Model output discussion - 16th Nov onwards

[TSNWK]

I may have missed something but that doesn't quite make sense? The 00z ECM did turn zonal and stormy, MOGREPS and ECM ensembles support the ECM so why would it turn less zonal and stormy?

Me bad... I misread on phone. Sorry

[Frosty.]

The longer term signal is encouraging for coldies with temperatures either close to average or slightly below which indicates there will be plenty of polar maritime incursions and only short-lived milder interludes which is what the Gfs 6z op run shows and there is always the chance of the upstream pattern occasionally becoming more amplified  with an even colder arctic maritime blast similar to what we will have this weekend..Enjoy the wintry weekend.  

Edited November 20, 2015 by Frosty.

[nick sussex]

It looks like a period of very unsettled weather coming up next week with the PV pushed further south as the Alaskan ridge builds.

 

Theres very good agreement on this, the point of uncertainty is more to do with the angle of attack and whether the Siberian high can withstand the onslaught and hold on to help force the jet further se into mainland Europe. On the face of it the PV looks in an angry mood, the ECM in particular is very progressive, the GFS less so with the high remaining an influence.

 

Earlier the big 3 disagree at T144hrs, the UKMO is the main interest today from a colder perspective but has little support in terms of holding the pattern much further west. The GFS which was more bullish has gone off that idea and the ECM is again most progressive.

 

Part of the reason for the differences is how the models handle a low developing in the eastern Gulf of Mexico which runs ne. The UKMO has the strongest and more amplified low over the north east coast of the USA at T120hrs. You'll see the ECM is much flatter, with the GFS in between.

 

The PV and associated troughing near the UK is likely to verify the uncertainty more in relation to the Siberian high and any trough disruption into Europe. The ECM ensembles are pretty resolute in terms of supporting the unsettled PV driven outlook however you can see by the spread in terms of dew points which in turn can give an idea of the source of the flow that it might be making too much of high pressure building into southern Europe and its been too quick to blast the Siberian high away.

 

I think we're more likely to see more dig of the jet into Europe, and the Siberian high although battered and bruised not totally relenting.

 

 

[MP-R]

It looks like a period of very unsettled weather coming up next week with the PV pushed further south as the Alaskan ridge builds.

 

Theres very good agreement on this, the point of uncertainty is more to do with the angle of attack and whether the Siberian high can withstand the onslaught and hold on to help force the jet further se into mainland Europe. On the face of it the PV looks in an angry mood, the ECM in particular is very progressive, the GFS less so with the high remaining an influence.

 

Earlier the big 3 disagree at T144hrs, the UKMO is the main interest today from a colder perspective but has little support in terms of holding the pattern much further west. The GFS which was more bullish has gone off that idea and the ECM is again most progressive.

 

Part of the reason for the differences is how the models handle a low developing in the eastern Gulf of Mexico which runs ne. The UKMO has the strongest and more amplified low over the north east coast of the USA at T120hrs. You'll see the ECM is much flatter, with the GFS in between.

 

The PV and associated troughing near the UK is likely to verify the uncertainty more in relation to the Siberian high and any trough disruption into Europe. The ECM ensembles are pretty resolute in terms of supporting the unsettled PV driven outlook however you can see by the spread in terms of dew points which in turn can give an idea of the source of the flow that it might be making too much of high pressure building into southern Europe and its been too quick to blast the Siberian high away.

 

I think we're more likely to see more dig of the jet into Europe, and the Siberian high although battered and bruised not totally relenting.

 

 

 

Which outcome do you think is better for a return of cold conditions (not that the progged zonality is going to be particularly mild)? i.e. a resistant Siberian High or a full on PV attack?

[bradymk]

Snow cover chart from MetO model for tomorrow.

[nick sussex]

Which outcome do you think is better for a return of cold conditions (not that the progged zonality is going to be particularly mild)? i.e. a resistant Siberian High or a full on PV attack?

A resistant Siberian high most definitely because this can have implications later in the season on the PV, also if you hold that high and the models are overdoing the PV attack you might get trough disruption further west. The ECM T240hrs is definitely something you don't want to see!

[Mucka]

It looks like a period of very unsettled weather coming up next week with the PV pushed further south as the Alaskan ridge builds.

