Model Output Discussion

[bluearmy]

just looked through the ecm ens run. had to double check i wasnt looking at the operational. crazy. maybe summer is finally coming.

[Thundery wintry showers]

The ECM after T+168 looks promising for warm dry sunny weather over the majority of the country, with the stronger high pressure most likely restricting low cloud to areas bordering the North Sea, but with a pronounced north-easterly flow stubbornly persisting, from an IMBY perspective I would really need that high further east, or less intense (the latter promoting lighter winds) to have much confidence of joining in with the warm sunshine that central and western areas would get.

Interestingly the ECMWF ensemble mean has shifted very strongly in favour of bringing the high further east, gives less of a NE flow and also supports the GFS evolution for this weekend, a combination that probably represents the warmest, driest and sunniest evolution that we could get from where we're at now, and unlike the operational would give us a decent weekend for outdoor stuff. Re. the operational run for this coming weekend, I don't think it would be particularly showery. Modified air is clearly indicated as spreading across from the NE, so depending on the positioning of the occluded front wrapped around the depression, the weekend would either be cool, cloudy and mostly dry, or cold dull and wet.

[tinybill]

Various options for late July from the models today. ECM keen on bringing something much more settled, whereas GFS and UKMO are siding more with continued changeable conditions.

Too early to call at this stage. Much will depend on what happens at the end of the week, should we see retrogression of the low pressure into the south north sea, this will set up a much better position for a dry settled warm spell thanks to building of heights to our N/NE, whereas a slack northerly flow as shown by GFS does not bode well as this will maintain low heights to our NE and thus instead we are more likely to see weaker heights develop to our SW enabling the trough to attack from the NW again - very much a continuation in the overall pattern of the summer so far.

On a personal note, I would prefer GFS to ECM not because it promises changeable weather next week, but simply it will mean a relatively good weekend, whereas ECM paints another poor picture for this weekend with cool windy showery conditions, east coast would do very poor. It is good weather at the weekends which really counts at this time of year.. the next 3-4 weekends in my book are the pinacle of the summer and are those which leave the most lasting impression on how we rate the summer just gone.

tell me about i looked at the models im off to north norfolk on sunday and the weather looking poor to say the least

[Thundery wintry showers]

The UKMO FAX charts only go out to Friday. I was going to suggest that this FAX chart suggests that the experts at Exeter think that the models are overdoing that low for the weekend, but actually the UKMO/ECM operational runs don't look hugely different to this:

http://www.wetterzentrale.de/pics/brack4.gif

So no clear indication yet there.

[J10]

The UKMO FAX chart for Friday seems to suggest that the experts at Exeter think the UKMO/ECM operationals are over-egging the weekend's low in the North Sea:

http://www.wetterzentrale.de/pics/brack4.gif

I don't see how the Scandinavian trough would get into the western North Sea from there.

That is yesterday's FAX though. But still it will be very interesting to see how this compares to today's FAX

forecast fro Friday.

[snowmackem]

Various options for late July from the models today. ECM keen on bringing something much more settled, whereas GFS and UKMO are siding more with continued changeable conditions.

Too early to call at this stage. Much will depend on what happens at the end of the week, should we see retrogression of the low pressure into the south north sea, this will set up a much better position for a dry settled warm spell thanks to building of heights to our N/NE, whereas a slack northerly flow as shown by GFS does not bode well as this will maintain low heights to our NE and thus instead we are more likely to see weaker heights develop to our SW enabling the trough to attack from the NW again - very much a continuation in the overall pattern of the summer so far.

On a personal note, I would prefer GFS to ECM not because it promises changeable weather next week, but simply it will mean a relatively good weekend, whereas ECM paints another poor picture for this weekend with cool windy showery conditions, east coast would do very poor. It is good weather at the weekends which really counts at this time of year.. the next 3-4 weekends in my book are the pinacle of the summer and are those which leave the most lasting impression on how we rate the summer just gone.

Personally prefer ECM from weekend onwards. The weekends through the next 6 weeks are not as important as they have been recently in my books. For the next few weeks the kids are off school and a lot of people are holidaying in the uk, so just having fine wwekends isn't bl##dy good enough, we want it nice all the time lol!!

