Model Output Discussion - September Onwards

[Bottesford]

A warm but getting less warm welcome into a new model discussion thread!

Please stick to the topic in hand - which is of course the model output. All other fascinating and not so fascinating incites should be spoken in the appropriate threads....

[Radiating Dendrite]

GFS 18z and 00z both have a significant warm up from the 12th with a deep trough out west and a high to the east pumping in warm uppers!

Could be looking at 30c if that was to happen. Certainly a trend developing.

[Gibby]

For the benefit of those who didn't see this morning's report in the old thread I have copied it across.

Good morning folks.

GFS shows Low pressure moving east close to Northern regions through the weekend and into next week with troughs moving east through Britain on the west or southwest flow which develops from tomorrow. There will be rain or showers for all, some heavy but more especially in the North and West with some drier, brighter spells more likely in the south. In FI the model shows a westerly flow continuing for the most part. However, pressure will become high close to the South steering the sometimes powerful Atlantic storms away south of Greenland while the UK sits under very warm southerly winds for a while. Troughs would continue to affect the NW so staying unsettled there but a lot of dry pleasant early Autumn/Late Summer weather would develop elsewhere.

UKMO shows Low pressure developing to the North of the UK and lasting through to the end of the run. A broad westerly flow would develop for all with troughs embedded in the flow delivering rain or showers, heaviest in the North in the fresh West or Southwest wind. After a warm start temperatures would fall to near normal values or slightly below.

The Fax Charts confirm the raw UKMO output with complex troughing moving east periodically through the UK, especially into next week when strong winds are shown to accompany the unsettled nature of the weather.

ECM today follows the others in bringing a broad westerly flow over the UK with Low pressure to the North and strong West or Southwest winds developing early next week. After today and tomorrows more stable conditions a cold front moves East Saturday night and Sunday bringing a band of possibly thundery rain east and introducing the Atlantic mobile pattern. Towards the end of next week high pressure builds just to the SE in response to a major Atlantic storm SW of Iceland. The net result would be a NW/SE split in the weather with wind and rain for the NW while the SE half of the UK become dry, bright and warm. This better weather would then extend North to other areas too for a while ending the run with a warm and potentially very warm Southerly flow developing as pressure becomes High over most of Europe.

In Summary an unsettled week is on the way with full model support. Thereafter, there is a tendency shown for more settled conditions to develop as High pressure develops to the SE and East with major Atlantic depressions held well away to the NW and consequently keeping any wind and rain to the NW. However, even here if ECM is to be believed there will be room for some drier, warmer weather for a while in 9 or 10 days time.

[MP-R]

A more settled run on the GFS this morning beyond Thursday with heatwave synoptics falling into places for a few days as has already been mentioned. If it was to turn out like that it would definitely be a case of 'too little too late' but I reserve judgement for anything settled.

Just like the monster lows, I don't believe the juicy highs overhead either. I think a plume event could occur before the Atlantic nudges in again,

[Summer Sun]

My personal opinion is for those wanting Autumn storms then September is going to be the best chance because as we move into October things look like becoming more settled for maybe periods of several day's at a time this diverts any storms into Greenland. November is looking like been cold with the chance of Snow at times just like last year.

Hopefully GFS and ECM are onto something.

[Liam J]

My personal opinion is for those wanting Autumn storms then September is going to be the best chance because as we move into October things look like becoming more settled for maybe periods of several day's at a time this diverts any storms into Greenland. November is looking like been cold with the chance of Snow at times just like last year.

Hopefully GFS and ECM are onto something.

September is usually the quieter month of the Autumn which can deliver periods of settled weather and the last gasps of some summer warmth. While it can deliver unsettled weather and occasionally the left overs of ex hurricanes I don't show to much interest in September for Autumn storms until the later part of the month.

October especially can be a very active month with vigorous depressions racing across the Atlantic.

If you are looking at the CFS models charts I would take them with a big pinch of salt, sometimes we can't rely on the model output out to 144hrs let alone one or two months ahead.

But in the short term the first week of September is looking quite disturbed with strong winds and rain at times, so I shall be watching developments with interest!

[Radiating Dendrite]

06z decides to push the trough over the top of us and then onto Norway, meaning that although we still get some warmth in the south it is nothing compared to waht was previously on offer.

Hints of a Northerly/North Westerly at the end on the run First one of the season I make that!

[ANYWEATHER]

Yep 06z is pretty much Unsettled from end to end with just fleeting ridges of High Pressure. Seems to me that there is a very lively jet stream stearing the Vigourous low pressure systems right across the Uk....

