Model Output Discussion 30/06/2012

[bluearmy]

Hello from a soggy south west.

MJO has apparently staggered into phase 3.

I'm a total novice on these things so i would not like to offer an opinion on what bearing it will have. There have been posts (Chino or bluearmy i think ), that have suggested this is where we need it to be heading in July but i would guess there are plenty of other drivers to what weather we will get over the next month.

What i would like to comment on, is that i've been watching the forecasts for this over the past week and i feel their accuracy has been poor. Many have been very keen to reverse the movement in the short and long term back into phase 1.

The above are illustrative and the ECMF outputs have not been so bullish regarding a reversal into phase 1 but even they have to some extent underestimated the motion towards phase 3. I know these plots are effectively a snap shot of broad tropical convection but i'm wondering that if they are regularly struggling to forecast this correctly a day in advance, how much confidence should we have with the mid range model output being shown for the northern hemisphere?

Cheers

S

it wasnt me swebby - i'm not a scholar of the MJO and my anecdotal take on it is that in fairly low amplitude, it isnt generally too relevant for us as other global influences supercede it.

[swebby]

i share your reserve about accepting the MJO forecasts as gospel. Like any other forecast tool they can be wrong at times.

Yes i quite agree John but what i'm wondering is that if these prove to be continuously wrong how much confidence should we have in the longer range outputs for the US/N.alantic? Is it a case that the tropics are modelled differently (i assume calling the convection found across the who;e equator accuratley is very difficult) and so the model output for higher lattitudes can be treated as a separate entity?

Cheers

S

Edit - thanks for the clarification BA and yes i also believe from what i've seen from other posters that we do need a high amplitude to see an impact.

Cheers

S

Edited July 7, 2012 by swebby

[Alex]

Yes I see the MJO is in phase 3, this is of little use with low angular momentum at probably record low figures. Pattern change very unlikely until angular momentum starts to increase.

[Cloud 10]

Yes I see the MJO is in phase 3, this is of little use with low angular momentum at probably record low figures. Pattern change very unlikely until angular momentum starts to increase.

Angular momentum nearly on the floor.

The composite for the MJO in phase 3 for July looks a long way from what is actually happening?

[johnholmes]

Yes i quite agree John but what i'm wondering is that if these prove to be continuously wrong how much confidence should we have in the longer range outputs for the US/N.alantic? Is it a case that the tropics are modelled differently (i assume calling the convection found across the who;e equator accuratley is very difficult) and so the model output for higher lattitudes can be treated as a separate entity?

Cheers

S

the comment by ba about its amplitude is also very true, small amplitude and other things swamp its effect even if it is a correct forecast.

Edited July 7, 2012 by johnholmes

[Cloud 10]

Thanks to all those who have explained about the MJO,more caution needed regarding those composites!

Meanwhile,no surprise to see the models predicting another unsettled week.

Friday the 13th

[Methuselah]

What is it with bloody Fridays! Whatever the models predict the previous week, every Friday has been rotten...

[Bobby]

Unsettled looking ECM too

[Summer Sun]

Low pressure dominates the 12z from GFS again

http://www.netweather.tv/index.cgi?action=nwdc;sess=

Same from ECM

http://www.netweather.tv/index.cgi?action=ecm;sess=

And UKMO

http://www.netweather.tv/index.cgi?action=meto;sess=

[AWD]

I know it FI etc, but the Azores High looks a lot closer to the UK than it has done for a very long time, on tonight's FI ECM output.

If the ECM went out further, it is quite possible a settled scenario would evolve with a more influential Azores High.

Considering there isn't much to look for in terms of warmth and sun in the reliable timeframe, FI tonight from both the GFS and ECM holds promise. A positive, yes very tentitive, sign and long term outlook from the models tonight I feel.

Edited July 7, 2012 by Active Weather Dude

[Snowyowl9]

What is it with bloody Fridays! Whatever the models predict the previous week, every Friday has been rotten...

I`m glad I`m not the only one whose noticed that.

http://www.wetterzen...cs/Recm1441.gif

[A Winter's Tale]

Hello there.

We've seen severe conditions recently as this long period of notably wet, cool, and dull weather for this time of year continues - however recently we've seen some milder and warmer temperatures in places. So as the search for longly anticipated prolonged summer warmth and brightness continues it's worth looking at what sort of weather conditions we'll see in the next few days and whether there could be some decent spells to make the most of or severe conditions to warn about.

