Model Output Discussion

[grab my graupel]

A brand new thread to discuss the Models

All the latest output can be viewed in the Netweather Datacentre: http://www.netweather.tv/index.cgi?action=nwdc;sess=

Please continue

Brian

[Gibby]

GFS 00z output this morning begins with Low pressure moving east near Southern England today with attendant rain moving east with it over Southern England. Further North the slack North flow continues to provide showers today and this spreads south over the days Thursday through Monday with the east seeing the most showers but perhaps more generally again by Monday as Low pressure sits in the North Sea, Further out and high pressure is held much more to the SW today allowing weak troughs to ride round the top of the high and then move SE over Britain bringing the risk of rain at times with dry, bright and warm conditions restricted to being temporary features as ridges move in between the troughs with the parent high held much further SW this morning.

UKMO this morning continues to show the UK plagued by Low pressure to the east of Britain providing the risk of showers in the east at least while the west stays drier. However, as a Low pressure trough gets entwined in the flow come Sunday/Monday a band of rain could move through off the Atlantic to leave early next week under an unstable west then variable flow with slack Low pressure over England and Wales and further showers.

ECM this morning although looking the less progressive of the models keeps the weather a little unsettled between now and Monday before it is shown to have watered down the movement of high pressure into the UK next week. It instead keeps the windflow between west and north throughout its run and although a lot of dry weather is still shown under ridges of high pressure weak troughs moving down from the NW in the flow at times would keep cloud amounts large for much of the time and consequently temperatures not as high as progged yesterday. Doubtless too some rain would occur from time to time as the weak troughs pass by.

As expressed yesterday a lot of synoptics would have to pass before the evolution of ECM yesterday's output came to pass has been illustrated this morning. Both GFS and ECM show what happens when the synoptics simply don't play ball with just small differences from day to day having fundamental changes further on down the line. Of course things may well change for the better again but for now there is no doubt the weather is going to improve next week, especially in the south but those hoping for wall to wall sunshine from azure blue skies might need to think again as cloud amounts are going to be high with a continued chance of at least a little rain in places from time to time.

[ANYWEATHER]

Well Once again the models are downplaying the high pressure scenario again

[snowingman]

....awful............... no heat, not sun... just awful.... I am away back to bed!

[shedhead]

Very much so AW, caution was always required and still is, but things have definately drifted more towards UKMO's version of events, rather than visa versa. GFS has clearly moved towards a more unsettled outlook, with

any decent AH ridging now back in FI (again), but the biggest change of all has come from the hiterto fairly consistent ECM which has seen a major change across just 12hrs.

[swebby]

Morning,

It seems the ensembles are playing up again. Below is the percip chart for Devon taken from the 0z output.

Note the two peaks in the op on the 28th and 30th-31st.

These are the percip charts for those times....

Looks to me as if the location of devon is somewhere in scotland when we get to the low res part of the run?

Cheers

S

[Backtrack]

Well there we go, just as I expected. The settled spell has been downplayed 10 fold and the GFS has fell very much in line with the UKMO. It introduces a low pressure system into the North Sea, bringing cloud and sometimes rain with it.

It would seem that it is too much to ask for at the minute to have a decent spell of sun and heat. Can someone remind me what season this is?

ECM still looks okay, no LP system in the North Sea and the Azores High has ridged much further North and East with strength. This output is less likely to verify, but I expect it soon to fall in line with the GFS and UKMO.

The ECM would also bring a breakdown in from the North West around 30th July. But this may not affect all areas as illustrated on the FI charts.

So, expect plenty more downgrades!

Edited July 20, 2011 by Vegito

[AWD]

Considering most people that aren't going abroad will be heading to Devon and Cornwall in the coming days and weeks the output by all models isn't that bad really! Granted it could be better nationwide but there are still plenty of positives to take from them!

The GFS and UKMO show dry and warmer conditions in the west and south west still, with temps in the low to mid 20s!! Not so good in the north and east due to that Low in the north Sea!

ECM has the warmth and sunnier weather across much more of the country brining pleasently warm sunny days to much of England and Wales!!

All models show an improvement next week and all models show settled and warmer

weather over the south western quarter of the country so if your of to the Cornish Riveria next week expect sone pleasently warm summery conditions!!

Nothing stopping the ECM from verifying either just because it's on it's own doesn't mean it's wrong!!

Edited July 20, 2011 by Active Weather Dude

[chrisbell-nottheweatherman]

Considering most people that aren't going abroad will be heading to Devon and Cornwall in the coming days and weeks the output by all models isn't that bad really! Granted it could be better nationwide but there are still plenty of positives to take from them!

