Model Output Discussion - 15th March onwards

[sundog]

1 hour ago, bluearmy said:

Whilst we struggle to lose the current pattern, the med is going to frazzle next week as a heat dome establishing this week remains broadly in situ without any pattern changes to move it on. 

The heat dome can stay there as  far as I'm concerned or just diminish. 

[danm]

2 hours ago, bluearmy said:

Whilst we struggle to lose the current pattern, the med is going to frazzle next week as a heat dome establishing this week remains broadly in situ without any pattern changes to move it on. 

I suppose it gives us a good source of heat to tap into should we get a southerly at some point!

[Man With Beard]

Going by the latest ensemble trends, I'm starting to think we may get through the whole of July without a notable heatwave, which has been pretty rare recently. The signal for a slight improvement around the 20th has not developed, yet, into anything more than "slight" - the general picture of westerly or even north-westerly influence remains, with the trough to the north reluctant to progress far enough away to allow neither a longer settled period nor a southerly draw for more than the briefest period. The clusters look pretty clear this morning in that regard:

So whilst comparisons with 2012 are inaccurate, it does look like July 2023 will come in underneath the average July by 21st century standards, unless a dramatic change occurs soon.

[Don]

4 minutes ago, Man With Beard said:

Going by the latest ensemble trends, I'm starting to think we may get through the whole of July without a notable heatwave, which has been pretty rare recently.

Remember though, it looked similar in July 2020 and then a heat spike popped up at the end of the month.  Not saying that will be the case this year, but shows what can happen.

[Mike Poole]

36 minutes ago, Man With Beard said:

Going by the latest ensemble trends, I'm starting to think we may get through the whole of July without a notable heatwave, which has been pretty rare recently. The signal for a slight improvement around the 20th has not developed, yet, into anything more than "slight" - the general picture of westerly or even north-westerly influence remains, with the trough to the north reluctant to progress far enough away to allow neither a longer settled period nor a southerly draw for more than the briefest period. The clusters look pretty clear this morning in that regard:

So whilst comparisons with 2012 are inaccurate, it does look like July 2023 will come in underneath the average July by 21st century standards, unless a dramatic change occurs soon.

Yes, I think the signal from the EPS (at the moment) is for higher pressure to influence the UK, but to remain resolutely to our west, and not push across the UK.  

Yesterday’s 12z clusters showed this well in the T264+ timeframe:

A common theme here is the Atlantic ridge regime (purple border) - (I know, I whinge when there is only one cluster, and when there are more of them, I comment on the common theme!).  Still there this morning, although less notable.  But what is notable is still the absence of the red (Scandi block) regime, which has been the expected ultimate ‘direction of travel’, both from a background signals and longer range models point of view.  

Speaking of regimes, the recent ECM 46 take has been as follows:

Note the increasing probability of the purple Atlantic ridge regime (highlighted on the most recent chart) for week 2.  But also note the red later on - still very much the ‘jam tomorrow’ theme of this July!

[Addicks Fan 1981]

Thank you @Mike Poolefor the clusters and the probabilities, it sheds the light on what will probably come for the next fortnight.  I saw the ECM ensemble mean at 240 hours and got to say it didn't deliver as big a trough as the deterministic chart.  Reckon its a case of sit tight on this to be honest with you.   

[danm]

Just now, Addicks Fan 1981 said:

Thank you @Mike Poolefor the clusters and the probabilities, it sheds the light on what will probably come for the next fortnight.  I saw the ECM ensemble mean at 240 hours and got to say it didn't deliver as big a trough as the deterministic chart.  Reckon its a case of sit tight on this to be honest with you.   

The Op was definitely a worst case scenario amongst the ensembles, so let’s see what happens. All we can say right now is that this weekend looks autumnal, early to mid next week looks better with more settled and sunny weather and then after that is a big question mark. It could turn more unsettled again. 

[Guest]

Another extremely disappointing 06Z from GFS which again is heavily supported by a very strong signal from the ensembles of low pressure never being too far away from the uk. Every time pressure appears to build momentum always appears to favour a low pressure dropping down from the Icelandic region. 
 

While certainly not as bad as 2012 it’s becoming clearly 2023 will likely be the worst July since then and make a mockery of the LRF’s probably the biggest fail since the infamous bbq summer forecast. 

