Model Output Discussions 12z 03/05/2016

[Frosty.]

6 minutes ago, ajpoolshark said:

whilst the NMM medium resolution progs temps of 25C plus for friday/sat/sunday in the south/south east with not too much in the way of cloud and no ppn....quite a contrast of just goes to show that one model output's brings disappointment to some.....other model output's bring nirvana 

Hi aj, well taking London as an example, 23/24c on Saturday with a mix of clouds and sun and 22c on Sunday with a lot of cloud..from the met office..nowt special..and cooler further north.

[MP-R]

Charts like this are just infuriating (GFS cloud cover from NAE):

The south underneath a decent high pressure area, yet cloudcover extending right down to the south coast then magically disappearing over the English Channel. 

All eyes on the 06Z to see if we can get this ruddy high to move further north so we can at least get a nice weekend.

[coldcomfort]

7 minutes ago, ajpoolshark said:

whilst the NMM medium resolution progs temps of 25C plus for friday/sat/sunday in the south/south east with not too much in the way of cloud and no ppn....quite a contrast of just goes to show that one model output's brings disappointment to some.....other model output's bring nirvana 

GFS goes for 25-26c in the extreme south on Sat and 27-28c on Sun, but only across a very small area, so quoting those kinds of values is just as misleading as quoting the 11-12c expected in Shetland. On balance temps this weekend look set to be pretty close to average for the southern half of the UK and a little below average across the northern half...with the near standard local anomalies.

 

[Nick L]

35 minutes ago, Scorcher said:

A slightly misleading post from a poster with a very appropriate name

Going by GFS which has more precise timings (rather than just the ECM which has only one chart per day, albeit the best performing model overall), we can see the warm uppers arriving during the early hours of Monday, which will allow temperatures to reach comfortably above average values for most- even the BBC are suggesting this on the website already despite their usual caution until a couple of days before.

The warm spell has actually been extended this morning by all of the major models- yesterday evening it looked like the heat would be swept away by Wednesday, but it's now looking like there could be another hot day for most of the UK. Perhaps it could be extended even further. There does seem to be some denial from those wanting it to stay cooler- as I said the other day, most of us who want warmer conditions would have bitten someone's hand off for these charts a week or so ago.

It doesn't like there will be much 'cold comfort' on Tuesday night into Wednesday, that's for sure 

I'll just point out that the EC does have 3 hourly timesteps, although obviously not for public view. EC is far cooler than the GFS but it is still very pleasant for a couple of days. Monday generally 24c, Tuesday 24-27c before a deluge on Wednesday.

[A.J]

Just now, Karl. said:

Hi aj, well taking London as an example, 23/24c on Saturday with a mix of clouds and sun and 22c on Sunday with a lot of cloud..from the met office..nowt special..and cooler further north.

as I said, the NMM mr model paints a completely different picture!..............rather than take anyone's/any media forecasts as set in stone, I'd rather wait and see

[Nick L]

Further to my post above, just a couple of freebies from the EC for you...

[A.J]

1 minute ago, coldcomfort said:

GFS goes for 25-26c in the extreme south on Sat and 27-28c on Sun, but only across a very small area, so quoting those kinds of values is just as misleading as quoting the 11-12c expected in Shetland. On balance temps this weekend look set to be pretty close to average for the southern half of the UK and a little below average across the northern half...with the near standard local anomalies.

 

good grief, look at the NMM output!....It is not misleading in the slightest!...If you think it's misleasding then I honestly suggest you go and look up the definition of the word 'misleading'....I have no agenda, and post only factual information when I do post, no guesses, hunches, or random interpretations.....It quite clearly shows the forecast temperatures I quoted in the south and south east.....If you can't see that, then I honestly recommend a visit to specsavers

[cheese]

5 minutes ago, Nick L said:

Further to my post above, just a couple of freebies from the EC for you...

So thoroughly unremarkable by all accounts. 

[Frosty.]

