Model output discussion 9th April onwards

[Man With Beard]

There's something slightly stuck about the ECM right now, though? Although pressure is generally high on the op runs, there is a tendency to throw weak troughs through the pattern with destinations just to our south and east Europe. Although 500mb pressure charts might suggest acceptable weather, even a shallow trough can produce copious amounts of rain in July, as evidenced by the 10 day accumulative rainfall chart tonight, which shows 154mm rain for N London.

[Man With Beard]

Most of the rain for London, interestingly, falling next Sunday night on the ECM, maybe 60mm in just 6 hours!

JFF this far out but imagine the footie final in these kind of conditions

[Uncertainty]

9 minutes ago, knocker said:

Yup...allied to a Scandy ridge not looking too bad with temps around average, maybe a tasd above, aklbeit not completre agreement

 

Great to have you back in here Knocker.

With the EPS and GEFS still very opposed on the passage (or not) of the tropical signal out of the Indian Ocean there is still a way to go to be sure on developments beyond next weekend.

But, as @Mike Poolehas laid out, cross model agreement now exists on a Scandi ridge and some semblance of Azores connection, with a cut off low potentially to the SE (again!) still to nail down.

 

[Singularity]

2 hours ago, mushymanrob said:

Mean upper trough anchored west of iceland, moderate southwesterly upper flow over the UK, coupled with a weak but positive pressure anomaly...

Not bad, not so sure it supports the azores ridge over us, but not bad... plenty of useable summers weather in that.

The divergence of the green contour lines indicates a large area of decelerating flow aloft. That air must then sink, building high pressure UK-Scandinavia.

It seems the pattern EPS kept shouting for in the longer range is finally starting to take shape for the middle third of July.

[bluearmy]

The general direction of travel looks more positive ref summery conditions than for quite some time and yet, the op models are all still chucking weak upper troughs into the mix. These will not show on ens output so I’m wary about digging out additional garden furniture just yet! 

maybe the outlook is decent with interspersed bad days or two as to the other way around. Appreciate that the north of the U.K. have seen better conditions than the south over the past month or so. 

[bluearmy]

these are becoming increasingly optimistic ref the 5 dam spread line inching further north 
 

[Methuselah]

Still no sign of any imminent northward heat-surge, but the GFS 00Z is still headed in the right direction; lots of very warm conditions, should it pan out:

    

    

    

[Guest]

Well I mentioned a couple of days there was always a risk high pressure wouldnt ridge in enough leaving the door open to the north west and that’s exactly what’s been picked up this morning. 
 

Where’s the high gone? Very disappointing. 
 

GEM @144

UKMO @144

GFS @144

 

Looks like any decent weather is back into the day 8-10range….

[mushymanrob]

31 minutes ago, Alderc said:

Well I mentioned a couple of days there was always a risk high pressure wouldnt ridge in enough leaving the door open to the north west and that’s exactly what’s been picked up this morning. 
 

Where’s the high gone? Very disappointing. 
 

GEM @144

UKMO @144

GFS @144

 

Looks like any decent weather is back into the day 8-10range….

You should know better by now than to make such an assertion based on one run...

[sheikhy]

I will take the ecm this morning!!to hell with the rest of the models lol!!!ukmo goes troughy at 144 hours and gfs is has been so bad in the last 24 hours in terms of consistency its shambolic!!!

[Guest]

12 minutes ago, mushymanrob said:

You should know better by now than to make such an assertion based on one run...

Normally I’d agree but it’s a pretty universal trend. Even ECM which is the least bad this morning has an upper trough once again crossing the UK and manages to dump over 100mm of rain over London though just the weekend….either way a really disappointing shift IMO.

[Scorcher]

26 minutes ago, Alderc said:

Normally I’d agree but it’s a pretty universal trend. Even ECM which is the least bad this morning has an upper trough once again crossing the UK and manages to dump over 100mm of rain over London though just the weekend….either way a really disappointing shift IMO.

We've been through this before about rainfall totals too...

I'm struggling to see what is so awful about the ECM this morning.

[mb018538]

56 minutes ago, Alderc said:

Normally I’d agree but it’s a pretty universal trend. Even ECM which is the least bad this morning has an upper trough once again crossing the UK and manages to dump over 100mm of rain over London though just the weekend….either way a really disappointing shift IMO.

Think you must have the wrong charts? Certainly no 100mm or anything close on the 00z ECM run. ECM ENS starting to nose the 10c line in from the SW, which is usually a sign of an Azores high starting to flex:



Two of the 3 clusters build the high in like the op run between day 8-10:



Might be a case of it taking a bit longer than anticipated, but early to middle next week looks to be the sweet spot if we're going to change this pattern.
 

Edited July 5, 2021 by mb018538

[Guest]

1 minute ago, mb018538 said:

Think you must have the wrong charts? Certainly no 100mm or anything close on the 00z ECM run.



Two of the 3 clusters build the high in like the op run between day 8-10:



Might be a case of it taking a bit longer than anticipated, but early to middle next week looks to be the sweet spot if we're going to change this pattern.
 