From a nimby p.o.v., we are camping in the Norfolk Broads from next Wednesday, so it can do what it wants this weekend. Could it be that we have timed our holiday under canvass perfectly? We'll see but things are looking up,

SM

[Slowpoke]

ECM shows a massive improvement next week with very warm 850s and high pressure! GFS beginning to show the same aswell looking at the 18z! Let's hope this isn't another effin tease!

[Backtrack]

ECM shows a massive improvement next week with very warm 850s and high pressure! GFS beginning to show the same aswell looking at the 18z! Let's hope this isn't another effin tease!

Would very much fall in line with SP1986's post earlier.

As I also posted earlier, but deleted because I posted the wrong set of ensembles, was that I felt that the 06z GFS operational run was a bit of an outlier, turns out that I was right. Summer could finally be coming to the British shores... probably briefly. :lol:

[mushymanrob]

i dont share the optimism some are expressing. the gfs is having non of the ecms tease, but the ecm currently isnt all that good. the azh ridging towards us may kill off any precipitation, but i reckon it wont be wall to wall sunshine, typically with atlantic high there will be the cloud problem to contend with. the ecm also highlights why i refer to the azh as 'the enemy of summer'.. because whilst it sits there, it will prevent anything hot off the continent, or even home grown heat, to materialise.

i dont expect things will be as cool, wet or windy for the rest of summer, but my monies on the summers form horse to date... pretty average, normal, pleasant at times weather to see summer out.

[The Northern Ramper]

I must be looking at something else this morning to Mushy, the settled spell begins this weekend and is now looking reliable. The progression north east of the azores high settles nicely across the country by 216 with 15 850's suggesting hot weather. Fi yes but its a plausible run and the gfs has counted down to this weekend from 240 very consistently in my opinion.

[Gibby]

GFS this morning shows a showery few more days to come as Low pressure fills and slowly moves away to the east. Over the weekend and early next week winds back WNW with further weak disturbances moving across the UK from off the Atlantic. However, pressure slowly builds from the SW with dry and more settled weather spreading its influence North and East across the UK at the end of the hi-res part of the run. Further out things stay warm and dry for several days before complications set in from the NW and the eventual breakdown takes place from the NW by day 15.

UKMO is not too good this morning as it too shows a showery few more days with the odd longer spell of rain in the far SW tomorrow. Low pressure remains to the east and re-invigorates over the weekend as it drifts down the North Sea from Scandinavia bringing further showers to the UK late Sunday and Monday as the Atlantic ridge close to the west early in the weekend decays.

ECM looks OK with last nights pressure hike from the SW still very much in evidence. So after a showery three or four more days as low pressure fills and moves away to the east the ridge moves in by Tuesday of next week. In fact its more favourable than was shown last night as its axis is directly over the UK bringing a return to dry, bright and increasingly warm weather to our shores with sunny periods and patchy cloud. By day 10 the High is situated just off SW England with virtually dry, fine and warm conditions for most if not all of Britain.

Still not as straightforward as I would like this morning with UKMO not playing ball at the moment. It continues the theme of retrogression at the weekend which scuppers the chance in the short term to allow a strong build from the SW. It instead shows further complications in the form of further weak Low pressure coming into the mix as well early next week-something which GFS hints at too. However, GFS is more favourable towards the high pressure build in the longer term albeit more short lived while ECM shows a longer and welcome return to summer from early next week. I think there will be a few more twists and turns along the way and we need the UKMO to come on board before any champagne corks be popped.

[Spurry]

Despite the optimism of many on here and the charts appearing to show HP building, the BBC (Chris Fawkes) are still forecasting 'nothing summery for the foreseeable future'..i'm confused , or am i just reading the charts wrong (again!!)

Edited July 19, 2011 by Spurry

[ANYWEATHER]

I must be looking at something else this morning to Mushy, the settled spell begins this weekend and is now looking reliable. The progression north east of the azores high settles nicely across the country by 216 with 15 850's suggesting hot weather. Fi yes but its a plausible run and the gfs has counted down to this weekend from 240 very consistently in my opinion.

