model discussion Model output discussion 11th July onwards

[johnholmes]

My apologies for not posting charts when I said=workmen causing a degree of upset in the house!

Anyway here with the 500 mb anomaly update as I see it.

Saturday 25 September update

Ec By the 24th it showed an upper low circulation centred off the Norwegian coast with a contour flow over the uk  from just about west and quite strong running in from the atlantic and from another deep upper low off the w coast of n America, all the time at fairly high latitude, so never all that warm at 500 mb.

Noaa much as a week ago remains similar to the ec output, as shown below. So a degree of confidence in what these output are showing.

The weather is likely to be unsettled rather than settled and cool rather than warm. Better in the far se and more changeable the further north and west one lives in the UK. As the surface features move between Iceland and the UK then very strong winds around NW’ern coastal areas seem probable at times. Rainfall amounts are difficult to suggest this far out. However, we remain in the ex hurricane period so any input from one of those will increase rainfall amounts and probably wind strengths. The 8-14 chart  is quite similar so an extended period of this pattern seems highly likely.

NOTE: the Ec chart is for 24/09, at 0905 the 25th was still not available

 

ECMWF/GFS DAY 8-10 MEAN 500MB HEIGHT COMPARISON

WWW.METEO.PSU.EDU

http://www.meteo.psu.edu/fxg1/ECMWF_0z/hgtcomp.html

 

[Frosty.]

I found the ECM 0z operational day 10 of particular interest as it’s not far off from bringing a stunning early October plume to our shores!   ?

 

 

Edited September 25, 2021 by jon snow

[Frosty.]

Although I’m far from an expert… ….even I can see the GEFS 6z mean indicates an unsettled outlook but perhaps not so bad across the south compared to the north and longer term, an improvement generally, apart from perhaps the far north? 

[Cambrian]

06z GFS op 120 to 144h - low pressure anchored near the Faroe Islands, seems to be just lurking, bringing the typical batches of wind and rain through from the west. 

120h - 988mb                                              144h - 984mb

 

 

But it is shown to have been lurking with intent as it suddenly deepens 16mb in 12h, bringing some heavy rain through many parts next Friday evening 

156h - 968mb

  

 

And deepens a bit more by 168h - 964mb

Before slowly losing its intensity and drifting north.

But don’t go thinking that’s it, not on this operational run at least, this low has some extra possibilities thrown in for next weekend. The main depression spawns a secondary low that forms over Biscay and the Brest peninsula around (192h) and deepens to 972mb as it travels up through the UK next Sunday (201h), would bring some strong winds and heavy rain over inland areas too, though a long way off and as is often said around here, probably gone next run!

  

[Frosty.]

Maybe it’s only me that can see this (maybe I’m the special one).. ?.. ..but Shirley .. ..there are hints of improvement by the end of the ECM 0z ensemble mean???….pffffft.. I give up..wow, I’m so looking forward too the 12z now! 

Edited September 25, 2021 by jon snow

[Mike Poole]

1 hour ago, jon snow said:

Maybe it’s only me that can see this (maybe I’m the special one).. ?.. ..but Shirley .. ..there are hints of improvement by the end of the ECM 0z ensemble mean???….pffffft.. I give up..wow, I’m so looking forward too the 12z now! 

Well, Jose doesn’t seem to like it from the photo, Karl .

12z runs get underway with the ICON, T144, T180:

It’s at this time of year, end September, that I start to look less for late summer warmth, but more for indicators for the coming winter.  Yes, we might get stuck in a trough of some sorts going forward.  But it isn’t a zonal onslaught, if it were the pattern would have moved east much more between the T144 and T180 across the NH.  It hasn’t.  BLOCKED.  As it has been since last December.  So my view is that this is not standard early October fayre…we will see…

Edited September 25, 2021 by Mike Poole

[Frosty.]

3 minutes ago, Mike Poole said:

Well, Jose doesn’t seem to like it from the photo, Karl .

