Model Output Discussion - Autumn arrives

[damianslaw]

19 minutes ago, MattStoke said:

It’s pressure anomaly over 3 months rather than static, omnipresent areas of high pressure. You could have one month in a particular area which is dominated by low pressure and 2 months dominated by high pressure, giving a positive anomaly overall, for example.

That's true bit equally you would expect at least one other part of northern hemisphere to average out lower pressure than high.. unless I guess the polar vortex just holds in situ in one place over the Pole..

[summer blizzard]

37 minutes ago, damianslaw said:

This looks wrong. There is virtually no low pressure over whole northern hemisphere.

It's been the theme of the year so far, long settled spells, temporary unsettled ones which affect the north mostly. 

To me it looks like two different setups. 

Note over the US for example that we have a low over west Canada and high over east Canada. Now while it's possible to have a flat high underneath it seems more probable that we have a -PNA setup described but in at least month a fairly zonal setup.

You see the same thing over the Atlantic where it's possible to get that setup but more likely that the low near Iceland matches better to that high over Eurasia. It probably indicates in at least one month that the high in the Atlantic ridges north, hence the trough signal is weaker.

Being a La Nina year and that being a Nov-Jan period it perhaps would not shock me if we had the more amplified pattern dominant early and the flatter suggestion late.

[mb018538]

48 minutes ago, MattStoke said:

It’s pressure anomaly over 3 months rather than static, omnipresent areas of high pressure. You could have one month in a particular area which is dominated by low pressure and 2 months dominated by high pressure, giving a positive anomaly overall, for example.

Simon Lee also mentioned there is an issue with 500hpa seasonal forecasts overdoing +ve 500mb heights in the modern climate. Trying to find his excellent post on the reasoning!

[MATTWOLVES 3]

Quick one from me regarding tonight's ECM mean. The trend looks some of our friends,there is a clear signal for that uptick in pressure and the mean by and large agrees with the op. There also seems a fair bit of support for another warm up later on. Infact it looks a more solid mean and ens than the 0Z run.

Let's see where next week takes us...im sure the forums storm chasers who are not posting much on this thread just lately (unfortunately) are getting twitchy fingers..I hope something comes off for you guys and gals.

Truelly remarkable Summer for many reasons this year..some for the good some for the bad...only thing missing is a good old storm...Heres hoping.

[minus10]

Just noticed that the ecm 12z 240 chart is not that different to the anomalies that Mushy posted earlier for the 8 to 14 day period.....

[clark3r]

8 hours ago, tight isobar said:

Had- to drop in 1 last time this amazing summer.. and the gift that likely keeps on giving “ to those whom like such “.. enjoy the cool down and some possible storm/ rain activity!.. because the heat is almost BOUND to bounce bk last 3rd.. and perhaps we’ll into September!! Everything now aligned ( and will likely solidify furthermore).. enjoy your day.. no matter ya preference it’s a definiate ciao for now see you when autumn decides to poke its nose in... could be a fare while

This guy has been spot on with heatwave forecasts so far this summer, so I agree and have seen some evidence of this in some gfs ecm runs 

[damianslaw]

14 minutes ago, MATTWOLVES said:

Quick one from me regarding tonight's ECM mean. The trend looks some of our friends,there is a clear signal for that uptick in pressure and the mean by and large agrees with the op. There also seems a fair bit of support for another warm up later on. Infact it looks a more solid mean and ens than the 0Z run.

Let's see where next week takes us...im sure the forums storm chasers who are not posting much on this thread just lately (unfortunately) are getting twitchy fingers..I hope something comes off for you guys and gals.

Truelly remarkable Summer for many reasons this year..some for the good some for the bad...only thing missing is a good old storm...Heres hoping.

Think this summer has caught many out.. just like last winter being so dry and mild. Interesting ho compare to the last equally hot August nationwide, 2003. From memory the heat came back in  September albeit short lived. 

Edited August 14, 2022 by damianslaw

[northwestsnow]

Well we don't have a Winter 2022 thread but the  August update from the LRF's aren't a disaster at this stage...

Edited August 14, 2022 by northwestsnow

[seb]

7 hours ago, northwestsnow said:

Well we don't have a Winter 2022 thread but the  August update from the LRF's aren't a disaster at this stage...

Depends on your view.

7/8 indicate anomalous high pressure which will do nothing for the drought situation. Remember, many parts need in excess of 150% of the average Aug-Mar rainfall to kind of get back to normal.

If you’re hoping for an autumn and winter with calm weather then it looks like your wishes will be granted.

Temps, contrary to what one would expect with the above average high pressure and blocking patterns currently predicted, are indicated to be above average with a 60-70% probability. 

That’s good news for energy bills but not so much for those who look forward to a cold winter.

[PiscesStar]

4 minutes ago, seb said:

Depends on your view.

7/8 indicate anomalous high pressure which will do nothing for the drought situation. Remember, many parts need in excess of 150% of the average Aug-Mar rainfall to kind of get back to normal.

If you’re hoping for an autumn and winter with calm weather then it looks like your wishes will be granted.

Temps, contrary to what one would expect with the above average high pressure and blocking patterns currently predicted, are indicated to be above average with a 60-70% probability. 

