Model Output Discussion 22/07/12 Onwards.

[William of Walworth]

Tentatively reassuring, or starting to be perhaps, that GFS, ECM and UKMO (as far as it goes) may be beginning to agree about more HP influence, at least further South, by the time we get to next week.

I agree prospects look pretty unsettled -- away from the more sheltered SE areas at times -- until then. Frosty's summary looked about right IMO.

My own main personal focus is for next week, but I'm also interested in possible movement of the trough as this week progresses. As stated above, any kind of noticeable position shift further away from us, of the main LP track, could change conditions on the ground quite radically -- at least further S. May not happen though, in fact I doubt it myself, but we'll see.

BBC written four week forecast (broadly UKMO based, updated today) is cautious as ever, but is by no means as downbeat about some modestly more summer-like conditions after this week. Albeit very much on a N/S divide basis ....

Edited July 30, 2012 by William of Walworth

[Thundery wintry showers]

After the sunshine and showers of the last few days, frontal rain certainly looks like making a return widely over the next two days. A warm front will push north-eastwards tomorrow, followed by a cold front on Wednesday, and there will be strong winds making it feel quite autumnal in the north and west of the country. In the "warm sector" in between the fronts, Wednesday could well turn out to be warm and humid in eastern England with highs of 22-24C suggested for East Anglia and the southeast.

From Thursday onwards, the model outputs are suggesting a generally bright and showery picture for most, with winds slowly easing off, and potentially some interest for the convection/storm fans into next weekend in particular. However, there will be persistent fronts on the northern flank of the low pressure, so it will only take a small southward adjustment (as happened with the slow-moving low near the beginning of this month) to produce generally cloudy conditions accompanied by showers and longer spells of rain for the majority of the country. Having been "bitten" once by the low at the start of the month I'm not going to stick my neck out too much on sunshine amounts past Wednesday.

[shedhead]

Where do people think we're heading into next week? There seems to be some signs of at least two models wanting to drag in a High from the Atlantic for a week or so but not a very warm one from some of the temperature forecasts. Any thoughts?

Unsettledville, stopping at Wet, then Showery and Often Cool on route.

[Robbie Garrett]

Personally I think the CFS has it spot on for the next few weeks, up till mid-September.

Mostly ever changeable weather patterns that we have experience over the past few months, and probably very similar to the previous Summer months that we have endured over the years. No point posting the latest CFS runs for August as it's pretty much doing what the GFS is doing, so there is some agreement over the models especially with the Greenland high and the trough over the UK.

Regular ridges of the Azores high may break the weather a bit, but other than that I can't see anything decent in the foreseeable future... except maybe a repeat of the record September/October warm weather spell we experienced in 2011.

So not all is lost as I am sure September has enough energy to get temperatures into the mid 30's across the whole of the UK, if that's what you're looking for.

The 1 monthly is showing quite a strong area of high pressure in the Greenland Area towards the end of the run and I am wondering if the cooler weather over this part of Europe and the very warm area near Greenland may persist throughout the Autumn period and into Winter 2012/13.

Just having a look through the 9 monthly and nothing indicative yet of any strong high pressure above Greenland, but lets be honest by the time the polar vortex comes about and the weather does what weather does, and we continue in the way we are with cooler weather and warmer weather over Greenland, it may prompt something out of the ordinary for the atmosphere again...

Interesting times coming ahead... especially if the Jet-stream continues to act in the abnormal way.

Edited July 30, 2012 by Robbie Garrett

[mushymanrob]

cant see any tangible signes this morning off any run that would give even a glimmer of hope that something warm, dry, settled and sunny is on the cards.

i expect an anticyclonic regime at sometime before winter, but tbh thats too late to enjoy the summer, light evenings, gardens in full bloom, etc.

[MattH]

Looks like a very deep low for the time of year will hit the north west Thursday and Friday could see gusts of 50mph maybe even 60mph in exposed areas

FI remains unsettled untill August 11th before high pressure begins to edge in and the Jet Stream heads north

So I wasn't actually that far off the mark for the 1st to 3rd of Aug after all despite your comment a week or two ago about me being a "coldie" and producing "sweeping statements".

I certainly like cold weather but as a few people mentioned at the time personal opinions should never be factored into a forecast and I don't believe I do.

Try and judge a forecast when it's been and gone not just because it may not be what you want to hear at one particular time.

