Model Output Discussion - Late October Onwards

[johnholmes]

I don't think anyone doubts the usefulness of teleconnections as a tool, but they also indicated did they not, that summer would be rather blistering, but it wasn't. That's not to say that we won't be stuck in the current pattern for some time, but lets not get ahead of ourselves, as the situation can and does change, as it clearly did late spring/early summer.

A convert? Is it not you John that says it is pointless comparing consecutive runs, i.e. in this case, the 18z and 0z, but to use the same run or couple of runs each day and compare those. There are often wild swings between consecutive runs, but less so when comparing the same run.

It is indeeed me that has over the years on Net Weather suggested that taking one run and comparing it day by day is much less up and down than following each run. By all means compare other runs but try and stick with just one for daily comparison. Also remember check it with the same time for other models. Check those in turn with the 500mb anomaly charts. It does work on about 85% of occasions as I showed earlier this year.

As to teleconnections being wrong in the summer forecast, they were way outside the time scale I use, for me out to 30 days. Stewart was using links for months ahead and as he demonstrates in his video explanation he chose the 'wrong' way. That type of wrong analysis happens with all forecasters, assessing what parameters are likely to affect the forecast, be it 24 hours or 3 months ahead, and then making your assessment on which line to follow. Just as professional forecasters learn by this kind of error so we do with the longer term parameters. Trying to predict weather pattern 3 months ahead is a different ball game to doing the more routine forecast 1-15 days ahead. Again like daily forecasting the seasonal efforts will improve albeit probably, like the short range, very slowly.

[Summer Sun]

GFS FI Is nice and settled tonight with high pressure around. Rain fall looks low for a good while yet.

[summer blizzard]

This mornings runs it seem have backed away from the cooler scenario towards day 10.

ECWMF 0z has little in the way of cool air unless you live in Scotland or Ireland where it will be heavily modified anyway. GFS6z did not have the cold front clearing the south coast within the day 10 period although it was a mild outlier before then.

There was some support from the GFS ensembles for a cold shot from around the 5th.

GFS12z is out and shows nothing but average/above average weather within the next ten days.

[Liam J]

GFS FI Is nice and settled tonight with high pressure around. Rain fall looks low for a good while yet.

I don't think the people who are desperate for rainfall will see that as a good thing, thank god it's only FI which is subject to alot of change - as I want some active autumn weather! GFS changes FI with every run maybe two, I'm hoping it flips back to unsettled weather on future runs which the ECMWF has been consistent with lately. GFS seems all over the place in low res.

UKMO 12z also keeps an unsettled theme but that only goes out to 144hrs, very warm for the time of year later in the run with southerly winds dragging warm air up from Iberia as a large area of LP sits out to the west of Ireland.

Edited October 27, 2011 by Liam J

[snowlover2009]

GFS FI Is nice and settled tonight with high pressure around. Rain fall looks low for a good while yet.

Anything after next week is looking a bit better, but that is way out and probably going to change a lot. The models have been flipping a lot out in FI. It is looking very autumnal and unsettled next week to my eye, so rainfall won't be all that low as you say.

To my eye, I see the jet heading south, which could result in more unsettled weather, but if it tracks too far south, we stay dry.

[nick sussex]

The GFS may have indeed been right about bringing that trough further east, the UKMO looks similar at 144hrs.

A little interest to the ne with that ridge developing near Scandi, aswell as this the models do seem to suggest that a shortwave maybe ejected off the main trough, as this heads east it could help weaken the trough with some possible trough disruption.

Still no sign of anything a great deal colder but it will be interesting to see what the ECM does with any possible pressure rises towards the ne.

[ANYWEATHER]

GFS FI Is nice and settled tonight with high pressure around. Rain fall looks low for a good while yet.

Gavin ,have you not learned anything since you have been on here?!!!

[Frosty.]

