Model Output Discussion 06Z, 13 Sep. 2013 ---->

[SMU]

Evening-

 

Nothing great to be excited about tonight- all be it a 24/36 window which sees a ridge thrown over the UK- Happily that may coincide with late Saturday & sunday next week-

 

In the means though unsettled & below ave- I recorded 11c on the car to work today- some 8c below ave.... - The CET is going to take a hammering this week...

 

Still most notable overall is the polar heights- something that is very interesting to watch develop in October & november...

 

I would like most actually like a few more weekends of warmth- 20C & sunny is cracking weather..... maybe the jet will ease up just enough to elongate the window to say 48-60 hours-- but I dont hold out much hope- & all the decent weather seems reserved to the extreme south-

 

S

[Summer Sun]

Latest from Gibby

 

Good evening folks. Here is the evening report taken from the midday outputs of GFS, UKMO, GEM, NAVGEM and ECM for today Saturday September 14th 2013.

 

All models continue to show the current quiet weather quickly being replaced over the next 24 hours with wet and windy weather as a deep and deepening Low advances East to the North of Scotland. A Warm and Cold front will cross all areas to be clear of the UK in 36 hours time. Rain and strong winds in association with these troughs will move quickly SE across the UK tomorrow clearing to squally showers tomorrow night and Monday with some heavy and squally ones affecting many Northern and Western areas perhaps with hail and thunder locally. On Tuesday complications in the pattern could produce more persistent rain for a time across the South as a fast moving frontal wave moves through in the strong breeze. By midweek the winds die down and back more towards the West with most of the output continuing to show changeable and often unsettled conditions especially for Northern and Central areas.

 

GFS then brings steady improvements across Southern Britain next weekend as High pressure builds up from the South with some dry and bright conditions when it could also feel reasonably warm in the daytime. It isn't long though before shallow troughs of Low pressure move across all of the UK from the West with the 2nd week looking like being changeable for many with rain at times but with some drier intervals too when it shouldn't feel too cold. This changeable and often windy theme, the latter later in the North develops further and lasts until the end of the run tonight.

 

The Jet Stream forecast shows the flow moving SE across the UK and strengthening markedly over the next few days before it slowly weakens and tilts back more West to East over the Nation by the end of next week. It then shows signs of returning back North clear of the UK mainland in the outer limits of the reliable timeframe.

 

UKMO tonight closes it's run showing a broad WSW flow over the UK with mostly changeable conditions for all. Having said that amounts of rain from Eastward moving troughs in the South look likely to be small with the windiest and wettest conditions looking likely for Scotland and Northern Ireland at the end of the week.

 

GEM shows a similar 144hr chart to UKMO's version tonight leading on to build High pressure across Southern Britain for a time next weekend when temperatures would exceed average values in dry and bright conditions but probably with a lot of cloud. From the Midlands Northwards though the unsettled theme will be more enhanced with outbreaks of rain at times in a blustery WSW wind. In this airflow it would be technically mostly mild in the North too but would probably feel cool in the cloud, wind and rain.

 

NAVGEM has a broad Westerly flow over the UK at the end of next week and the weekend with showers or spells of rain likely over all areas, heaviest in the North with temperatures quite close to average but cooler at times in the far North.

 

ECM tonight shows a build of pressure late next week and weekend across the South with Southern and Western areas seeing some fine weather for a time. More Northern areas are more likely to continue changeable with some rain at times though the gales and inclemency of the early week weather should of gone with temperatures recovering somewhat. Towards the end of the run indications are shown that changeable conditions will affect all areas of the UK as a broad Westerly flow ensures troughs move West to East in the flow always most active in the North but sufficiently so in the South too to give some rain at times here too. 

 

The GFS Ensembles show a typical mixed Autumnal pattern of days of just below average uppers and some with above average with nothing extreme either side of normal likely. This goes for rainfall too with a short drier interlude from around the 21st in more southern locations

 

In Summary tonight's output reflect a changeable Autumn period to come with spells of wind and rain in the coming week with very cool conditions for a time. Most models then support a moderation in conditions towards the end of the week when the South becomes fair for a time with our old friend the Azores High having inched closer by then. Longer term is anybody's guess quite frankly with either a push further North of an Azores High influence to most of Britain or a return to windy and changeable conditions in a Westerly flow with Low pressure near the far North the most likely outcomes.

