Model output discussion 9th April onwards

[knocker]

1 hour ago, Uncle_Barty said:

exactly this. Better to look at the clusters. I usually pretty much ignore the mean.

But as has been said before they are not mutually exclusive. If the 500mb mean anomaly charts, for example,  are in consistent agreement then you have a fair idea of the framework within which the det runs will sort the surface detail. Which is where the clusters help immensely to fine tune the output, spottimg inconststencies or even possibly a new trend. Speaking entirely for myself, I find it impossible to evaluate a coherent NH pattern just by looking at five days of clusters

Edited June 30, 2021 by knocker

[Frosty.]

I think the longer term GEFS mean Azores high / ridge signal will wax and wane, that seems logical with 4 runs per day but even when the signal wanes (12z), there’s still some encouraging signs by around mid July?, we may not even have to wait that long?..some models show a ridge either building in or poised to build in by 10th July, I’m thinking specifically about the Gem / ECM 12z! ....anyway, for sure, next week looks cooler and more cyclonic / unsettled..but it may not be too long before the trough fills and pressure rises!  

 

Edited June 30, 2021 by Jon Snow

[Guest]

ECM really delivers a really poor weekend again, I was hoping the low would at least hold off for Saturday but it just surges eastwards through Friday night. Showers and plenty of cloud both Saturday and Sunday temps clearly going to struggle mid to high teens at best I would have thought. Monday looks a howler. Then showers and cool, breezy conditions through the week. While pressure rises unfortunately even by day ten on the ECM we are still stuck under an upper trough so mild and showery. Could be some really poor sunshine totals in places. 

[Djdazzle]

20 minutes ago, Alderc said:

ECM really delivers a really poor weekend again, I was hoping the low would at least hold off for Saturday but it just surges eastwards through Friday night. Showers and plenty of cloud both Saturday and Sunday temps clearly going to struggle mid to high teens at best I would have thought. Monday looks a howler. Then showers and cool, breezy conditions through the week. While pressure rises unfortunately even by day ten on the ECM we are still stuck under an upper trough so mild and showery. Could be some really poor sunshine totals in places. 

Not supported by the anomalies though.

[I remember Atlantic 252]

23 minutes ago, Alderc said:

ECM really delivers a really poor weekend again, I was hoping the low would at least hold off for Saturday but it just surges eastwards through Friday night. Showers and plenty of cloud both Saturday and Sunday temps clearly going to struggle mid to high teens at best I would have thought. Monday looks a howler. Then showers and cool, breezy conditions through the week. While pressure rises unfortunately even by day ten on the ECM we are still stuck under an upper trough so mild and showery. Could be some really poor sunshine totals in places. 

Tues onwards dosen't matter for Wimbledon, all matches due on centre and court 1

[Frosty.]

Just look how tonight’s ECM 12z ensemble mean improves / recovers between the mid / longer term...the in situ trough gradually fills and pressure rises...next week May just be a blip in an otherwise decent July! ...of course..I could be wrong!  

[Mike Poole]

23 minutes ago, Jon Snow said:

Just look how tonight’s ECM 12z ensemble mean improves / recovers between the mid / longer term...the in situ trough gradually fills and pressure rises...next week May just be a blip in an otherwise decent July! ...of course..I could be wrong!  

Yes, I think we just have to wait the low out now, and after that the Azores ridge should start to build in.  The low is annoying but there is nothing we can do about it!  I’d just add the spread T240, little uncertainty about that rise in pressure locally:

Edited June 30, 2021 by Mike Poole

[mushymanrob]

13 hours ago, mushymanrob said:

Sorry, im not buying the ops rapid breakdown and return of the atlantic low.

High pressure of that size and strength doesnt often get shunted aside by any Atlantic trough. The ops also all suggest an Azoreshigh helping shunt the trough over the UK. The anomalies do not have that feature.

So im backing the anomalies for those reasons and the trough remains to our near West

Interesting as this is likely to be proven right inasmuch as the high to our north will not get removed by the atlantic trough.

Over the last 12 hours we have seen the ops back down from bringing that trough across us and to our east, and now stall it much longer to our near west whilst the anomalies have brought the trough over us slowly.