What has brought the today's and the past few days rainfall is a low pressure system that's situated over the country with an easterly flow with a lot of moisture in it. We've seen more of these low pressure systems in the past few weeks because air pressure is high over Greenland and this sends the jet stream a lot further south than usual. The jet streams drives low pressure systems from west to east across the Earth and brings unstable air that can result in changeable conditions and often assoctiated with rainfall, wind and limited sunshine to area - however there are a variety of weather conditions that can occur as a result of low pressure so it doesn't always mean that conditions will be wet, cold and dull.

We've also had some mild and muggy temperatures recently with air coming from the continent and mixing with the damp conditions with all the seas around us. At the moment, this low pressure has two main areas of rainfall: one over parts of Northern Ireland, Western, Northern and North Eastern parts of Scotland and another that's over towards the souther areas of England and perhaps South East Wales. Inbetween this, it's a lot brighter with sunny spells with showers although some coasts of NE England and C and S Scotland remain cloudy. Temperatures are disapointing in the NE but elsewhere temperatures are typically 15-20C.

Overnight, we see the area of prolonged rain in the north move a little further north-westwards with further damp and dull conditions lingering into tomorrow morning for northern and north western Scotland. The rain may hang around for a while in Northern Ireland with overcast skies but the precipitation should be light with overnight temperatures around 13C. In the south of England, the current area of rain is expected to fizzle out and clear out into the north sea and continent. Cloud cover is expected to last quite widely in the southern and eastern areas - possibly a few clear spots around the Wash - with some showers and light rain patches around south east coasts and some central areas. Here, temperatures should be 14-15C tonight. The SW of England may well have some clear skies although the possibility of a rain shower remains. For Wales, any rain should disapear with widespread clear skies with only the coasts having the cloud cover. NW England could see clear skies - especially around the Irish Sea coasts - with cloud cover further east and showers are possible as far north as Manchester. SW Scotland may remain clear, elsehwere it's cloudy although skies may clear up in the east for a time.

The chart above highlights where the main areas of rain should be tonight.

Tomorrow morning, the best of the sunny intervals are likely to be in Wales, the SW, NW England and SW Scotland with some temporary clear skies in east Scotland and the Midlands. The heaviest and prolonged of the rainfall is to be the NW and N of Scotland. As the morning goes on we'll see cloud cover increase in Wales with some showers by lunchtime. In SW England, skies will fluctuate from being clear to partly cloudy to overcast with the possibility of showers. The South coast of England will see a mostly cloudy morning but as we approach lunchtime some sunny intervals could be found the further west you are with some showers. The morning shall start overcast in the SE with showers increasing as the morning goes on. Further west from here sunny intervals are possible as is the risk of thundery showers. The east of England may see clear spells for time to time and further west in the Midlands a showery morning is likely. The North of England skies will become overcast with rain arriving in the NE but sunshine is possible behind the rainfall. Sunshine in Scotland is restricted to the west with an overcast picture with light rain in the SE and heavy rain clearing the NW. For Northern Ireland it'll be an overcast morning with light rain for most.

In Scotland, the afternoon skies may brighten up in a strip of land between Angus and Argyll with rain leaving the NW but a heavier area of precipitation arriving in the SE. Temperatures could max as low as 11C in the NW but central areas may see highs up to 17C. The morning rain in Northern Ireland will clear and fizzle out with some sunshine in the east - temperatures here maxing at 16C. The north of England will remain cloudy with precipitation around with some heavy rain in the NE. In the Midlands it'll still be a story of sunny intervals and showers and it's very similar story for the east, south and parts of Wales. Temperatures in these areas will max at 16-20C.

The evening will see cloud and some light rain in the SW, Ireland and NW Scotland. Heavy rain will be located over SE Scotland but some evening sunshine is possible north and west of this. North England will continue to be overcast whereas further south there should be some good periods of sunshine mixed with a few showers.

Into the night, we're set for cloudy conditions for most except some clear skies in the south of England. There's a threat of rain around Ireland, the SW of England and Wales with patchy light rain in the north of Scotland and the focal point of the rain being the east of Scotland. Minima should be 12-15C.

On Monday, the wind direction will be more of a NNEly and a widespread overcast day is forecast with dampness across the S, Wales, NE Scotland and in particular NE England and SE Scotland - some heavy rain is predicted here. Some central areas of England, coasts of NW England and Wales, the majority of Ireland and Western Scotland could be dry for periods. Maximum temperatures of 16C in the north to 21C in the SE.

Winds will turn to a northerly on Monday night and again the UK should see largely overcast conditions. Thankfully, precipitation should be less heavy and widespread although some light precipitation is forecast for the Hebrides, SW Scotland, parts of the Midlands and east of England and perhaps the south coast. A cooler night in the north with lows of 10-12C but further south minima should be 13-15C.