[johnholmes]

incites

come on Botty-incites=insights, I hope?

come on Botty-incites=insights, I hope?

or are you really trying to incite folk?

[Costa Del Fal]

Yep 06z is pretty much Unsettled from end to end with just fleeting ridges of High Pressure. Seems to me that there is a very lively jet stream stearing the Vigourous low pressure systems right across the Uk....

Hardly low pressure right across the UK but more of deeper lows to the North West around Iceland generally and fairly strong high pressure to our South also influencing us at times. Not a terrible outlook right now imo. If the lows were slap bang over us and to our East and dragging cool air from the North then I would be complaining! We have seen worse charts this summer imo.

Fairly wet for Scotland and possibly NI maybe but for England and Wales, occasional fronts on the 06z at most and some showers. Things are changing a fair bit right now anyway.

Edited September 2, 2011 by Blizzards

[k19]

Way out in FI, and i'm not going to suggest this will happen, but it's an interesting chart

The temperature difference would be huge!

[summer blizzard]

GFS 18z and 00z both have a significant warm up from the 12th with a deep trough out west and a high to the east pumping in warm uppers!

Could be looking at 30c if that was to happen. Certainly a trend developing.

I am quite sceptical. The plume seems to rely on a weak tropical looking low interacting with the jet stream and causing the low to bomb.

[Summer Sun]

Met Office now hinting at high preesure building from late next week, with temperatures prehaps well below average for some, in the final 2 weeks of the month.

Temperatures are likely to be below average for the majority of the country, perhaps well below average across parts of England and Wales, where the first frosts of the autumn are possible in rural areas. However, there are still likely to be some warm days at times, especially in the south and east.

[Kentish Kiwi]

I just thought I'd quickly mention while this thread is quiet that this new version of the forum is very frustrating to use on an iPhone. From what I can see there is no 'skip to last page of posts' so you can only access the first page of every thread and then have to manually go through every page of the thread to get the most up to date posts. This can be incredibly annoying and time consuming on a thread such as this one which runs into the 40's of pages.

Can anyone help me with this situation? It could just be that I'm missing something obvious.

Sorry to be off topic Mods, I wasn't sure where else to put this. Feel free to delete once you've seen it, any help would be appreciated.

[Bottesford]

come on Botty-incites=insights, I hope?

Crikey that's a terrible one - consider me absolutely told off for such a poor mistake!

[mintblue]

I just thought I'd quickly mention while this thread is quiet that this new version of the forum is very frustrating to use on an iPhone. From what I can see there is no 'skip to last page of posts' so you can only access the first page of every thread and then have to manually go through every page of the thread to get the most up to date posts. This can be incredibly annoying and time consuming on a thread such as this one which runs into the 40's of pages. Can anyone help me with this situation? It could just be that I'm missing something obvious. Sorry to be off topic Mods, I wasn't sure where else to put this. Feel free to delete once you've seen it, any help would be appreciated.

.

Hi KK. First post here after reading for years, still a complete novice with weather but not so with iphone stuff.

From what I have seen after sharing your frustrations, is to go to the very bottom of the page then click on full version and it will revert to the normal forum you would see on the PC.

Hope that helps

[Paul]

There is a thread about the upgrade here:

http://forum.netweat...upgrade/unread/

And yes there is a bug which is the cause of the page numbering not being on the mobile skin right now..

Edit - I've put a fix in place just now...

[johnholmes]

Crikey that's a terrible one - consider me absolutely told off for such a poor mistake!

I put it down to it being the start of the winter half of the year and your dislike of cold, wind and wet for the next 6 months!

[Gibby]

GFS tonight shows an unsettled spell up and coming with a period of strong winds and squally showers or more prolonged rain in places through the mid stages of next week, It all begins tomorrow with a cold front moving erratically SE across all parts by midday Sunday. Then a deep area of Low pressure moves steadily east to the North of Scotland with fronts bringing rain followed by squally showers. The rest of the week sees changeable weather continuing with the most rain towards the NW while the SE sees brighter and drier weather at times. FI tonight shows an ex tropical storm moving east northeast to the North of Scotland with gales and rain in the North before a rise of pressure brings a drier and warmer spell with sunny spells to most areas by the end of the run.

UKMO also shows a similar pattern to its synoptics as GFS through next week with a series of troughs through Saturday and Monday setting up a windy spell as deep Low pressure moves close to Northern Scotland on Tuesday and Wednesday. On its last chart High pressure is shown ridging up behind the depression settling things down from the SW again late next week.