The GFS and UKMO show dry and warmer conditions in the west and south west still, with temps in the low to mid 20s!! Not so good in the north and east due to that Low in the north Sea!

ECM has the warmth and sunnier weather across much more of the country brining pleasently warm sunny days to much of England and Wales!!

All models show an improvement next week and all models show settled and warmer

weather over the south western quarter of the country so if your of to the Cornish Riveria next week expect sone pleasently warm summery conditions!!

Nothing stopping the ECM from verifying either just because it's on it's own doesn't mean it's wrong!!

So the forecast for other coastal areas doesn't matter because nobody goes there on holiday? What about my region? Plenty of people come to East Anglia for their holiday, to say nothing of other coastal areas. Ironically, one of the reasons for many people coming to the east coast is that it's usually drier here!

[paul tall]

So the forecast for other coastal areas doesn't matter because nobody goes there on holiday? What about my region? Plenty of people come to East Anglia for their holiday, to say nothing of other coastal areas. Ironically, one of the reasons for many people coming to the east coast is that it's usually drier here!

Absolutely correct.

Last time we holidayed in the UK, we stayed in South Wales and it absolutely hammered it down 5 days out of 7 with temperatures around 15-19º. I remember watching the BBC forecast every night and it was generally warm and sunny in the SE. The constant rain and wind, and knowledge that moving 100 miles East would improve the weather no end made things even more frustrating and to be honest the weather ruined our holiday as we were stuck on site in the amusement arcades. We certainly didn't feel like going anywhere in the wet.

So this time we "played safe" and are in Lincolnshire 22nd-29th July - the East is drier and sunnier - but already the models make the first 3 days look a write off, and to find the settled weather downgraded is...heartbreaking.

[Thundery wintry showers]

So this time we "played safe" and are in Lincolnshire 22nd-29th July - the East is drier and sunnier - but already the models make the first 3 days look a write off, and to find the settled weather downgraded is...heartbreaking.

Actually, you might be surprised to find that the Lincolnshire coast is, on average, a bit cloudier than the Devon/Cornwall resorts despite being drier, and rain falls on a similar number of days:

http://www.metoffice.gov.uk/climate/uk/averages/7100_1km/Sunshine_Average_1971-2000_14.gif

http://www.metoffice.gov.uk/climate/uk/averages/7100_1km/Rainfall_Average_1971-2000_14.gif

http://www.metoffice.gov.uk/climate/uk/averages/7100_1km/RainDays1_Average_1971-2000_14.gif

In Lincolnshire you'd be less likely to be heavily rained on but also more likely to get low cloud and chilly winds off the North Sea. The best bet for a combination of sun and dryness out of coastal resorts is the Eastbourne/Brighton/Bournemouth stretch.

It's not looking great for sunshine or warmth in eastern England over the coming week (although it may be mostly dry) with northerly winds remaining common.

[paul tall]

I am surprised actually. South Wales has put me off heading SW for life!

[Thundery wintry showers]

Ah, I didn't realise you meant South Wales- yes, except for some coastal fringes it is both duller and wetter than Lincolnshire there. Ironically they may do fairly well for warmth & sunshine out of the coming setup with the high pressure centred mostly to the west and south-west.

The upcoming weekend looks like a mixed bag, with some sunshine and showers on Saturday (sunniest in the west, cloudiest in the east is my reckoning, with showers concentrated towards the south) and Sunday will probably be dry and sunny in the west and cloudier in the east. On neither day is it likely to be warm but with light winds in the west it may feel relatively warm.

[Backtrack]

GFS 06z has upgraded to my surprise. It's shunted the Azores Ridge further East and has down played the low in the North Sea. Can only be great news for Eastern areas. But for a change... It's looking like 'West is best'!

Edited July 20, 2011 by Vegito

[Summer Sun]

Wide spread 20c + if these charts comes off,

http://www.wetterzentrale.de/pics/Rtavn1561.png

http://www.wetterzentrale.de/pics/Rtavn1801.png

Cloud cover could be a problem in some areas though

[Summer Sun]

Slow improvements from Sunday

http://www.wetterzen...s/Rtavn1021.png

http://www.wetterzen...s/Rtavn1261.png

http://www.wetterzen...s/Rtavn1501.png

http://www.wetterzen...s/Rtavn1741.png

http://www.wetterzen...s/Rtavn2161.png

GFS Has certainly upgraded for the end of July and into August the only problem is it's 2 weeks away so nothing is certain even for next week yet, though things are slowly becoming clearer now.

http://www.wetterzen...s/Rtavn2401.png

http://www.wetterzen...s/Rtavn2641.png

Edited July 20, 2011 by Gavin D

[The PIT]

The trend indicated by both the ECM and GFS for a warm end to the month is still there. It is still well in FI but since there's fairly good agreement between the two the odds are higher than normal for it to actually come off.

