Model Output Discussion 01/09/17

[Dennis]

very blocking 

[Frosty.]

All you need to know about the week ahead..Boom....

And some nice Gfs 6z charts I didn't post earlier

 

[Timmytour]

58 minutes ago, Snowy L said:

 

This is why I can't stand anomaly charts. They build up hope with anomalies literally off the scale over Greenland yet in reality all that translates into is a little wobble in the jet.

Note that I can't stand anomaly charts but I don't find it easy to get a feel what's going on with them.

That's why I'm happy just to read Knocker's excellent analyses and interpretations and am pleased he posts them so frequently   

[Shunter]

2 hours ago, Steve Murr said:

GFS already backtracking now as the upper air cold pool expands over NW europe-

The SE corner doesnt lose the -6line

where as the 00z had it over debilt-

s

Seems the latest Met O Longer update supports your theory too Steve...

https://www.metoffice.gov.uk/public/weather/forecast/gcpvj0v07#?date=2017-11-14

[Northwest NI]

18 minutes ago, Frosty. said:

All you need to know about the week ahead..Boom....

And some nice Gfs 6z charts I didn't post earlier

 

Hating that last chart for 2nd Dec!

9 degrees in my area. Yuk

[nick sussex]

Looks like the models are latching onto the retrogression of the high with the ECM delivering an excellent evolution to locked in cold for some time to come.

Strong Arctic high and Greenland ridge in combination with sinking trough is very good, the GFS still not quite as interesting so something to bear in mind.

In terms of the upstream pattern a word of caution because the pattern in the east USA which allows the evolution to retrogress the high and then subsequently help the low to drop south is still uncertain. That's effected by an amplified trough heading in from the Pacific which impacts on how energy comes off the ne USA into the Atlantic.

The big 3 disagree upstream at T144hrs so still a lot to be resolved.

[Frosty.]

Holy ice cubes, sounds like there could be more northerly (arctic) outbreaks to come beyond the week ahead..very very encouraging update and model output if you love cold weather..right out to around mid December the potential is for wintry ppn with snow, ice and frosts so hopefully we will hit the ground running for the first few weeks of winter.!

Edited November 26, 2017 by Frosty.

[northwestsnow]

2 minutes ago, nick sussex said:

Looks like the models are latching onto the retrogression of the high with the ECM delivering an excellent evolution to locked in cold for some time to come.

Strong Arctic high and Greenland ridge in combination with sinking trough is very good, the GFS still not quite as interesting so something to bear in mind.

In terms of the upstream pattern a word of caution because the pattern in the east USA which allows the evolution to retrogress the high and then subsequently help the low to drop south is still uncertain. That's effected by an amplified trough heading in from the Pacific which impacts on how energy comes off the ne USA into the Atlantic.

The big 3 disagree upstream at T144hrs so still a lot to be resolved.

Yes Nick- EC is stunning today, no doubting that- the best news for all Exeter appear to be solidly behind that evolution - as requested the update today is quite a significant upgrade, and we all love a good upgrade

[bobbydog]

4 minutes ago, nick sussex said:

Looks like the models are latching onto the retrogression of the high with the ECM delivering an excellent evolution to locked in cold for some time to come.

Strong Arctic high and Greenland ridge in combination with sinking trough is very good, the GFS still not quite as interesting so something to bear in mind.

In terms of the upstream pattern a word of caution because the pattern in the east USA which allows the evolution to retrogress the high and then subsequently help the low to drop south is still uncertain. That's effected by an amplified trough heading in from the Pacific which impacts on how energy comes off the ne USA into the Atlantic.

The big 3 disagree upstream at T144hrs so still a lot to be resolved.

whilst the ECM is excellent, i do particularly like the GFS 06z...

[Polar Maritime]

Some post have had to be hidden. Can we please keep on topic, And only use the meto thread for discussion on there further outlooks.

Thanks.