My bad, that was the 12Z from last night, but still surface conditions are poor both Saturday and Sunday. 
 

[Cambrian]

We had 40mm of rain yesterday from showers throughout the 24 hours, not so sure we need tonight and tomorrow’s rain so much now! Ah, the UK summer! That’ll teach me. 

After the immediate system is out of the way by later Tuesday, Thursday / Friday looks a bit better, though some showers remain, indeed 0z ECM and GFS are still struggling to settle it down even through next weekend, 1012-1016mb and a slow westerly isn’t going to cut it for a reliable spell just yet, though as others have said it does look more promising from around 10 days time.

Leading up to then, general agreement at 120 hrs for a showery start to Saturday in a col / shallow trough (could that be called an “upper low” on the ECM?)

ECM 0z +120h           GFS 0z + 120h.  GFS Precipitation 

  

 

The two models diverge by 168 hrs. ECM keeps us in the unremarkable temperatures “flab” but more immediately awaiting the AH nose, while the GFS extends the Atlantic low closer to the northwest which tucks us into a firmer westerly and sends some more persistent rain our way for later next Monday and Tuesday. 

ECM 0z +168h           GFS 0z + 168h GFS Precipitation 

 

[mushymanrob]

3 hours ago, Alderc said:

Normally I’d agree but it’s a pretty universal trend. Even ECM which is the least bad this morning has an upper trough once again crossing the UK and manages to dump over 100mm of rain over London though just the weekend….either way a really disappointing shift IMO.

A "universal trend"?... true theres a degree of uncertainty around days 6-8 but all GFS and ECM runs bring the Azores high into play by day 10 at the latest, and the anomalies support this too... the only trend i can see is a gradual improvement towards above average conditions , a settling down, drier and warmer with the usual MW/SE divide likely by midweek next.

Once we have ridging in place even if its "only" to our South then the final step towards a hot spell is in place... imho the outlook is good.

[northwestsnow]

Excellent GFS 6Z...

Lots of warm settled weather as the jet is pushed further North...

[mb018538]

4 minutes ago, northwestsnow said:

Excellent GFS 6Z...

Lots of warm settled weather as the jet is pushed further North...

I think this is the classic UK summer chart that most people would think of - Azores high building in from the SW with low pressure back towards where it should be in July. We just need this trend to start pulling back to day 9/8/7/6 through this week and we should be good for settled weather around mid-month (which is what teleconnections have progged as a potential return to better conditions since the last week of June).

[Downpour]

17 minutes ago, mb018538 said:

I think this is the classic UK summer chart that most people would think of - Azores high building in from the SW with low pressure back towards where it should be in July. We just need this trend to start pulling back to day 9/8/7/6 through this week and we should be good for settled weather around mid-month (which is what teleconnections have progged as a potential return to better conditions since the last week of June).

Indeed so, and it's also a shade better earlier term for the south at least. Probably enough ridging to give a few fine-ish days from late this week onwards...

[MATTWOLVES 3]

A few of us have been mentioning it for a fair few days now regarding an improving situation,and it finally appears that the ops are smelling the Nescafe! Much better ridging in place with the Jet taking a hike further North...this would implie settled conditions and a gradual warming to become evident! Infact the chances of much warmer spells eventually....dare I say the H word?? HOT HOT HOT wouldn't rule it out towards mid month for sure.

Enjoy your week's folks and hopefully proper Summer just around the corner now! Hoorahh the lads.

Edited July 5, 2021 by MATTWOLVES

[knocker]

But any ridging appears to be quite fragile towards the end of the ten day period from the det output in what is quite a fluid pattern

And the mean ens supports this

Edited July 5, 2021 by knocker

[Guest]

2 hours ago, mushymanrob said:

A "universal trend"?... true theres a degree of uncertainty around days 6-8 but all GFS and ECM runs bring the Azores high into play by day 10 at the latest, and the anomalies support this too... the only trend i can see is a gradual improvement towards above average conditions , a settling down, drier and warmer with the usual MW/SE divide likely by midweek next.

Once we have ridging in place even if its "only" to our South then the final step towards a hot spell is in place... imho the outlook is good.

So again we are back to day10? We were at day8 2days ago? 

[summer blizzard]

As Singularity has alluded to, there's a substantial difference in tropical convection modelling so yes we may see an Azores ridge in a week or so but don't allow oneself to get too excited until the Euro and GFS have consensus.

[mushymanrob]

21 minutes ago, Alderc said:

So again we are back to day10? We were at day8 2days ago? 

nope... well i wasnt.

Azores high domination isnt nailed, its just the direction we appear to be heading in but at the worst its a NW/SE divide with no sign of anything long lasting below average. There may be no heatwave, but average or above average for mid July is pretty good.

[Faronstream]

GFS long range still keen on letting the colder than average 850hpa temps getting closer to northern europe instead of being around svalbard/artic ocean area just like we saw for most of april/may. I'm getting strong vibes of a much colder 2nd half of this summer.