So imho the anomalies were right, and all those operational runs showing the atlantic trough crossing the UK and drawing down cold northerlies - were wrong.

 

[Mike Poole]

ECM clusters, post T192 only one cluster so that tells us nothing.  T120-T168 here:

What faces us is characterised by clusters 1 and 2 here.  1 low pressure under a -NAO regime.  2 Scandi blocking.  I am strongly of the view that when we get the pesky low out of the way, it will be Scandi blocking that is more likely than -NAO.  We will see…

Edited June 30, 2021 by Mike Poole

[Fourty Point Three Degrees]

I have a small feeling the Atlantic wont last very long and heights will rise sooner than later and erase that pesky little trough quicky as a rubber can erase 'trough' written in pencil.  And latest pub run GFS doesnt look bad later on either. 

[Captain Shortwave]

This mornings runs suggest that we may see low pressure lift out around day7/8 with pressure steadily building.
ECM

GFS

However the immediate outlook looks rather unsettled. I guess given the evolution there is a risk of another shallow low forming over the continent as the trough sharpens and splits.

The airmass doesn’t look particularly cool even with low pressure directly overhead. So if there are some decent sunny spells then temperatures shouldn’t be too bad (high teens north/low twenties south).

Edited July 1, 2021 by Captain Shortwave

[mb018538]

3 minutes ago, Captain Shortwave said:

This mornings runs suggest that we may see low pressure lift out around day7/8 with pressure steadily building.
ECM

GFS

However the immediate outlook looks rather unsettled. I guess given the evolution there is a risk of another shallow low forming over the continent as the trough sharpens and splits.

The airmass doesn’t look particularly cool even with low pressure directly overhead. So if there are some decent sunny spells then temperatures shouldn’t be too bad (high teens north/low twenties south).

It's still quite unsettled though even without a low over us - low 500mb heights and cool upper trough still in situ (again). So even though pressure is around 1020mb, it's an unstable atmosphere and unsettled with lots of very heavy showers bubbling up. Recurring theme for summer 2021!




 

[Guest]

8 minutes ago, mb018538 said:

It's still quite unsettled though even without a low over us - low 500mb heights and cool upper trough still in situ (again). So even though pressure is around 1020mb, it's an unstable atmosphere and unsettled with lots of very heavy showers bubbling up. Recurring theme for summer 2021!




 

Yup things just move from unsettled to less unsettled in the Day 8-10 period. GFS keeps an upper trough in place right through to end of the run. Little chance of any dry, sunny weather until at least the 10-12th July at best I would have thought. 

[Methuselah]

Some quite interesting weather on offer, should the GFS turn out to be correct; low twenties & thundery showers will do me just fine:

    

    

    

But, sunshine-wise, nothing's clear; except that I'll no' need invest in a man-sized lobster pot!

Anywho, temps look like being okay . . . is that a warm cluster (around and above the mean) I see, there?

    

[johnholmes]

The 500 mb anomaly outputs today

Ec now shows ridge between Iceland and uk with trough over e’ern uk and east

Noaa not that different to its Monday issues; elongated trough from main trough Canada/Greenland, into nw’ern uk with w’ly flow over s’ern areas. There is a –ve area centred over sw uk and a +ve anomaly centred e of Greenland. Its 8-14 output shows a broadly w’ly flow into a broad shallow trough east of the uk

Uk surface weather? Largely based on Noaa suggests to me rather unsettled  with about a w’ly 500 flow much of the time, temperatures either side of average. A moderate prob of fairly warm at times with any drier and sunnier days that are likely.

Looking at the Met O extended chart out to 7 July they show a surface feature finally into the N sea by mid next week, still with an upper (500 mb) low with twin centres straddling the UK.

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

WWW.METEO.PSU.EDU

[johnholmes]

In the immediate future, today, the lovely sunshine here at the moment is not likely to last it seems.The visual shows low cloud off the N Sea and the movie sequence, not shown, suggests it is moving west.

Satellite images / Europe | MeteoCentre.com

METEOCENTRE.COM

The XC weather reports also show pretty much anywhere east or NE of here has extensive low cloud!"

[johnholmes]

Just now, johnholmes said:

In the immediate future, today, the lovely sunshine here at the moment is not likely to last it seems.The visual shows low cloud off the N Sea and the movie sequence, not shown, suggests it is moving west.