[Addicks Fan 1981]

Just seen the GEFS 6Z ensemble mean @danmand it looks like a continuation of the westerly regime we are having at present.  What we need now is the next downwelling kelvin wave to develop and that will be the real game changer as if it were.  Question over this weekend is how unsettled it will get exactly?   

[alexisj9]

4 hours ago, bluearmy said:

Whilst we struggle to lose the current pattern, the med is going to frazzle next week as a heat dome establishing this week remains broadly in situ without any pattern changes to move it on. 

Yep, reminds me of something, how hot will the next heat dome burst north be.

[alexisj9]

3 hours ago, sundog said:

The heat dome can stay there as  far as I'm concerned or just diminish. 

Agreed, but unfortunately unlikely. The dome will burst at some point.

Edited July 12, 2023 by alexisj9

[Uncle_Barty]

17 minutes ago, Alderc said:

Another extremely disappointing 06Z from GFS which again is heavily supported by a very strong signal from the ensembles of low pressure never being too far away from the uk. Every time pressure appears to build momentum always appears to favour a low pressure dropping down from the Icelandic region. 
 

While certainly not as bad as 2012 it’s becoming clearly 2023 will likely be the worst July since then and make a mockery of the LRF’s probably the biggest fail since the infamous bbq summer forecast. 

July mean here so far is 17.6°c - 2020 and 2015 were both lower (17.2 and 17.1 respectively).

2012 was a pitiful 16.2°c, dragged down by some very poor temps in the first 10 days or so. On only 4 days of that month (around the 23rd) did each day's mean exceed the July average mean temp here (17.9) since 2000.

2 hours ago, Mike Poole said:

Yes, I think the signal from the EPS (at the moment) is for higher pressure to influence the UK, but to remain resolutely to our west, and not push across the UK.  

Yesterday’s 12z clusters showed this well in the T264+ timeframe:

A common theme here is the Atlantic ridge regime (purple border) - (I know, I whinge when there is only one cluster, and when there are more of them, I comment on the common theme!).  Still there this morning, although less notable.  But what is notable is still the absence of the red (Scandi block) regime, which has been the expected ultimate ‘direction of travel’, both from a background signals and longer range models point of view.  

Speaking of regimes, the recent ECM 46 take has been as follows:

Note the increasing probability of the purple Atlantic ridge regime (highlighted on the most recent chart) for week 2.  But also note the red later on - still very much the ‘jam tomorrow’ theme of this July!

Whats the colour decode for the other ones, please?

[*Stormforce~beka*]

5 hours ago, ANYWEATHER said:

More green snot not just for this weekend but for next as well ! 

That couldn't get more centrered over us if it tried LOL! Sick ...

[Man With Beard]

2 hours ago, Mike Poole said:

Yes, I think the signal from the EPS (at the moment) is for higher pressure to influence the UK, but to remain resolutely to our west, and not push across the UK.  

Yesterday’s 12z clusters showed this well in the T264+ timeframe:

A common theme here is the Atlantic ridge regime (purple border) - (I know, I whinge when there is only one cluster, and when there are more of them, I comment on the common theme!).  Still there this morning, although less notable.  But what is notable is still the absence of the red (Scandi block) regime, which has been the expected ultimate ‘direction of travel’, both from a background signals and longer range models point of view.  

Speaking of regimes, the recent ECM 46 take has been as follows:

Note the increasing probability of the purple Atlantic ridge regime (highlighted on the most recent chart) for week 2.  But also note the red later on - still very much the ‘jam tomorrow’ theme of this July!

The Scandi block will need to get its skates on now, or there's going to be a bit of an inquest into these LRFs!

[Mike Poole]

23 minutes ago, Uncle_Barty said:

July mean here so far is 17.6°c - 2020 and 2015 were both lower (17.2 and 17.1 respectively).

2012 was a pitiful 16.2°c, dragged down by some very poor temps in the first 10 days or so. On only 4 days of that month (around the 23rd) did each day's mean exceed the July average mean temp here (17.9) since 2000.

Whats the colour decode for the other ones, please?

Blue: +NAO, Green: -NAO, Purple: Atlantic Ridge, Red: Scandi Block. 