12z runs get underway with the ICON, T144, T180:

It’s at this time of year, end September, that I start to look less for late summer warmth, but more for indicators for the coming winter.  Yes, we might get stuck in a trough of some sorts going forward.  But it isn’t a zonal onslaught, if it were the pattern would have moved well east much more between the T144 and T180 across the NH.  It hasn’t.  BLOCKED.  As it has been since last December.  So my view is that this is not standard early October fayre…we will see…

Hats off to you mike..great post!, I’ve been drinking Jack Daniels which has certainly helped me in my observations!.. ,..

 

..

[Mike Poole]

26 minutes ago, jon snow said:

Hats off to you mike..great post!, I’ve been drinking Jack Daniels which has certainly helped me in my observations!.. ,..

 

..

Beer for me, Karl, but I’ve been on it this afternoon because I aspire to Sober October this year, so it is last chance beer!  

Meanwhile, back at the ranch, UKMO out to T144:

Some Aleutian low there, the N Atlantic low not encroaching to UK as much as ICON.  As David ‘Bumble’ Lloyd, cricket commentator, might have said, if that is a normal mid Autumn NH profile, my backside’s a fire engine .

Edited September 25, 2021 by Mike Poole

[Mike Poole]

GFS T144 and T180:

Once again a stuck pattern over much of the NH as per ICON.  

I’m not seeing this as a surprise, more as a confirmation that the blocked patterns all year are persisting (so far) into autumn.  

Edited September 25, 2021 by Mike Poole

[Frosty.]

The longer term Ukmo 12h doesn’t look so bad…hmm.hmm…wow perhaps I’m a genius of the lamp?!..  

Edited September 25, 2021 by jon snow

[Mike Poole]

GEFS mean and spread at T180:

The most uncertainty around the low in the Atlantic of course.  Smirking face too, big ears, from the spread, maybe it knows something we don’t .  But the very meridional pattern persists for the foreseeable, I think.  

I would caution against looking further than about T180 at the moment, even on ensembles, there looks to me to be high uncertainty beyond this point - here be dragons

Edited September 25, 2021 by Mike Poole

[Frosty.]

29 minutes ago, Mike Poole said:

GEFS mean and spread at T180:

The most uncertainty around the low in the Atlantic of course.  Smirking face too, big ears, from the spread, maybe it knows something we don’t .  But the very meridional pattern persists for the foreseeable, I think.  

I would caution against looking further than about T180 at the moment, even on ensembles, there looks to me to be high uncertainty beyond this point - here be dragons

For sure, I completely agree Mike, a blustery outlook according too the GFS 12z op etc could be ours?!….here be dragons indeed!  

Edited September 25, 2021 by jon snow

[Frosty.]

Jose never rated Spurs..too much of a soft touch..and I’m a sad pathetic Spurs fan! ….anyhoo, the Gfs 12z op didn’t end so bad.. wow 1025 mb ..awesome!!!!!!!.  

Edited September 25, 2021 by jon snow

[Frosty.]

Looking at the GEFS 12z mean longer term, I’m going with a north / south split..anyone concur with that?…  

[Mike Poole]

ECM T120, well you can see decent weather holding on in the SE of the UK.

But the bigger picture is the Aleutian low, east Scandi high combo.  Vortex ain’t getting off to a flier this year!  Anything but!

 

[Mike Poole]

ECM T216

So the trough swings by, maybe, but look at the low pressures upstream masquerading as an improvement!  

My last post today

But I think the takeaway message is that it is all very uncertain, and the resurgence of the Atlantic in mid-autumn is probably not a banker.  Other things can, and most probably will happen.  Keeps it interesting!

[Cambrian]

GFS 12z models a consistently stronger jetstream in the 168-216h period than it did for the equivalent times on the 06z run. Looks like the Atlantic might be pepping up a bit.

6z run vs 12z run @168h

 

@192h

 

@216h 

 

The lack of a buckle at 168h brings the low for next weekend in further south, clipping northern Scotland.