7 minutes ago, ajpoolshark said:

as I said, the NMM mr model paints a completely different picture!..............rather than take anyone's/any media forecasts as set in stone, I'd rather wait and see

Absolutely right aj, Sunday in particular could be warm and sunny across the south with mid 20's c..

[coldcomfort]

10 minutes ago, ajpoolshark said:

good grief, look at the NMM output!....It is not misleading in the slightest!...If you think it's misleasding then I honestly suggest you go and look up the definition of the word 'misleading'....I have no agenda, and post only factual information when I do post, no guesses, hunches, or random interpretations.....It quite clearly shows the forecast temperatures I quoted in the south and south east.....If you can't see that, then I honestly recommend a visit to specsavers

Firstly I don't think there's any need to get personal and question my eyesight. Secondly you missed the point I was making. I was not questioning what the NNM model was saying, indeed I pointed out that GFS was going for even warmer temps across a very small area of the south, my point was focusing on these higher values no more paints a representative picture of the UK as a whole this weekend than mentioning the temps in Shetland. The comment was not aimed at you directly, it was just a general observation of how things can become skewed if we don't look at our whole island.

[Man With Beard]

5 minutes ago, Nick L said:

Further to my post above, just a couple of freebies from the EC for you...

Nick, I know you're only posting what you see so I'm sure you will understand this is not a dig at you ... but I will post a naked photo of myself on this thread if this mornings ECM op chart for next Tuesday verifies (with its pressure, cloud cover, 850s and rainfall forecast as it is) and 30C is not exceeded.

My reasoning - uppers forecast to be between 16C and 17C by midday Tuesday - in a continental airflow within minimum sea track, fairly light winds, probably clear blue skies, not a monumental increase in heat from previous day, dry ground conditions for the previous week - in August that should translate to a near optimum transition between upper air temps and lower air temps, so between 14C and 17C higher than upper air temperatures depending on local conditions (e.g. exposure to sea air, height above sea level, shelter from wind direction e.g. Cheltenham is sheltered by the Cotswolds in a SE wind)  - therefore a maximum should be 30C at very least (16C uppers + 14C) and maybe just maybe 34C (17C uppers + 17). 

We reached 28C this past Sunday on charts nothing like these!

[Nick L]

3 minutes ago, Man With Beard said:

Nick, I know you're only posting what you see so I'm sure you will understand this is not a dig at you ... but I will post a naked photo of myself on this thread if this mornings ECM op chart for next Tuesday verifies (with its pressure, cloud cover, 850s and rainfall forecast as it is) and 30C is not exceeded.

My reasoning - uppers forecast to be between 16C and 17C by midday Tuesday - in a continental airflow within minimum sea track, fairly light winds, probably clear blue skies, not a monumental increase in heat from previous day, dry ground conditions for the previous week - in August that should translate to a near optimum transition between upper air temps and lower air temps, so between 14C and 17C higher than upper air temperatures depending on local conditions (e.g. exposure to sea air, height above sea level, shelter from wind direction e.g. Cheltenham is sheltered by the Cotswolds in a SE wind)  - therefore a maximum should be 30C at very least (16C uppers + 14C) and maybe just maybe 34C (17C uppers + 17). 

We reached 28C this past Sunday on charts nothing like these!

The thing is though it isn't modelling clear blue skies on Tuesday, there is a far amount of haze showing up which will probably be pegging temperatures back a little. The Sunday just gone was as clear as anything for me! 850 pot wet bulbs are only about 12-13 across much of the south during the day, the properly warm air mass doesn't move in until later in the day/evening, it's not the best timing for properly high temperatures.

Anyway, discussing specifics at this stage is a waste of time really!