The northerly wind is set to bring rain with it as much of the UK is in for a wet Tuesday - some of that rainfall heavy in places. Conditions will be largely damp and overcast with only the SW, Wales, NE Scotland and the coasts escaping from most of the rainfall. Quite a cool day in some areas with temperatures reaching highs of 13C from anywhere north of Manchester. The SE should see the warmest conditions up to 19C.

Tuesday night - heavy and widespread rain is forecast for anywhere between Manchester and Inverness with some showers for coastal regions. A mostly cloudy night with only some coasts in Ireland seeing any clear skies. The majority of Wales, South England and Wales and North and North-East Scotland should escape the widespread rainfall - temperatures at 10-13C.

Wednesday sees the rainfall move further south with much of Ireland, England and Wales having a wet day. Scotland a lot drier with a few showers in the Moray Firth. Again, 19C in the SE is the best of the temperatures with 13-15C elsehwere. Wednesday night looks like being a lot drier with some clear spells possible in S Ireland and England. Some temporary light rain restricted to eastern coasts.

The end of next-week also looks like being a wet one. So, in the next 5 days it looks like temperatures are set to drop a bit with cooler northerly winds and just about everywhere is set for some rainfall at some point. The majority of the clear skies in the coming days will be found tomorrow in southern and central parts of England and Wales. We may not see the same rainfall of the past few days but Tuesday and Wednesday next week look like being pretty wet indeed. And generally, next week looks like being overcast, cool with showers dotted around the coasts and some precip in land.

In the latest run, it remains unsettled towards the end as high pressure continues over Greenland. In some recent days we've seen some tentative signs of a possible change in air pressure over Greenland so any trend in FI can't be ruled out but I think if we're to become more realistic about discussing a change in the weather pattern is when we see a consistent change in FI and appearing in earlier runs. But at the moment, it looks like we're going to have a first-half of July that's similar to June with cool, wet, dull conditions and I can see this continuing into the latter part of the month but I feel that the later we go on with this pattern the nearer we'll get to a change and I think this could happen sometime after the end of this month. But of course a change could happen a lot earlier so again it's worth keeping an eye on the model outlook trends as at any moment we could see an end to this long run of unsettled weeks. As ever, it's still worth focusing on the current and near-future weather and seeing how it all goes and keeping an eye on any possible spells of decent weather or severe weather to follow and report on. I hope that we'll soon see a change in the synoptics and I really do feel that this month is a do or die month for summer 2012 - even still a memorable change or event in the weather can happen anytime in August. With all this Northern Blocking you do wonder what on earth winter would have been like and it's interesting to see how regular and persistent it still is - of course, it will disapear in time for winter - and I wonder what Autumn 2012 will have in store after last year. The coming weeks and months will be important in shaping how summer ends and how autumn starts that's for sure but before we can start talking this far ahead we've got a wet week to concentrate on first and an ongoing search for summer.

[bluearmy]

no sign of anything remotely settled for a fortnight. the ecm mean precip charts have ticked up back towards 60mm for london. there are sniffs at the end of naefs that things may improve with a general rise in heights from the south but we've seen that before and without anything concrete being shown on the anomoly charts, i'd be cautious of reading too much into that. the best you can say at T384 is that the low anomoly pulls back into the atlantic. too far away to take anything from that yet. it does seem that the mid atlantic block is going but the general high heights in the greeny area remain and with them, the southerly jet. i doubt we'll be seeing a stuck trough as per now but more likely a succession of depressions headed west to east. at least that should give us a chance of a better day here and there with transient ridging.

[BLAST FROM THE PAST]

The ECM is trending back to sending LPs on a more southerly track again as pressure holds firm to our N/NW. Not a good signal over last couple of runs. We can't write July off yet though, but half of it is certainly taken care of.

As for GFS, well just as gloomy.........I have to say if this were winter we'd be buried in snow.....but it ain't we're just washed out. The GHP and the southerly tracking lows are impressive in their persistence. Indeed the southerly tracking lows have strengthened somewhat on most recent runs and the hint of the AZH taking a tentative hold have gone. Lets see how the runs continue over next few days.

BFTP

Edited July 8, 2012 by BLAST FROM THE PAST

[kev238]

A pretty dire ste of outputs taking us beyond MId July, with barely a sniff of summer to be had for most of the country. The weather for the week ahead looks cool and showery before a new low pressure heads in later in the week.

Whilst this unsettled regime remains, further bouts of extremely wet weather look likely especially if we tap into warmer plumes from the continent.