Well sorry, but I dont agree with you. For those who know how volatile our weather is and how volatile the model output is , nothing is certain at this stage.! I dont see any settled spell in the more reliable timeframe, only "if" you put your faith in the FI output. What I do see is a continuation of unsettled conditions for a good many and after that well, a very mixed up spell, How many times have we seen the models portrayed this high pressure dominated spell over the last few months and its come to nothing,Ive yet to be convinced of a pattern change, and I hope for Summer lovers that there is one, but as yet I dont see it...

[Cecil Hogmanay Melchett]

i dont share the optimism some are expressing. the gfs is having non of the ecms tease, but the ecm currently isnt all that good. the azh ridging towards us may kill off any precipitation, but i reckon it wont be wall to wall sunshine, typically with atlantic high there will be the cloud problem to contend with. the ecm also highlights why i refer to the azh as 'the enemy of summer'.. because whilst it sits there, it will prevent anything hot off the continent, or even home grown heat, to materialise.

i dont expect things will be as cool, wet or windy for the rest of summer, but my monies on the summers form horse to date... pretty average, normal, pleasant at times weather to see summer out.

Mushy,are you looking at the same 0z ECM run?

As far as nothing hot is concerned i'll have you a wager ecm 0z would produce high 70's low 80's if it came off.

The only problem this morning is UKMO which is having absolutely none of it.

Despite the optimism of many on here and the charts appearing to show HP building, the BBC (Chris Fawkes) are still forecasting 'nothing summery for the foreseeable future'..i'm confused , or am i just reading the charts wrong (again!!)

Well i guess he's siding wit the ukmo 0z run which is poor,to be fair.

[johnholmes]

it might help newcomers attempting to try and understand what the models are showing IF we said, for example, at T+96 ECMWF shows such and such, GFS something like so and so etc.

Putting the time scale we are talking about helps to work out what you are actually suggesting. Most of the above posts have no mention, other than FI, of any time scale.

How about

At T+96 this is the Wetter version of GFS

http://www.wetterzen...n/fsavneur.html

the ECMWF version same time

http://www.wetterzen...n/fsecmeur.html

and UK Met

http://www.wetterzen...n/fsukmeur.html

or whichever date/time you want to compare

then go on to discuss the differences and likely consequences as you see it?

just a suggestion!

my comments do not include Gibby who routinely and clearly explains the model differences followed by his interpretation of what that means.

Edited July 19, 2011 by johnholmes

[I remember Atlantic 252]

GFS certainly seem to give a washout sunday, not looking great another wet sunday, but hopefully overdoing it

[shedhead]

Whilst I think 'less unsettled' weather is now almost a given for next week, that's as far as I'm prepared to go at this stage, with still way to much uncertainty around to call for a return to full on Summer. UKMO in

particular is very reluctant to build the AzH northeastwards, keeping relatively low pressure firmly in charge at 144hrs, meanwhile GFS, albeit slightly better is nowhere near as keen as ECM to raise pressure over

the UK.

[Thundery wintry showers]

I think the ECMWF outputs post T+168 would certainly bring warm dry sunny weather away from the north and west of Scotland (where there would be cloud/drizzle) with temperatures widely into the mid 20s, and for eastern areas we would no longer have that north-easterly wind, and thus no issues with low cloud off the North Sea. Thus, for a large majority of us, a definite return to "summery" conditions. The problem with those outputs is that they're at a timeframe where outputs are notoriously fickle.

GFS eventually gets there further out into FI, but the outputs inside T+180 rather reflect the essence that I get from Mushymanrob's post- the Azores High nudges close in, but not close enough to prevent cooler cloudier westerlies from dominating Britain's weather on its northern flank, and indeed, as Shedhead mentions, we get a pretty active frontal system moving across next Sunday. As we saw starkly during the last week of August 2008, "settled" doesn't always equate to warm dry and sunny, the high also has to be in the right place.

It's amazing how much uncertainty there is over the coming weekend as UKMO doesn't even bring in the Atlantic at all, instead persisting with the scenario of low pressure drifting west from the North Sea. Overall, if nothing else the models have moved away from those scenarios with a pronounced north-easterly flow.

