Good morning. A new thread and a new trend in the weather?.. Let's see.

All models show a showery Westerly flow over the weekend with showers in the North and West today gradually extending to all areas by tomorrow. Temperatures have now returned to average levels in the South.

GFS then shows next week with a Low-pressure area persistent and dominant near the NW of the UK. Troughs will move slowly NE across the South and West bringing rain and rather humid air following to all parts by Tuesday. Thereafter any warmth and humidity in the SE is swept away midweek as a showery WSW flow becomes established for the remainder of the week. In FI this morning the Low fills steadily in situ before moving away NE allowing several more showery days. Then a brief respite occurs as a ridge moves across from the West settling things down briefly. However deep Low pressure moves East to the North of Britain with troughs moving East in the flow bringing bands of rain and showers through, especially in the North. Things would warm up in the South somewhat with humidities on the rise too.

The GFS Ensembles show the much cooler air having reached the Sputh with a couple of cooler than average days of 850's before they pick up to average levels for the rest of the run. Rain at times is likely even in the South. Further North the ensembles show a run of average level 850's in mostly unsettled conditions.

The Jet Stream forecast shows the UK under the Jet Stream for the next week with the current arm running South to the West of Britain weakening as the main arm exits the USA east across the Atlantic and over Britain. Another somewhat weaker arm is shown from more Southerly latitudes in the Tlantic moving NE over Spain.

UKMO shows Low pressure close to Sotland through the week with sunshine and showers for much of the time. It would likely become somewhat warmer and more humid briefly in the SE Tuesday before more showery and cooler conditions spread back midweek. The SE though could well stay dry and bright for much of the time with the heaviest and most widespread showers in the North and West.

ECM too follows the trend of the other two with the weather next week governed by a large Low pressure area near NW Britain delivering the mix of sunshine and showers already described. Later in its run Low pressure remains in control centred close to the west with slacker winds than previously. The weather would remain quite showery though as with UKMO the SE could fair better at times with some longer dry spells with warmer, more humid weather between the potentially thundery showers. By day 10 things improve little as Low pressure stretches from Ireland to Southern England with thundery showers for many.

In Summary the weather looks like being controlled by low pressure towards the NW of Britain. Towards the SE the weather could improve at times with some warmer and more humid interludes between the showery spells. The one overall message this morning though is that a return to the very warm settled conditions that the South enjoyed in the past week is unlikely to be repeated anytime soon.

Yep, certainly no return to the very wet and cold weather we had earlier in summer.

And generally speaking a slightly improving trend (albeit nothing stunning!) as we move into the second week of August.

http://www.wxmaps.org/pix/temp4.html

http://www.wxmaps.org/pix/prec4.html

As has often been the case in the last few months the likelihood of better weather improves nearer the south east. 

Today looks really rather pleasant which is much better than some of the output for the south was suggesting a week ago and the midweek rain looks to have been cut back too. 

Pretty uninspiring it has to be said for high summer. As has been said above the best of the weather in the south east so the Olympics wont be a complete washout but would have been nice for better weather for the games.

http://www.wetterzentrale.de/pics/MT8_London_ens.png

Wetter in the north and west.

http://www.wetterzentrale.de/pics/MT8_Manchester_ens.png

http://www.wetterzentrale.de/pics/MT8_Aberdeen_ens.png

Edited by user 28 July 2012 08:38:41(UTC)  | Reason: Not specified

Yes - no doubt that the models have been over egging the ppn in the South East - Today's sun fest is a classic case in point.

What never fails to amaze me is how often the MO thread ends up suicidal over highly improbable monster lows at 5-7 day range. Verification rates on those, as I warn time and again, are probably lower than 10%.

Edited by user 28 July 2012 09:44:19(UTC)  | Reason: Not specified

There are no monster lows in the current output as far as I can see, just a generally unsettled outlook across most of the UK.

Model verification data at 5 to 7 days are available online and tend to be up at 70 to 90% accuracy at that time scale as far as I remember, for general synpotic patterns at least.

Edit: I've just read you post above Tamara and it looks like a pretty good/accurate summary to me. :)

Edited by user 28 July 2012 09:58:36(UTC)  | Reason: Not specified

Indeed, "slightly less wet and slightly warmer" or "no return to the very wet and cold weather we had earlier in summer."

Or "the likelihood of better weather improves nearer the south and east" or "the best of any drier and sunnier weather is probable for more south eastern area."

In general looking at June the north and west of England has been wetter and less sunny than the south and east.

http://www.metoffice.gov...ne_Anomaly_1971-2000.gif
http://www.metoffice.gov...ll_Anomaly_1971-2000.gif

In Scotland the situation has been perhaps reversed with the north west drier and sunnier.