Regards to all. Matt

[bluearmy]

Nothing very positive to say about the outlook. Yes, the low anomolys lessen in intensity but we still fail to see any positive anomolys anywhere close to our shores. The concenration of low anomolys look set to return by the end of week 2 although currently, they appear set to be centred a few hundred miles further north than the current trough. guess that's a plus, given the context of this summer.

[Frosty.]

The Gfs 00z operational run is showing unsettled weather for the next few weeks with trough replacing trough and no sign of high pressure gaining a foothold although it does show some brief ridging, mainly for the south which would bring some warm and dry weather between the downpours but in all honesty, the new month which is almost upon us is looking every bit as poor as the 2 previous summer months and the next week is looking very cyclonic with more heavy and slow moving showers and in FI it's spot the difference with more troughing over the BI with yet more heavy showers and more persistent rain at times.

[shedhead]

Nothing very positive to say about the outlook. Yes, the low anomolys lessen in intensity but we still fail to see any positive anomolys anywhere close to our shores. The concenration of low anomolys look set to return by the end of week 2 although currently, they appear set to be centred a few hundred miles further north than the current trough. guess that's a plus, given the context of this summer.

Indeed ba - little or nothing in the overnight runs to suggest a break in this unsettled pattern, with GFS maintaining the general theme through until mid month - at least. Once again those expecting this return to unsettled weather to be a brief one will be disappointed, with the dry, hot and sunny conditions (for some) of late proving to be very much 'the blip' in the overall context of this Summer.

[Bristawl Si]

Indeed ba - little or nothing in the overnight runs to suggest a break in this unsettled pattern, with GFS maintaining the general theme through until mid month - at least. Once again those expecting this return to unsettled weather to be a brief one will be disappointed, with the dry, hot and sunny conditions (for some) of late proving to be very much 'the blip' in the overall context of this Summer.

No where near as bad as June and 1st half of July, for those of us in the South though - sunshine and showers with temps around normal for August i'd think.

[Milhouse]

The ECM mean showing signs that pressure could rise for the second week of the month so an emphasis on drier conditions looks likely next week at this stage.

Before that its more low pressure but the south and east will be drier and quite warm.

[shedhead]

The ECM mean showing signs that pressure could rise for the second week of the month so an emphasis on drier conditions looks likely next week at this stage.

Before that its more low pressure but the south and east will be drier and quite warm.

The ECM mean has been wrong at times recently and I think it will be wrong again this time. Don't expect any sig pressure rise until after mid month and probably not until the final 3rd.

[Evening thunder]

The ECM mean has been wrong at times recently and I think it will be wrong again this time. Don't expect any sig pressure rise until after mid month and probably not until the final 3rd.

Any charts/evidence to back those thoughts up?

They probably have been wrong at times recently, but then so have the GEFS means and all other models at times. I've seen some praising the GFS and bashing the ECM recently, but I remember the ECM operationals going for a cool N/NW flow to end the warm/hot spell in the south last week whereas the GFS had a warm thundery low moving up from the south directly over us and then even drifting round to our west. Of course the ECM was closer to the mark there and there was no interesting thundery breakdown.

None the less I wouldn't be at all surprised if the ECM ensembles were off the mark though.

Edited July 31, 2012 by Stormmad26

[Frosty.]

The Gfs 06z op run is the polar opposite of the gfs 00z run in FI with the main troublesome trough pushing away northeastwards and high pressure building strongly across all parts of the uk with a fine and increasingly warm spell although low pressure over the near continent could generate some storms which could possibly drift north into southern england but a generally anticyclonic outlook from the 6z which is a nice surprise after the trough fest 00z.

[shedhead]

The Gfs 06z op run is the polar opposite of the gfs 00z run in FI with the main troublesome trough pushing away northeastwards and high pressure building strongly across all parts of the uk with a fine and increasingly warm spell although low pressure over the near continent could generate some storms which could possibly drift north into southern england but a generally anticyclonic outlook from the 6z which is a nice surprise after the trough fest 00z.

Hopefully it's picking up on a new trend Frosty, but I'd expect it to be a rather large outlier in terms of both air pressure and ppt once the ensembles are out.

[OldMetMan]

Some early thoughts on today's model output.

There is much agreement in there being LP domination for the short- to mid-term, with the unusually deep low wandering slowly across the UK for some days to come slowly filling. I am still intrigued by the forecast warm sector trough the UK Met is showing, suggestive of the possibility of a thunderstorm line forming. At the moment, there is not much sign of instability over France and Spain and the 500mb upper trough is not that sharp, but I notice from the IR satellite this morning that the cold front on this developing LP seems quite active with extensive cold cloud tops suggesting it is quite an active feature in itself, which is somewhat unusual. I think much depends on how quickly this front moves through and how hot it gets over France tomorrow ahead of it but I think the risk remains. I suspect any such storm line would form very quickly if it is going to, so the satellite images need watching overnight and into tomorrow.