 

Theres very good agreement on this, the point of uncertainty is more to do with the angle of attack and whether the Siberian high can withstand the onslaught and hold on to help force the jet further se into mainland Europe. On the face of it the PV looks in an angry mood, the ECM in particular is very progressive, the GFS less so with the high remaining an influence.

 

Earlier the big 3 disagree at T144hrs, the UKMO is the main interest today from a colder perspective but has little support in terms of holding the pattern much further west. The GFS which was more bullish has gone off that idea and the ECM is again most progressive.

 

Part of the reason for the differences is how the models handle a low developing in the eastern Gulf of Mexico which runs ne. The UKMO has the strongest and more amplified low over the north east coast of the USA at T120hrs. You'll see the ECM is much flatter, with the GFS in between.

 

The PV and associated troughing near the UK is likely to verify the uncertainty more in relation to the Siberian high and any trough disruption into Europe. The ECM ensembles are pretty resolute in terms of supporting the unsettled PV driven outlook however you can see by the spread in terms of dew points which in turn can give an idea of the source of the flow that it might be making too much of high pressure building into southern Europe and its been too quick to blast the Siberian high away.

 

I think we're more likely to see more dig of the jet into Europe, and the Siberian high although battered and bruised not totally relenting.

 

 

 

Agree with all that nick,

The hope was that after UKMO stuck to its guns this morning ECM may give it a little support but that didn't happen and GFS appears to backing away as well.

Given that we would expect UKMO to be the model that falls into line this evening.

 

While it does appear 99% certain Dec will begin mobile I think some folk are overplaying the storminess for now.

Next week will not be stormy beyond some very usual wind and rain for the North toward weeks end.

Thereafter though there is potential for some real storminess as the mean trough digs SE as this gives potential for low pressure to form at the base of the trough and develop rapidly and then cross the UK.

Alternating milder/cooler SW,WNW flow, as is usual as systems pass through so pretty normal Dec fare on the cards for now, mobile, wet and windy.

[WillinGlossop]

Snow cover chart from MetO model for tomorrow.

Whats the scale on the map ie orange and reds etc? Looks good....

[Paul]

Snow cover chart from MetO model for tomorrow.

 

Not too dissimilar to our NetWx model. 

 

[fergieweather]

Whats the scale on the map ie orange and reds etc? Looks good....

Caution! Dont know who circulated that graphic...but that UKV considered overdone by Exeter although spatially ok. 2/3rds of that prog accumulation being followed. Amounts in S will be intensity-dependent.

[WillinGlossop]

Caution! Dont know who circulated that graphic...but that UKV considered overdone by Exeter although spatially ok. 2/3rds of that prog accumulation being followed. Amounts in S will be intensity-dependent.

Even 2/3rds of that would do me..... Latest gfs coming out....

[Captain Shortwave]

Day 5 charts

 

 

Well at least the UKMO has been consistent. A risk of wintry showers with the flow turning increasingly towards the north east by day 6 as the low becomes cut off to our south east. A Scandi high with a UK based battleground would be likely beyond this.

 

GFS

 

Quite a bit flatter, it does turn cooler but with temperatures near normal rather than anything cold after a brief spell of milder weather. The battleground here would probably set up over central Europe with the UK remaining in a westerly flow.

Edited November 20, 2015 by Captain shortwave

[Mucka]

Day 5 charts

 

 

Well at least the UKMO has been consistent. A risk of wintry showers with the flow turning increasingly towards the north east by day 6 as the low becomes cut off to our south east.

 

GFS

 

Quite a bit flatter, it does turn cooler but with temperatures near normal rather than anything cold after a brief spell of milder weather.

 

 

Yes UKMO sticking with the slower more amplified pattern which would be overrun no doubt but would also aid the Siberian high/Scandi ridge and all that goes with that.

 

Edited November 20, 2015 by Mucka

[SMU]

Mucka if you took UKMO at face value im not 100% sure it would be overrun-

 

Looks like a bit of disruption there- possibly enough to force an undercut-

 

S

[Geordiesnow]

In a way, what the UKMO and GFS shows are not too dissimilar in all honestly, they both show some sort of heights to the East of us with a slight ridge in the Atlantic, the UKMO is obviously a bit more amplified and slower thus a little bit colder also. 

