Model Output Discussion

[Gibby]

GFS shows a showery and unsettled week to come as Low pressure remains close to Eastern Britain before moving slowly away east late in the week. Thereafter pressure slowly but surely rises from the SW so that by the days towards the end of the run High pressure sits over the UK with fine and warmer weather for all. However, we take a long time getting there and the preceding times are shown to be governed by Northerly winds, and the risk of showers in the far NE remains with dry, bright weather elsewhere albeit no heatwave.

UKMO also shows unsettled weather all week as Low pressure remains close by. It's fly in the ointment is on day 6 is that it shows a retrogressing Low from Scandinavia move SW out into the North Sea maintaining the very showery theme through the week last into the weekend too more especially to the east.

ECM also shows Low pressure in control throughout the working week with showers or longer spells of rain almost everywhere at some point or another especially in the south midweek as a small secondary depression moves through. Even by day 6 Low pressure remains to the NE with some showers in Central and Eastern areas while the west would see few showers and longer bright spells if still on the cool side. Towards the end of the run ECM as per UKMO shows a retrogressing Scandinavian Low meaning the run is less keen to bring any meaningful rise of pressure sufficient enough to settle things down with showery weather persisting in the north and East while an atlantic trough would be sliding SE near to the SW for a while. By day 9 and 10 things do look a little more promising as High pressure inches closer from the SW although winds remain from a west or northwest point with cloudier periods and the chance of rain still chiefly in the North.

In Summary GFS is the pick of the bunch as it shows gently rising pressure from the SW from the end of the week resulting in a spell of more settled weather-eventually. The Euro models are less convincing as both UKMO and ECM show a retrogressing low in a week or so which determines where the weather goes thereafter. In tonight's run ECM looks less favourable than this morning and it underlines how on a knife-edge any substantial pressure rise from the SW is and how long it is sustained.

[mushymanrob]

you mean this one rob ?

http://www.meteo.psu.edu/~gadomski/ECMWF_0z/hgtcomp.html

given that the ecm ens are't quite out yet, its clear that this is a mean of the op runs days 8 thru 10 so the two will obviously edge towards a similar picture!! i'll try and post a link to the ecm 500mb mean flows at T168/T240 to compare whether its accurate

here you go

http://www.ecmwf.int/products/forecasts/d/charts/medium/eps/ensm/essential!Geopotential%20at%20500hPa!Europe!168!pop!od!enfo!plot_ensm_essential!2011071700!!/

if you flick through the timescales T168 to T240, you'll see the differences between the mean on the left and the op on the right. clear that the earlier chart reflects the op run but the ens isnt too far away, given that it is bound to be less amplified. exactly where will the trough sit and how quickly can it fill ????

changing the parameter to MSLP also shows that the pressure anomolies are fairly well reflected by the mean though again, with rather less gusto.

wonder if the naefs 00z update will be better than yesterdays 12z which was quite unenthusiastic about prolonging any improvement during the last week july. the spreads on the ecm 00z look interesting if we can get the trough to fill out as they lift the jet well north of where its been sitting.

thanks for that info

[TEITS]

No i think if i'm looking correctly, it dies a death by Monday or Tuesday

http://www.wetterzentrale.de/pics/Recm1921.gif

http://www.wetterzentrale.de/pics/Recm2161.gif

ECM is showing the pressure rise from the south west it's just doing it slower than GFS at present

Whilst I admire your positive spin on the models, in my opinion the outlook continues to be rather disappointing especially if you're seeking a hot spell. I keep reading the words "slow improvement" but to be honest synoptically it has to improve because at the moment it doesn't really get any worse with a relatively deep LP system centred across the UK.

As we enter next weekend the UKMO/ECM both show a N,ly flow which is what I commented on a few days ago with regards to John H post. Beyond and the ECM continues to show the same problem that we have had all summer and that is the Azores HP remaining surpressed to our SW.

So in summary it will turn more settled but temps will only remain around average, possibly slightly below normal during the N,ly. Absolutely no sign of any heatwave or prolonged settled weather. Any settled weather is only likely to be brief. So really a continuation of what we have seen so far!

[95 Degrees]

Whilst I admire your positive spin on the models, in my opinion the outlook continues to be rather disappointing especially if you're seeking a hot spell. I keep reading the words "slow improvement" but to be honest synoptically it has to improve because at the moment it doesn't really get any worse with a relatively deep LP system centred across the UK.

As we enter next weekend the UKMO/ECM both show a N,ly flow which is what I commented on a few days ago with regards to John H post. Beyond and the ECM continues to show the same problem that we have had all summer and that is the Azores HP remaining surpressed to our SW.

