Model Output Discussion - mid Autumn

[Ross90]

I'd take the ecm over the gfs at day 10 all day. Gfs has 60-70 mph winds across the northern half of the UK, maybe higher. Ecm is at least sending a less deep low much further south.

[Mike Poole]

One thing I’ve noticed on recent runs at about 10 days is that many of the GFS runs look to be heading towards default with a substantial lobe of vortex taking shape in its more usual location upstream.  Less tendency for this to show on the other models, so I wonder if a bit of GFS bias is showing here..  

This morning’s 0z runs illustrate well, first GFS at T240, lobe of vortex gathering to our west.

Whereas GEM, ECM and JMA show more blocking and a more disturbed vortex:

[carinthian]

19 hours ago, carinthian said:

Yuk, don't like the look of that chart for next Sunday . Another slow moving storm not really wanted for you guys and more windy conditions across mainland Europe. I just hope the British Isles does not gets stuck in a rinse and spin cycle with Easterlies domination at 60N and Westerlies' 50S with more flooding. Longer term signs the main trough will slowly anchor further east with a bit drier conditions, hopefully.

C

Morning all. A rather depressing full set of model runs this morning with the unsettled spell prolonged to months end. Obviously not good news for rain soaked Britain with more flooding expected by the end of the week. The rinse and spin cycle not exclusive to The British Isles with much of Western Europe getting plenty of wet weather with gusty winds at times. Looks like  a fair bit of Scandinavia escaping the worse of the bad weather where colder more seasonal condition prevail. My daughter who lives in Stockholm already reporting frosty nights over there and the Tv weather reports of snow and low temps already well established up north .

[Rain All Night]

A chilly Hallowe'en looks possible...

[Cambrian]

Some crucial changes early on in the run determine the ultimate path of the 0z ECM op and lead to some striking differences in the setup by day 10. 

Focus has been on the resilience of the block of Icelandic heights and the equally determined Atlantic trough working around the south of the block into the UK and Ireland. 

It’s Scandinavia where the sleight of hand is happening though, in the push of low heights south between days 2 and 3. 

 

With bridgehead secured, the Atlantic trough transfers the low to the base of the Scandinavian trough at day 5, which pulls it northeast along the trough through the UK and Ireland during the weekend, day 6. 

 

The eastward movement of the low, combined with the resolute Icelandic-Svalbard heights, secures us a northerly flow for days 7 and 8, 

 

before a shallow ridge gives way to repeat of the process of Atlantic cyclogenesis and transfer of the resulting low pressure, another deep one, to the base of the Scandinavian trough during days 9 and 10. 

 

The animations are great value, showing the change for the UK and Ireland setup from Atlantic trough cyclonic to an ongoing transfer of low pressure systems between the Atlantic and Scandinavian troughs. 

 

This should serve to bring us better breaks and colder interludes between the systems as we move into November. Have a great day.

[minus10]

Models still homing in on very unsettled/disturbed spell for sunday..

Gfs/Ecm/Ukmo/Gem 0z

..the secondary low formation from the main trough the culprit ...after that still not looking that good...although gfs tries to raise pressure somewhat as we go into November..

...however ecm still doesnt want to know with yet another stormy low..

...very wet October on the cards and beginning of November...got to hope that there is a change as we go further into November..

Maybe the anomalies can give us some hope..mmm ..well as of yesterday for 10 to 14 days they paint a westerly unsettled picture  with main trough centred further west...

 

 

 

 

[Aiden2012]

I’m liking the gfs 6z so far 

[alexisj9]

2 hours ago, minus10 said:

Models still homing in on very unsettled/disturbed spell for sunday..

Gfs/Ecm/Ukmo/Gem 0z

..the secondary low formation from the main trough the culprit ...after that still not looking that good...although gfs tries to raise pressure somewhat as we go into November..

...however ecm still doesnt want to know with yet another stormy low..

...very wet October on the cards and beginning of November...got to hope that there is a change as we go further into November..

Maybe the anomalies can give us some hope..mmm ..well as of yesterday for 10 to 14 days they paint a westerly unsettled picture  with main trough centred further west...

 

 

 

 

More wet easterly strong gales in Scotland, hope this doesn't happen, they've had more than enough of this already.

[TSNWK]

2 hours ago, Aiden2012 said:

I’m liking the gfs 6z so far 

In what sense?

[Aiden2012]

2 hours ago, TSNWK said:

In what sense?