The Ecm 12z looks generally mild and unsettled, windy at times and occasionally very mild with low pressure remaining to the west allowing warm winds to pump northwards from spain/africa at times or from around the azores. There are signs that the jet could become more southerly tracking by T+240 hours with the uk becoming north of the PFJ but still no signs of anything wintry...I know it's early november i'm talking about but there really is no sign of anything cold upstream..yet.

[Gibby]

Good evening. Here's my evening look at the 12zs.

Up To 168hrs(1 week)

GFS, UKMO and ECM tonight show the same sequence of events between now and this time next week. A ridge of High pressure crosses Southern Britain later tonight replacing todays cloud and rain with mist and extensive fog inland away from the SE by morning. With slack winds in the South tomorrow clearance of fog would be slow while further North winds will freshen from the SW with some rain late in the day. This SW airflow then slowly extends SE over the weekend with dry weather hanging on in the South and East with milder than average temperatures. Further to the NW Low pressure deepening to the West and NW throw troughs in off the atlantic with rain at times. As next week progresses deep Low pressure is placed in the mid Atlantic with mild Southerlies for us all. Central and Western areas could experience some very heavy rain once more as troughs ease eastwards across the UK.

GFS then disrupts Low pressure close to the UK with further rain for all as it fills. High pressure slowly develops from the South though the far North remains very windy and unsettled for a while as deep Low pressure crosses the East from Iceland. By the end of the run pressure has risen for all and with static conditions this situation could produce some cold and persistantly foggy conditions in places.

The GFS Ensembles show normality for the whole period with the operational being on the warmer side of normality for the pack especially for more Northern locations.

ECM follows the other two up to next Thursday and then keeps things very disturbed and Atlantic based with a series of troughs and Lows continuing the spells of rain and wind though with these winds keeping blowing from the SW temperatures will remain technically mild.

In Summary tonight the pattern remains very autumnal with mild South or SW winds and spells of rain, heaviest in the West. Some short drier spells could occur in places, mostly in the East with temperatures holding up well.

[BlueHedgehog074]

Not a huge difference with the 18Z GFS run, with another generally mild outlook. Seems as though yesterday, GFS were being a little too eager programming those Lows to break through the block to the East. The other problem with this was it was in deepish FI where it would have likely to have changed somewhat anyway. It's possible GFS may bring the Northerly winds back, although I have to confess I have my doubts about how far East those Lows/Depressions go with that blocking to the East looking very sturdy.

Again, the South-East is likely to see the most settled of the weather, although even in these areas, their may be some spells of rain/showers at times, particularly as we progress further into next week - The 18Z GFS shows quite a wet day for many areas next Thursday (according to the GFS UK Precipitation Chart).

In the deepest FI, the latest GFS is keen to settle numerous places down as High-Pressure takes a nap over the UK.

[Gibby]

Good morning. Here’s my take on the 00zs from GFS, UKMO and ECM today.

GFS this morning shows a SW flow gradually developing over the UK over the next 24-48hrs. To the NW this would bring increasing cloud and some rain but for many in the South and East a dry weekend looks likely with some sunny spells and it would again become very mild. As we move into next week the weather becomes more unsettled generally as Low pressure deepens to the UK’s west with strong but still mild Southerly winds and bands of heavy rain moving slowly East across the UK. In the latter stages of the semi-reliable timeframe Low pressure becomes complex near Britain continuing the rainfall but making winds more variable and probably less mild. Eventually in FI pressure rises from the NW and North with an East flow setting up though with little cold air to tap into things look like they would become very benign.

The GFS Ensembles for London and Aberdeen show a period of sustained normality with tight clustering throughout with rain a frequent occurrence over the oncoming weeks. In Aberdeen 850’s remain above average for most of the run.

UKMO looks very similar this morning bringing mild South-Westerly winds to all over the weekend with some rain in the NW while the SE see the best of dry and brighter conditions where once more it will feel very mild for early November. Next week sees a front move East with rain for most late Monday before winds back Southerly and strengthen with active weather fronts moving slowly east into the UK with heavy rain extending slowly east later in the week.