 

Be interesting what the ECM model will show, continue with its own of the Atlantic racing through with no real signs of any height rises to the East? 

[knocker]

For what it's worth

Chart weatherbell

 

[nick sussex]

It would be great if the UKMO was the trend setter here. Normally its the "eat your greens " model, the one that's often resolute against colder ECM/GFS solutions and rarely does it prog a colder outlook which the others pick up on.

 

Unless the ECM backs it tonight then I'd be very dubious of its output, however in the spirit of hope heres my T168hrs projection of its output:

 

 

 

 

 

 

[Methuselah]

I think we should be dubious of all the model-output just now - the signals and their respective responses seem to be all over the place??

[Snipper]

Well for what it is worth, after ploughing through all the posts, I have decided that anything in my location is likely to be not too severe. So I have decided not to take all my fuscias into my greenhouse.

Unfortunately the usual excitement seems to be going bobbies up. Compared to what some posters are willing. Not expecting a nice day tomorrow but probably seen a lot worse. As a 1946 baby had the fun in past winters of riding down the local river on my bike in my location. Not very often I must admit. Like once. But everything seemed to be so much colder as I was growing up. Floods on the fields followed by very hard frosts so ice everywhere.

Probably not the right thread but I am not looking at any of them.

S

[Snipper]

Forgotten how to indicate my location.

In meantime it is central Essex

[nick sussex]

Indeed Nick, GFS an gem are shockers after this weekends cold. We need the ECM to back your T168 ukmo lol.....lows into Europe highs stretching from Scandinavia across top of uk with a low diving under......Please Santaâ„ï¸â„ï¸â„ï¸

Well I think its a long shot! Its likely there will be some trough disruption with a low dropping se into Europe but it might happen too far east, and even if the ECM backs the UKMO the PV is looking in a bad mood. Models are generally not great at trough disruption past T144hrs and will prefer to take energy ne not se especially when confronted by that fierce looking PV chunk. Not long now till the ECM!

[mb018538]

Just slightly reverting back to this weekends cold blast....does anyone know why the tmax forecast charts on the models are so badly wrong? They were constantly showing maxes of 2-3c here for saturday, which I just didn't buy at all. Yes it's a northerly, yes 850s are between -5 and -10....but it is still only late November! I just couldn't see it being that cold. In late Jan/Feb, by all means. BBC have shown 5-7c widely in the SE, which is much more what I was expecting from the given set up. Any reason at all??

[Snipper]

Forgotten how to indicate my location.

In meantime it is central Essex

Ok found it. I think?

[Singularity]

 

Look at that bubble of high pressure nosing across Svalbard on this GFS det. run at +192 hours. It kind of makes you wish the Atlantic trough was more submissive doesn't it?

 

As it is, the run goes on to deliver us the kind of relentlessly unsettled, variable-temperature westerlies that I warned off yesterday evening, as the Siberian High locks in that segment of the PV close to our N/NW. At the same time, though, the wave breaking into the strat continues in earnest. No pain, no gain 

 

 

There's that strange looking UKMO run to consider though. A remarkably clean drop of low pressure down toward Italy, achieved with the minimum of trough disruption during its Atlantic days. You could get a sort of 'easterly toppler' out of that but I'm not sure how cold it would be.

 

 

In the meantime, I'll be on the look out for a light snow shower soon after dawn tomorrow... it won't settle but seeing snow fall in November is an enjoyable novelty nonetheless - particularly after such a major run of mild conditions. 

[fergieweather]

Just slightly reverting back to this weekends cold blast....does anyone know why the tmax forecast charts on the models are so badly wrong? They were constantly showing maxes of 2-3c here for saturday, which I just didn't buy at all. Yes it's a northerly, yes 850s are between -5 and -10....but it is still only late November! I just couldn't see it being that cold. In late Jan/Feb, by all means. BBC have shown 5-7c widely in the SE, which is much more what I was expecting from the given set up. Any reason at all??

Yes: E4 was overdoing lying snow. Hence raw values were too low for various districts.