Edited August 10, 2016 by Nick L

[A.J]

Just now, coldcomfort said:

Firstly I don't think there's any need to get personal and question my eyesight. Secondly you missed the point I was making. I was not questioning what the NNM model was saying, indeed I pointed out that GFS was going for even warmer temps across a very small area of the south, my point was focusing on these higher values no more paints a representative picture of the UK as a whole this weekend than mentioning the temps in Shetland. The comment was not aimed at you directly, it was just a general observation of how things can become skewed if we don't look at our whole island.

if the comment was not aimed at me directly, then why did you directly quote my post?.....secondly, my comment was not personal, rather voicing frustration at your apparent inability to see factual information as quoted in my post.........so I hope that's cleared that up  ...........You're absolutely correct in saying that the upcoming warm/hot snap is not a nationwide event (as it currently stands in the current model output)....The various model outputs are inconsistent in painting an accurate picture (temps/cloud/rainfall) for this weekend for the midlands southwards, but one thing the outputs all agree on is that for at least the first half of next week, a good chunk of England will see temperatures well above the seasonal norm (anywhere from 23/24C to 30C depending on location) before a breakdown of the warmth from the west...Anything after that at this stage is pure conjecture

[A.J]

11 minutes ago, Man With Beard said:

Nick, I know you're only posting what you see so I'm sure you will understand this is not a dig at you ... but I will post a naked photo of myself on this thread if this mornings ECM op chart for next Tuesday verifies (with its pressure, cloud cover, 850s and rainfall forecast as it is) and 30C is not exceeded.

My reasoning - uppers forecast to be between 16C and 17C by midday Tuesday - in a continental airflow within minimum sea track, fairly light winds, probably clear blue skies, not a monumental increase in heat from previous day, dry ground conditions for the previous week - in August that should translate to a near optimum transition between upper air temps and lower air temps, so between 14C and 17C higher than upper air temperatures depending on local conditions (e.g. exposure to sea air, height above sea level, shelter from wind direction e.g. Cheltenham is sheltered by the Cotswolds in a SE wind)  - therefore a maximum should be 30C at very least (16C uppers + 14C) and maybe just maybe 34C (17C uppers + 17). 

We reached 28C this past Sunday on charts nothing like these!

With the greatest respect, I love the heat, but on this occasion, I seriously hope Nick is correct! 

[Nouska]

52 minutes ago, MP-R said:

Charts like this are just infuriating (GFS cloud cover from NAE):

The south underneath a decent high pressure area, yet cloudcover extending right down to the south coast then magically disappearing over the English Channel. 

All eyes on the 06Z to see if we can get this ruddy high to move further north so we can at least get a nice weekend.

The ECM cloud cover for 18Z Saturday looks a little better.

  

@Scorcher You'll get the ECM 6 hourly time steps you like on the IMO weather page - limited view and limited parameters but better than nothing.

http://en.vedur.is/weather/forecasts/atlantic/

An edit to add the ARP cloud for same time, this shows the different cloud levels.

http://www.meteociel.fr/modeles/arpege.php?ech=3&mode=38&map=330

Edited August 10, 2016 by Nouska

[Man With Beard]

3 minutes ago, ajpoolshark said:

With the greatest respect, I love the heat, but on this occasion, I seriously hope Nick is correct! 

I won't go off topic anymore than this, but just to say, honestly, I wouldn't hope so, it's not a pretty sight.

[cheese]

14 minutes ago, Nick L said:

The thing is though it isn't modelling clear blue skies on Tuesday, there is a far amount of haze showing up which will probably be pegging temperatures back a little. The Sunday just gone was as clear as anything for me! 850 pot wet bulbs are only about 12-13 across much of the south during the day, the properly warm air mass doesn't move in until later in the day/evening, it's not the best timing for properly high temperatures.

Anyway, discussing specifics at this stage is a waste of time really!

Most hot days in my experience are hazy - in fact, a deep blue sky is a pretty rare occurrence. There is nearly always a milky haze. 

Edited August 10, 2016 by cheese

[Man With Beard]

14 minutes ago, Nick L said:

The thing is though it isn't modelling clear blue skies on Tuesday, there is a far amount of haze showing up which will probably be pegging temperatures back a little. The Sunday just gone was as clear as anything for me! 850 pot wet bulbs are only about 12-13 across much of the south during the day, the properly warm air mass doesn't move in until later in the day/evening, it's not the best timing for properly high temperatures.