6z run / 12z run 

 

Even when it buckles at 192h-216h, it doesn’t break, keeping the trough over us deeper. 

6z run / 12z run

 

The vagaries of one run, or a direction of travel? Next couple of runs are important. 

[damianslaw]

1 hour ago, Cambrian said:

GFS 12z models a consistently stronger jetstream in the 168-216h period than it did for the equivalent times on the 06z run. Looks like the Atlantic might be pepping up a bit.

6z run vs 12z run @168h

 

@192h

 

@216h 

 

The lack of a buckle at 168h brings the low for next weekend in further south, clipping northern Scotland.

6z run / 12z run 

 

Even when it buckles at 192h-216h, it doesn’t break, keeping the trough over us deeper. 

6z run / 12z run

 

The vagaries of one run, or a direction of travel? Next couple of runs are important. 

A much more unsettled pattern starting tomorrow evening, we've had weeks of nothingness, and not surprising to see at this late point in September. Aleutian low, east scand/west russian high , mid atlantic high = persistant trough over the UK.. much cooler and wetter. 

[Cambrian]

The 18z GFS op is more like a reversion to the 06z.

Weaker jet at 168h, with the low that bit further north again.

12z run vs. 18z run

 

Through to 210h, when on the 18z it fragments again

12z run vs. 18z run

   

So we know we’ve probably got a good few days in the trough but no real idea yet quite how deep the trough will be.
 

For next weekend, the GFS inter-run variability currently accommodates anything from deep secondary lows over southern UK with strong winds and rain, to a few showers in the west, for example at 186h:

12z run vs. 18z run

 
 

With midday temperatures over central England on Sunday held at an autumnal 8 degrees in the rain, or perhaps up to 14 degrees on a really quite barmy early October day. 
12z run vs. 18z run

 .

Edited September 26, 2021 by Cambrian

[Methuselah]

Things are starting to look a tad more interesting, according to the GFS 00Z operational run. And, as I've no desire for anything cold just yet, I still cling to hopes of unseasonal warmth:

    

    

    

Uncertainty anyone?

  

[Iceaxecrampon]

Quick skim through this weeks GFS

Needed.

Yes please - something seasonal.

.....and I'll leave this one here.

 

[Cambrian]

That’s looking more like a direct hit from the operational runs for 144h, especially for northern parts. Getting into the reliable now.

ECM / GFS / UKMO

  
 

The GFS in particular is packing a bit of a punch.

[Iceaxecrampon]

36 minutes ago, Cambrian said:

That’s looking more like a direct hit from the operational runs for 144h, especially for northern parts. Getting into the reliable now.

ECM / GFS / UKMO

  
 

The GFS in particular is packing a bit of a punch.

We're ready.

[damianslaw]

4 hours ago, Iceaxecrampon said:

Quick skim through this weeks GFS

Needed.

Yes please - something seasonal.

.....and I'll leave this one here.

 

Agree quite happy with this week's prospects. Some much needed rain for NW parts, wind and much cooler seasonal temperatures. How late September should be.

Key question right now is how deep the long wave Atlantic trough due to take up residence across our shores will be? Differing output from the models. Some suggesting quite deep which would aid secondary low development on its southern flank. Others a less deep feature which would produce more variable affair with southern parts holding on to more drier conditions. A messy picture and one that will chop and change in the model runs over next few frames. 

Edited September 26, 2021 by damianslaw

[Cambrian]

I don’t like wasps at all. I’ve been stung twice in the last two days. So I have to take it easy this afternoon, and take some antihistamines with several glasses of wine. It’s a real bind, absolutely terrible way to spend a Sunday afternoon. But it appears there is some good news on the way, as wasps become much less active below 10 degrees.

Dawn temperatures for the next few days from 0z ECM.

Monday 7am, you can run (fly), but you can’t hide.

 

Tuesday 7am, single figures for most to start the day, haven’t seen that so widely for a while.

 

Wednesday 7am, single figures pretty much across the board, low single figures in parts.

 

Hahahahahahaha.