Model output discussion 14/04/18

[mushymanrob]

19 hours ago, mb018538 said:

Just digging this up from Saturday - not to have a go at @johnholmes at all or anything like that, more to illustrate the fact that the anomaly charts are only as good as the current data that is being fed into them. Only 3 days ago there was no suggestion of any sort of strong anticyclone building.....and that has quickly changed. So while these charts are useful a lot of the time, sometimes they aren't!

i disagree about no suggestion of any high pressure building. there has been a gradual build of pressure for a while now, but not strong enough to develop a large pressure build.  i actually mentioned this some time ago.

the anomaly charts rarely send you up the garden path, and whilst the gfs can sometimes spot a change before the anomaly charts do, like this time, its fi predictions are proven inaccurate time and time again.

its extremely rare for a large pattern change within 6 days to occur without the noaa charts picking up on this.

so i for one will carry on viewing them first, then ill see which op run is closest, that way is the best way of discovering the most likely pattern we will get in the 6-14 day period. no garden paths, no false hope, just reality.

[Frosty.]

Stunning Gfs 6z..here are the gorgeous charts!

[Weather-history]

Manchester ensembles are very dry

[Guest]

The GFS 06Z Ops run was in top quatile from the ensembles however was in no way at an any time an outlier with the mean being dragged down by a couple of members which look hugely out of touch. One thing I find promising in the ensembles is that there is no huge spikes followed by an abrupt crash indicating a rapid trough disruption and eastwards shunt of the heat. While there's almost no thundery weather anticipated yep there is plenty of time for that to develop, lets get a lengthy spell of heat going first and worry about TS activity later. 

[mb018538]

@mushymanrob I disagree slightly - john holmes knows his stuff and can interpret these charts as good as anyone else - he clearly said:

'Looking at the latest 6-10 day 500 mb anomaly output suggests that any upper ridging is a short lived affair with a mainly westerly pattern showing. You can see this, albeit certainly not cast in stone, on this morning's ECMWF if you play the previous chart from yesterday. This has a marked +ve ehight anomaly this morning no sign. NOAA also shows this over the past 2 days or so. I generally take NOAA as the most reliable with EC following and GFS some way behind unless it is similar to the other two. No GFS either yesterday or today on the link I have. The 8-14 NOAA similar to the 6-10. To me it remains looking like a NW-SE split on average through the next 2 weeks. Obviously they are 'mean' charts and some divergence on occasasional days will occur but no major difference over the period as a whole.'

Which is what we were shown - transitory Azores ridging, better in the SE compared to the NW, broadly westerly, temps probably 15-23c. Certainly no sustained imminent settled/hot spell. 
A couple of days later and we could possibly end up with a 5 day+ heat wave with temperatures potentially into the upper 20's/ low 30's. Completely different if you ask me.
The anomaly charts are good as a broad schematic, and most of the time are pretty accurate, but they can be subject to unexpected changes such as going on now. They are only as good as the data available when they are made, so if we get some unexpected changes a couple of days later, they aren't going to verify as you'd expect.

[Frosty.]

The GEFS 6z mean is sensational..it shows extensive azores high / ridge + continental influence delivering a very lengthy increasingly very summery outlook nationwide with southern uk becoming HOT! 

Edited June 19, 2018 by Frosty.

[Captain Shortwave]

Day 5

UKMO/GFS/GEM

      

High pressure centred over southern England in all three to end the weekend with temperatures already into the mid-twenties with sunny spells and light winds. Pretty good agreement there.

Day 6

      

Slight variations as to how much cold Atlantic air gets pulled towards that shallow low west of Portugal, the GFS has more than the other two which tends to lift the high a little further north to sit in the north sea whilst the UKMO/GEM keep the high over southern England though I suspect all three would start to develop a wind from the south east as we approach the middle of next week.

Edited June 19, 2018 by Captain Shortwave

[mushymanrob]

3 hours ago, mb018538 said:

@mushymanrob I disagree slightly - john holmes knows his stuff and can interpret these charts as good as anyone else - he clearly said:

'Looking at the latest 6-10 day 500 mb anomaly output suggests that any upper ridging is a short lived affair with a mainly westerly pattern showing. You can see this, albeit certainly not cast in stone, on this morning's ECMWF if you play the previous chart from yesterday. This has a marked +ve ehight anomaly this morning no sign. NOAA also shows this over the past 2 days or so. I generally take NOAA as the most reliable with EC following and GFS some way behind unless it is similar to the other two. No GFS either yesterday or today on the link I have. The 8-14 NOAA similar to the 6-10. To me it remains looking like a NW-SE split on average through the next 2 weeks. Obviously they are 'mean' charts and some divergence on occasasional days will occur but no major difference over the period as a whole.'

Which is what we were shown - transitory Azores ridging, better in the SE compared to the NW, broadly westerly, temps probably 15-23c. Certainly no sustained imminent settled/hot spell. 
A couple of days later and we could possibly end up with a 5 day+ heat wave with temperatures potentially into the upper 20's/ low 30's. Completely different if you ask me.
The anomaly charts are good as a broad schematic, and most of the time are pretty accurate, but they can be subject to unexpected changes such as going on now. They are only as good as the data available when they are made, so if we get some unexpected changes a couple of days later, they aren't going to verify as you'd expect.

what john said was spot on.... thats what those charts were showing

what you said was spot on... those charts didnt predict a 5 day heatwave 14 days in advance.

that doesnt make them wrong, it means they were uncertain and only jumped on board, so to speak, when it was more likely. to me its not about who spots what first, but who spots it correctly first

personally, i expected this sudden change and said so on my daily local blog. because when you follow these charts you get used to how they act, and they can be behind the ops sometimes, this was one time. but overall they do iron out the more bullish, fanciful, fantasy island paths the ops take at the timeframe they refer too.

they work for me, as they do very much nearly all the time get the mean upper flow bang on. but as john said, they are falible, as all model suits are. tbh theres so many ways of trying to untangle whats likely we all have our favoured methods. im a huge fan of this way, because they do iron out the vagaries of the ops.

