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Posted
  • Location: Runcorn, Cheshire
  • Weather Preferences: Snowy winters, hot, sunny springs and summers.
  • Location: Runcorn, Cheshire

Slight backtrack again tonight

The gfs has the high pressure cell barely ridging over us and never quite properly for early next week.

ECM will be key but so far you would have to back the form horse all Summer, being the azores high unable to move in properly.

Very frustrating that we cant get a decent bit of weather. Let's hope the ECM agrees with this mornings run!

Where are you getting any sort of backtrack from? The GFS is still showing very similar summery conditions regarding the Azores High as the earlier runs.

h500slp.png

Whilst the operational run isn't showing any signs of backing down, there might be a spanner in the works for a short time at least as the ensemble run is showing a slight pressure drop around July 25th, there's pretty good agreement for this too.

prmslcheshire.png

But as you can see from the above, there is some decent agreement for a pressure rise thereafter, but regardless of the pressure drop the 850 temperatures continue to rise, and I suspect that these may be underplayed somewhat, so temperatures in the mid twenties look likely:

t850cheshire.png

The ECM however has none of the pressure drop, and looks fantastic for summer conditions. Will it finally return though is the big question?

ecm500192.png

It looks like that the ECM would prolong the spell for the longest too looking at the main three, this would also bring the highest temperatures and sunniest conditions with no hint of low pressure close enough to the British Isles to have an influence, so none of the North sea low cloud crap, or coastal cloud, it would just be plain sailing, I for one hope that the ECM verifies as the UKMO is having none of it still.

met120.png

As you can see from the chart above (UKMO) it has the Azores High much weaker and throws a pesky low into the North Sea, meaning that we could see a West - East split, where as the West sees the best of any sunshine and warmth. Where as the East sees the showery regime continue.

Although I posted earlier that I was going to back the UKMO, I am losing confidence in this output, as the ECM and GFS have been very consistent in their runs, and there's some fairly good agreement for a settled spell starting around July 25th.

In summary, summer is likely to return to the British Isles for a time at least. When I say likely, I mean there is around a 66.6% chance, as the UKMO is not on board....YET!

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Posted
  • Location: Redbourn,Herts AL3. 122M ASL
  • Weather Preferences: Hot summers, Storms and epic cold snowy winters
  • Location: Redbourn,Herts AL3. 122M ASL

As most post,s are stating treat output with caution so to speak. However you cant help but be excited as this is at present the best chance we have had for along while. If the ECM pulls through again tonight...Well lets wait and see.:good:

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Posted
  • Location: Runcorn, Cheshire
  • Weather Preferences: Snowy winters, hot, sunny springs and summers.
  • Location: Runcorn, Cheshire

ERM, i think you will find ukmetoffice base their forecasts on the ukmo/ecm and ensemble data knowitall. :rofl:

I just emailed them, would be interesting to know actually, I thought they would of just based their forecasts on their own model?

Oh well, we'll see lol.

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Posted
  • Location: Lincoln, Lincolnshire
  • Weather Preferences: Sunshine, convective precipitation, snow, thunderstorms, "episodic" months.
  • Location: Lincoln, Lincolnshire

.... i expect IF the ecm came off, there would be the problem of cloud, only the other august (04?05?06? memory lets me down) there was alot of high pressure sited just to our west, this produced (here at least) a cloudy sun-less lengthy spell. atlantic high = moisture in its circulation = possible problem with cloud.

The first halves of Augusts 2005 and 2006 both had high pressure to the west and northerlies over Britain. From your description, it sounds like you're recalling the second week of August 2006, which in Leeds (where I was at the time) was persistently grey and drizzly, and the synoptics were somewhat reminiscent of what the models had been showing for next week until a couple of days ago. Indeed, that's the spell I had in mind when I talked about dry cloudy weather and modified air from the NE in some earlier posts:

http://www.wetterzentrale.de/archive/ra/2006/Rrea00120060812.gif

I remember the northerlies in early to mid August 2005 brought rather brighter weather but again it was never particularly warm:

http://www.wetterzentrale.de/archive/ra/2005/Rrea00120050808.gif

The models have drifted away from those scenarios in the last couple of days which is why I've been getting more optimistic, but as late August 2008 starkly showed, banks of cloud can still be an issue if we get high pressure to the SW/S, so it's still a cautious optimism.

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Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington
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which means there is going to be monumental climbdown by either gfs/ecm OR ukmo tomorrow morning.

my moneys still on ukmo being correct

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Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

I just emailed them, would be interesting to know actually, I thought they would of just based their forecasts on their own model?

Oh well, we'll see lol.

somewhere within Net Wx files is the reply I posted after e mail chats with senior staff I still have contact with at UK Met.