 

http://www.norton-radstockweather.co.uk/Model-Analysis%282859336%29.htm

[Frosty.]

The Ecm 12z operational and the Gfs 12z equivelant run look similar towards the end of next week in how they build the azores high into the uk, they both show a warm up with increasing amounts of sunshine and lighter winds, the south continues to have fine and pleasant weather at times with high pressure close to the south but with a few unsettled interludes, most of the unsettled weather becomes focused on the northwest corner of the uk but even there, some fine and pleasant weather is shown, so the ecm has changed quite a lot in the last day or so with that deeper cool unsettled pool of weather shunted much further east across scandinavia and beyond.

Edited September 14, 2013 by Frosty.

[SMU]

Frosty the Pleasant weather is the interlude as its 2 days surrounded by 7 days of unsettled weather - not the other way around

 

If the heights to the north remain strong the nice weather wont be around for more than 2 / 3 days max-

S

Edited September 14, 2013 by Steve Murr

[No Balls Like Snow Balls]

Ridge of HP in FI shown on the ECM 12Z as it is shown on other models. Looking at the associated 850c the +5 isotherm barely makes it North of the M4 most of the time.

Looks like from that run daytime temps would struggle to even reach average in most places. The window for any warmer temps still remains very very small.

 

 

 

 

 

 

 

 

 

 

[Gaz1985]

With increasing pressure pushing down on us this will feel good 

 

[Frosty.]

Frosty the Pleasant weather is the interlude as its 2 days surrounded by 7 days of unsettled weather - not the other way around  If the heights to the north remain strong the nice weather wont be around for more than 2 / 3 days max-S

At least the ecm ops have improved compared to when that limpet trough dropped anchor just to the northeast, although the ecm ens mean was never onboard with the persistenty cool ne'ly unsettled pattern at any stage. Next weekend currently looks warmer and sunnier and that will do for now.

[Summer Sun]

ECM ensembles continues to back the Op with the Azores never moving too far away

 

 

Wednesday onwards should sees things becoming quieter again with winds easing and temperatures slowly rising especially in the south

[Summer Sun]

With increasing pressure pushing down on us this will feel good 

 

 

 

Trouble with that Gaz is it is midnight (00z) the 12z temperature for that date is much lower away from the SE

 

[Captain Shortwave]

Good cross model agreement on perhaps next weekend making up for the rather stormy weekend we are currently experiencing

 

 

 

Not too bad

[Gaz1985]

Trouble with that Gaz is it is midnight (00z) the 12z temperature for that date is much lower away from the SE

 

 

 

Cheers Gav, I should of posted this one  

 

[No Balls Like Snow Balls]

Cheers Gav, I should of posted this one  

 

 

 

I think this chart illustrates well that in meteorological terms we are a million miles away from seeing any warm spell turn into reality when the date reads 22nd September. This chart is 7 days away from happening, and before this chart "happens" there is nothing in the models apart from cool and unsettled weather to get through until at least day 5.  

Edited September 14, 2013 by No balls like Snow Balls

[Captain Shortwave]

If anything the GFS is raising the stakes on next weekend

 

Edited September 14, 2013 by Captain shortwave

[Gaz1985]

High pressure nudging into the UK on Thursday

 

 

Azores pressure increasing it's influence into Friday... 

 

 

Saturday we have 1020-1025mb high pressure over us and with a slack flow away from the far NW it will feel nice and warm in any sun 

 

[Frosty.]

If anything the GFS is raising the stakes on next weekend

As sir bruce used to say on play your cards right......higher..higher..great trend.

[Frosty.]

Whilst we need to remain cautious, overall, the models have downgraded the cool unsettled outlook and upgraded the subsequent recovery from thursday onwards, there is more chance of a warmer and sunnier spell by next weekend as the azores high builds in.

[Bonjangle]

As sir bruce used to say on play your cards right......higher..higher..great trend.

Nice to see you , to see you Nice

[syed2878]

haven't u guys been forecasting asummery spell for the last few weeks for always next week and yet those charts haven't really miterialise. The only person that got it neara to the mark is j.holms?