Anyway, discussing specifics at this stage is a waste of time really!

Genuine question Nick, the Icelandic charts appear to show cloudless skies (chart is for Tuesday early morning), is there something missing here?

[mb018538]

I too would be amazed if those ECM temperatures are correct. 27/28c maxes just look way too low. 30c somewhere at the very least if you ask me, up around 32c somewhere. 

We could all need an 18 style film warning on the MO thread if MWB is unlucky enough to see temps of 28c!

[Nick L]

5 minutes ago, Man With Beard said:

Genuine question Nick, the Icelandic charts appear to show cloudless skies (chart is for Tuesday early morning), is there something missing here?

Such charts can struggle to show high level cloud and haze. The charts I'm looking at show a broad area of 1-2 oktas. On the EC somewhere would definitely see a 30c, but by and large it would be mid-to-high 20s, which is still good going!

[MP-R]

18 minutes ago, Man With Beard said:

Genuine question Nick, the Icelandic charts appear to show cloudless skies (chart is for Tuesday early morning), is there something missing here?

It's possible to have cloudless days with consistent haze if you get what I mean. I'm guessing the models can't pick that up as easily.

Edit: just realised Nick has already answered.

Edited August 10, 2016 by MP-R

[knocker]

1 minute ago, MP-R said:

It's possible to have cloudless days with consistent haze if you get what I mean. I'm guessing the models can't pick that up as easily.

Of course. Anticyclonic conditions with a SE flow often produce reduced visibility because it drags in continental pollution. Even in Cornwall it can be very annoying and twice in recent years I've taken a trip down the Fal armed with a camera hoping for some good shots only for haze to put the kybosh on that. Of course I should know better and plan the trip behind a cold front.

[Man With Beard]

GFS 06Z is less hot. Perhaps 31C would be the tops here

Edited August 10, 2016 by Man With Beard

[johnholmes]

Having been on this forum since 2004 I do find it sad when folk argue over relatively small issues over what a particular model they say is showing.

Post your comments with charts to back them up but please keep the personal digs out, it is after all only the weather. We all see things from different perspectives and almost everyone on here has a bias one way or another for particular weather. One does not have to be on here for long before that becomes apparent. Get outside and have a life and enjoy whatever the weather chucks at us.

Hope I am excused not posting charts, pretty unusual from me not to do that.

 

[MP-R]

59 minutes ago, knocker said:

Of course. Anticyclonic conditions with a SE flow often produce reduced visibility because it drags in continental pollution. Even in Cornwall it can be very annoying and twice in recent years I've taken a trip down the Fal armed with a camera hoping for some good shots only for haze to put the kybosh on that. Of course I should know better and plan the trip behind a cold front.

Indeed, it's a particular issue when you get a straight easterly too at any time of year. I find it is a particular issue when winds are lighter, however (such was the case with the late June / early July heatwave in 2009). Both July 19th 2016 and June 30th 2015 on the other hand saw southeasterlies but with quite a breeze. Not only were the skies crystal blue, the temperatures had no problem responding either. Will be interesting to see how this one pans out, a few runs have shown quite a squeeze in the isobars from the southeast for a time which may help clear the haze but bring in the risk of more cloud from the west given the presence of the trough out west.

To add to the above, GFS 06Z is showing a sort of reloading pattern of repeated plume opportunities (a bit like late June and early July 2001, late August and early September 2005, late July 2008 and late June to early July 2009).

Tuesday 16th:

Saturday 20th:

Friday 26th:

That one could go one of two ways depending on if the Iberian and Atlantic trough link up. 

Nice run to see. The 10C never really leaves the south until next Wednesday after today, so just need to get over the issue of cloud. Further north always more in the firing line for less clement conditions in the short term.

Edited August 10, 2016 by MP-R