Model Output Discussion

[chapmanslade]

The 12z continues the misery

Extraordinary really the way it just vanishes the high pressure that was looking odds on for late this week.

The azores high proves weaker than first thought and doesn't even extend it's ridge over the far west mow.

All and all very depressing but c'est la vie......

Any chance of posting some charts to explain this as I for one cannot see it ? There still seems to be an increasing signal for HP to build next week and beyond - all the models seem to be picking this up. It may initially have a NW flow over the UK so not hot, but not a string of depressions either.

I'm hoping the high centres over the UK by the time I go to France mid-month to drag up some nice heat from Spain.

[butler_son]

Not been here since Friday, and I don't really remain much more the wiser than I was on Friday about what later this week will be like in the detail, apart from being somewhat warmer.

All I can do is pray that the heavy rain threatened in the South East for later this week remains confined to the SE and far E. From latest runs, and from the links Paul B and Snowyowl posted, my guess is that Dorset (where I'll be 7-9) will still escape the worst and may even enjoy some reasonably pleasant weather including sunshine for the w/e. No heatwave though for the weekend as once seemed promised.

MetO's updates today supports this cautious optimism for the SW.... GFS less dry though.

EIID, by any chance?

Yes, I've been keeping an eye on this. I'd rather not be wading through mud (as it appears I might have to from what I've seen for the days up to Thursday) in a field in the Cranborne Chase, but it seems that it's going to be comfortable for that weekend. Good job too rather. Seems the tents I saw them putting up just outside of Sixpenny Handley today for the festival may be useful later on though, time for that to change.

[Frosty.]

The 12z continues the misery

Indeed it does, the GFS 12z is full of misery for more eastern and north eastern areas later this week/weekend with a deep thundery low extending north westwards, the ukmo 12z has the low further inland across england whereas the gfs has it more coastal moving towards eastern scotland, wonder which if any will be right. It looks warmer at least but with rain around and some large rainfall totals associated with that low between fri/sun. Nice deep FI GFS 12z charts with the Azores High finally making an impact for the first time since late June but it's too far ahead to get too excited about sadly.

[damianslaw]

Synoptics and outlook in my opinion for later this week are increasingly looking like delivering more in the way of unsettled poor summer weather than settled good summer weather. Atlantic looks too strong and heights to the south and east are being squeezed out by the weather front which will be stubbornly close to the se, in fact the hallmarks of a developing low pressure and intensifying front look on the cards.

[La Bise]

Damian, am I daydreaming when I look at the forecast for the next few days in the Lake District, once tuesday is out of the way, to me it looks rather good...?

[johnholmes]

looking at the Exeter Fax chart at 18Z I find it hard to believe how the senior man can get 6 surface fronts at 50N over just a few hundred miles, one for sure, the cold front with blank markers is to do with what appears to be a line of convective activity sandwiched between the warm and cold fronts-so fair enough along with the two fronts I've mentioned, but 6!

It would be interesting to see his 1000-500mb thickness chart that goes with it-each front is supposed to be evident on that chart as well.

I'd eat any hat offered if that was the case!

the 850mb GFS chart, see below, shows the warm and cold front and perhaps a trough behind it but certainly no sign, even at 850mb, of six.

and on that note

night night

Edited August 3, 2009 by johnholmes

[shuggee]

Said chart is quite entertaining over central/southeastern Europe too John. Bizarre.

[johnholmes]

perhaps its a new Met O incentive plan for their senior forecasters

the most fronts

the most high pressure centres

the most low pressure centres

the most troughs

in any one month wins a prize?

anyone able to link that to B-B-Q summer gets Ewan McCallums' job

[damianslaw]

Damian, am I daydreaming when I look at the forecast for the next few days in the Lake District, once tuesday is out of the way, to me it looks rather good...?

Granted once tomorrow is out of the way it does indeed look fairly decent for us with a dry spell beckoning, but the longer term trend towards the weekend still in my eyes is for unsettled conditions to pounce, I'd be much more upbeat if I saw a prolonged spell of summery weather on the cards, a few decent days in high summer is nothing special, perhaps I'm just expecting too much, but I always do at this time in the summer, this is peak high summer this is when we see on average our hottest weather of the year, I guess it has been the poor lacklustre weather of the last 4 weeks which is making me feel rather downcast, temps between 20-22 degrees and sunny spells isn't going to do it for me, it could do alot better!