So in summary it will turn more settled but temps will only remain around average, possibly slightly below normal during the N,ly. Absolutely no sign of any heatwave or prolonged settled weather. Any settled weather is only likely to be brief. So really a continuation of what we have seen so far!

Not sure where you are getting that assumption from because all models currently show that the AZ will make it into NW Europe, sometime between 26th July-1 august, all could change for the worse but things are looking pretty good on the models atm.

[TEITS]

Not sure where you are getting that assumption from because all models currently show that the AZ will make it into NW Europe, sometime between 26th July-1 august, all could change for the worse but things are looking pretty good on the models atm.

Not an assumption but what the ECM shows.

Your right with regards to the GFS output but certainly not with the ECM!

http://www.wetterzentrale.de/pics/Rtavn2401.png

http://www.wetterzentrale.de/pics/Recm2401.gif

Massive difference between the two models!

Just add how can the models look pretty good at the moment. Both the UKMO/ECM show a N,ly at +144. Im only happy to see a N,ly flow in winter!!

Edited July 17, 2011 by THE EYE IN THE SKY

[William of Walworth]

UKMO also shows unsettled weather all week as Low pressure remains close by. It's fly in the ointment is on day 6 is that it shows a retrogressing Low from Scandinavia move SW out into the North Sea maintaining the very showery theme through the week last into the weekend too more especially to the east.

ECM also shows Low pressure in control throughout the working week with showers or longer spells of rain almost everywhere at some point or another especially in the south midweek as a small secondary depression moves through. Even by day 6 Low pressure remains to the NE with some showers in Central and Eastern areas while the west would see few showers and longer bright spells if still on the cool side. Towards the end of the run ECM as per UKMO shows a retrogressing Scandinavian Low meaning the run is less keen to bring any meaningful rise of pressure sufficient enough to settle things down with showery weather persisting in the north and East while an atlantic trough would be sliding SE near to the SW for a while. By day 9 and 10 things do look a little more promising as High pressure inches closer from the SW although winds remain from a west or northwest point with cloudier periods and the chance of rain still chiefly in the North.

Just been watching the synoptic-filled Countryfile forecast on BBC1, which very much echoes the UKMO and ECM theme -- any HP influence seems very slow to move in from those two models. In fact it looke to me like the very latest output is significantly slower than before in terms of wanting to bring in heights from the SW.

Not washout weather later in the week by any means, especially not to the West, but yet again summer seems likely to be delayed, and more so than in earlier runs.

Surely there's got to be an occasion -- in subsequent models this week perhaps? -- when something more HP-progressive (GFS like?) will verify as opposed to the current Euros?

I'm none too optimistic though, right now.

Edited July 17, 2011 by William of Walworth

[johnholmes]

The pdf below gives my views on how things seem likely to develop towards the month end the and two possibles as I see it for the first week in August and possibly beyond?

by all means disagree but please try and back up any comments + or - with your own charts to explain your view. Remember I've based this outlook ONLY on how I see the 500mb anomaly charts over the past 3-5 days, missing yesterdays' as well.

To get a real feel for the latter part it really needs a close look at teleconnections further out and I've not had time to do that this evening.

No 27 issued 22 jul for-500mb anomaly update for Net Wx.pdf

[Bale]

The pdf below gives my views on how things seem likely to develop towards the month end the and two possibles as I see it for the first week in August and possibly beyond?

by all means disagree but please try and back up any comments + or - with your own charts to explain your view. Remember I've based this outlook ONLY on how I see the 500mb anomaly charts over the past 3-5 days, missing yesterdays' as well.

To get a real feel for the latter part it really needs a close look at teleconnections further out and I've not had time to do that this evening.

No 27 issued 22 jul for-500mb anomaly update for Net Wx.pdf

Evening JH...an excellent read and very easy to understand,thanks for your effort

[Thundery wintry showers]

A good analysis by John, well-reasoned and backed up by synoptic information. There's one part that I'm uncertain about:

Much of the country should see mainly dry weather with, dependent on sea track, reasonable sunshine totals for several days and with rising temperatures. I doubt any real heat wave but pleasant enough for many. The one fly in the ointment, well there are two actually, but I’ll come to the second one in a moment. The first one is that area of the north east, chiefly east/north east Scotland but possibly the far north east of England and south eastern Scotland could be rather slow to join in with improvement.