Edited November 26, 2017 by Polar Maritime

[Captain Shortwave]

Add to that the regional threads for more local events

For example..... The GFS shows a few potential wintry events

Looks like the usual places fairing well, west Wales and the South west benefiting from showers off the Irish sea and particularly eastern England on Thursday as we see showers become heavier and more frequent, the chances of accumulations over the hills in Yorkshire perhaps and parts of East Anglia.

[JBMWeatherForever]

A very good further outlook from Exeter. Does anyone who watched the weather for the week ahead on the Beeb, just now, though, think like me, that they were underestimating the cold for later this week or do you think they are on the money. Just seemes that 6 or 7c for much of central and South East England on Wednesday and Thursday seems a bit generous  given the synoptic and likely airmass at that time ?

Edited November 26, 2017 by JBMWeatherForever

[dain_bramaged]

5 minutes ago, JBMWeatherForever said:

A very good further outlook from Exeter. Does anyone who watched the weather for the week ahead on the Beeb, just now, though, think like me, that they were underestimating the cold for later this week or do you think they are on the money. Just seemes that 6 or 7c for much of central and South East England on Wednesday and Thursday seems a bit generous  given the synoptic and likely airmass at that time ?

I think I am right in saying that these temps are for the city centres, which due the urban heat shield are usually 1-3 degress warmer than the surrounding countryside. 

Edited November 26, 2017 by dain_bramaged

[Winter-Chaser]

5 minutes ago, JBMWeatherForever said:

A very good further outlook from Exeter. Does anyone who watched the weather for the week ahead on the Beeb, just now, though, think like me, that they were underestimating the cold for later this week or do you think they are on the money. Just seemes that 6 or 7c for much of central and South East England on Wednesday and Thursday seems a bit generous  given the synoptic and likely airmass at that time ?

Any chance you can send me the link to this forecast please? keep seeing people talk about this "Exeter Forcast"  Thanks. 

[Frosty.]

9 minutes ago, JBMWeatherForever said:

Just seemes that 6 or 7c for much of central and South East England on Wednesday and Thursday seems a bit generous to say given the synoptic and likely airmass at that time ?

Temps would drop close to freezing in showers, especially if they are heavy and prolonged which could mean some wet snow to all levels as the arctic air digs south and those 6's and 7's are the early afternoon max so colder mornings and then colder from mid afternoon onwards with ice and frost quickly forming in the evenings and overnight periods...wintry

Edited November 26, 2017 by Frosty.

[Polar Maritime]

No more on BBC or meto extended foreast as per my plea a few post back as they will go missing.

Thanks again ☺

[Dancerwithwings]

2 hours ago, johnholmes said:

The two very high anomalies on the 500 mb chart shown are just that - anomalies to what the 500 mb pattern normally shows. Please be very careful when using anomaly charts and how you interpret them. They can and do give very useful guidance on the probable placement of upper ridges and troughs but they do need very careful assessments. I am not knocking anyone but just be careful. you will soon get used to a few who use them sensibly and if anyone has any questions then please pm me and I will do my best to answer you, or point you to someone who I feel could perhaps do it better than me. Rather than clutter up the model thread.

Hi, John,

I would PM you but I'm sure this would helps others that are not totally with it. 

In been told those charts can be very misleading and have no idea where the surface HP or LP may end up  confused!!!

But then it was mentioned and I always thought this was the case as (boddy dog) stated the two very high anomalies does show that it's very likely to be centred near to the 'black hole' (high anomalies)

Always you make it very clear (the two highlighted areas) and be careful/pinch of salt and all that goes with it.

Thank you.

 

Edited November 26, 2017 by Dancerwithwings

[Newberryone]

4 hours ago, BLAST FROM THE PAST said:

Talk about being miles off target?  Can you demonstrate that as I for disagree,

Again runs demonstrating cold continuing in varying degrees.  It is bound to get less cold at times but the opportunity for further surges of real cold remain very much on the table.  