[Captain Shortwave]

GFS control run for day 7

 

Ens mean

 

@AVFC, with Humberto on the scene, I don't think there is any reliable method of forecasting beyond 5 days, just have to look for trends and developments in the model output. This issue is similar to a couple of weeks back where we had a split in energy and the models only got things right at about 2 days out. I expect all output to be rather all over the place until this gets resolved. The one thing which is making me lean to the GFS output is that it appears the models have underplayed the effect of this ex tropical storm on the surface pattern over the UK and Europe and hence I expect the model with the biggest north east push to be the model closest to the right answer. Bit crude and I'm sure others can find decent arguments to the contrary, but hey it wouldn't be a model discussion thread otherwise. 

[William of Walworth]

I'd say BANK** to the above for next w/e, there've been considerably less usable runs recently for those of us who'll be outdoors ...

 

**Unless a trend is building for further HP encroachment in a week's time, but that's foolish talk!

 

 

Today's (ie Saturday's) model run developments lead me into actual hopecasting territory now, for next w/e ... was I so utterly foolish this morning then?

 

We'll see!

 

</hopecasting ... >

Edited September 15, 2013 by William of Walworth

[Man With Beard]

More encouragement this morning for those seeking an Indian summer, the ex-hurricane tracks far to the west of the UK, pulling up the Azores High with it and we are left in the A1 position for warm weather - a settled picture and a southerly feed. Both GFS and UKMO show this evolving. Not what I had been expecting a few days ago but the possibility always existed. Still a few more runs before this one is sorted though.

[Captain Shortwave]

More steps in the right direction this morning

GFS T144

 

UKMO T144

 

Both look very good for prospects over the UK

ECM is not as good

 

But even the ECM has extended the settled spell by an extra 24 hours at least, now the following Monday would be dry, warm and sunny for many areas, the breakdown is pretty slow and soft as the Atlantic trough slowly moves ENE towards northern Scotland.

[mushymanrob]

It's amazing how quickly things change, it looked for a time as though we would be staring down the barrel of a week or more of very autumnal weather but now it just looks like 4 days of progressively less unsettled weather and then from thursday the balance shifts to more in the way of fine and warm weather, at least across the southern half of the uk.

 

trouble is mate, theres no support for it being more then short lived (as has been mentioned), the anom charts do appear to be shifting away from a northwesterly flow, but as things stand there no suggestion for a decent lengthy settled anticyclonic spell. even if we did get one it might deliver cool nights with fog..  i hope we do get more settled, but its not looking likely atm.

 

... cool? if 'cool' is mid teens then ill take that anyday! it could be worse. (referring to various posts which are trying to paint a more gloomy picture then what we are likely to get). yes temps are below average, but thats the nature of the season. yes its going to cool down... yes the chances of heat is becoming very remote.... so what!

[mushymanrob]

haven't u guys been forecasting asummery spell for the last few weeks for always next week and yet those charts haven't really miterialise. The only person that got it neara to the mark is j.holms?

 

yes... but thats because the operational runs have consistently suggested the azores high will ridge in to produce a summery spell. the posters that did that were perfectly correct in doing so, its the data that has changed and 'got it wrong', not the posters.

 

and yes, the anomaly charts did not support a lengthy settled spell, so john was right because the charts he used didnt suggest another summery spell...

 

the lesson?... well the anomaly charts do appear to the ones to watch if theres a major pattern being projected. if its not supported on those, then its not looking likely to manifest in reality. (im following johns conclusions after a 3 year study (for those who havnt read them) )

[Yarmy]

trouble is mate, theres no support for it being more then short lived (as has been mentioned), the anom charts do appear to be shifting away from a northwesterly flow, but as things stand there no suggestion for a decent lengthy settled anticyclonic spell. even if we did get one it might deliver cool nights with fog..  i hope we do get more settled, but its not looking likely atm.

 

... cool? if 'cool' is mid teens then ill take that anyday! it could be worse. (referring to various posts which are trying to paint a more gloomy picture then what we are likely to get). yes temps are below average, but thats the nature of the season. yes its going to cool down... yes the chances of heat is becoming very remote.... so what!

 

Who's worried about that if we get a nice day or three? Anyway, I'd bank these uppers (albeit at 2am!). And look at that Siberia-bound cold.

 

Edited September 15, 2013 by Yarmy