[Backtrack]

We have been in this sort of situation where as the ECM has been very keane to build heights across the UK and the GFS soon followed suite, only for the UKMO to be persistent in keeping a more unsettled scenario and for these reasons I will back the UKMO and go for this to win over the other 2

[Milhouse]

ECM at T192 has 850hpa temps of 15c flirting with the west coast so theres the possibility of mid to high 20s. If this very warm spell did come off it would tie in perfectly with the warmest part of the summer.

[shedhead]

I think the ECMWF outputs post T+168 would certainly bring warm dry sunny weather away from the north and west of Scotland (where there would be cloud/drizzle) with temperatures widely into the mid 20s, and for eastern areas we would no longer have that north-easterly wind, and thus no issues with low cloud off the North Sea. Thus, for a large majority of us, a definite return to "summery" conditions. The problem with those outputs is that they're at a timeframe where outputs are notoriously fickle.

GFS eventually gets there further out into FI, but the outputs inside T+180 rather reflect the essence that I get from Mushymanrob's post- the Azores High nudges close in, but not close enough to prevent cooler cloudier westerlies from dominating Britain's weather on its northern flank, and indeed, as Shedhead mentions, we get a pretty active frontal system moving across next Sunday. As we saw starkly during the last week of August 2008, "settled" doesn't always equate to warm dry and sunny, the high also has to be in the right place.

It's amazing how much uncertainty there is over the coming weekend as UKMO doesn't even bring in the Atlantic at all, instead persisting with the scenario of low pressure drifting west from the North Sea. Overall, if nothing else the models have moved away from those scenarios with a pronounced north-easterly flow.

Indeed TWS, good news for your location for sure. I'm reluctant to believe we'll see the LP drifting W as UKMO suggest, but given the nature of things right now I just don't think we can rule it out completely - what odds on the 06 GFS backing that evolution, just to add to the confusion?

[The Northern Ramper]

Well sorry, but I dont agree with you. For those who know how volatile our weather is and how volatile the model output is , nothing is certain at this stage.! I dont see any settled spell in the more reliable timeframe, only "if" you put your faith in the FI output. What I do see is a continuation of unsettled conditions for a good many and after that well, a very mixed up spell, How many times have we seen the models portrayed this high pressure dominated spell over the last few months and its come to nothing,Ive yet to be convinced of a pattern change, and I hope for Summer lovers that there is one, but as yet I dont see it...

96 Hours to saturdays weather has been consistent since 240 on the runs i have seen, i am very confident that is reliable. I then believe the high will move in, that is fi.

it might help newcomers attempting to try and understand what the models are showing IF we said, for example, at T+96 ECMWF shows such and such, GFS something like so and so etc.

Putting the time scale we are talking about helps to work out what you are actually suggesting. Most of the above posts have no mention, other than FI, of any time scale.

How about

At T+96 this is the Wetter version of GFS

http://www.wetterzen...n/fsavneur.html

the ECMWF version same time

http://www.wetterzen...n/fsecmeur.html

and UK Met

http://www.wetterzen...n/fsukmeur.html

or whichever date/time you want to compare

then go on to discuss the differences and likely consequences as you see it?

just a suggestion!

my comments do not include Gibby who routinely and clearly explains the model differences followed by his interpretation of what that means.

I am on a phone John, bit of a struggle to post links etc.

[minus 9]

Gfs 06 looks like its backing ecm at the mo anyway. Summer just round the corner. Positive thinking!!

[Buzzit]

Current MJO output is currently looking positive and condusive to assisting with the % probability of summer weather for the UK. UK Met is currently wanting to reduce amplification and revert back to Phase 1 more quickly and may a general part indicator of why the UK Met output is at odds with GFS and ECM at the end of the output we see

ECM

GFS

UKM

Edited July 19, 2011 by Buzzit

[johnholmes]

96 Hours to saturdays weather has been consistent since 240 on the runs i have seen, i am very confident that is reliable. I then believe the high will move in, that is fi.

I am on a phone John, bit of a struggle to post links etc.

understood in that situation

forgive my not understanding but what is this meant to mean please

phase backwardation