Model Output Discussions 12z 01/06/2017

[Cheshire Freeze]

5 minutes ago, Singularity said:

ECM has the quick recovery too so that's something. 

Worth noting that plume timing on that run looks right for a 30+ day Wednesday and with the heat reaching well north so at least taster for most. 

Still... it seems very harsh to have to make do with that for midweek.

ECM doesn't turn out so bad in all honesty

Don't get why we need to see searing uppers from the S when people can enjoy the strong sun and fine weather that set up would bring (more especially further S).

Edited July 13, 2017 by CreweCold

[northwestsnow]

5 minutes ago, CreweCold said:

ECM doesn't turn out so bad in all honesty

Don't get why we need to see searing uppers from the S when people can enjoy the strong sun and fine weather in the S that chart would bring.

Trouble is it seems to be playing catch up to gfs,i have 2 weeks off from next friday 21st , i got loads of outdoor activities planned, cant begin to tell ypu how utterly hacked off im gona be if we are stuck under a ruddy trough..

Edit by day 10 it looks good, but it was wrong last night at day 7 so...

Edited July 13, 2017 by northwestsnow

[Frosty.]

Actually the best Ecm chart is day 10

 

[Singularity]

Bottom line is, background signals continue to strongly support ridging of Azores in from SW so that remains most likely as the overall trend with time. 

This midweek madness is just plain bad luck if it unfolds as the 00z op run consensus depicts. A smaller scale development interrupting the settling down tendency (Mon & Tue look largely settled).

[northwestsnow]

2 minutes ago, Singularity said:

Bottom line is, background signals continue to strongly support ridging of Azores in from SW so that remains most likely as the overall trend with time. 

This midweek madness is just plain bad luck if it unfolds as the 00z op run consensus depicts. A smaller scale development interrupting the settling down tendency (Mon & Tue look largely settled).

Hope you are right! Gfs00z shows no such scenario with the awful green circle trapped in our locale while Europe bakes under a hot southerly...

[knocker]

A quick look at the nh pattern on the ecm at T144 illustrates very well the amplification and the important role the Canadian vortex lobe is playing in all of this. Why this sudden spurt of amplification (if indeed it does happen of course) I've no idea,

The chances are that by the end of the run we are looking at a return to a more familiar pattern although the strength of the the trough in the NW Atlantic is still a concern with the upper flow still likely to bring unsettled weather to the north. In the mean time back to a slack area of low pressure to south. This is the point where there the Azores should now ridge NE and we are back to a warm and settled end of July.

 

[Captain Shortwave]

The ECM op fits fairly well with the GEFs version of events with a trough edging in after the middle of next week before pressure rises from the south/south west into the following weekend.

GEFs

   

ECM op

   

With a deep trough over Canada which will move east during week 2, I can easily see another push north east from the Azores high, ironically for the east and north east this could potentially turn into an upgrade in prospects as we remove the option of the Azores high and Euro high joining up with low pressure to our south allowing a flow between the east and north and the usual north sea gunk that comes with it.

Wednesday does look hot as others have said with 30C very possible. Beyond that, treat the output with caution as the models try to place different suggestions in terms of how that deep Canadian trough contributes to proceedings downstream over Europe. Strangely in my view this mornings ECM offers the potential for something much hotter than the output yesterday and whilst the GFS is more unsettled it does suggestwith a few tweaks that it could do something similar.

Edited July 13, 2017 by Captain Shortwave

[mb018538]

Seems to a be a very common theme for this summer, in that small disturbances keep rumbling up from the south and causing chaos!

hopefully we still get a nice settled spell and this doesn't just end up a damp squib. GFS is a bit of an outlier in the ensembles, so let's hope it improves later on.

[johnholmes]

Following on from my promise yesterday, a look at the 500 mb anomaly charts.

ECMWF-GFS first

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

Both show +ve heights over Europe extending into Scandinavia and a hint of west from there. They also both make a lot of the upper low and have it quite close to NW'ern parts. The charts this morning are noticeably different to those from yesterday which showed ridging as the main feature, see below. Prior to yesterday they generally showed a westerly Atlantic flow into a trough east of the UK. So the charts yesterday were a bit different to most they have shown.

http://mp1.met.psu.edu/~fxg1/ECMWF_12z/hgt,

so not much continuity here. Prior to yesterday comp.html

The 6-10 version has really not much in common with the EC-GFS idea with a fairly slack Atlantic flow into a trough with its main feature being off Iberia. Only very small +ve heights shown.Its 8-14 does show more +ve heights superimposed on a similar contour flow.

Not easy to make a summary of what this could mean for the UK in the 6-14 day period. The idea of a more settled spell again developing during next week seems a reasonable bet but as to how long less easy. The 500 mb charts, to me, suggest no major Atlantic influence but are not really convincing for a prolonged settled and very warm/hot spell of weather, even for the SE of the UK. 