I think the "dependent on sea track" part is why, particularly before this evening's set of runs, I've been rather less optimistic about sunshine amounts across the eastern half of England in particular. A lot depends on specifically how the high pressure and the trough to the east line up, but if the trough stays fairly close to the E/SE then I can see a rather nippy and probably cloudy north/north-easterly flow affecting the eastern side of England. However, this evening's runs have tended to place the low further north, typically over Scandinavia, giving more of a north-westerly type which would bring rather less cloud to eastern England, and leave east/north-east Scotland more prone (which is more consistent with John's analysis). The UKMO and ECM operationals have the low rather too close and too strong to enable the high to have much of an impact but the GFS operational and ECM ensemble mean certainly have the high come close enough to suggest a generally dry sunny outlook bar the odd shower in eastern areas, and probably a combination of warm days and cool nights.

Some backup charts to illustrate: the GFS T+144, with a significant ridge from the Azores High giving a slack north-westerly:

http://www.netweather.tv/gfsimages2/gfs.20110717/12/150/h500slp.png

...and the UKMO at T+120 and ECM at T+144 giving a more cyclonic outlook:

http://www.netweather.tv/models/meto/20110716/12/images/met.120.png

http://www.netweather.tv/ecmimages2/20110717/12/ecm500.144.png

...and a GFS run from yesterday showing the "cool cloudy east" scenario that I mention:

http://www.netweather.tv/gfsimages2/gfs.20110716/12/216/h500slp.png

[Milhouse]

Summer returns in style on the 18z.

[Cheshire Freeze]

Late July settle down of the weather looks plausible to me as the ridge asserts itself for possibly upto a week. After that it's down the pan again in my eyes, with the METO further outlook concurring with this as things stand. The beginning of August could be quite wet again in my opinion. We should at least have some fine, warm and dry days before that though.

[Costa Del Fal]

No high pressure really on this mornings GFS 06z and has sided more with the ECM, that is the low to the North East of the UK becoming too much of an influence with more rain and showery conditions. No High pressure shown for the rest of the run. Not the best of charts but still could be worse imo.

[mushymanrob]

hopes of something 'better' occuring later in the week look like itll be breif, as no high pressure looks set to dominate more then a day or two... ie this summers pattern looks set to continue... normal and average. judging by this mornings outputs writing off a decent hot spell this summer looks a fairly safe bet.

[ANYWEATHER]

The "phanton" progged ridge by the end of the week as not surprisingly dissapeared and been replaced by the usual unsettled conditions. Im on Holiday Next Week in what would be nice to say Sunny SouthWales, but im not expecting anything like ,Oh Well!!

[Gibby]

GFS this morning shows low pressure to the east of us for the majority of this week with bands of cloud and showers spinning around it and down over the British Isles. As the week passes showers will become more restricted to eastern areas as a ridge attempts to push in from the west. However, a retrogressing Low from Scandinavia halts that process by over the weekend with a couple of days of very showery conditions again in a rather cool North or Northwest breeze. Further out into FI and yesterdays excursion to more summery weather has evaporated as a weak ridge early next week quickly collapses to bring us back under Atlantic Low pressure together with wind and rain right through to the end of the run.

UKMO shows a showery week too as the process of filling Low pressure just to the east continues to move away east by the weekend. So heavy showers for all through the week these restricted to eastern coastal counties by Saturday with some dry, bright weather albeit still rather cool further west.

ECM shows an unsettled week for the UK with heavy showers for many, especially but not exclusively to the east before it continues its retrogression theme going next weekend. This squeezes the ridge of high pressure near Western Britain late in the week out of existence as Low pressure puts pressure on it from the west too, which eventually wins the battle to bring the UK further Low pressure, wind and rain by the runs end.

No sign of summer again this morning I'm afraid as GFS has flipped to a very unsettled operational after more promising conditions were favoured yesterday. ECM also looks decidedly unsettled throughout despite a brief window of dry weather over the coming weekend for some western regions though never very warm. The UKMO 144hrs chart is very hard to call this morning as it looks quite promising for oncoming days at first glance as it looks like the Azores ridge could affect southern Britain thereafter settling things down at least there, though it's too early to call at that range and how its shown.

[shedhead]

Very much back down to earth with a bump this morning, with the signal for improved conditions, particularly from GFS, being completely blown away. ECM has shown far better consistancy across the last few weeks, being

far less prone to HP 'wobbles' and remains the model to watch imo, with GFS no doubt coming up with further teases across the coming days.

[Alex95]

The set up for the end of the week and the weekend is the worst possible scenario for NE England and NE Scotland. The GFS has even given maximums of 6-9°C in these areas on Saturday with heavy rain coming in off the North Sea! This could well be the coolest July day(s) for many years. Interestingly, it is a similar setup to the start of the November cold spell which brought that excessive snowfall to the North East, but this time its just going to be raw, dull and wet. Thank God I'm gonna be in Florida by then.