ECM also brings the mild South-westerly winds over the weekend. Through next week winds back Southerly and strengthen. After rain on Tuesday the midweek period looks like becoming very windy and wet for many if mild. Towards the end of the run the model follows GFS in bringing Low pressure into the UK and away to the SE setting up a cooler Easterly flow which could well turn out to be dull and drizzly for a while as pressure builds slowly from the North.

In Summary this morning it looks likely that after a mild weekend with the traditional NW/SE split things will turn disturbed everywhere early next week with strong if mild Southerly winds and heavy rain. Late in the week both GFS and ECM disrupt the Low pressure to the West with one part moving away NW while a secondary portion moves into the South and away SE by next weekend. So unsettled weather continuing then though drier weather would likely extend South next weekend with an East wind and probable low cloud cover developing but nothing overly cold.

[nick sussex]

I'm surprised theres not more interest in this mornings output. The ECM especially holds out the chance of something colder in the later outlook.

Overall the key timeframe post 168hrs suggests the upper trough weakening as shortwaves run into southern Europe and its what happens to pressure rises to the ne that will determine whether some colder conditions develop.

Unfortunately all the interest is well into FI but the ECM is not outlandish in its way forward and if these shortwaves do head east into southern Europe the natural knock on effect is for a rise of pressure to their north, its really how strong this will be and whether it orientates favourably to bring some colder conditions in.

[Liam J]

ECMWF and GFS 00z runs point towards a rise in pressure to the NE in FI, a good signal if you are hoping for blocking of sorts near Scandinavia which could lead to colder conditions in time. I'm not so sure about the evolution currently shown, with no decently cold air to the east as it's currently being progged, I feel it's to early to be looking for easterlies anyway as the current set up would probably lead to grey and mucky weather towards eastern areas, also remaining mild or very mild for the time of year. At this time of year we need to be looking to the N/NNE for decent cold which is still bottled up over the Arctic and Polar regions.

All still lurking out in FI and all speculation at this stage.

Edited October 28, 2011 by Liam J

[Isolated Frost]

GFS says extremely mild (about 4-5c above the average around this time of year) up until Tuesday morning, with Scotland and Northern Ireland possibly closer to the average on Sunday morning.

Typically tropical maritime air from a rather more southerly Azores high and a strong Euro high (which infact has gave ne Europe some frosty, cool weather lately). Tuesday looks more average to start off November; as a deeper low moves towards the west, and introduces a warm, southerly flow which keeps Wednesday and Thursday next week very mild once more.

Towards the end of the hi-res, a low system emerges in the northern half of Britain, and a low moves in from the SW, with the southeast clinging on to any warmer southerlies, while the rest of the nation is average and possibly cool in the west where a Pm flow reaches.

At the latter half of the hi-res, a low in Newfoundland moves e/se to give a southerly tracking low that eventually brings in the Pm towards the end; this pushes the Azores high further south, and gives less of a Euro high dominance. That would push the cold air much further south if a pattern were to evolve from this; but currently the outlook would be very mild indeed, with Scotland and Northern Ireland managing the cooler weather, which would still be a fair degree or so above average.

[No Balls Like Snow Balls]

ECMWF and GFS 00z runs point towards a rise in pressure to the NE in FI, a good signal if you are hoping for blocking of sorts near Scandinavia which could lead to colder conditions in time. I'm not so sure about the evolution currently shown, with no decently cold air to the east as it's currently being progged, I feel it's to early to be looking for easterlies anyway as the current set up would probably lead to grey and mucky weather towards eastern areas, also remaining mild or very mild for the time of year. At this time of year we need to be looking to the N/NNE for decent cold which is still bottled up over the Arctic and Polar regions.

All still lurking out in FI and all speculation at this stage.

Um yes the 500mb charts also indicate a weakening of the trough out west and a shift in the high pressure to more Northerly lattitudes.

[joggs]

whats peeps ideas for bonfire night re the models thanks

[Isolated Frost]

whats peeps ideas for bonfire night re the models thanks

GFS says cloudier and wetter but quite cool in Scotland and NI, mainly clear throughout much of Ireland, Wales and England but a low in the bay of biscay makes a charge and gives heavy dramatic showers for the south moving northwards throughout the evening.