Chart shows the detail of the regimes, plus their climatology probabilities, for summer:

Incidentally, these are both slightly different for winter, as shown below:

[Derecho]

1 hour ago, Alderc said:

Another extremely disappointing 06Z from GFS which again is heavily supported by a very strong signal from the ensembles of low pressure never being too far away from the uk. Every time pressure appears to build momentum always appears to favour a low pressure dropping down from the Icelandic region. 
 

While certainly not as bad as 2012 it’s becoming clearly 2023 will likely be the worst July since then and make a mockery of the LRF’s probably the biggest fail since the infamous bbq summer forecast. 

I'd say July 2015 and 2020 were worse. 2015 saw UEA campus flood at the end of the month after a day of non stop heavy rain. The last week if I recall was the coolest last week of July since the 1920s. Just a sense of some perspective. 

The CET so far is also at 16.5C which is above the 61-90 average, 2020 could have finished over 1C below the same average if that hot day at the end of the month didn't happen.

The 06z delays the digging of the trough southwards in its later stages (last full working week of July), wouldn't surprise me if it didn't materialise though yes the ensembles do seem to be leaning somewhat that way.

Despite the cooler outlook, the GFS doesn't see much rain from Sunday onwards here before that low meanders in the North Sea towards the end.

EC does have a trough digging south but I wouldn't be calling it at this point.

Generally though, intense heat over the central southern Med equates to poorer weather here.

Edited July 12, 2023 by Derecho

[Don]

53 minutes ago, alexisj9 said:

Yep, reminds me of something, how hot will the next heat dome burst north be.

Final day of July 2020?  Agreed, whilst that heat dome remains, it potentially has our name on it eventually!

[danm]

1 hour ago, Alderc said:

Another extremely disappointing 06Z from GFS which again is heavily supported by a very strong signal from the ensembles of low pressure never being too far away from the uk. Every time pressure appears to build momentum always appears to favour a low pressure dropping down from the Icelandic region. 
 

While certainly not as bad as 2012 it’s becoming clearly 2023 will likely be the worst July since then and make a mockery of the LRF’s probably the biggest fail since the infamous bbq summer forecast. 

 

1 hour ago, Addicks Fan 1981 said:

Just seen the GEFS 6Z ensemble mean @danmand it looks like a continuation of the westerly regime we are having at present.  What we need now is the next downwelling kelvin wave to develop and that will be the real game changer as if it were.  Question over this weekend is how unsettled it will get exactly?   

 

38 minutes ago, Derecho said:

 

The 06z delays the digging of the trough southwards in its later stages (last full working week of July), wouldn't surprise me if it didn't materialise though yes the ensembles do seem to be leaning somewhat that way.

Despite the cooler outlook, the GFS doesn't see much rain from Sunday onwards here before that low meanders in the North Sea towards the end.

EC does have a trough digging south but I wouldn't be calling it at this point.

Generally though, intense heat over the central southern Med equates to poorer weather here.

Just had a peak at the 6z and whilst it’s far from a cracker, I also wouldn’t call it extremely disappointing- at least for the southern half of the UK, and excluding the very end of the run. Pressure remains fairly high in the south whereas low pressure is most of the time only making inroads to the far north. It’s not heatwave territory but if that run were to verify it would give the south a fair amount of pretty respectable weather. Lower pressure does briefly get into the south at times, so not totally dry.

 

[Guest]

1 hour ago, danm said:

 

 

Just had a peak at the 6z and whilst it’s far from a cracker, I also wouldn’t call it extremely disappointing- at least for the southern half of the UK, and excluding the very end of the run. Pressure remains fairly high in the south whereas low pressure is most of the time only making inroads to the far north. It’s not heatwave territory but if that run were to verify it would give the south a fair amount of pretty respectable weather. Lower pressure does briefly get into the south at times, so not totally dry.

 

But you are assuming that anything ridge related will be decent in the south. 

I randomly took on of those charts and looked at surface conditions. The 23rd looks decent generally decent above at the 500mb level translates into this, while those conditions Will absolutely change those sorts of ridges are nearly moist generating tons of cloud with weak fronts embedded in them.  

In fact I just looked, nearly all those day are showery and cool at the surface across the entire country. Yes some areas will do better but if that’s the better stuff we’re really clutching at straws. 

Edited July 12, 2023 by Alderc

[danm]

20 minutes ago, Alderc said:

But you are assuming that anything ridge related will be decent in the south. 

