model discussion Model output discussion - the final third of Autumn

[I remember Atlantic 252]

cool NW'lys then my guess for mid month

[Methuselah]

27 minutes ago, BLAST FROM THE PAST said:

3x 20  60 Yr cycle, do some reading and digging for info rather than do some inane side wiping ‘digging’ . Might  help

 

BFTP

[legritter]

Great forum gang ,snoooow will come .as for current charts ,nothing to get excited about yet .Perhaps the advance guard of winter is brewing .sausage baps tomorrow as i have no baps today , we need some good 10 day charts to wet our appetite, Boxing day 1962 would be nice ,but as rare as a three humped camel ,photo attached, cheers gang .

[Mike Poole]

ECM 12z clusters, and at T192-T240 we have these two:

Neither are zonal, of course we wouldn’t expect that given the longer term pattern, they differ in the position of the blocks that affect the UK, cluster 1 marginally to the east, cluster 2 marginally to the west.  Red v purple on the chart borders!  

T264+

From a cold perspective I’m happy with either 2 or 3 given we know that any proper cold pattern is beyond T240.  The potential is there, it is just a question of how the dice fall…

[MATTWOLVES 3]

7 hours ago, swfc said:

I've not heard of it tbh. Is it linked to the mfi or b+q

Tbh mate I think you will find the b n q is a DIY store,and has no place for discussion on a weather forum

On a more positive note tonight's ecm was a little optimistic regarding 850s...it looks well out of place.

But there is agreement for pressure to rise so perhaps more settled towards day 10....i will take that over non stop rain anyway!

Know point in getting to stressed over current sypnotics at this stage of the month regarding the upcoming Winter. Whatever pattern we have right now won't necessarily mean anything to what pattern we may be looking at come next month!

So in 4 weeks time....its then game on...

And let's make the countdown to Xmas a memorable one folks.

The very best of Health to you all.

 

[Frosty.]

The longer term ECMWF 12z ensemble mean tonight pretty much mirrors the operational in showing high pressure building in across at least southern u k with probably an increasing risk of overnight / early morning fog….I’ve mentioned quite a few times fairly recently about heights to the south becoming more influential and that seems to be the case going forward. ️ ? 

 

[Ali1977]

22 minutes ago, jon snow said:

The longer term ECMWF 12z ensemble mean tonight pretty much mirrors the operational in showing high pressure building in across at least southern u k with probably an increasing risk of overnight / early morning fog….I’ve mentioned quite a few times fairly recently about heights to the south becoming more influential and that seems to be the case going forward. ️ ? 

 

Not too far away from the GEFS mean to be fair, so I think we can assume this is pretty accurate - Let’s hope in a few days the 10 day means on both are starting to look a little colder with some more prevalent blocking appearing to our north!! 

[Ali1977]

The control and P5 looking nice, not much cold showing in the Op this morning though

Edited November 4, 2021 by Ali1977

[mulzy]

8 hours ago, jon snow said:

The longer term ECMWF 12z ensemble mean tonight pretty much mirrors the operational in showing high pressure building in across at least southern u k with probably an increasing risk of overnight / early morning fog….I’ve mentioned quite a few times fairly recently about heights to the south becoming more influential and that seems to be the case going forward. ️ ? 

 

Pretty much ties in with ECMWF sub-seasonal.  The real interest is what happens next - do heights remain persistent to the south or do they drain away leading to height rises to the north-west?

[mb018538]

Latest forecasts showing that the MJO isn't going to make it at the moment....probably Nina putting the brakes on. So any assistance from this is now going to be pretty much non existent.

The weather looks settled for many out to mid month (NW/SE bias, NW areas will still see bouts of heavy rain), then we have some potential for things to turn more unsettled once again:

 

[Don]

36 minutes ago, mb018538 said:

Latest forecasts showing that the MJO isn't going to make it at the moment....probably Nina putting the brakes on. So any assistance from this is now going to be pretty much non existent.
 

That's a shame.  Perhaps later in the month/December for any marked changes to the pattern?

Edited November 4, 2021 by Don

[bluearmy]

Looks like quite an amplified pattern in a fortnight but where the pieces of the jigsaw fall is uncertain …..ridge or trough to our east ????

[mb018538]

8 minutes ago, Don said:

That's a shame.  Perhaps later in the month/December for any marked changes to the pattern?

With regards to the MJO - there's the possibility it could move into phase 5 later into November which could amplify things once again, though it's hard to say at present. With a La Nina developing it usually puts the MJO to the sword, and it isn't as much of a player.

Certainly the risk of anything significantly cold is off the table for the next fortnight.

[Weather vane]

The models have done a good job at forecasting the upcoming heights into central/NW europe, which they picked up on at least a week ago if not more. We often complain about the flipping and flopping, but there has been remarkable consistency with the incoming settled spell.

[Wimbledon88]

8 minutes ago, Weather vane said:

The models have done a good job at forecasting the upcoming heights into central/NW europe, which they picked up on at least a week ago if not more. We often complain about the flipping and flopping, but there has been remarkable consistency with the incoming settled spell.

True enough. Though to be fair, next door's cat could have a fair go at forecasting the semi permanent area of high pressure to the south of UK and Ireland. 

[Weather vane]

2 minutes ago, Wimbledon88 said:

True enough. Though to be fair, next door's cat could have a fair go at forecasting the semi permanent area of high pressure to the south of UK and Ireland. 

True enough, though not necessarily the hp across Europe which has come after a very significant northerly plunge of the jet. To me, I thought that scenario could easily lead to further NW driven southerly dips in the jet, but not so.