 

[Mike Poole]

Yes, at T144 the models look in quite close agreement now for a high more or less over the UK.  Add in the ICON too.  My interest now is in how this (probably) slow moving feature positions itself with respect to possibilities of sourcing hot air from the south, or will it be dry but with light winds from a less favourable direction?

GEM done to T240 now, looks great:

And you can really see the hot air approaching on the south flank:

Typing this as the run unfolds but getting interested about the 12z GFS, this looks to be bringing real heat, now at T240:

Taken me 5 edits to get these charts to display in the right order! Sorted now, but what fantastic summer charts! 

Edited June 19, 2018 by Mike Poole

[Ice Man 85]

8 minutes ago, Mike Poole said:

Yes, at T144 the models look in quite close agreement now for a high more or less over the UK.  Add in the ICON too.  My interest now is in how this (probably) slow moving feature positions itself with respect to possibilities of sourcing hot air from the south, or will it be dry but with light winds from a less favourable direction?

GEM done to T240 now, looks great:

And you can really see the hot air approaching on the south flank:

Typing this as the run unfolds but getting interested about the 12z GFS, this looks to be bringing real heat, now at T240:

We looking at the same GEM here? Heat's gone from everywhere bar the far SW if thats right....

 

Edited June 19, 2018 by Ice Man 85

[Frosty.]

The ukmo 12z is looking really peachy this evening, increasingly warm and anticyclonic.

[Fourty Point Three Degrees]

Just seen BBC weather hinting of a heatwave next week with Darren Bett suggesting 30C highs all week.

GFS 18z is a real blowtorch later next week - you know its going to be a scorchio when the charts are showing 27C at 09:00

 

[Ice Man 85]

GFS 12z also shows it gone by saturday (from NW anyway). What follows is more typical weather.

[Djdazzle]

1 minute ago, Ice Man 85 said:

GFS 12z also shows it gone by saturday (from NW anyway). What follows is more typical weather.

Deep FI. How many times do we see heat simply blown away only for it to hang on?

[Ice Man 85]

2 minutes ago, Djdazzle said:

Deep FI. How many times do we see heat simply blown away only for it to hang on?

Thats what the chart shows, not saying its right. The heat you crave is also FI. GFS is useless at that range.

Edited June 19, 2018 by Ice Man 85

[Djdazzle]

2 minutes ago, Ice Man 85 said:

Thats what the chart shows, not saying its right. The heat you crave is also FI.

Well mid to high twenties from Monday. So not really FI.

[I remember Atlantic 252]

7 minutes ago, 38.5*C said:

Just seen BBC weather hinting of a heatwave next week with Darren Bett suggesting 30C highs all week.

GFS 18z is a real blowtorch later next week - you know its going to be a scorchio when the charts are showing 27C at 09:00

 

you mean last nights? not had todays 18Z yet?

[Ice Man 85]

1 minute ago, Djdazzle said:

Well mid to high twenties from Monday. So not really FI.

thought we considered over 5 days away as outside the reliable?

[Mike Poole]

27 minutes ago, Ice Man 85 said:

We looking at the same GEM here? Heat's gone from everywhere bar the far SW if thats right....

 

Yes, think so, Meteoceil chart seems to match yours as far as I can see.  The interest on this particular run is more about the ESE wind at T240 which should allow the heat to build further away from NE?

Edited June 19, 2018 by Mike Poole

[Fourty Point Three Degrees]

3 minutes ago, Ice Man 85 said:

Thats what the chart shows, not saying its right. The heat you crave is also FI. GFS is useless at that range.

All models are reaching an agreement that next week is going to be hot if not then very warm.  It could upgrade, it could downgrade.

 

1 minute ago, I remember Atlantic 252 said:

you mean last nights? not had todays 18Z yet?

That's my mistake, should say todays 12z chart.

[cheese]

 

1 minute ago, Mike Poole said:

Yes, think so, Meteoceil chart seems to match yours as far as I can see.  The interest is more about the ESE wind at T240 which should allow the heat to build further away from NE?

Oh no, not again. I was hoping we'd seen the back of any easterly winds this summer.

[Ice Man 85]

1 minute ago, cheese said:

 

Oh no, not again. I was hoping we'd seen the back of any easterly winds this summer.

Moans thread please, Cheese. I would use a violin myself but can't be bothered

[Djdazzle]

4 minutes ago, cheese said:

 

Oh no, not again. I was hoping we'd seen the back of any easterly winds this summer.

ESE wind wouldn’t be bad at all. Would be warm and dry.

[I remember Atlantic 252]

3 minutes ago, cheese said:

 

Oh no, not again. I was hoping we'd seen the back of any easterly winds this summer.

Ay, does seem a trend over last few runs for an easterly breeze starting around Tues, not great for summer sun fans away from the west/SW/NW, see what EC says but GFS could start to trend cooler

[Mike Poole]

20 minutes ago, 38.5*C said:

Just seen BBC weather hinting of a heatwave next week with Darren Bett suggesting 30C highs all week.

GFS 18z is a real blowtorch later next week - you know its going to be a scorchio when the charts are showing 27C at 09:00

 

BBC weather hinting of a heatwave?  We've been hinting at it on here for days now! 

Edited June 19, 2018 by Mike Poole