I randomly took on of those charts and looked at surface conditions. The 23rd looks decent generally decent above at the 500mb level translates into this, while those conditions Will absolutely change those sorts of ridges are nearly moist generating tons of cloud with weak fronts embedded in them.  

In fact I just looked, nearly all those day are showery and cool at the surface across the entire country. Yes some areas will do better but if that’s the better stuff we’re really clutching at straws. 

 

Well it's hard to say what surface conditions will be like at this range, but there is still likely to be some respectable weather at times - what does that mean? Dry, some sunshine, a few showers can't be ruled out, temperatures 20-24c. 

Grasping at straws? Not really. I'm not saying it's good, let alone great. Just not extremely disappointing. It is in the context of wanting a heatwave - which I do too - but in terms of average UK summer weather, it wouldn't be miles off that for the south. 

[Addicks Fan 1981]

Apparently the MJO is set to get a bit more active so that could correlate to more settled conditions, although the signs are very tentative currently.   

https://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ecmf.shtml

[summer blizzard]

Modelling to day 10 essentially gives a choice between low pressure or an Atlantic High. It does not look like we will see meaningul warmth until at least the final week of July.

[Tamara]

5 hours ago, Uncle_Barty said:

July mean here so far is 17.6°c - 2020 and 2015 were both lower (17.2 and 17.1 respectively).

2012 was a pitiful 16.2°c, dragged down by some very poor temps in the first 10 days or so. On only 4 days of that month (around the 23rd) did each day's mean exceed the July average mean temp here (17.9) since 2000.

Whats the colour decode for the other ones, please?

 Based on a record breaking June (in UK) and the first 10 days of July actually perfectly respectable against long term temperature averages, there is a lot of excess reactivity instead of proactivity to be waded & skipped through. Considering calling time on seasonal LTF's is just as absurd (based on a good match overall so far) and extrapolating weeks ahead at a time based on face value numerical model interpretations. Signals lead models, not the other way around - and models do always read signals impeccably particularly in periods of excess of 10 to 15 days ahead. 

The facts are repeatedly laid out as to how & why the pattern is the way it is and what will change it (and will change it) Latest GSDM updated consolidated data confirms a full volte face to a Nina-esque type of forcing, so the synoptic response should not be a surprise with such a collapse of angular momentum,

As part of the broken record, one context of this is a natural lull in the mini ENSO cycle ahead of the next upswing (and associated reconfiguring of the pattern which for NW Europe means a return to more summer like weather) It just so happens that this cyclical downturn has coincided with (part) of the peak of summer. However, another context is the record breaking June that came before it & the fact that this lull phase is not long term sustainable.

[terrier]

So looks like the latest GFS goes off on one around T336 with warmer and drier conditions. Let’s see if this is a new signal it’s picking up on. Or if it’s a huge warm outliner.

[Uncle_Barty]

40 minutes ago, Tamara said:

 Based on a record breaking June (in UK) and the first 10 days of July actually perfectly respectable against long term temperature averages, there is a lot of excess reactivity instead of proactivity to be waded & skipped through. Considering calling time on seasonal LTF's is just as absurd (based on a good match overall so far) and extrapolating weeks ahead at a time based on face value numerical model interpretations. Signals lead models, not the other way around - and models do always read signals impeccably particularly in periods of excess of 10 to 15 days ahead. 

The facts are repeatedly laid out as to how & why the pattern is the way it is and what will change it (and will change it) Latest GSDM updated consolidated data confirms a full volte face to a Nina-esque type of forcing, so the synoptic response should not be a surprise with such a collapse of angular momentum,

As part of the broken record, one context of this is a natural lull in the mini ENSO cycle ahead of the next upswing (and associated reconfiguring of the pattern which for NW Europe means a return to more summer like weather) It just so happens that this cyclical downturn has coincided with (part) of the peak of summer. However, another context is the record breaking June that came before it & the fact that this lull phase is not long term sustainable.

Exactly... and I've seen this happen several times before (and I now understand better why that is)  - when a pattern change comes "apparently" Out of the Blue in the model output, when before we'd all be Standin' in the Rain, then Mr Blue Sky arrives like a Wild West Hero.

And it won't be a surprise when the Sweet Talkin' Woman above kept telling us to keep the faith. Meanwhile, the Big Wheels of model output keep on turning, and promise us some Summer and Lightning further down the line.

 

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