ECM says something quite similar but is more progressive and would probably give heavy rainfall for much of England and Wales from that low, while it's generally brighter/drier over NI and Scotland.

Long way to go yet though; ask us by Nov 1st and we'll probably have a much better idea.

[Frosty.]

The latest models bring us no closer to anything cold, indeed they bring us closer to something very mild with winds originating in spain and western africa. There is some good news for the rain starved midlands and southeast as late next week it looks like low pressure will be over the uk with a lot of rain possible but that brings the risk of flooding as winds could become light and fronts become slow moving or even stalling which would be bad news but then high pressure looks like forming to the north and then expanding south to bring a settled spell towards mid november with frost and fog likely but no sign of anything wintry at all.

[Frosty.]

I'm surprised theres not more interest in this mornings output. The ECM especially holds out the chance of something colder in the later outlook.

Sorry to disagree nick as I normally value your input, there is nothing in the models to show anything cold for the uk as far as mid november and probably way beyond that. The Gfs 00z is a good example, it shows a raging easterly at the end of FI but temps of 9-12c across the uk as there is no cold air in europe at that time..and that's mid nov! no wonder teits and steve murr are staying in hibernation for a while longer.

Edited October 28, 2011 by Polar_ Low

[Aaron]

The weather is unbelievably boring right now, no wonder there's a lack of interest in the output for most of the year..

[wolvesfan]

The weather is unbelievably boring right now, no wonder there's a lack of interest in the output for most of the year..

more frustrating at the moment for most.

[Isolated Frost]

The weather is unbelievably boring right now, no wonder there's a lack of interest in the output for most of the year..

Maybe for you- and some other 'fair weather' watchers- but it's an interesting array of atlantic dominated weather. Think hemispherically , not locally. Interesting height builds over arctic, and watch whereabouts the lows move at newfoundland. Predicting the medium-term future (15-25 days) will become much easier thereafter

[Aaron]

Atlantic weather - interesting - never thought I'd hear the three words in the same sentence.

[Isolated Frost]

Atlantic weather - interesting - never thought I'd hear the three words in the same sentence.

Well, tbf that's your opinion; but some people on here enjoy all types of weather; and comment impartially on all types of weather, which in turn makes it easier for people who want to learn about the models.

6z gfs quite cooler after being similar until +108.

Colder air further east as the low moves into the UK on this run, so it's quite an average/slightly cool run towards the end. Looks very cloudy with maxima under 10c with a mean northerly flow for the west, and a cyclonic flow, but mainly easterly for many other parts as we progress into the first few days of November- could easily be an average start to November- but some very mild days are still to come; and nothing is definite right now.

[feb1991blizzard]

I'm surprised theres not more interest in this mornings output. The ECM especially holds out the chance of something colder in the later outlook.

Overall the key timeframe post 168hrs suggests the upper trough weakening as shortwaves run into southern Europe and its what happens to pressure rises to the ne that will determine whether some colder conditions develop.

Unfortunately all the interest is well into FI but the ECM is not outlandish in its way forward and if these shortwaves do head east into southern Europe the natural knock on effect is for a rise of pressure to their north, its really how strong this will be and whether it orientates favourably to bring some colder conditions in.

I was thinking that myself. I think the reason for a lack of interest to be honest though is that the chances are that any cold air being advected into Britain by way of a scandi high this early would be sure not to bring anything wintry but i would look at if the bigger picture to be honest and would be happy to see ECM 0z or even GFS 0z verification because any decent spell of high pressure over Scandi really isnt in the script for at least the first 3 weeks of Nov so would be a promising sign although the 06z GFS FI has trended away from this and has a slow moving trough tracking gradually NE and the Met office 30 dayer suggests only a brief spell of HP and is more likely to be centered over the SE of the country rather than to the NE and looks only brief with the Atlantic powering through again although im not sure they have updated it properly going on the wording.