[Eugene]

GFS 12Z is excellent for warm weather fans, looks like the azores high will be coming into play big time with the jet becoming sluggish and pushed northwards, this could be the beginning of a very warm and dry August, the current unsettled spell has hardly delivered any rain to my area so drought could become a concern to farmers.

[mushymanrob]

one run does not a summer make...

the gfs today has thrown up a range of POSSIBILITIES over what might evolve, just because the 12z shows what most here would like to see, dont believe it just yet. things do appear to be suggesting a possible summery theme about a week away, but itll take several more runs before the bbq can be dusted off!

so dont take this one run as the one to set hopes on... its good, but possibly a warm outlier (of sorts).

drought could become a concern to farmers.

not at harvest time! :lol:

the last thing they want now is rain...

[January Snowstorm]

Excellent ukmo tonight along with improved gfs

I expect a stormer of an ECM tonight

Summer looks like arriving folks, indeed for Irish members it will feel like a heatwave!

[Nick F]

The 500mb height charts were full of +ve height anomalies this morning across Northern Europe into the medium range:

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

... and the trend appears to continue for a slow rise in heights and surface pressure from the Azores ridge as we head toward late July, with the jet perhaps finally shifting north from it's unseasonably southerly track of recent days.

[PubliusEnigma]

00Z ECM models a northerly flow out to and well into FI so with this in mind, average temps by day seem to be the mark with

some legnthy cloudy spells, as low pressure never far from the east coast. Polar Troughs coming down from the north could well

proprogate some lively showers at times more so in eastern areas. So average British summer temps 14-17oC generally a tad cooler

in the rain. I have to say we are now into our sixth consecutive overcast day with rain or heavy showers. Northerlies should bring

a respite from the continous rain, to that of more showery rain.

Well to the east of the trough developing over the North sea, temps have again been very high indeed ! :o

Volvograd

[Thundery wintry showers]

It certainly looks increasingly likely that high pressure will end up "there or thereabouts" as we head towards the end of July, and the result should eventually be a spell of warm dry sunny weather. However, I'm not sure how long that spell will last, and note "eventually"- the high is still not quite far east enough to guarantee warm, dry and/or sunny weather this side of T+168.

On the basis of UKMO I would have doubts about all three variables as it keeps us in a northerly or north-westerly regime through to the end of the run, and while it would be dry by T+144 with a north/north-easterly flow on the eastern flank of high pressure, those of us in central and eastern areas could still do with the high being placed a little further east. Similarly, while the GFS shows a very warm, sunny, summery outlook post T+168, we do keep troughs meandering around the high's northern and eastern flank before then bringing cloud and bits and pieces of showery rain.

I'll be surprised if we don't get some warm dry sunny weather out of the upcoming setup, particularly with longer-term signals suggesting that this high could stick around for a while, but until I see a warm dry sunny outlook this side of T+168 I'm going to continue to be quite cautious about it.

[Costa Del Fal]

Annoyingly the NAO has been downgraded to now stay just below neutral into negative suggesting Mid Atlantic based highs. The AO is still forecast just below neutral as well. It may suggest why any High Pressure is not forecast to be quite as "East" as we may like or why it may not last too long.

[Summer Sun]

00Z ECM models a northerly flow out to and well into FI so with this in mind, average temps by day seem to be the mark with

some legnthy cloudy spells, as low pressure never far from the east coast. Polar Troughs coming down from the north could well

proprogate some lively showers at times more so in eastern areas. So average British summer temps 14-17oC generally a tad cooler

in the rain. I have to say we are now into our sixth consecutive overcast day with rain or heavy showers. Northerlies should bring

a respite from the continous rain, to that of more showery rain.

Well to the east of the trough developing over the North sea, temps have again been very high indeed ! :o

Volvograd

Don't agree with that at all, temps will be much higher than 14 to 17c next week they will be upto around 22c in the south on Saturday by next week 20c plus quite widely

And given the fact GFS under does temps you can add 2 or 3c to that.