Model Output Discussions 12z 01/06/2017

[blizzard81]

I really do hope the GFS is barking up the wrong tree here

[Polar Maritime]

Again, Just model discussion please as more posts will have to be hidden.

Thanks.

[blizzard81]

5 minutes ago, Frosty. said:

Wow the 6z turns into a nightmare with trough after trough attracted to the uk like a swarm of bees to honey.

we needs gfs to be way off here

[Derecho]

2 minutes ago, blizzard81 said:

we needs gfs to be way off here

Worryingly its backed up by a number of ensemble members, 13 of them have a low over the UK at T196 - including the control run.

I'm off to Italy on July 22nd - I may have picked a good time!

[draztik]

34 minutes ago, blizzard81 said:

I really do hope the GFS is barking up the wrong tree here

Interestingly, GFS Control, GEFS mean and now even the GFS parallel... go for an unsettled spell which lingers well into wk 2 in stark contrast to the EPS. Makes for fascinating model watching.

[blizzard81]

9 minutes ago, Quicksilver1989 said:

Worryingly its backed up by a number of ensemble members, 13 of them have a low over the UK at T196 - including the control run.

I'm off to Italy on July 22nd - I may have picked a good time!

Oh dear. The 12z runs will be interesting to say the least. 

[blizzard81]

6 minutes ago, draztik said:

Interestingly, GFS Control, GEFS mean and now even the GFS parallel... go for an unsettled spell which lingers well into wk 2 in stark contrast to the EPS. Makes for fascinating model watching.

Luckily I have never rated the 06z run. Let's hope it is as abysmal as usual today

[Interitus]

The 0z ECM may appear more mobile with the low not lingering into next weekend, however it brings lower 850 temps on Thurs/Fri than any other model.

[Gael_Force]

31 minutes ago, draztik said:

Interestingly, GFS Control, GEFS mean and now even the GFS parallel... go for an unsettled spell which lingers well into wk 2 in stark contrast to the EPS. Makes for fascinating model watching.

There must be a similar solution on a number of the EPS to have this degree of spread.

[Ross Andrew Hemphill]

I don't think that Scotland is meant to have a prolonged spell of summer weather. Models are really moving away from what we all seen a few days ago, absolutely abysmal summer here so far...

[Frosty.]

The general outlook / extended still looks good for summery weather. Fine and warm early next week followed by heat and humidity for the s / se with a thundery breakdown followed by a couple of cooler changeable days before the azores high ridges in again, settling the weather down across the southern half of the uk and warming up again.. it may take a little while for northern uk to recover but I still think there is plenty to be positive about. I mentioned how horrible the Gfs 6z turned out but I'm not anticipating anything like that to develop and wreck the next few weeks of summer.

Edited July 14, 2017 by Frosty.

[Man With Beard]

And here is the problem:

    

There's a colossal difference in the way the entire ensemble suites are handling the trough. The GEFS is now a portfolio of dartboard lows over the UK by T162. On the ECM, I'm guessing no more than 20-30% of members go that way; on the ECM ensembles for London, after next Wednesday's thundery front, most members show flat-lines (i.e. zero) for rainfall until D15. 

The knock on further down the line is stark. Very rare to see such divergence between the means of the models:

      

Who's going to blink? If there's a middle ground, what would that be? 

[Frosty.]

Further to my post above, I firmly believe the azores high + continental weather will have a big part to play during the second half of this summer, especially for the south..so plenty of warmth / heat / sunshine and probably some thundery outbreaks during the weeks ahead together with occasional cooler changeable intervals..I still get nervous about posting my opinions for fear of ridicule but this is what I think will happen.

Edited July 14, 2017 by Frosty.

[Fourty Point Three Degrees]

GFS seems to have lost the signal and has been sent off the radar..  Its a bit like travelling on a train with a mobile phone and you enter a tunnel - you will lose signal but takes time to re-connect. GFS is the same, its entered its own tunnel and lost the signal.  It will take a few runs/days to pick back up and re-connect considering how strong the signal and support was for a rise of the Azores.

[Captain Shortwave]

1 hour ago, Man With Beard said:

And here is the problem:

    

There's a colossal difference in the way the entire ensemble suites are handling the trough. The GEFS is now a portfolio of dartboard lows over the UK by T162. On the ECM, I'm guessing no more than 20-30% of members go that way; on the ECM ensembles for London, after next Wednesday's thundery front, most members show flat-lines (i.e. zero) for rainfall until D15. 

The knock on further down the line is stark. Very rare to see such divergence between the means of the models:

      

Who's going to blink? If there's a middle ground, what would that be? 

Good new is historcally over the past few years these sinking lows have not verified, in that the breakdown next Wednesday which is now universally forecast is due to a low not sinking and becoming cut off but instead lifting out north east and merging with the incoming Atlantic trough.