Essentially they take the ECMWF T+6/700 hours plus, run just once weekly as a basis for 16-30 day outlooks. Process it with their own soft ware first. The 6-15 days is a mix of their own multitude of models from T+6 out and from 5km grid square length out to the global model at, I think, 60km.

For more info on their own models then go to their web site and search for the necessary link.

jh

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Posted
  • Location: Runcorn, Cheshire
  • Weather Preferences: Snowy winters, hot, sunny springs and summers.
  • Location: Runcorn, Cheshire

somewhere within Net Wx files is the reply I posted after e mail chats with senior staff I still have contact with at UK Met.

Essentially they take the ECMWF T+6/700 hours plus, run just once weekly as a basis for 16-30 day outlooks. Process it with their own soft ware first. The 6-15 days is a mix of their own multitude of models from T+6 out and from 5km grid square length out to the global model at, I think, 60km.

For more info on their own models then go to their web site and search for the necessary link.

jh

Oh right, thanks very much John!

Odd how they just use one run weekly, myself I would find that to be inaccurate if I was basing a forecast on a once a week run, but as you said they process it with their own software, must increase accuracy 10 fold.

Interesting stuff, cheers! drinks.gif

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Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

As you can see from the chart above (UKMO) it has the Azores High much weaker and throws a pesky low into the North Sea, meaning that we could see a West - East split, where as the West sees the best of any sunshine and warmth. Where as the East sees the showery regime continue.

Although I posted earlier that I was going to back the UKMO, I am losing confidence in this output, as the ECM and GFS have been very consistent in their runs, and there's some fairly good agreement for a settled spell starting around July 25th.

In summary, summer is likely to return to the British Isles for a time at least. When I say likely, I mean there is around a 66.6% chance, as the UKMO is not on board....YET!

thanks for doing the links so folk can see what you are discussing-if only all posts were done that way.

Just one point, I think you will find that UK Met have, for several days, gone with the idea of a spell of settled weather moving up from the SW, much as I've shown a couple of times using the 500mb anomaly charts to help explain things.

What happens after is the interesting bit and I support their view that its a temporary change to more settled anticyclonic type with a reversion to the unsettled type after- ? 3-6 days.

I'll try and post these ideas illustrated with the last 3 outputs from the NOAA 500mb anomaly version in a bit.

Oh right, thanks very much John!

Odd how they just use one run weekly, myself I would find that to be inaccurate if I was basing a forecast on a once a week run, but as you said they process it with their own software, must increase accuracy 10 fold.

Interesting stuff, cheers! drinks.gif

cost in a word is the reason and also time for the senior man to be able to do a 16-30 day 'new' outlook every day other than simply tidying up the end of the 6-15 and the start of the 16-30 day is VERY time consuming. His priorities are on matters closer to T+00, military, civil etc etc

hope that helps explain why?

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Posted
  • Location: Kilmersdon Radstock Somerset
  • Weather Preferences: None Really but a snow lover deep down
  • Location: Kilmersdon Radstock Somerset

GFS tonight shows a slack Northerly flow over the UK with showers particularly for Eastern Britain while many western areas become dry from Friday. Over the weekend the model shows low pressure deepening near Northern Denmark with a trough moving in close to the east coast while another weak Atlantic one moves SE over the UK on Monday. This would mean some rain likely in the far east on Sunday while other regions see more showery conditions again as the trough runs south. Further out and High pressure builds in from the SW but is dented at times by weak troughs moving around the high and down over the UK in the continuing west or northwest flow. Nevertheless, the weather would show a marked improvement on recent events and temperatures would be rather higher too.

UKMO is still not having any of the short term improvements tonight. The showery and unsettled conditions of recent days remains for a few more days before a drier interlude over Friday and Saturday. Low pressure over Scandinavia then retrogresses west then SW to be centred near NE Scotland by Monday with a slack and showery west flow over all parts once more.

ECM also shows an unsettled theme up until the weekend with Low pressure somewhere close to the East filling slowly. A disturbance crossing close to the south coast tomorrow will bring a spell of rain across parts of southern England tomorrow. Thereafter, showers for Thursday, less on Friday and Saturday as a ridge lies close to the west. Later in the weekend weak troughs move SE as well as Low pressure near Denmark gives eastern coastal counties a dismally cool and possibly wet day Sunday. As next week progresses High pressure extends NE from the SW over Northwest Britain with lower pressure over the near continent. The High pressure exerts its influence over all of the UK then with temperatures rising above normal for many in sunny spells and dry conditions though at 240hrs it shows the high beginning a retreat back into the Atlantic.