[❄️❄️❄️❄️❄️❄️❄️❄️❄️]

perhaps its a new Met O incentive plan for their senior forecasters

the most fronts

the most high pressure centres

the most low pressure centres

the most troughs

in any one month wins a prize?

anyone able to link that to B-B-Q summer gets Ewan McCallums' job

I see what you mean

14 Low pressure centres!

Edited August 3, 2009 by RAIN RAIN RAIN

[La Bise]

Granted once tomorrow is out of the way it does indeed look fairly decent for us with a dry spell beckoning, but the longer term trend towards the weekend still in my eyes is for unsettled conditions to pounce, I'd be much more upbeat if I saw a prolonged spell of summery weather on the cards, a few decent days in high summer is nothing special, perhaps I'm just expecting too much, but I always do at this time in the summer, this is peak high summer this is when we see on average our hottest weather of the year, I guess it has been the poor lacklustre weather of the last 4 weeks which is making me feel rather downcast, temps between 20-22 degrees and sunny spells isn't going to do it for me, it could do alot better!

Cheers Damian. Selfishly, my window is wed-fri and after having spent sun/mon in sunshine in the Yorkshire Dales, I'm feeling very happy at the weather I had/should have for my hols...

[MR EXTREMES]

I see what you mean

14 Low pressure centres!

haha that is a hell of a fax chart there is it what met o are going to base there forecast on

[Eugene]

The runs are as frustrating as yesterdays play on edgbaston so near yet so far, it looks like the SE might have to suffer a lingering front for days on end which might move into the midlands by the weekend then a strengthening jet might ruin any HP pushing up from the SW too, at least england are one nil up in the ashes, cant say that about the weather after the dreadful July.

[Shiny_Bottom_1]

Seems like some are missing the potential when looking at the ensembles on the GEFS. Pressure rise, warming up and drying up.

I really cant see the negativity in the mid to long term.

[Iceberg]

Indeed SB, If I look at the ensembles they are pretty fantastic really, where I live the 850 average is around 10C, Pressure average between 1020 and 1030. Below is the precip forcast.

So after this spell over rain, very warm, dry and settled. Certainly BBQ weather.

[johnholmes]

if we look at other outputs beyond GFS and ECMWF basic outputs then its clear that both NOAA and the GFS/EC 500mb hemisphere anomaly charts are showing up building pressure from the SW from about the end of the first week in August. Its a feature that caused me to suggest, no more than that, in my last lrf, that things might change. This mornings' EC/GFS charts out to 14 August both continue to show a large + area now just WSW of the UK. This agrees with the NOAA charts which now go out to 11-17 August showing a similar idea. How that ties in with sea temps in the mid Atlantic area I'm not sure.

Both the AO and NAO are showing a rise to zero or above but in summer this seems to have less direct impact than it would in the winter months.

So I would expect that the period from about 10 August, perhaps for a week or more, to have high pressure as the increasingly major theme, first for the south, then extending north. Overall, I would also expect, for this area of high pressure to edge more into the continent with less likelihood of an upper trough being close enough to the NE to prevent this happening.

How warm its going to get is very much open to question but a period with the Atlantic less dominant than for some time seems the most likely outcome.

As always we will have to wat until closer to the time for more detail to become apparent.

[chionomaniac]

Indeed SB, If I look at the ensembles they are pretty fantastic really, where I live the 850 average is around 10C, Pressure average between 1020 and 1030. Below is the precip forcast.

So after this spell over rain, very warm, dry and settled. Certainly BBQ weather.

Morning Iceberg,

There are big differences between the ECM and GFS on th 0Z wrt the trough to the north of the country at T+168. So the GFS looks promising but the exact southward positioning of this trough could determine whether or not the Azores successfully migrates this way or not. We will probably end up with a scenario somewhere in the middle, though I would favour the ECM presently as it is in line with what I suspect may occur.

c

[mushymanrob]

if we look at other outputs beyond GFS and ECMWF basic outputs then its clear that both NOAA and the GFS/EC 500mb hemisphere anomaly charts are showing up building pressure from the SW from about the end of the first week in August. Its a feature that caused me to suggest, no more than that, in my last lrf, that things might change. This mornings' EC/GFS charts out to 14 August both continue to show a large + area now just WSW of the UK. This agrees with the NOAA charts which now go out to 11-17 August showing a similar idea. How that ties in with sea temps in the mid Atlantic area I'm not sure.

Both the AO and NAO are showing a rise to zero or above but in summer this seems to have less direct impact than it would in the winter months.

So I would expect that the period from about 10 August, perhaps for a week or more, to have high pressure as the increasingly major theme, first for the south, then extending north. Overall, I would also expect, for this area of high pressure to edge more into the continent with less likelihood of an upper trough being close enough to the NE to prevent this happening.