NOAA

http://www.cpc.noaa.gov/products/predictions/610day/500mb.php

Edited July 13, 2017 by johnholmes
sorry mucked up the words and link, not time to alter just now

[Glacier Point]

Not surprised we're getting either N/NW or southerly options from the models. 

All modelling agrees in a displaced vortex over the Canadian Maritime. The issue here is how longwave troughs passing through this axis interact. If the get pinched off and closed upper lows form off Newfoundland, we get the NW option where the sub-tropical ridge (which is very displaced poleward  right now) gets pulled NW. If the troughs remain broadly intact and sweep NE through the Atlantic, the Azores sits very close to the UK or even displaces just to our east.

The sign and scale of the AO would be a good proxy here. More positive, the more eastward the sub-tropical ridge. More negative, the further west the sub-tropical ridge and cooler more unsettled for NW Europe.

I'm playing the percentages here. Atlantic predisposition to troughing allied to a +AO (polar easterlies are the weakest since 1981) translate to better conditions for the UK. 

Also worth re-iterating that there remain issues for modelling in the longer term across the Atlantic just to our west. The flow is complicated and ripe for development of lows driving SE through ridges. All of which gives you better chances of ridges getting thrown up over or just east of the UK, particularly the closer we get to August (background signals become more cohesive towards this for August as opposed to July).

Longer term modelling towards month's end does retreat the ridge more towards the Atlantic, which I think is not unreasonable given we are likely to wax and wane with this over a 10 day oscillation - not withstanding my comment above about small scale disturbances driving us towards warmer, drier solutions in the short range. So what follows a wane at months end is a waxing again, so Azores ridge + driving low to the SE part 2......

Edited July 13, 2017 by Glacier Point

[Man With Beard]

Thanks John.

Well as a southerner I should be quite happy with the charts - 6/7 days ahead of sunny spells and building heat, a welcome cooling off day next Thursday or Friday (and to give the grass a top-up) followed by probably yet more sun. But I'm frustrated at how difficult it is to get settled weather up to the north!! Yesterday, I'd have thought there was a 7 or 8 in 10 chance that the north was finally going to get a week of settled/warm weather (even allowing for a day blip). Today, I have to lower that to 5 or 6 in 10. 

Just consider how unlucky this chart is!! No greens at all from Greenland to pretty much everywhere - except for poor Ireland and Scotland.

Actually, the ECM was on to this at the weekend, and then dropped it, but with a key difference that makes this morning's charts worse...

  

which is that this morning's charts cut the low off. Whilst on the ECM archive charts above, the low is not undercut and is free to move off to the north, on today's GFS 00Z chart there would be a great risk of the low getting stuck, surrounded by good heights all around - until the Atlantic regroups, fuses with the UK low, and resets the normal pattern of greens covering the whole of the northern Atlantic and going back to a NW/SE split.

This morning's charts really are worst case scenario. I think further runs today can only get better. There's still a very reasonable chance that this low will not do what the ECM/GFS ops suggest. Below are two ensemble members that I think also have a good chance of verifying. The first shows the incoming low failing to "cut-off". The result is one slightly less settled day next week before the low easily clears off and the Azores High ridges in nicely after:

The second is that the low holds even further west - something we often see - keeping most of next week dry, sunny and warm except in Ireland and perhaps extreme western coasts - and maybe a couple of thunderstorms for all:

Or thirdly, a quick move back towards yesterday's charts. 

But positivity definitely more restrained just now.

[Fourty Point Three Degrees]

9 hours ago, Scorcher said:

Two words for you: one run. Another two words: pub run. Don't be so dramatic about one run!

just saying what I see in models and this is for model chat

[Man With Beard]

30C back on the charts again for the SE as early as this Sunday:

[Paul]

Matt's made an extended synoptic guidance blog which is worth a read:

http://www.netweather.tv/index.cgi?action=news;storyid=8286;sess=

Quote

• Increasing interest in the medium and long term with potential convective weather by middle of next week
• After that, a more anticyclonic period of weather, within the long-term, has been signalled
• Temperatures set to rise through next week, possibly becoming hot and humid
• Disrupting upper trough to the SW by the 18th, aids in drawing a thundery low north from Iberia
• Developments after that crucial to the late July weather, but an anticyclonic outlook is certainly possible

 

[knocker]

The EPS this morning shows the transient troughing next week that has already been discussed but quickly recovers towards the end of the period The Azores again ridges to the west and with positive anomalies north of the UK much of the upper flow is diverted NNE leaving a slack westerly over the UK with the trough to the south west remaining influential and perhaps receiving sneeky top ups from breakaway upper troughs . So the percentage play for the surface analysis could well see the Azores ridging to the north with all to play for to the south with shallow unstable lows drifting north. Temps warm or even very warm in the south. This remains the scenario into the ext period although towards the end the flow becomes more zonal as the Azores retrogresses west.