It does seem nailed on now, that the first half of summer will go down as one of the worst of the past twenty or thirty years. The models have shown small signs of improvement but these seem to have disappeared, and the Greenland high looks stubborn as ever.

[William of Walworth]

I haven't checked into this thread for the best part of a week now and what do I find?

No change synoptically ....

However, thanks for some semi-enclouraging thoughts from A Winters Tale in that excellent summary above. Lets hope we don't have to wait to August for summerlike conditions to get established. No sign yet though ...

<praying for w/e of 20-22 July to be half way decent in the South. At least dry anyway!>

[bluearmy]

Those green shoots beyond the 20th continue courtesy of naefs deep fi. No high anomolys to see yet but the blue ones draw back well to the sw.

The mean jet not looking too strong by then. Its a fair while since we lost the low anomolys - seeing as this a trend rather than one run, we may be seeing the light at the end of the tunnel ?

[Thundery wintry showers]

The GFS continues to suggest "sunshine and showers" through to Wednesday, but in reality extensive cloud cover may well restrict both sunshine and showery/thundery activity over most parts of the country- in particular we still have a slow moving front over northern and western Scotland with a large associated mass of cloud, and this is set to move south-eastwards over the next couple of days. The Atlantic looks like powering up again on Thursday/Friday, and a southerly tracking low pressure system will probably bring cloud wet weather especially to the south.

A "return of the westerlies" type pattern is suggested for the 7-10 day timeframe with the jet moving back towards its normal position but still leaving the British Isles in the firing line for belts of cloud and rain off the Atlantic, with the Azores high occasionally ridging into the south- a pattern which characterised most of summer 1998 for instance. It could be a stepping stone towards a more significant pattern change, or perhaps a move from one cool cloudy rainy type pattern into another, at this range it's hard to tell.

[TonyH]

My weather guide for the week ahead (west Wales and the Midlands specifically):

http://forum.netweather.tv/blog/309/entry-4435-weather-guide-monday-9th-to-sunday-15th-july-wet-wales-and-central-midlands-specific/

[johnholmes]

We now have two days with very close agreement in the 7-15 day time frame from the 500mb charts of a change, not major but a change to occur.

All 3 now show no sign of the trough which has been the cause of such widespread rainfall, both frontal and showery/storm types for the past weeks.

They each now suggest low contour heights across the Atlantic with the main trough to be around 50W and the main -ve area of heights just forward of it. The broad westerly flow at 500mb from this trough way out into Europe. It certainly is not a settled type of upper air pattern nor a warm summery settled one. However, it does give the prospect of somewhat less unsettled conditions at times, even a possibility of a ridge from the Azores area at times being the main influence. This SHOULD give some respite for the holiday areas in the SW if it happens. Something of a NW-SE split may develop with the more settled weather, for the most part, the further SE you are. Again in this type of unsettled westerly upper pattern that does NOT preclude the odd thundery outbreak IF a short lived pattern develops with a flow more from a S'ly rather than a W'ly point for southern areas.

7-10 days down the line will prove whether this idea is reasonable or another bout of jh hot air!

[phil nw.]

We now have two days with very close agreement in the 7-15 day time frame from the 500mb charts of a change, not major but a change to occur.

All 3 now show no sign of the trough which has been the cause of such widespread rainfall, both frontal and showery/storm types for the past weeks.

They each now suggest low contour heights across the Atlantic with the main trough to be around 50W and the main -ve area of heights just forward of it. The broad westerly flow at 500mb from this trough way out into Europe. It certainly is not a settled type of upper air pattern nor a warm summery settled one. However, it does give the prospect of somewhat less unsettled conditions at times, even a possibility of a ridge from the Azores area at times being the main influence. This SHOULD give some respite for the holiday areas in the SW if it happens. Something of a NW-SE split may develop with the more settled weather, for the most part, the further SE you are. Again in this type of unsettled westerly upper pattern that does NOT preclude the odd thundery outbreak IF a short lived pattern develops with a flow more from a S'ly rather than a W'ly point for southern areas.

7-10 days down the line will prove whether this idea is reasonable or another bout of jh hot air!

Yes a flatter looking pattern in week 2 has been suggested by the daily outputs for about 3 days i think John.

Still a flow off the Atlantic as you suggest with a generally suppressed Azores High and some shrinking of that stubborn upper trough away from the UK.

The main driver though is this southerly tracking jet and we only likely to get brief drier spells but if it weakens down the line then the chance of some height rises from the south in the form of some ridging would be more likely.