How warm its going to get is very much open to question but a period with the Atlantic less dominant than for some time seems the most likely outcome.

As always we will have to wat until closer to the time for more detail to become apparent.

so a possible settling down as shown by the 00z gfs is likely into next week courtesy of the AZH ridging in. ok, not heat as such but if its pretty dry, warm and bright (cloud is my main concern regarding a ridging AZH) which sounds good to me!

[Guest North Sea Snow Convection]

The Azores westerly dirge still unfortunately looks to be on track to follow the brief Scandinavian High influence. Fairly cloudy bland weather off the atlantic with probably a few drizzly showers as weakening fronts come across the top of the high. Nothing of any interest or excitement at all from that.

The AZH has been absent since about Feb (when it stone dead killed the MMW party!) so six months is a fair gap not having to put up with it I suppose!

[johnholmes]

The Azores westerly dirge still unfortunately looks to be on track to follow the brief Scandinavian High influence. Fairly cloudy bland weather off the atlantic with probably a few drizzly showers as weakening fronts come across the top of the high. Nothing of any interest or excitement at all from that.

The AZH has been absent since about Feb (when it stone dead killed the MMW party!) so six months is a fair gap not having to put up with it I suppose!

I think you are being a touch pessimistic about the outcome 'me dear!

[Guest North Sea Snow Convection]

I think if one looks at most of the main models for days 5 to 7 there is a theme of a not too strong but broad westerly flow off the atlantic with the High not really close enough to provide clear enough skies imo and I think that quite a lot of cloud and moisture will be sucked off the atlantic with fronts coming around the high courtesy of low pressure just to the north. My tone was rather downbeat in terms of my own preference maybe, but I think in weather terms, based on what the charts show, then such an outcome is not unrealistic. So in that sense it is not pessimistic at all, at least IMO.

Of course the next day or so may show the high with a greater influence, but equally low pressure may make greater inroads with a tendency for pressure to drop over the north sea and scandinavia and the high centre to pull back even further west so that cloud and a few showers are even more likely. The latter theme has been hinted at in some modelling over the last day or two.

[Jack Wales]

The Azores westerly dirge still unfortunately looks to be on track to follow the brief Scandinavian High influence. Fairly cloudy bland weather off the Atlantic with probably a few drizzly showers as weakening fronts come across the top of the high. Nothing of any interest or excitement at all from that.

The AZH has been absent since about Feb (when it stone dead killed the MMW party!) so six months is a fair gap not having to put up with it I suppose!

I must admit that I do share your concerns a little, there is a potential spoiler for this weekend being the lingering front to our east and that the short wave may intensify along it as per recent UKMO outputs. Then into next week I fear the jet could flatten the Azores high as per the recent pattern.

What is encouraging though is that there finally does appear to be a shift in key factors such as the AO trending positive (which is consistent with the jet taking a more northerly track)

AO

There is also wide agreement in the ensembles of a pressure rise from this weekend, so fingers crossed I believe there is a more than 50/50 chance of experiencing something more like summer from tomorrow onwards!

[ANYWEATHER]

Ecm teases us with a pattern change, with the Azores high trying to flirt with the UK , but thats about as good as it gets! If this pattern pull off, then we are left in a rather cool, west to northwest airflow with rain bands moving into the west and north, although having said that ,like many times this year the southeast of England will get away with some half decent warmth and decent Summer weather,,,

[ANYWEATHER]

It looks as though the gfs is now making more of that little trough moving north on Friday and the thundery rain is further west to, would not surprise me if that trend continues and brings some very heavy rain to many part of central and eastern England in picticular!

[William of Walworth]

EIID, by any chance?

Yes, I've been keeping an eye on this. I'd rather not be wading through mud (as it appears I might have to from what I've seen for the days up to Thursday) in a field in the Cranborne Chase, but it seems that it's going to be comfortable for that weekend. Good job too rather. Seems the tents I saw them putting up just outside of Sixpenny Handley today for the festival may be useful later on though, time for that to change.

Yes, EiiD it is for us this weekend.

I'm really hoping that GFS is overdoing the Westward movement of that rain in its latest output, Dorset for now risks being just on the cusp between dry and wet weather ....

But MetO's latest updates indicate a predominantly drier picture for Cent South and SW England this weekend and beyond, so we can but hope these wetter trends shown on some models reverse themselves .........

As ever, I will continue to be unsure until right near the time ...

Edited August 4, 2009 by William of Walworth