Edited July 13, 2017 by knocker

[Frosty.]

I was a bit concerned what the met office update would be like following the 00z output, especially the dismal Gfs 00z but there doesn't seem to be any downgrade at all. Next week is set to warm up with plenty of sunshine as high pressure builds in early next week followed by very warm / humid conditions across the south with a risk of thunderstorms. The far northwest could have another brief atlantic incursion but then settling down and staying warm / very warm nationwide and still a chance of thundery weather from time to time, especially further south. :- )

[sparky1972]

5 hours ago, Man With Beard said:

30C back on the charts again for the SE as early as this Sunday:

yes please, off to Silverstone on sunday so a warm day would be fab.

[Summerstorm]

13 minutes ago, Frosty. said:

I was a bit concerned what the met office update would be like following the 00z output, especially the dismal Gfs 00z but there doesn't seem to be any downgrade at all. Next week is set to warm up with plenty of sunshine as high pressure builds in early next week followed by very warm / humid conditions across the south with a risk of thunderstorms. The far northwest could have another brief atlantic incursion but then settling down and staying warm / very warm nationwide and still a chance of thundery weather from time to time, especially further south. :- )

Sounds like they are promoting ECM's run with a brief changeable period at the end of next week and through next weekend before the azores high ridges in again and sets itself up over us by the end of that week by the looks of the last ECM run. Hopefully the GFS will improve tonight but through the last two runs they seem set on promoting low pressure throughout the whole of the week after next so we'll see what it comes up with over the next few runs. The GFS is only one model though i guess as some of the other members have said but hopefully we get something akin to the ECM and Met Office's predictions for the next two weeks. 

Edited July 13, 2017 by Summerstorm

[Frosty.]

2 minutes ago, Summerstorm said:

Sounds like they are promoting ECM's run with a brief changeable period at the end of next week and through next weekend before the azores high ridges in again and sets itself up over us by the end of that week by the looks of the last ECM run. Hopefully the GFS will improve tonight but through the last two runs they seem set on promoting low pressure throughout the whole of the week after next so we'll see what it comes up with over the next few runs. The GFS is only one model though i guess as some of the other members have said but hopefully we get something akin to the ECM and Met Office's predictions for the next two weeks. 

Agreed, much prefer the Ecm 00z to either the Gfs 00z / 6z which show too much green snot for my liking..I would settle for this setting up a prolonged settled and warm / very warm spell.

[Frosty.]

The Ecm 00z ensemble mean / operational both finish on a high note with the azores anticyclone looking strong going forward..hopefully as the saying goes, all's well that ends well!

[Weather Boy]

42 minutes ago, Frosty. said:

I was a bit concerned what the met office update would be like following the 00z output, especially the dismal Gfs 00z but there doesn't seem to be any downgrade at all. Next week is set to warm up with plenty of sunshine as high pressure builds in early next week followed by very warm / humid conditions across the south with a risk of thunderstorms. The far northwest could have another brief atlantic incursion but then settling down and staying warm / very warm nationwide and still a chance of thundery weather from time to time, especially further south. :- )

I think that I would be surprised if they adjusted their forecast based on one particular run.  They normally aren't as influenced as that.  They tend to take a line and stick to it, presumably based largely on stuff that we don't get to see. 

[Frosty.]

29 minutes ago, Weather Boy said:

I think that I would be surprised if they adjusted their forecast based on one particular run.  They normally aren't as influenced as that.  They tend to take a line and stick to it, presumably based largely on stuff that we don't get to see. 

It wasn't just one particular run though, there were issues yesterday too..anyway, still looking generally very good which is what matters most.

[Weather Boy]

Just now, Frosty. said:

It wasn't just one particular run though, there were issues yesterday too..anyway, still looking generally very good which is what matters most.

Yes, also not just one model.  Sorry, my post was quite lazy.  I meant that they aren't overly influenced by short term (presumably??) changes in modelling and are evidently not purely reliant on the public models.

[Methuselah]

36 minutes ago, Weather Boy said:

I think that I would be surprised if they adjusted their forecast based on one particular run.  They normally aren't as influenced as that.  They tend to take a line and stick to it, presumably based largely on stuff that we don't get to see. 

I think you're right about that, WB...Whereas Karl's telling us what the models say, run-by-run, the MetO is telling us what (based on all the information that's at their fingertips) they think will happen...

Reportage and interpretation are not the same thing...

[knocker]

Gfs still going for the complex double centred Atlantic trough  and cold blast into the south next week