Model Output Discussion - heading into April

[Guest]

That's a very slack picture on the GFS @ T180, you'd expect either a trough from the north west or one to south to form and move over the UK from there. 

[Methuselah]

This 12Z is getting rather good, peeps. And no sign of any energy-sapping heat!

    

[mb018538]

4 minutes ago, Mike Poole said:

I made that mistake yesterday, Zak!  Easily done when the runs are coming out fast.  GFS quite different to UKMO and ICON, looks like continuation of the settled weather with very little impact of the trough feature, T162:

Indded @Mike Poole. GFS sends the trough harmlessly down to the west of Iberia.

[Mark wheeler]

Blimey I’ve only just seen the UKMO this afternoon. What a beauty .

Edited May 24, 2020 by Mark wheeler

[MATTWOLVES 3]

22 minutes ago, Leo97t said:

Yes worth remembering how dry soil means lapse rates are way way higher at the moment than normal although I'm quite perplexed at the temperatures the GFS is predicting (21-23C) - should be higher than that.

Very different to the BBC with 25-27 for all this week in London

I think the Beeb are about right, they won't just be analysing GFS when it comes to those temps.. And let's face it GFS nearly always undercooks em.. I would have thought 25-28C in more S/SE areas looks a good call through next week. 

Edited May 24, 2020 by MATT☀️

[mb018538]

GFS is always under by a few degrees. It’s so bad I wouldn’t even bother using it. ARPEGE is much better.

[Mike Poole]

21 minutes ago, mb018538 said:

Indded @Mike Poole. GFS sends the trough harmlessly down to the west of Iberia.

I'm not sure that is the same feature, compare GEM at same time T168, which also shows that, but also the feature in close proximity to the UK too, as per UKMO?

[MATTWOLVES 3]

I'm liking the GEM.. I can't see much unsettled conditions from those charts.. Orange and reds are the new in colours for this season..

[Zak M]

I'm liking the GEM tonight!

It has a blip of unsettled weather on day 7 but after that HP dominates again

Edited May 24, 2020 by Zak M

[Mike Poole]

The reason I'm fascinated by the cut off low scenario, that first cropped up yesterday on some models, is similarity with summer 2018.   Take the GEM at T204 (and ICON and UKMO would probably head in a similar direction by this point):

Now look at June 2018, reds are stronger because it is a month later, but looks similar to me:

That was the heat pump that kept on giving!

[Methuselah]

I must admit that I'm a tad worried by the 12Z at T+327...even though it probably won't happen!

    

[Mike Poole]

GEM run finished now, and I tell you what if this happens then heat for the first month of summer is locked in, in my opinion.  

Jet stream T240;

UKMO and ICON were headed the same way, as earlier post....

[Guest]

GFS 12Z Ops run swan dives from the high platform from about 324hrs and becomes a ridiculous outlier. Honestly not sure why GFS shows its output beyond 240hrs, its as much use as snooze button on a smoke alarm!

[Allseasons-Si]

The gefs mean is going to be a good one folks,it's already a lot warmer than the 06z.

and there it is...

compared to yesterday's 12z

the op still having it's wobbles in la la land though.

Edited May 24, 2020 by Allseasons-si

[chrisbell-nottheweatherman]

15 minutes ago, Mike Poole said:

GEM run finished now, and I tell you what if this happens then heat for the first month of summer is locked in, in my opinion.  

Jet stream T240;

UKMO and ICON were headed the same way, as earlier post....

How often have we heard such predictions based on a single model run, especially in winter?  Suggesting that we can be highly confident or certain at nearly a months' range is surely inadvisable?

[MATTWOLVES 3]

4 minutes ago, chrisbell-nottheweatherman said:

How often have we heard such predictions based on a single model run, especially in winter?  Suggesting that we can be highly confident or certain at nearly a months' range is surely inadvisable?

In fairness to Mike he does tend to way up a fair few options with his predictions.. And tbh, there are others in the game who seem to think June will be not only just settled, but probably above av temps also.. And these guys see far more than we do. Even so any predictions beyond 10 day's is total chaos, and it can quickly go wrong, but at this stage the early signs do look promising. 

[Mike Poole]

Just now, chrisbell-nottheweatherman said:

How often have we heard such predictions based on a single model run, especially in winter?  Suggesting that we can be highly confident or certain at nearly a months' range is surely inadvisable?

Well it isn't one model run.  As I said the UKMO and ICON were similar as far in time as they went, and also it is consistent with the 'background signals' a term that I know some people hate!  As long as AAM remains above average, ridging to the east is possible, and we have a reinforcing pattern re SSTs in the Atlantic.  

Now:

A month ago:

Positive feedback, the cooler area is cooler now, and the warmer area from Azores to Southern UK is warmer, the differential is much more pronounced now.  This should make the jet stream take a SW -> NE trajectory and that is what the GEM run showed clearly.  ECM in 23 minutes, bet me it won't follow?

[Allseasons-Si]

And here it is in all it's glory,what's not to like about this mean,oranges all the way

[mb018538]

GFS mean looks great tonight - spoiled yet again by the Dominic Cummings op run - gone miles away from everyone else when it should have been close to home.

[chrisbell-nottheweatherman]

7 minutes ago, Mike Poole said:

Well it isn't one model run.  As I said the UKMO and ICON were similar as far in time as they went, and also it is consistent with the 'background signals' a term that I know some people hate!  As long as AAM remains above average, ridging to the east is possible, and we have a reinforcing pattern re SSTs in the Atlantic.  

Now:

A month ago:

Positive feedback, the cooler area is cooler now, and the warmer area from Azores to Southern UK is warmer, the differential is much more pronounced now.  This should make the jet stream take a SW -> NE trajectory and that is what the GEM run showed clearly.  ECM in 23 minutes, bet me it won't follow?

I'm not disputing your thesis, more the unwarranted rejection of the inevitable margin of error, and the notion that any of us can accurately predict the weather a month from now, as opposed to the general trend which does seem clear.

[Mike Poole]

6 minutes ago, chrisbell-nottheweatherman said:

I'm not disputing your thesis, more the unwarranted rejection of the inevitable margin of error, and the notion that any of us can accurately predict the weather a month from now, as opposed to the general trend which does seem clear.

Of course there is uncertainty, I'm the first to admit that, it is one of the reasons I'm interested in weather anyway, I'm interested in uncertainty.   On a monthly timescale, all I am claiming is the general trend really, which you agree from what you say, so I am not sure what we are disagreeing about?

Edited May 24, 2020 by Mike Poole

[Methuselah]

The GFS 12Z op really is the runt of the litter, tonight:

    

    

As Mike (was it Mike?) said earlier: the line between 'stonking' and 'crap' is a very fine line indeed!

[chrisbell-nottheweatherman]

16 minutes ago, Mike Poole said:

Of course there is uncertainty, I'm the first to admit that, it is one of the reasons I'm interested in weather anyway, I'm interested in uncertainty.   On a monthly timescale, all I am claiming is the general trend really, which you agree from what you say, so I not sure what we are disagreeing about?

Fair enough - I think my argument is regarding semantics.

[Mike Poole]

ECM T96, with GEM and GFS for comparison 

Seems more inclined with the trough intrusion, let's see what happens next...

[Zak M]

What a gem!!

12z ECM @120

   

Edited May 24, 2020 by Zak M