Model Output Discussions 12z 01/06/2017

[damianslaw]

More of the same for the foreseeable, the trough reluctant to move away from the UK for any great length of time, with only tentative weak ridge development most likely, but at least progged to arrive for the weekend. The last 4 weeks has seen quite a marked shift in conditions, so we could be looking at a summer of two halves, the first predominantly fine and warm for most with wettest weather reserved for the NW quarter, the SE fairing very well, but the second half perhaps predominantly wet unsettled and rather cool. Indeed August has started off an undecidedly chilly week, on average the first week of August is the warmest of the year - but not this one. 

Looking further ahead as we move out of what will have been a very poor high summer period (mid July-mid Aug), signs of greenland heights rises showing up, never a good sign for sustained warm settled continental high pressure spell, but we might just end up on the warm side of the jet, if we see low pressure anchored further to our SW, temporary shot of heat perhaps, but the odds probably that we end up on the colder side, with low pressure anchored to the east - just like we have now, The behaviour of the current low sat over the SE of the country is quite unusual not out of the ordinary but perhaps a sign its not going to be business as usual in the weeks ahead with heights locked in the wrong direction for any appreciable warmth, and low pressure and troughs becoming slow moving and sat over or just to our east. ECM chart 10 days looks very ominous and would be indicative of such a development - but yes its 10 days away..

[Frosty.]

My hopes of a sustained summery spell this month have died, the Gefs 12z mean for example looks generally changeable / unsettled Atlantic dominated, generally worst further north but then by late August there are hints that the azores high could build across southern uk..I know what you're all thinking, yeah yeah..I've tried to be positive but I think the writings on the wall for summer 2017 now!..naturally there will be some fine warm days here and there but mainly across the s / se.

[Man With Beard]

4 hours ago, knocker said:

The case of the migrating ridge

A theme of the ECM ensembles too, rock solid on this morning's set. Heights to the north west, troughing over the UK, wet weather with a northerly element, summer 2017 haven't you had enough?

[Frosty.]

29 minutes ago, Man With Beard said:

A theme of the ECM ensembles too, rock solid on this morning's set. Heights to the north west

A dress rehearsal for winter..he said hopefully!

[Northern Sky]

25 minutes ago, Frosty. said:

A dress rehearsal for winter..he said hopefully!

Hmm, I think we all know what'll happen then Frosty!

Clutching at straws I know but before the trough returns with some venom (as looks likely) we will have a few days of pretty decent weather. No great warmth but at this time of year if the sun is shining it will feel lovely.

If the trough does return as expected I'm hoping it moves away to the NE fairly quickly, allowing the azores high to nudge in for the last third of August.

[knocker]

After some extended ridging into Greenland in the 6-10 period which concentrates the trough somewhat the anomalies shift the whole pattern, (N. America and trough to our NW) very slightly east. Ergo no significant change in the outlook from the previous spiel The EPS is similar

Meanwhile back on the farm. After a couple of inches of rain in some areas yesterday more to come today mainly  concentrated around the Dorset, Midlands, NE at first then East Anglia and the SE later.

And on to this morning's gfs. Essentially we are looking at a not too bad scenario for the next few days including the weekend before the stuation goes downhill again.

Tomorrow the best day of the week as the Azores ridges north east but a trough to the MW tracks rapidly east and the associated fronts track south east and bring rain on Friday before the ridge reasserts itself over the weekend. Thus isolated showers for the latter and although none too warm with light winds will feel pleasant enough. Certainly better than currently for many.

Monday sees the next low arrive over Ireland bringing some more rain, concentrated in the north, over Monday and Tuesday as the quite complex low pressure are moves north east to be north east of Scotland by 00z Wednesday.

And this is where we started with the ridge into Greenland and the Atlantic getting more organized and our weather becoming more unsettled again.

 

[knocker]

The ecm is significantly different to the gfs at the beginning of next week  At Tuesday 00z it has the upper trough just to the west extending south to NW Iberia which activates the surface low pressure over the area which leads to another intense thundery low tracking north east into the North Sea with the possibility of some torrential downpours effecting England and Wales next Tuesday. Midnight Wednesday sees the low in the North Sea and the rain just effecting the far south east.

 

Edited August 9, 2017 by knocker

[Summer Sun]

Very few decent days over the coming week today is going to be an improving day for the northern half but a washout in the SE

Tomorrow looks decent for many

Another decent day on Sunday

 

[Frosty.]

Some good news at last, the weekend looks largely dry with sunny spells and feeling warmer, compared to recently / currently.

Edited August 9, 2017 by Frosty.

[Timmytour]

Personally I suspect this low winging its way towards us from off the eastern seaboard of Canada will find a lot more resistance than the GFS is finding for it at present

 

 

But assuming it does wind up on our shores, the GFS portrays the end of next week looking like..

It drags down a pretty cold bit of air that sits to the east of Iceland. Would I be right to think that it's pretty rare to see a patch of blue so far south less than two months after the longest day?