That`s more in hope though to be honest and even with some adjustment to those wavelenghts(flatter) the general theme is still unsettled and rather cool in this current pattern of warm 500hPa anomalies further north.

http://www.meteo.psu...WF_0z/test8.gif

[Backtrack]

An annoying, upsetting, frustrating update from the Met Office. The models reflect their output. Summer is over.

Climatologically this is the warmest part of the year, but this year a protracted spell of hot, sunny weather looks very unlikely. In fact inclement weather that has characterised June and early July will probably still be in evidence, although overall conditions are unlikely to be as bad. Forecasts for the southern half of the UK favour below average sunshine amounts, with mean daytime temperatures about four times more likely to be below average than above. Rainfall in the south is extremely uncertain, though very wet conditions are a little more likely than very dry. For the northern half of the UK there are no clear indications of above or below average sunshine, rainfall or temperature, although as we move into August conditions here may improve.

Edited July 8, 2012 by Backtrack

[Luke McDonnell]

An annoying, upsetting, frustrating update from the Met Office. The models reflect their output. Summer is over.

Climatologically this is the warmest part of the year, but this year a protracted spell of hot, sunny weather looks very unlikely. In fact inclement weather that has characterised June and early July will probably still be in evidence, although overall conditions are unlikely to be as bad. Forecasts for the southern half of the UK favour below average sunshine amounts, with mean daytime temperatures about four times more likely to be below average than above. Rainfall in the south is extremely uncertain, though very wet conditions are a little more likely than very dry. For the northern half of the UK there are no clear indications of above or below average sunshine, rainfall or temperature, although as we move into August conditions here may improve.

Hi BT,

I don't agree with the "Summer is over" statement - here at least in Liverpool it feels like summer today - it is quite sunny and around 20C - just because the Met Office update says that poor weather is still in evidence does not rule out recent days. Actually, I think the average July max for our area is around 20C so you could say that today is like a typical summer's day for us. How long does that update go out into - does it take us into August? - sorry for going a bit OT.

I would like to see a pattern change soon though as I think we should be due one - even if thier wasn't a long term pattern change is thier anything stopping us getting a period simliar to the end of May at the end of July - e.g. a 7 day warm spell considering the summer so far I think a lot of people on here would kill for that LOL!. Another question for you is does anyone think that 30C will not be breached anywhere in the British Isles during official summer this year - what do you think the odds of that is at the moment? as I think you have to go back to 1993 to get a summer that did not breach 30C but I think thier were some summers in the 1960s that did not reach it.

Luke

[damianslaw]

Reliable timeframe - its a poor outlook for anyone wanting any decent warm settled dry sunny weather. Indeed the next 7 days look positively cool for the time of year with maxima well below average, by the middle of next week, many places in the north could struggle to make 15 degrees, which is very poor indeed for July. The synoptical set up for the next 3-4 days is a classic 'cold' one - a snow lovers dream in the winter, with a strong high pressure alignment from greenland into mid north atlantic, warm air advection up the west side of greenland and consequently a draw of air from the arctic with embedded trough feature. Alas it is July and instead it will be showery outbreaks of rain, possibly heavy rain in places with dull skies and very supressed temps, with some very cool nights.

By the end of the week, all the models suggest a renewed atlantic attack from the west, with yet again another low pressure system due to hit our shores on Friday - I think this will the sixth week in a row such a scenario has occured.. quite remarkable, and therefore another dissapointingly cool dull wet weekend looks on the cards.

Longer term as we move towards the latter part of the month, there are signs from the models of a change to a more traditional westerly type spell of weather, as the southern arm of the jet begins to weaken somewhat - it is abnormally strong for the time of year at present, and we see the azores high tentatively trying to ridge NE. Whilst as others have said, such a change is very unlikely to herald the beginnings of a major pattern change to something much drier settled and warmer, it does at least hold greater chance of perhaps some more shortlived drier warmer spells at least in the south as frontal activity hits the north more harder esp the NW. Such a pattern has dominated many second halves to recent summers, look at the likes of 1998, so in all honesty its not necessarily a pattern change I would be hoping for, but it would be better than the current pattern which is so conducive to major flooding and downright no prospect of anything even half decent.

We await to see if our fortunes are about to change as we head through the second part of this month, at the moment however, the prospects of a lengthy dry warm sunny spell happening anytime soon remain very low indeed. Oh dear!

[Weather Boy]

Optimists might note that the GFS and ECM agree on a modest pressure rise towards the end of next week, but we have been there before and I note that the GFS op struggles to get much support from its ensembles - although some of them have a rise earlier. Even what the op does prog is hardly what summer lovers are looking for and is relatively temporary.