That’s good news for energy bills but not so much for those who look forward to a cold winter.

I for one LOVE Cold weather but we are on an undeniable warm up hoping subsequent runs relent a little. 

[seb]

Really could not make it up. Latest blended modelling gives the SE corner of the UK a grand total of 2-4mm in the next 8 days. Even UKV (haven’t looked at it but am just going by the MetO app) seems to have removed everything today and tomorrow with a small chance of something convective on Wednesday. MetO forecast text a bit more positive.

[mb018538]

Plenty more heat on offer on the 00z GFS run from day 6 and beyond - though most of this is now concentrated towards the S/SE.

[mb018538]

ECM 00z shows the first heavy/active frontal system to cross the entire UK in what is literally months next Sunday - giving all areas a really good & much needed soaking.

[Gordon Webb]

8 minutes ago, mb018538 said:

ECM 00z shows the first heavy/active frontal system to cross the entire UK in what is literally months next Sunday - giving all areas a really good & much needed soaking.

certainly hope so , as even this breakdown looks a little more benign than expected

[Guest]

24 minutes ago, mb018538 said:

ECM 00z shows the first heavy/active frontal system to cross the entire UK in what is literally months next Sunday - giving all areas a really good & much needed soaking.

Hopefully not ECM embarrassing itself again with its overzealous precip forecasts.....although to be fair GEM dumps widely 20-40mm this weekend too. 

[mb018538]

10 minutes ago, Alderc said:

Hopefully not ECM embarrassing itself again with its overzealous precip forecasts.....although to be fair GEM dumps widely 20-40mm this weekend too. 

Could be quite heavy given the airmass is tropical/very warm & likely to contain plenty of precipitable water. Still needs nailing down though with regards to timing and track - GFS swings it away to the north and the south misses most of the heavy stuff.

[seb]

23 minutes ago, Alderc said:

Hopefully not ECM embarrassing itself again with its overzealous precip forecasts.....although to be fair GEM dumps widely 20-40mm this weekend too. 

Unfortunately the GFS moves most of it further north so at this point there is so consensus. As for GEM, while often useful, if its predicted rainfall amounts had come off over the last thee months then we would be in a far less severe drought situation than we currently are.

[Cambrian]

11 hours ago, MattStoke said:

It’s pressure anomaly over 3 months rather than static, omnipresent areas of high pressure. You could have one month in a particular area which is dominated by low pressure and 2 months dominated by high pressure, giving a positive anomaly overall, for example.

This is very interesting. Thank you for posting it. 

It’s a striking hemisphere-wide positive anomaly, taken on its own it makes a mockery of the long term average, and might either be ominous for our normal valuing and use of Glosea for this coming winter, or just plain ominous - for water supplies and a raft of other related issues. 

  

Whichever, it fits with the continuation of what we’ve seen this summer, in the trajectory to day 16 on the 0z GFS ensemble mean anomaly, positive heights so strongly in prevalence as has become commonplace - the same would be the case for any run that I might have picked for months; and the extended 0z GFS to mid September, get past the next few days, the mean pressure typically staying around 5mb higher than the 1013mb average.

Edited August 15, 2022 by Cambrian

[mushymanrob]

10 hours ago, minus10 said:

Just noticed that the ecm 12z 240 chart is not that different to the anomalies that Mushy posted earlier for the 8 to 14 day period.....

............ and the latest 8-14 day chart intensifies the high to our East. We have to be in plume teritory here..

[mountain shadow]

10 hours ago, northwestsnow said:

Well we don't have a Winter 2022 thread but the  August update from the LRF's aren't a disaster at this stage...

That is an impressive signal for a mid atlantic high across the suite of models at this range. 

As many have said though, it would be bad for getting water levels back up.

[Earthshine]

Warm.  Not really much more to say?

[Guest]

36 minutes ago, Earthshine said:

Warm.  Not really much more to say?

ECM ensembles look pretty similar although its mean is a bit more unsettled as through the weekend as it digs the low pressure down over the UK a little more. Plenty of ensemble members there afer lift back into the mid teens range to give high 20's, low 30's across the south again for quite an extended period. 

[Don]

5 hours ago, seb said:

Depends on your view.

7/8 indicate anomalous high pressure which will do nothing for the drought situation. Remember, many parts need in excess of 150% of the average Aug-Mar rainfall to kind of get back to normal.

If you’re hoping for an autumn and winter with calm weather then it looks like your wishes will be granted.

Temps, contrary to what one would expect with the above average high pressure and blocking patterns currently predicted, are indicated to be above average with a 60-70% probability. 

That’s good news for energy bills but not so much for those who look forward to a cold winter.

I believe the long range models do have a tendency to sometimes over do the temperatures though, as like you say, they do not really tie in with the pressure patterns.

[MattStoke]

Not much rain for the south on the GFS and pretty warm throughout for the south east with only one cool day on Thursday. It then really goes for high pressure building in next week once again. Clearly a strong signal for the high to build in around the 25-26th.

[Guest]

Nice GFS 06Z, pretty much 30C in the south every day from next Monday until the end of the run. Perfect and 25-27C before then. Good chance the CET record would go if the 06Z came off.