[jules216]

The importance of MJO is not only if its in a certain phase in Indonesia(4,5) but also the movement of the Rossby wave train Across from south America to Atlantic,where in this image in week two the blue colors of VP should be replaced by yellows and reds, if we neutral or no color it will hardly amplify pattern to our desired result, more less a tug of war between temporal amplification that soon gets flatened. I had spent some time observing MJO waves in Ninas that brought good cold spells in late autumn like years 1995,1998,2005 etc. And they almost all reached up to phase 7 at least. We need those +FT and +MT for +AAM to slow down mid lats westerlies as Nina seasonal wavelenghts will eventually get less and less amplified the longer the Pacific standing wave of subsidence persists.

 

[jules216]

Here an example of 2005 when MJO made it through to phases 5-8 in Nov. See how amplified the flow got.

[Frosty.]

I found some nice 0z perturbations for all the coldies as we head towards what will hopefully be a memorable winter, in a cold way!!    

[Cambrian]

Though there is agreement for a build of pressure first from the southwest (which we’re seeing now on a beautiful crisp morning), influencing our weather further over the next few days, this then gets squeezed south a bit by a low pressure passing west-east near Iceland, with notable differences between the models by 168h in respect of the intensity and northward extension of the reassertion of the high pressure from the south once the low goes by, which effects how long it is modelled to ultimately stick around. 

The 0z ECM and GFS operational runs (and the 6z GFS op too by the look of it) favour a quite stubborn high, holding its ground, with pressure 1025mb+ into the south, which serves to keep it settled out  to 240h and beyond.

ECM 168h / 240h

 

GFS 168h / 240h

 

 

The 0z GEM op at 168h is not quite so bullish with pressure around 1020mb, and by 216h has us under a low pressure.

 

The 0z UKMO extended has pressure in the south lower than 1020mb at 168h and is more progressive in bringing the next low in from the Atlantic to mingle with the complex low over Iceland, and is also keener on deepening it too, with an unsettled few days looking to follow, rather more like GEM.

 

So though it’s solidly looking like setting down a bit for a few days pleasant weather, especially in southern parts, there is a good deal less certainty after day 6 regarding how long the spell of quiet weather might last.

Edited November 4, 2021 by Cambrian

[Methuselah]

43 minutes ago, jon snow said:

I found some nice 0z perturbations for all the coldies as we head towards what will hopefully be a memorable winter, in a cold way!!   

And here's this morning's GFS 06Z at T+228. I remain quite unperturbed!

   

[Frosty.]

Looking at the Gfs 6z operational, let’s get all the remaining largely benign autumnal rubbish out of the way before winter proper starts…but what’s this…a coolish high?!  

 

[damianslaw]

3 hours ago, jules216 said:

The importance of MJO is not only if its in a certain phase in Indonesia(4,5) but also the movement of the Rossby wave train Across from south America to Atlantic,where in this image in week two the blue colors of VP should be replaced by yellows and reds, if we neutral or no color it will hardly amplify pattern to our desired result, more less a tug of war between temporal amplification that soon gets flatened. I had spent some time observing MJO waves in Ninas that brought good cold spells in late autumn like years 1995,1998,2005 etc. And they almost all reached up to phase 7 at least. We need those +FT and +MT for +AAM to slow down mid lats westerlies as Nina seasonal wavelenghts will eventually get less and less amplified the longer the Pacific standing wave of subsidence persists.

 

Interesting to note how La Nina interacts with MJO.. I don't understand the factors why it can aid amplification in some cases I.e. MJO phase 7 to 1.. and other times doesn't promote much movement is it stays below 6 which instead results in mid Atlantic heights waxing and waning but don't ridge far enough north to bring anything especially cold from the north.

Interesting to note the MJO and how ot behaved in 1995, 1998, 2005. All brought northerly airstream second half of the month, brief but quite potent especially 2005. The following Decembers were quite different though, 1995 started very mild but then became cold and stayed mostly so through to the end; exceptionally so later on. 1998 brought another northerly early Dec but the rest of the month was mild and Atlantic driven. 2005 was often settled and quite cold at times with lots of high pressure. A brief easterly after Christmas. 

As said I think we need to give the models a few days before we can see how things might pan out more clearly through middle of the month and into latter part. 

[mb018538]

7 minutes ago, damianslaw said:

Interesting to note how La Nina interacts with MJO.. I don't understand the factors why it can aid amplification in some cases I.e. MJO phase 7 to 1.. and other times doesn't promote much movement is it stays below 6 which instead results in mid Atlantic heights waxing and waning but don't ridge far enough north to bring anything especially cold from the north.

Interesting to note the MJO and how ot behaved in 1995, 1998, 2005. All brought northerly airstream second half of the month, brief but quite potent especially 2005. The following Decembers were quite different though, 1995 started very mild but then became cold and stayed mostly so through to the end; exceptionally so later on. 1998 brought another northerly early Dec but the rest of the month was mild and Atlantic driven. 2005 was often settled and quite cold at times with lots of high pressure. A brief easterly after Christmas. 

As said I think we need to give the models a few days before we can see how things might pan out more clearly through middle of the month and into latter part. 

On the whole, a fairly strong Nina event like we're seeing develop again just disrupts the MJO cycle and it's influence. Cooler Pacific waters just kill it off before it can propagate further east. 

[Don]

10 minutes ago, mb018538 said:

On the whole, a fairly strong Nina event like we're seeing develop again just disrupts the MJO cycle and it's influence. Cooler Pacific waters just kill it off before it can propagate further east. 

Could it be that the developing Nina may be too strong to give a front loaded winter?