslaw]

5 hours ago, joggs said:

Probably 2  and 3 knowing our luck.

Yes 1 will stick around.. 

[damianslaw]

1 hour ago, mb018538 said:

Tuesday is looking more and more likely to be unseasonably warm:

 

Strong NW/SE bias for rainfall in the next couple of weeks:

 

What feel any benefit under all that wind and rain. SW airstreams are the devil!

[Frosty.]

If it was winter I would be quite excited by the GEFS 6z mean looking like this later next week!..but it’s mid autumn, so I’m not!..having said that, there’s still a chance of a cold incursion across the far north, cold enough for snow to modest levels and some ice / frost?…longer term, following an increasingly unsettled spell next week, conditions ease somewhat to more of a northwest-southeast split with the SE becoming drier and brighter more often than not?.and milder too with winds from the southwest!

 

Edited October 14, 2021 by jon snow

[mb018538]

45 minutes ago, damianslaw said:

What feel any benefit under all that wind and rain. SW airstreams are the devil!

This is true. The very high temps correspond with the rain not making it across the S/SE corner. If the rain arrives then we can easily take 3-5c off those values.

[mushymanrob]

19 hours ago, Mike Poole said:

It still looks to me like there is a 5 wave pattern on the ECM T96 with a high over the pole:

Until circumstances change and this meridional signal is reduced, there is no opportunity for a zonal onslaught…

surely theres 6, with one over the uk...

[Frosty.]

Looking further ahead, the cfs 0z says Christmas Day will be cold! …well, that would make a pleasant change wouldn’t it!?…  

 

Edited October 14, 2021 by jon snow