One thing to look out for is the Scandi ridge and the WAA on this ridge, expect the models to slowly lose that negative tilt and intead we will see a more vertical tilt to the ridge and as such will allow the low in the Atlantic to steadily move east as the trough lifts out as per the ECM this morning. 

The UKMO/GFS/ECM day 6 charts.

      

Note how the ECM does not have that westwards push of WAA from the Scandi ridge. That is the key which shows the jetstream running over the top instead of cutting back on itself allowing the low to sink and become cut off like the GFS solution. The ECM still develops that cut off low but it is clear of the UK when this happens so not much of an issue there.

I do have reasonable confidence in the ECM solution with the Azores high pushing back in, but you never know and it would be sods law to see an area of low pressure sit over the UK with heights in every conceivable direction.

Edited July 14, 2017 by Captain Shortwave

[draztik]

25 minutes ago, 40*C said:

GFS seems to have lost the signal and has been sent off the radar..  Its a bit like travelling on a train with a mobile phone and you enter a tunnel - you will lose signal but takes time to re-connect. GFS is the same, its entered its own tunnel and lost the signal.  It will take a few runs/days to pick back up and re-connect considering how strong the signal and support was for a rise of the Azores.

Or the ECM, is, well, just wrong? GFS, from my knowledge can be wayward at times but usually returns kicking and screaming back towards the ecm.... but not this time. Output after output suggests its happy with the signal established. This afternoons runs will hopefully help us establish if the connection was stable or completely wonky. My gut tells me it has the evolution correct, on this occasion.

and let's be fair, the ecm does look rather isolated when compared to not only the GFS. That seems to have been forgotten. UKMO isn't exactly flattering ....

Edited July 14, 2017 by draztik

[mushymanrob]

the 06z gfs looks like it was compiled under the heavy use of alcohol. its one of the biggest messes ive ever seen, and whilst it might be picking up on the gist of things, its bonkers in its current form.

[blizzard81]

14 minutes ago, draztik said:

Or the ECM, is, well, just wrong? GFS, from my knowledge can be wayward at times but usually returns kicking and screaming back towards the ecm.... but not this time. Output after output suggests its happy with the signal established. This afternoons runs will hopefully help us establish if the connection was stable or completely wonky. My gut tells me it has the evolution correct, on this occasion.

and let's be fair, the ecm does look rather isolated when compared to not only the GFS. That seems to have been forgotten. UKMO isn't exactly flattering ....

The GFS stubbornly sticks to its guns even when it is hopelessly wrong. Lost count how many times I have seen this happen 

[knocker]

Quite intriguing the differences between the gfs and the ecm. I'm not privy to the upper air detail but in very simplistic terms the problems start pretty early in the runs.

At T120 the gfs has quite an intense elongated trough with a negative tilt running down to north west Iberia,This in a quite amplified pattern with strong ridging just to the east of the UK. Thus a double whammy vis eastward movement of the centre of the tough and bringing forces into to play to track it south east. The ecm for the same time has already deconstructed the trough and has much less amplification

Wind it on 48 hours and the twin HP surges have neatly nutmegged the upper low on the gfs which intensifies and is pushed down just NW of the UK. This doesn't apply to the ecm as the trough has already disassociated allowing the less intense low to move more to the east brushing aside the weaker ridging Well that's my take for what it's worth. 

Edited July 14, 2017 by knocker

[draztik]

5 minutes ago, blizzard81 said:

The GFS stubbornly sticks to its guns even when it is hopelessly wrong. Lost count how many times I have seen this happen 

folk quick to criticise gfs when it's not showing what they want.

Edited July 14, 2017 by draztik

[A Frayed Knot]

Well next week do look like some heat will build in the south then all goes downhill with even sever gales going by Netweathers weekly forecast by the honourable Michael Fish .

[blizzard81]

4 minutes ago, draztik said:

folk quick to criticise gfs when it's not showing what they want.

You are right in one respect. The GFS is not showing what I want but that wasn't the reason for my post. I was merely stating a fact. 

[knocker]

6 minutes ago, draztik said:

folk quick to criticise gfs when it's not showing what they want.

Or to be fair, any model.

[blizzard81]

Anyway, moving on. The latest met office update goes with the ecm way of thinking as we head into the last week of July. That's good enough for me. 

[cheese]

1 hour ago, draztik said:

folk quick to criticise gfs when it's not showing what they want.

It's shown unsettled weather countless times only for it to never verify - so people have every reason to be sceptical. Indeed, if every time GFS showed unsettled weather actually came to fruition then I'm sure this summer would have been a total washout already.  

Of course, it might be correct this time - no reason to totally discount it - but let's not pretend that you yourself don't have any vested interests. You always appear out of nowhere to bang on about unsettled weather in fantasy island. You did the same thing in July 2013 - so please drop this silly facade of being impartial and objective when you are anything but. 

Edited July 14, 2017 by cheese