Beyond that, there is not much in the way of clarity from the models as to where we might go after the LP fills. I notice the GEM is being quite decisive and brings yet another LP towards us in the mid-term to long-term and this looks plausible given the current 500mb configuration. We seem to be stuck in a quite stable wave pattern at that level, with quite a deep vortex over NE Canada and one off the US/Canada west coast, whilst there is still a 500mb high covering much of the USA. I can't see all this changing any time soon.

I believe we need to keep an eye on the US to see if the upper high starts to erode and if the Canadian vortex starts to move further S or SE which may finally shift the pattern E bringing us closer to the downstream Atlantic ridge. Again, as I keep saying, any tropical storms could heavily influence such a process.

Meanwhile, coolish, showery conditions with more organised convection along any troughs that form seem to be on the cards for some time yet, plus once again the threat of slow-moving deluges as the LP fills.

[Frosty.]

Hopefully it's picking up on a new trend Frosty, but I'd expect it to be a rather large outlier in terms of both air pressure and ppt once the ensembles are out.

Yes hopefully the 6z is on to something because the gfs 0z was dire. We will probably end up with something between the 0z and 6z which at least would give some welcome respite from all the dull and wet weather mixed with heavy showers and sunny spells, so I think it's reasonable to expect a marked improvement in the weather pattern after the weekend but probably mostly for the southern half of the uk only.

[shedhead]

Some support for the 06 control MSLP, but still very much on the high side of the ensemble suites in both London and Aberdeen, so very unlikely to verify imho..

Edited July 31, 2012 by shedhead

[Gavin P]

Hi all,

Here's todays 8-10 Day model based video:

Cool And Unsettled To The Middle Of August? http://gavsweathervids.com/

All looking rather grim unfortunately.

[shedhead]

Hi all,

Here's todays 8-10 Day model based video:

Cool And Unsettled To The Middle Of August? http://gavsweathervids.com/

All looking rather grim unfortunately.

All looking very Summer 2012 unfortunately.

[summer blizzard]

Unfortunate - It looks great. Showery, cool and not humid.

http://62.89.145.4/gefs/gefsens850London0.png

Ensembles say it all really with the ensemble mean not really breaching 10C until after the 11th.

As for the ECWMF mean, if you are pleased at the 1015mb line making it over us then i have to laugh.

[rob48]

So I wasn't actually that far off the mark for the 1st to 3rd of Aug after all despite your comment a week or two ago about me being a "coldie" and producing "sweeping statements".

I certainly like cold weather but as a few people mentioned at the time personal opinions should never be factored into a forecast and I don't believe I do.

Try and judge a forecast when it's been and gone not just because it may not be what you want to hear at one particular time.

Regards to all. Matt

Excellent post.

Hope this attitude catches on instead of the ridiculous practise of praising a three month forecast on the very first day just because it promises the hot weather that you seek.

[Summer Sun]

Another unsettled outlook tonight from all 3 the first half of August is looking like staying unsettled, hopefully the 2nd half will see the jet shift as per Matt Hugo's blog last week

http://matthugo.wordpress.com/

[BLAST FROM THE PAST]

I am not confident of this jetstream northward shift. Its going to be interesting to see what happens BUT I suspect that a southerly tracking jet will dominate. The PDO seems to be in a less -ve state so maybe we'll get some improvement with HP not so dominant to our NW. Models show no encouraging signs as yet.

BFTP

Edited July 31, 2012 by BLAST FROM THE PAST

[legritter]

hi gang ,looking at all available data i will stick my neck out and say it looks rather unsettled and at times more akin to october ,with a bit of north atlantic cold air and troughs a plenty thrown in . and thats out till T 192 . there will be some winners who pick up some milder air and perhaps if sun comes out it could feel pleasant .i did say the other day about a competition but thinking about it and with all the work involved for someone on netweather ,perhaps some other day but using current charts and iv not yet seen tonights ECM i will have ago for mid day wednesday 15TH AUGUST 2012 ,JETstream a bit more fired up but still south of average position ,pressure over central southern britain low at 1005 mb , azores high further west with a ridge extending north , unusually high pressure over NEWFOUNDLAND , but an area of v low pressure for its location ,off the southwest coast of portugal ,this forecast is also based on gut feeling ,i was looking foreward to those bacon butties