Aha - the old general synoptic patterns. I'm more interested in actual
conditions - at least five times this summer we've been progged very wet periods at 5-7 day range and got nothing. Today is an extreme example. (and I was referring to the past not the future)

Well this is the model output discussion thread and I thought we were commenting on the accuracy of the output i.e. the synoptics, rather than people's interpretations. That aside, the BBC highlight the unsettled outlook for next week, including from Tuesday for the Olympic venues so perhaps the output should not be dismissed?

Tomorrow and Minday look largely decent (in the SE) but it looks like becoming a good deal more unsettled after that. Not flooding, not monster lows or washouts, just nettled and breezy. At 20-21°C on some days it will be a little below average but it will feel fine between showers. Maybe the SE will be lucky and miss them. We certainly won't in the north as today has demonstrated nicely.

The proximity of the low pressure in the next week or so seems pretty consistent, but the Jetstream being a little better for the south flooding looks less likely. Perhaps the Olympic visitors will get what many probably expect in a UK summer - sunshine and showers.

Edited by user 28 July 2012 16:50:58(UTC)  | Reason: Not specified

There are no monster lows in the current output as far as I can see, just a generally unsettled outlook across most of the UK. Model verification data at 5 to 7 days are available online and tend to be up at 70 to 90% accuracy at that time scale as far as I remember, for general synpotic patterns at least. Edit: I've just read you post above Tamara and it looks like a pretty good/accurate summary to me. :)[/quote] Aha - the old general synoptic patterns. I'm more interested in actual conditions - at least five times this summer we've been progged very wet periods at 5-7 day range and got nothing. Today is an extreme example. (and I was referring to the past not the future) [/quote]

So your saying the verification at 5-7 days is really quite good then if it has only been wrong 5 days out of the last 60 or so?

[/quote]


No - I was saying that the models have completely over ramped five out of six "rain events" - but I think you knew what I meant and I'm now just feeding the troll! :-)

Good evening folks. Here's my take on the 12zs of the big three tonight.

All Models tonight show a showery Westerly flow over the UK tomorrow with Low pressure near northern Scotland. A ridge of High pressure drifts east across the South of the UK on Monday with Southern areas having a dry day with some sunny spells. The North would see another showery day with some heavy showers towards Eastern Scotland. Late in the day a trough of Low pressure moves slowly NE into the SW approaches with a veil of cloud and rain reaching the far Southwest of Britain to end the day. Tuesday then sees this front move slowly NE with rain at times though the North and East could stay dry at least until the end of the day.

GFS then shows midweek governed by Low pressure near Northern Ireland and Western Scotland with bands of rain and showers moving NE across all parts at times. The best of any drier and brighter spells will be towards the SE though even here rain would occur quite frequently. At the end of the first week and through the weekend sees very little synoptic changes with the same split of weather over the UK. In FI short drier interludes occur as ridges temporarily ridge up from the South but the general pattern remains changeable at best.

The GFS Ensembles tonight are very uninspiring if its prolonged dry, sunny and warm weather your after. Instead the preferred option sees very normal 850 temperatures and with the Atlantic source to our winds the weather at the surface will see normal temperatures at best with rain at times nationwide.

The Jet Stream Forecast long term from GFS shows the Jet Stream becoming very diffuse the main part of which stays close to Southern Britain. UKMO shows a direct USA to France flow by three days time.

UKMO tonight shows a Low pressure close to NW Britain with a showery flow over the UK. Also shown are other frontal features (better shown on the later faxes) to deliver some more prolonged outbreaks of rain at times in near normal temperatures.

ECM also looks very unsettled throughout next week with showers or longer periods of rain, heaviest and most frequent in the North and West. Towards the end of the run Low pressure fills in situ with a slack cold pool of air sitting over the UK with by then slow moving and thundery daytime showers inland with the best of the bright, dry and sunny conditions near coasts. On Day 10 a trough is shown moving SE over Britain carrying yet more showers ahead of what looks like a short lived ridge of high pressure to follow.

In Summary the weather remains in fickle summer mood. All models show variations on the same theme of Low pressure near or over the NW with a showery west or SW flow covering most areas. As usual shower distribution will likely be unevenly distributed with the best of any drier and brighter spells towards the SE, though even here some occasionally heavy showers are likely to occur. There is still little sign of anticyclonic summer conditions on the horizon tonight.

Edited by user 28 July 2012 19:48:38(UTC)  | Reason: Not specified