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

[Captain Shortwave]

Take your pick at day 6 (T144)

GFS

 

UKMO

 

GEM

ECM

 

Edited September 20, 2013 by Captain shortwave

[Man With Beard]

UKMO may have weaker pressure but it keeps pumping up air from France, where temps are forecast to be 27-32C by mid-next week. The longer we keep the southerly feed, the better the chance of reaching really high temps for the time of year.

Longer term and the option of northern blocking strengthening certainly an option, which would bring temps back to earth with a bump

[Frosty.]

GFS 12z op run looks great for the south next week, generally fine with sunny periods and very warm for the time of year, low to mid 20's celsius, favoured spots may hit 80F but mid to high 70's looks realistic with winds either light and variable or sourced from the very warm/hot near continent, it eventually trends cooler across scotland after a warm start with an increase in unsettled weather later next week, FI stays fine and pleasantly warm in the south until well into the low res, fair at times further north, for the last full week of september it will feel more like summer for many.

[Captain Shortwave]

ECM looks more like the UKMO at T72, in fact it's more extreme than the UKMO solution

Oh well

 

All 4 models show 4 completely different solutions a day 4

Edited September 20, 2013 by Captain shortwave

[Frosty.]

The GEFS 12z mean looks very warm and settled the further south you are next week, it looks like the southern half of england & wales would do best of all with long sunny spells from monday onwards and very warm for the time of year, it will feel just like summer next week for many although not  as good obviously as the sun is a lot lower now but low to mid 20's celsius is about as good as it gets so late in september and a lot better than the recent below average temps and windy, rainy weather, further north across the uk the trend appears to be for a slow erosion of the fine and warm spell as time goes on with a risk of showers developing as pressure falls a little, but the south should be mainly dry next week, maybe a few showers by the end of the week and temperatures drifting back towards average eventually but the PFJ stays to the north of the uk and most of this run looks fine and benign with light winds and pleasant, nights would probably trend cooler later with an increased risk of fog if the overall pattern remains stagnant but scotland would probably have a more definate unsettled and cooler trend by early october. I'm a bit surprised that there is not more enthusiasm for what looks like being a very good last full week to september.

[East_England_Stormchaser91]

These really warm fetches from as far down as Morocco always seem to happen at this time of the year!! If we were looking at these charts for the beginning to mid August, it would be absolutely record breaking. I guess as low pressure systems get much much deeper, and the contrast of air gets much greater, that will be the reason why we can at times see these huge fetches of benign unusually warm air. The weaker jet with a very sleepy delayed hurricane season must also play a key part to these synoptics.

[Captain Shortwave]

Posting the JMA for the lols

 

 

 

 

 

Just insane.

ECM unsettled from day 8

Not much of this matters as they are probably all wrong

Edited September 20, 2013 by Captain shortwave

[Mark Neal.]

ECM RUN, shows it turning less settled towards mid next week before low pressure arrives for end of week and into next weekend. 

[NorthNorfolkWeather]

ECM looks more like the UKMO at T72, in fact it's more extreme than the UKMO solution

Oh well

 

All 4 models show 4 completely different solutions a day 4

Talk about FI being a moveable feast.

 

When FI is out at 5-6 days, we see it as normal.  I find it strange that FI has come so much when the weather doesn't look to be springing any major surprises.

 

A personal opinion is that the ECM has been poor all summer, in fact it was the ECM that gave us the title "That ECM" last winter, so the model has had some hard times in the last 10 months.

 

For once the GFS has (IMHO) outperformed the ECM (but perhaps it's a season thing.

Edited September 20, 2013 by NorthNorfolkWeather

[Captain Shortwave]

Talk about FI being a moveable feast.

 

When FI is out at 5-6 days, we see it as normal.  I find it strange that FI has come so much when the weather doesn't look to be springing any major surprises.

 

A personal opinion is that the ECM has been poor all summer, in fact it was the ECM that gave us the title "That ECM" last winter, so the model has had some hard times in the last 10 months.

 

For once the GFS has (IMHO) outperformed the ECM (but perhaps it's a season thing.