 

 

Edited August 9, 2017 by Timmytour

[Frosty.]

Looking at the Ecm 00z, the weekend looks like an improving picture with pressure rising bringing plenty of dry and sunny pleasantly warm weather, especially for sunday and continuing on monday away from the far west. Tuesday there could be a thundery outbreak in the south with an incursion of warmer more humid continental air.

Edited August 9, 2017 by Frosty.

[Frosty.]

Looking at the Gefs 6z mean shows a better weekend coming up, becoming largely dry with sunny spells and lighter winds for most of the uk as a ridge of high pressure builds in and monday also looks  fine further s / e before it briefly turns more changeable from the northwest but then another window of fine and pleasantly warm weather follows, mainly across southern uk as another ridge builds in but then the second half of next week indicates a trend to widespread unsettled / atlantic weather from the NW with the worst of it affecting n / w areas. Towards late August there are signs of recovery as pressure rises to the south and the jet lifts further north so at least southern parts of the uk could see a more benign summery last week or so to this meteorological summer. 

Edited August 9, 2017 by Frosty.

[Frosty.]

Here are the weekend GEFS 6z mean charts I forgot to post which indicates a significant improvement, especially for sunday with sunny spells, light winds and pleasantly warm surface conditions which will be a welcome relief following all the rain and pathetic temperatures! 

[mb018538]

Weekend is looking ok...



Into next week though, and it's a familiar story. Southerly tracking Jetstream that is fairly strong for August firing low pressure in our direction once again.



Now that is one hell of a warm anomaly across the USA/Canada. Persistently strong western ridge, and 850s of 16-20c well into Canada.

[Frosty.]

8 minutes ago, mb018538 said:

Now that is one hell of a warm anomaly across the USA/Canada. Persistently strong western ridge, and 850s of 16-20c well into Canada.

How exciting for them..I'm more interested in the uk weather though, couldn't care less about usa / canada!

Edited August 9, 2017 by Frosty.

[mb018538]

Well I am too - but this warm anomaly spread right across this region is in part helping to cause the strong gradient firing the jet across our way. It's all inter-connected in one way or another.

[Frosty.]

29 minutes ago, mb018538 said:

Well I am too - but this warm anomaly spread right across this region is in part helping to cause the strong gradient firing the jet across our way. It's all inter-connected in one way or another.

I apologise for the dismissive tone of my original post, I see what you mean about how the upstream conditions affect our side of the pond but I'm just fed up of hearing about amazing summery weather in other countries when the uk is enduring the current dross since mid July with no sign of a pattern change.

Edited August 9, 2017 by Frosty.

[knocker]

Just a quick observation

The gfs this evening has a different orientation of the North American ridge and is not ridging it NE into Greenland.ans thus the Atlantic troughs can be 'topped' up from the NW and SW. The warm/cold air interface is still too far south for the UK with the jet very strong for this time of year which of course bodes more unsettled weather next week. Hopefully I, as well as everyone else I suspect, will make the most of the next four days, (forget Friday)

Edited August 9, 2017 by knocker

[Matthew.]

At least the ECM has something to offer at +168. Now if that low can continue to dig south and see saw the high further north we will be in the money.

[mb018538]

15 minutes ago, Matthew. said:

At least the ECM has something to offer at +168. Now if that low can continue to dig south and see saw the high further north we will be in the money.

It looks ok on face value - but there is a strong W-E jet running across the Atlantic, and sadly that low is destined only for the UK. By day 8-10 (late next week/weekend) things look decidedly dodgy.

[Matthew.]

4 minutes ago, mb018538 said:

It looks ok on face value - but there is a strong W-E jet running across the Atlantic, and sadly that low is destined only for the UK. By day 8-10 (late next week/weekend) things look decidedly dodgy.

Yes it just brushes the high away like a feather. 

[knocker]

The ecm isn't still promoting the thundery low tracking NE into the North Sea at the beginning of next week although it is paying lip service to the idea. It has a shallow depression over Scotland at 12z Monday with a front lying down through Wales/the tip of Cornwall and points to the south west. It appears to develop a small wave depression on this that tracks north east to be in the North Sea 24 hours later and in the process brings some very wet weather (perhaps thundery) to England.

By Thursday there is a deep upper low over Greenland with associated trough orientated south east across Ireland and a nasty surface low over the UK bringing some more very inclement weather.

[Frosty.]

Looking at the Ecm 12z is a reminder that autumn is just around the corner..roll on winter! 

[mb018538]

It sure is, BBC have also noted that there is the potential for gales/severe gales towards next weekend as that low deepens and slams straight into somewhere in the U.K. 

I hate this sort of weather at this time of year, but I suppose as it's a weather forum I should throw in the usual sound bite about any extreme of weather is exciting....so there we have it folks. Gales in August, don't all get too excited now..

[knocker]

Although this is totally off topic it shouldn't be forgotten that the Fastnet race ( this year's is currently underway) disaster occurred on the 14th August, 1979 when a depression rapidly intensified resulting in 18 fatalities.