Edited July 18, 2011 by alza

[Methuselah]

Odd how all the dire warnings of 'only 14C in London on x-day this week' have so-far failed to materialize?? Once again, it looks like the SE at least will see maxes between 18 and 21C, for much of the coming week.

Not a heat-fest, I agree...but hardly destined for the Guiness Book Of (Cold) Records, either!

[Alex95]

Odd how all the dire warnings of 'only 14C in London on x-day this week' have so-far failed to materialize?? Once again, it looks like the SE at least will see maxes between 18 and 21C, for much of the coming week.

Not a heat-fest, I agree...but hardly destined for the Guiness Book Of (Cold) Records, either!

Indeed, but there was a day in July 2004 when maximums in the North East were around 10°C, that could be matched this weekend. Elsewhere it actually doesn't look too bad, it should be quite nice in Western areas for example

[shedhead]

Odd how all the dire warnings of 'only 14C in London on x-day this week' have so-far failed to materialize?? Once again, it looks like the SE at least will see maxes between 18 and 21C, for much of the coming week.

Not a heat-fest, I agree...but hardly destined for the Guiness Book Of (Cold) Records, either!

Even if we do see 18-21c across London this week, given an average max of almost 23c those values will represent cool, even very cool conditions. Max temps can also be misleading as to how the days really

feels, especially in showery situations. Quite often we see max temps for the day around 19c, but when you look back over the obs much of the time values were in the 15-17c, just popping up to 19c in a

lengthy sunny spell between the showers.

As you say perhaps not Guiness Book of Records cold, but this week represents just about as cold as we can get here in July outside persistent rain, so whilst a positive spin is always welcome so is a dose of

reality - and the reality is cool, unsettled and thoroughly disappointing for the 2nd half of July.

Edited July 18, 2011 by shedhead

[UV-RAY]

Looks like we will enjoy at least 3 days of fine warm weather next week before summer puts the sold sign up, thereafter things looking Autumnal. Ok a bit OTT, but certainly no signs of a prolonged warm/dry spell, and if anything August could turn out more unsettled than June/July.

[bluearmy]

interesting morning as the ops wobble about a possible better spell whilst the ecm ens + naefs (inc spreads) look more promising than they did yesterday. normally, i'd be far more supportive of the means/spreads at this timescale, but given the propensity this summer for blocking to strengthen to our north as verfication approaches, the trough may well be left with nowhere to go but ne europe (again). time for watching and measured responses rather than 'wrist slitting' and writing off the remainder of the summer.

the 500mb mean charts will be interesting this morning. neither gfs or ECM will reflect the ens mean too well. i imagine the ops will be quite similar though. all very uncertain. NOAA cpc (forecaster input) available tonight.

[shedhead]

Whilst 3 fine, warm days are possible next week, I cannot see anything in the current model output to suggest they are likely. ECM offers little if any significant change to the current pattern through much

of the run and even GFS looks a good deal more unsettled than it did 18-24hrs ago, so no real end in sight at the moment imo.

Edited July 18, 2011 by shedhead

[Thundery wintry showers]

Indeed, but there was a day in July 2004 when maximums in the North East were around 10°C, that could be matched this weekend. Elsewhere it actually doesn't look too bad, it should be quite nice in Western areas for example

Yes, it was the 8th July 2004. I was in Cleadon at the time (on holiday from Lancaster University) and my records indicate a maximum of 12.1°C, mainly because there were a few holes in the cloud sheet that evening, but I remember that some other parts of the regions, and also the Midlands, failed to reach 10°C all day, and that the midday temperatures there were widely the lowest since the 9th July 1993.

The GFS 18Z charts that Millhouse posted certainly looked good for some warm dry sunny weather across a large majority of the country, with the northerly having largely run out of steam and high pressure all over the place. However the models have taken a turn towards keeping the high pressure further west this morning, such that it never really gets close enough to have much of an impact. Generally speaking most of this coming week looks like having a mix of sun and showers and below-average temperatures, but an area of more persistent rain is suggested for northern England on Wednesday. I originally envisaged drier cloudier conditions spreading from the north towards the weekend (the "warmer settled weather arrived at via dry cloudy conditions and warmer nights" scenario), but as the GFS operational shows, if the low pressure is far west enough then wetter cloudier conditions with colder days and warmer nights will be the more likely result. It probably isn't the last word on the setup though and maybe the models might be over-egging the low at present.

Interestingly the NOAA 8-14 day outlooks now suggest highest pressure being positioned to our north, which suggests that they think the models are both over-egging the low to the east and the lows subsequently coming in from the Atlantic. I think from a warmth, sun or even dryness perspective things look somewhat iffy, but I would advise against writing anything off at present as the outlook keeps shifting.

[Paul]

That's from the 00z, 6z ensembles will be out shortly.