Satellite images / Europe | MeteoCentre.com

METEOCENTRE.COM

The XC weather reports also show pretty much anywhere east or NE of here has extensive low cloud!"

Sorry the sat image is courtesy of the Roger Brugge page at Reading Uni, this link will give you a mass of information, actual and forecast, a great site

MeteoCentre-Reading | The real-time weather portal for Reading and the United Kingdom

METEOCENTRE.COM

 

 

[Downburst]

Improving picture as next weeks low pressure moves along. Rain for many, but improving all the while. 

Edited July 1, 2021 by Downburst

[mushymanrob]

37 minutes ago, johnholmes said:

The 500 mb anomaly outputs today

Ec now shows ridge between Iceland and uk with trough over e’ern uk and east

Noaa not that different to its Monday issues; elongated trough from main trough Canada/Greenland, into nw’ern uk with w’ly flow over s’ern areas. There is a –ve area centred over sw uk and a +ve anomaly centred e of Greenland. Its 8-14 output shows a broadly w’ly flow into a broad shallow trough east of the uk

Uk surface weather? Largely based on Noaa suggests to me rather unsettled  with about a w’ly 500 flow much of the time, temperatures either side of average. A moderate prob of fairly warm at times with any drier and sunnier days that are likely.

Looking at the Met O extended chart out to 7 July they show a surface feature finally into the N sea by mid next week, still with an upper (500 mb) low with twin centres straddling the UK.

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

WWW.METEO.PSU.EDU

What im not getting, is the ops insistence of a strong Azores high, and this coming trough exiting Northwards. I see no strong Azores high on the Anomalies, and with a strong HP to our North, i cant see how such a feature as the low could exit North.
As i see it, and i could be wrong, is that the coming trough off the Atlantic arriving on Saturday, slows down considerably and stalls to our very near west.... and weakens. both the NOAA charts dont bring into play a strong Azores high.

[northwestsnow]

6z continuing the theme of troughing lifting out quickly to be followed by perhaps something more traditional, have to say it has been a lovely June up here at least.

[Singularity]

As tropical changes drive AAM upward again, what we should see is a shift of high pressure focus to Northwest Europe for a time. The Scandinavian High may then redevelop afterward via an extension of that ridge.

Currently, the forecast models have read only half the instructions. We see a lift out of the main surface low on Wednesday, but the ECM 00z and GFS 00z/06z runs have been leaving the upper trough behind until at least Saturday.

That trough should really either lift out or be quickly taken apart by 'proper' ridging of high pressure across from the Azores... provided that ridging is in a typical location for a response to AAM climbing through the neutral range. The models want to send it further north for reasons that will merit some research if such an outcome comes to pass. 

Usually, though, this proves to be the result of erroneous assumptions related to recent or near-term events. Hopefully this is another one of those times.

 

[Methuselah]

Could be some tasty thunderstorms around, next week -- if the GFS 06Z is smelling the coffee?

    

After that, and with the welcome exceptions of anything either too cold or too hot, just about anything might happen:

    

    

[summer blizzard]

1 hour ago, mushymanrob said:

What im not getting, is the ops insistence of a strong Azores high, and this coming trough exiting Northwards. I see no strong Azores high on the Anomalies, and with a strong HP to our North, i cant see how such a feature as the low could exit North.
As i see it, and i could be wrong, is that the coming trough off the Atlantic arriving on Saturday, slows down considerably and stalls to our very near west.... and weakens. both the NOAA charts dont bring into play a strong Azores high.

May be worth looking at the corresponding forecast discussion that the noaa produce to see if model divergence exists. Would appreciate the link myself.

[mushymanrob]

1 hour ago, summer blizzard said:

May be worth looking at the corresponding forecast discussion that the noaa produce to see if model divergence exists. Would appreciate the link myself.

I dont know where that is, but there is a prognostic explanaition below the charts. Their own verification is high at 4/5 for the 6-10 day chart.

[Frosty.]

Who says we can’t..won’t see high pressure further into July!?...mmmmmmm..GEFS 6z!!!.. Glass more than half full here!!!!!!   ? ..jeez is that Flash Gordon approaching?!  

Edited July 1, 2021 by Jon Snow