 

BFTP

Wasn't meant to be taken quite so literally BFTP. Ever hear of Tongue-in-cheek? 

[knocker]

19 minutes ago, Winter-Chaser said:

Any chance you can send me the link to this forecast please? keep seeing people talk about this "Exeter Forcast"  Thanks. 

If you are talking about the 0-30 day it is here but it doesn't normally update until after 1500.

https://www.metoffice.gov.uk/public/weather/forecast

Edited November 26, 2017 by Polar Maritime
No more on meto forecasts please.

[knocker]

27 minutes ago, Dancerwithwings said:

Hi, John,

I would PM you but I'm sure this would helps others that are not totally with it. 

In been told those charts can be very misleading and have no idea where the surface HP or LP may end up  confused!!!

But then it was mentioned and I always thought this was the case as (boddy dog) stated the two very high anomalies does show that it's very likely to be centred near to the 'black hole' (high anomalies)

Always you make it very clear (the two highlighted areas) and be careful/pinch of salt and all that goes with it.

Thank you.

 

If you are talking about what I said perhaps I didn't explain myself very well. There is quite good example of what I mean with the chart that Catacol posted earlier. I shouldn't really post the other chart but what the heck it is just this once. You should be able to see by looking at the chart with contours how just the anomaly could be very misleading and in fact tells you very little really apart from the obvious.I must admit if I'd known it was going to cause all this fuss I wouldn't have bothered. But yes it would give you fair idea of the ridge but this wouldn't always necessarily be the case.

 

Edited November 26, 2017 by knocker

[bluearmy]

22 minutes ago, Dancerwithwings said:

Hi, John,

I would PM you but I'm sure this would helps others that are not totally with it. 

In been told those charts can be very misleading and have no idea where the surface HP or LP may end up  confused!!!

But then it was mentioned and I always thought this was the case as (boddy dog) stated the two very high anomalies does show that it's very likely to be centred near to the 'black hole' (high anomalies)

Always you make it very clear (the two highlighted areas) and be careful/pinch of salt and all that goes with it.

Thank you.

 

Black hole anomolys are very rare on ens charts beyond a week. they generally show on op charts and the slp's are available for those anyway. Once you get into extended range ens output, the data is only for guidance anyway! 

Edited November 26, 2017 by bluearmy

[gottolovethisweather]

43 minutes ago, JBMWeatherForever said:

A very good further outlook from Exeter. Does anyone who watched the weather for the week ahead on the Beeb, just now, though, think like me, that they were underestimating the cold for later this week or do you think they are on the money. Just seemes that 6 or 7c for much of central and South East England on Wednesday and Thursday seems a bit generous  given the synoptic and likely airmass at that time ?

Yes, but they do invariably quote city Temperatures which these days are said to be, up to 5 degrees higher than surrounding areas. The peak (if you can use that word) of the current week's interest for inland parts is around about Thursday. See my post here for more on that aspect. But if the 850s are to believed, they could be at snow producing values by then, even away from the hills. 

Edited November 26, 2017 by gottolovethisweather

[bluearmy]

The largest eps cluster in the extended range (45%),  develops a upper greeny high which unfortunately drifts off so far that it allows a west based neg NAO to bring in a souwesterly upper flow to nw Europe with associated low Anomoly persisting over the uk. Obviously that does provide for a spell of colder conditions here that would probably bring widespread snowfall before it became less cold. 

The other two clusters provide for mid Atlantic ridging and sceuro troughing as we head through second part of  week 2 though not much different to the evolution we are currently seeing played out I suspect 

Edited November 26, 2017 by bluearmy

[Polar Maritime]

NetW-MR in house model showing 2m avg temps for mid-day next Wed/T/F and snow risk. All subject to change at this range but a good guide.

Edited November 26, 2017 by Polar Maritime

[Methuselah]

Get ready, eyes down, fingers on buzzers - the GFS 12Z approacheth. Deal or no deal?