Generally colder and a little sneaky snow band coming through lol 

[Frigid]

2 hours ago, TSNWK said:

In what sense?

If you're after a chilly start to November, the 6Z looks decent. Bit of snow too for northern areas.

Max of 1C here, with snow would be a very notable cold spell for this early in the season.

[Methuselah]

No sign of any snow (thank God!) on this week's Met. Office Deep Dive: 

 

[ANYWEATHER]

Gfs is still toying with a southerly flowing jet..........

[Rain All Night]

Since the model outputs themselves are depressing at the moment, I'll post something else of interest. The ECMWF site is now publishing verification stats (only in 3-month aggregated form for now, covering June/July/August) for their regular model alongside the four machine-learning models whose outputs they are currently publishing.

https://charts.ecmwf.int/products/plwww_3m_fc_aimodels_wp_mean?area=Northern Extra-tropics&parameter=Geopotential 500hPa&player_dimension=area&score=Anomaly correlation

Legend
IFS = regular ECMWF model
AIFS = ECMWF's own machine-learning model
FourCastNet = Nvidia's machine-learning model
GraphCast = Google Deepmind's machine-learning model
Pangu-Weather = Huawei's machine-learning model

This article explains some of the basics around these models, including the key point that they are vastly quicker and cheaper to run than traditional atmospheric models - you can apparently run any of them on any normal computer that has a graphics card (GPU), provided you have access to the ECMWF's licensed starting data (which these models all depend on to be able to run), with the outputs available in minutes rather than hours - no need for a supercomputer. This opens the door to the possibility of ensemble forecasts generated with thousands of members rather than just dozens.

https://www.ecmwf.int/en/about/media-centre/science-blog/2023/rise-machine-learning-weather-forecasting

This second article explains that the ECMWF's machine-learning model uses the same approach as Google Deepmind's machine learning model, which is interesting as these appear to be the two top-scoring models.

https://www.ecmwf.int/en/about/media-centre/aifs-blog/2023/ECMWF-unveils-alpha-version-of-new-ML-model

You can view a selection of actual forecast charts produced by the machine-learning models every 12 hours here:

https://charts.ecmwf.int/?facets={"Product type"%3A["Experimental%3A Machine learning models"]}

Edited October 24, 2023 by RainAllNight

[Downburst]

26 minutes ago, RainAllNight said:

Since the model outputs themselves are depressing at the moment, I'll post something else of interest. The ECMWF site is now publishing verification stats (only in 3-month aggregated form for now, covering June/July/August) for their regular model alongside the four machine-learning models whose outputs they are currently publishing.

https://charts.ecmwf.int/products/plwww_3m_fc_aimodels_wp_mean?area=Northern Extra-tropics&parameter=Geopotential 500hPa&player_dimension=area&score=Anomaly correlation

Legend
IFS = regular ECMWF model
AIFS = ECMWF's own machine-learning model
FourCastNet = Nvidia's machine-learning model
GraphCast = Google Deepmind's machine-learning model
Pangu-Weather = Huawei's machine-learning model

This article explains some of the basics around these models, including the key point that they are vastly quicker and cheaper to run than traditional atmospheric models - you can apparently run any of them on any normal computer that has a graphics card (GPU), provided you have access to the ECMWF's licensed starting data (which these models all depend on to be able to run), with the outputs available in minutes rather than hours - no need for a supercomputer. This opens the door to the possibility of ensemble forecasts generated with thousands of members rather than just dozens.

https://www.ecmwf.int/en/about/media-centre/science-blog/2023/rise-machine-learning-weather-forecasting

This second article explains that the ECMWF's machine-learning model uses the same approach as Google Deepmind's machine learning model, which is interesting as these appear to be the two top-scoring models.

https://www.ecmwf.int/en/about/media-centre/aifs-blog/2023/ECMWF-unveils-alpha-version-of-new-ML-model

You can view a selection of actual forecast charts produced by the machine-learning models every 12 hours here:

https://charts.ecmwf.int/?facets={"Product type"%3A["Experimental%3A Machine learning models"]}

We live in interesting times to say the least. This is exciting.

[Metwatch]

=

[minus10]

Its normally the case for the gfs to blow up potent lows but how about this for 12z day 10 ecm.....

955 mb ??? Quite remarkable...and quite disruptive if this was to verify...

...needless to say.....

...so i think ecm is kind of ..er...losing it here at day 10...well it is day 10 but interesting to see....