ECM also shows an unsettled week to come with Low pressure North of the UK controlling the weather with a series of troughs crossing east over the UK with rain or showers for all. Thereafter ECM shows a lot more tantalisation in rising pressure late next week with High pressure close to the SE briefly bringing dry and fine weather for a while late next week with one fine day in the North too as a weak High develops near Scotland. However, the pattern remains disturbed with active depressions returning later from the west with strong winds and rain for all by the runs end.

Still a changeable look from the models tonight with the long term evolution as much up in the air as ever. The short term output is in agreeance though of 6-7 days of unsettled weather to come. Long term is not worth dwelling on at this range as there will be many twists and turns in the days to come.

[damianslaw]

As I said yesterday, not worth looking beyond middle of next week. Those suggesting pressure rises and heatwaves in 9-10 days I think should be keeping quiet. Lots will hinge on the developing lows and in my eyes all I can see is a very vigorous jetstream with a tendency for westerlies to predominate. Yes the SE may see some warmer drier conditions at times, but hardly heatwave.

I do find this time of year the least interesting weatherwise.

[Geordiesnow]

I do find this time of year the least interesting weatherwise.

Interesting you say that as I find the onset of cold uppers appearing at higher altitudes and seeing the colder looking colours trying to dominate to be quite interesting, plus the chance of Atlantic low pressure systems increasing is also interesting but each to their own I suppose.

Speaking of Autumn lows, I think the one that is forecast for next week is a classic chart of the seasons changing, the size of the low(Not the strength!) that the models are predicting for it to be just hardly happens in the summer time, summer lows tend to be smaller and shallower and can often bring uninteresting weather if its filled with weather fronts but on this occasion we have pressure quite high across Europe, we get a tight gradient and gales becomes a player. Its basically charts I welcome in September/October but would dispair if it happened in 3-6 months time!

Bit of disagreement on strength and timing of the low but all the models are painting an unsettled picture with winds picking up next week from that major low. In any cooler airmasses from that low, Western facing coasts will have showers packing particularly the further North you are whilst elsewhere it will be sunny but quite breezy. Whatever happens, for my area and for alot of others, the weather should be more noticetable than this week has been.

[johnholmes]

the 500mb anomaly charts are less helpful than usual over the past 3-4 days. All 3 have shown variations on where any +ve heights might settle and also shift the major upper trough(in our area) around by some 30 degrees or more. So trying to give a reasonably accurate prediction in their time scale, 7-15 days, is open to considerable doubt and is perhaps the reason why ECMWF and GFS synoptic outputs is also swinging between differing ideas at that time scale.

Personally I would side with the idea of a fairly usual weather split NE-SE across the UK. Fairly settled for the SE and pretty unsettled and even windy at times for the NW.

As always at this time of the year the hurricane season could have a major impact. Indeed both models have suggested one breaking east at a lower latitude than the current one. Of course the 500mb anomaly charts rarely are able to pick this kind of feature up so we have to wait for 5 or 6 days to see how reliable this is and of course watch the output from the hurricane centre in the USA.

[Jason T]

I think its fair to say at the moment that current data and the 3 main models Offer far from a single result in terms of a set pattern, I believe that we are none the wiser now as to what began way back in may.

[Kentish Kiwi]

.

Hi KK. First post here after reading for years, still a complete novice with weather but not so with iphone stuff.

From what I have seen after sharing your frustrations, is to go to the very bottom of the page then click on full version and it will revert to the normal forum you would see on the PC.

Hope that helps

There is a thread about the upgrade here:

http://forum.netweat...upgrade/unread/

And yes there is a bug which is the cause of the page numbering not being on the mobile skin right now..

Edit - I've put a fix in place just now...

Thanks for the replies. Yeah cheers for the help, I had used that technique a few times and seems like I'll have to stick with it for the time being as there isn't really another way around it. Good to know the bug's already been noted though, liking the new look of the the board.

[Gibby]

Good morning. Just a quickie from me this morning.

In Summary GFS shows a very unsettled two weeks to come with the first week unsettled and windy with rain at times on a fresh to strong west airflow. In its second week the model brings the remains of an ex troipcal storm close to the North with severe gales and heavy rain for all.

UKMO shows an unsettled four or five days too withwest or SW winds and rain

at times.

ECM too offers much of the same and has downplayed the improvements progged previously for next weekend keeping the unsettled theme going through to the end of the run.

All in all a disappointing set of runs for those wishing for prolonged dry and warm harvest conditions. However, as we've seen this morning things can change and remain likely to change again so don't despair quite yet.