We have 2 cut off lows. We know from the summer that one cripples the reliability of the model output and we have 2 now 

I can't say that either the ECM or GFS is correct because quite simply they are changing the goalposts with every run. Next Tuesday onwards, going by the output, we are absolutely clueless about what lies ahead.

@any experienced posters. Has anyone ever seen such chaos in the model output that we are seeing now?

Edited September 20, 2013 by Captain shortwave

[Mr_Pessimistic]

"Has anyone ever seen such chaos in the model output that we are seeing now?"

 

virtually every time i look at them. 

[bluearmy]

The 12z gefs looks far more inclined to stay on the settled side for london. Rogue run? have to see the ecm 12z run graph later but i did think the 00z suite looked drier than previous runs had done. is the pendulum swinging back?

[SMU]

an odd comment to make Steve. I thought I had proved over a 2 years test that, with the provisos I always give that they give an accuracy of 70% for the upper air pattern 6-15 days ahead. I ask you to show me anything which gives that degree of accuracy in the synoptic outputs or from any other source that you and I are able to access on the web?

 

Because John, they never go AGAINST the ensemble mean -  from MY own perspective I make calls on what I thinks going to happen, for example last winter a few occasions calling ALL the ensembles wrong & to follow the ECM op- which more often than not proved correct-

I have never seen any image posted from that link that deviates to far from the mean-  & for general background purposes its OK, which with your scores of around 60/70% is probs correct-

 

But its not really any good other than broadbrush anomalies- which fit well for the US, but not so well for us on our little island- & indeed they are not really aimed at us-

The are for showing the general wave pattern across the US- be it + PNA or - PNA & how steep the gradient is as well / or how strong that index is-

 

Rermember last December failed easterly that was there run after run for about 10 days which collapsed in about 2 runs when the surface features were picked up-

 

These background anomalies are good, but only in the context in which they are aimed at, & for us 60% accuracy for the broad picture then filtered to the UK doesnt correlate to a surface forecast...

 

S

Edited September 20, 2013 by Steve Murr

[Frosty.]

There is something for all weather enthusiasts on tonight's Ecm 12z operational run, starting with fine and increasingly warm weather as this weekend goes on and especially early next week, a few very warm and fairly sunny days but then turning cooler and more unsettled from the north, not sure how accurate this run will turn out to be as it's chalk and cheese compared to the 00z run and the ens mean but let's look at what we have, a mix of fine and warm, cool and wet and average weather for the next 10 days..at least the british climate is rarely boring..I don't mind what happens now, we had a very good summer and we have also had some good weather earlier this month, if it turns colder I will be happy, if it stays warm I will be happy, it's win win for me.

 

I don't see how we can be any clearer about how next week will ultimately turn out although we do know it will start fine enough.

[Summer Sun]

"Has anyone ever seen such chaos in the model output that we are seeing now?"

 

virtually every time i look at them. 

 

Just imagine if there is this amount of flipping and flopping in the "main season" from the models

 

Edited September 20, 2013 by Summer Sun

[Methuselah]

"Has anyone ever seen such chaos in the model output that we are seeing now?"

 

virtually every time i look at them. 

I find that, after 10 years' disappointments with the likes of GFS and ECM, the anomalies and upper-wind forecasts are rather better than any individual synoptic model, for providing guidance as to future weather-patterns...If the information required for making highly detailed >7-day forecasts isn't there, to start with, what's the point in making one's self cross-eyed trying to extract it?  

[Summer Sun]

Latest from Gibby

 

Good evening. Here is the report on the midday outputs issued by GFS, UKMO, GEM, NAVGEM and ECM for today Friday September 20th 2013.All models show a warm front moving NE over the UK tonight and tomorrow bringing progressively moist and damp air across all regions over the next 24 hours. Amounts of cloud will  will become large with low cloud shrouding hilltops and moors of the west and North late tonight and tomorrow. Through the latter part of tomorrow and more especially on Sunday and Monday the weather will brighten in the East and South with some warm sunshine expected while amounts of cloud remain a big headache for the rest of the UK.

 

GFS shows changes being very slow as pressure gently becomes slack with the warmest of the uppers cooling through the week. Any rain is unlikely away from the North of Scotland as Low pressure passes close by. Later in the output tonight changeable conditions gradually develop but it is hardly shown as a rain fest with a lot of dry weather alternating with some showers or rain at times as Atlantic depressions pass over or North of the British isles with temperatures closer to average.