..actually gfs12z for day 10 has this..

...so looking like a volatile period coming up either way...

 

Edited October 24, 2023 by minus10

[WYorksWeather]

GFS vs ECM 12z. Once again, seeing if we can find a way out of the mess we're in.

The ensemble charts show that the GFS keeps the 850hPa temperatures close to average for the next week, but falling below average into FI. The GFS operational is broadly in line with the ensemble. ECM is possibly a little cooler than average, towards the bottom of its ensemble pack, but not notably so.

 

At T+72, both GFS and ECM have a deep low positioned west of the UK.

 

At T+120, GFS deepens the low more significantly, but unsettled on ECM as well.

 

At T+168, both GFS and ECM have us in a gap between two areas of deep low pressure, but not really any sign of even a transient ridge.

 

At T+240, GFS has a 965mb low over the UK (which is the second low to pass over the UK between T+168 and T+240!). As others have highlighted, a similar setup occurs on the ECM as well, with a 960mb low.

 

Into the GFS extended, we see a transient ridge developing at around day 12.

 

After that, another low flies in, but there is some indication of another raise in heights at T+384.

Both GFS and ECM show substantial rainfall accumulations by T+240. Accumulations over eastern Scotland will of course be of particular concern given recent events. Some possibility of further heavy rainfall for central and/or northern England, though a little more disagreement over that.

 

Certainly looks like no quick return to settled conditions, still no sign of a raise of heights in the reliable timeframe.

[Mark wheeler]

4 hours ago, ANYWEATHER said:

Gfs is still toying with a southerly flowing jet..........

Its all too early, so sad , someone will be happy though.

[Don]

2 hours ago, Metwatch said:

=

Us humans are going to evolve into marine mammals at this rate, albeit less intelligent!

[Nick2373]

00z brings back the trend for something colder from the 03rd of November for a few days, Higher elevations could possibly see snow the further north you go. Seems to be some rain mixed in with theses days but as above snow higher you go. 

[carinthian]

Morning, some evidence from the models this morning that NE Britain will tap into some of that early cold air from Scandinavia ( as shown from the UKMO chart at 144t ).  The models at this stage indicate the colder wedge will only be limited as another Atlantic low heads towards NW Europe during the fist week of November. However, its worth watching if the cold now getting established over NE Europe can hold and intensify over the coming weeks and maybe possibly start to increase a chance to some cold. Meanwhile much of mainland Europe and here in the Alps well out of reach from any cold.

C

Edited October 25, 2023 by carinthian

[Midlands Ice Age]

19 minutes ago, carinthian said:

Morning, some evidence from the models this morning that NE Britain will tap into some of that early cold air from Scandinavia ( as shown from the UKMO chart at 144t ).  The models at this stage indicate the colder wedge will only be limited as another Atlantic low heads towards NW Europe during the fist week of November. However, its worth watching if the cold now getting established over NE Europe can hold and intensify over the coming weeks and maybe possibly start to increase a chance to some cold. Meanwhile much of mainland Europe and here in the Alps well out of reach from any cold.

C

Carinthian...

For fans of blizzards.....

I had picked up on this trend and was about to post something similar.

I was thinking along the lines of with very warm moist Atlantic air and a southerly focussed jet stream (and if the Scandinavian cold can hang on) we could be in a position (seeing what has just happened with Babet) that just may be a bit later on,  this could be the forerunner to one of those very major events in the  UK.

A lot of ifs there I know....

MIA

Edited October 25, 2023 by Midlands Ice Age

[carinthian]

16 minutes ago, Midlands Ice Age said:

Carinthian...

For fans of blizzards.....

I had picked up on this trend and was about to post something similar.

I was thinking along the lines of with very warm moist Atlantic air and a southerly focussed jet stream (and if the Scandinavian cold can hang on) we could be in a position (seeing what has just happened with Babet) that just may be a bit later on,  this could be the forerunner to one of those very major events in the  UK.

A lot of ifs there I know....

MIA

Yes.the wheels of fortune hardly ever favours The British Isles regarding tapping into Scandinavian Cold. I know the Swedes are getting excited about the  current early on set of snow and cold. If  it does really bite then the UK  has a fair chance of some real winter weather, but the wheel of fortune has to land against great odds ! Keeping fingers crossed.

C

Edited October 25, 2023 by carinthian

[Rain All Night]

Is this what you guys refer to as a "wedge"?