It still looks good for an improvement next week as high pressure ridges up from the SW to bring a welcome change to warmer and sunnier conditions. GFS keeps enough of a west or northwest wind to allow weak troughs to breach the high at times while ECM has a worrying 240hrs chart showing high pressure retreating back out into the Atlantic to allow pressure to fall steadily over the UK. Also there is still the rest of the week and weekend to resolve first with the scenario of the retrogressing Low which UKMO has centred over Scotland by noon next Monday which could influence its evolution thereon. I still urge cautious optimism tonight as there is still a lot of synoptics to get through before we can verify ECM's outcome.

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Posted
  • Location: Lincoln, Lincolnshire
  • Weather Preferences: Sunshine, convective precipitation, snow, thunderstorms, "episodic" months.
  • Location: Lincoln, Lincolnshire

The ECM has re-introduced the north-easterlies, so if the ECM was to verify I would expect dry, sunny and fairly warm conditions to take over in western areas by next Tuesday but I would be pretty cautious about central and particularly eastern areas. The chart for Tuesday in particular is quite similar to the August 2006 chart that I posted earlier- high pressure is a bit further east, but remember that the August 2006 spell was cloudy at times even in the west. There would be few issues with banks of cloud and generally rising daytime temperatures come Thursday but that's at T+216, so we're still waiting for that widespread warm dry sunny weather to creep outside of the realms of FI.

I think we may have a relatively limited "window of opportunity" for warm dry sunny weather as I don't foresee the Atlantic remaining that quiet for so long- I think it's only a matter of time before it comes across and sinks the high pressure (rather like the ECM T+240 hints at), most likely into the beginning of August. There's a lot of agreement on this view as per John Holmes's post above.

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Posted
  • Location: Runcorn, Cheshire
  • Weather Preferences: Snowy winters, hot, sunny springs and summers.
  • Location: Runcorn, Cheshire

thanks for doing the links so folk can see what you are discussing-if only all posts were done that way.

Just one point, I think you will find that UK Met have, for several days, gone with the idea of a spell of settled weather moving up from the SW, much as I've shown a couple of times using the 500mb anomaly charts to help explain things.

What happens after is the interesting bit and I support their view that its a temporary change to more settled anticyclonic type with a reversion to the unsettled type after- ? 3-6 days.

I'll try and post these ideas illustrated with the last 3 outputs from the NOAA 500mb anomaly version in a bit.

cost in a word is the reason and also time for the senior man to be able to do a 16-30 day 'new' outlook every day other than simply tidying up the end of the 6-15 and the start of the 16-30 day is VERY time consuming. His priorities are on matters closer to T+00, military, civil etc etc

hope that helps explain why?

Yes thanks John it does! I do see now why they only issue a new forecast weekly, costs a lot of dough!

No probs, I do illustrate my posts with links/charts when I do have the time, and really sorry, I haven't been following this thread much, had no idea that the UKMO were introducing a settled spell of weather from the SW, I've just been looking mainly at the operational run, I've not even looked at the forecast on the website, I will do so now actually!

Thanks again.

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Will this be one of those spells which gives decent spells for some like us last week, or one which a prolonged settled spell over the UK. the latter does seem very possible going by tonight's charts, but some caution is possibly needed.

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Posted
  • Location: Cork City(Southern Ireland)
  • Location: Cork City(Southern Ireland)

Eventhough the ECM looks very good the ridge cast over us is far from bullet proof.

The azores high needs to nudge in just a tad bit more.

Tomorrow will tell a lot but for now next week is looking like Summer has arrived!

Cross your fingers and toes it's there in the morning!

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Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

still waiting for the NOAA 8-15 day 500mb chart to discuss the last 3 ouputs.

as time presses on it will be in pdf format.

Edited by johnholmes
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Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

Finally here with the pdf after watching the programme with John Hammond and the centre of the earth. Not bad other than the musak in the background-given the number of times I and every other person with a hearing problem along with RNID have complained about it this producer seems not to have read the script about background noise.

sorry I digress

re the 500mb charts and how the weather may turn out to be end July-early August.

pdf format below-the last link re Met O should not be there but unable to move it once in pdf format!

500mb charts again tue 19 july 2011.pdf

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Posted
  • Location: southeast wales
  • Location: southeast wales

Finally here with the pdf after watching the programme with John Hammond and the centre of the earth. Not bad other than the musak in the background-given the number of times I and every other person with a hearing problem along with RNID have complained about it this producer seems not to have read the script about background noise.

sorry I digress

re the 500mb charts and how the weather may turn out to be end July-early August.

pdf format below-the last link re Met O should not be there but unable to move it once in pdf format!

500mb charts again tue 19 july 2011.pdf

JH...try your post 897 for the options you gave..

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