 

UKMO tonight shows Low pressure to the SW gradually becoming more dominant as we move through the middle of next week with occasional rain on a cooler SE breeze gradually working it's way NE over the South and West of the UK with the drier but rather cooler conditions persisting over the North and East.

 

GEM shows a trend to somewhat more changeable conditions as next week progresses with cooler and eventually more changeable conditions developing across the UK with a cool NW flow for a time next weekend delivering a cool and showery spell, especially to the North and East. On balance though a fair amount of settled and dry conditions still looks likely.

 

NAVGEM shows High pressure leaking slowly away SE next week with cooler and eventually more unsettled weather with rain at times by next weekend.

 

ECM shows a decline in temperatures and a change to more unsettled weather by the end of next week as Low pressure winds up close to Ireland with fronts in association with it swinging North and East over most of the UK with rain then showers at times. The deep Low then moves slowly East across the UK and out into the North sea with a cool wrap around of strong winds and rain at times with the following days shaping up to maintain an unsettled spell as further Low pressure is approaching the West from the Atlantic by Day 10.

 

The GFS Ensembles tonight show a slow decline to average uppers by the end of the run. Throughout though the trend  though down holds conditions aloft above average levels for most of the run. There is tonight, as this morning a lot of spread from members from quite an early point of the run with a slow increase in the incidence of precipitation through the second half of the run.

 

The Jet Stream shows the flow moving North to be clear of the North Scottish coast over the next few days. It is then shown to ease back South over Scotland next week at the same time as weakening as a new arm exits the States on a more Southerly latitude though not particularly strongly.

 

In Summary tonight's output show's variation on a complex theme of High pressure declining slowly next week and allowing Low pressure in one guise or another to affect most of Britain by next weekend. Amounts of rain look small until late in the week with ECM leading the way in introducing a potent looking Low directly over the UK next weekend. UKMO also shows approaching Low pressure from the SW at the end of it's run with an inconclusive clue shown as to what might happen post 144hrs tonight. GFS and GEM have their own versions of a more slight change to unsettled conditions which when all put together shows the fine and warm spell may only last a few days before something more Autumnal again arrives later next week.

 

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

 

[Frosty.]

What's wrong with the ecm, no two runs even vaguely alike. Next week looks finely balanced, gawd knows how the experts can call next week with any confidence.

[summer blizzard]

Having not looked at the models in 3 days the trend in FI is certainly towards a reversion back to pre-Humberto setup. While not all models get the cool air all the way down, the real settled spell is confined to 2-3 days.

[Gaz1985]

Looking good for high pressure this Sunday 

 

 

Warming up too..

 

 

 

Pressure still high on Monday...

 

 

Still decent temperatures, I won't grumble at those for late September 

 

[Captain Shortwave]

I find it bizarre that somehow the weather in 10 days time is somehow "nailed on" despite the models not agreeing in 4 days time and flip flopping all over the place.

Another run, another solution

Edited September 20, 2013 by Captain shortwave

[East_England_Stormchaser91]

Cant believe I'm saying this, but summer looks like poking us with its last fingertip this weekend and into next week with 15c uppers knocking on the door perhaps! All could change though as I have also noticed on the 18z a very cold pool digging its way into Northern Scandi, certainly should be watched.

[Yarmy]

4 separate areas of LP affecting us from Tuesday onwards. Glad I'm not trying to draw the Fax chart. Who'd be a weather forecaster.

[Captain Shortwave]

Ironically as Summer blizzard makes his speech, the GFS delivers a settled solution from day 7, just some showers down eastern coasts. Everywhere else would be dry. cool and pretty bright.

I expect everything to be different in the morning 

Edited September 20, 2013 by Captain shortwave

[mushymanrob]

who cares what we are going to get after tuesday? we have several nice, very nice days to enjoy first. we know its autumn, we know its getting colder, so the next few days are a bonus, with possibly more to come.

 

wednesday onwards looks like a right dogs breakfast... a mess. looks like a gradual decline in temps, becoming more unsettled, back to normal really... but theres potential for something chilly, and something warmer, to evolve, everythings in the mix!