Model Output Discussion 12z 01/06/13

[Cloud 10]

12z ECM ensemble mean height anomalies for mid-month look a lot different to its last few days output.

 

 

 

Has the ECM picked up on a new trend?

 

NAEFS and NOAA say no for now....

 

Edited June 6, 2013 by Cloud 10

[Alex]

From a respectful massive newbie, and forgive me or remove this if I'm ruining the thread, but in a nutshell what are AAM and MJO?

Hi Jimmy, in a nutshell these are teleconnections or background signals, which can give us hints rather than details of upcoming weather in the medium term.

If you want to know more about the MJO, I would recommend the link below using the "educational material" link.

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/mjo.shtml

@alexbweather

Edited June 6, 2013 by Alex

[J10]

12z ECM ensemble mean height anomalies for mid-month look a lot different to its last few days output.

 

EDM101-240.gif

 

 

Has the ECM picked up on a new trend?

 

NAEFS and NOAA say no for now....

 

naefs-0-0-240.png 814day.03.gif

noaa has been consistent in moving this trough steadily eastwards over the last few days.

[phil nw.]

From a respectful massive newbie, and forgive me or remove this if I'm ruining the thread, but in a nutshell what are AAM and MJO?

 

 

Hi Jimmy, in a nutshell these are teleconnections or background signals, which can give us hints rather than details of upcoming weather in the medium term.

If you want to know more about the MJO, I would recommend the link below using the "educational material" link.

@alexbweather

Hi Jimmy.

 

Just to add a little more on this.Here's 2 links from our Net-Weather guides wrt these.

 

http://forum.netweather.tv/topic/52083-gwo-and-global-angular-momentum/

 

http://forum.netweather.tv/topic/46153-mjo-rossby-and-kelvin-waves/

 

Hope this helps.

[johnholmes]

Thing is John you first mentioned the 6-15 day period as becoming unsettled...well....erm....about 6 days ago.

Indeed, and the signal fronm them remains much the same after this weekend. One can only use them to indicate the upper air trend. If one has a lot of experience then it can lead to a reasonably accurate idea of what we can expect at the surface. As to time scales, again sometimes they are pretty accurate. In this case they look to be 3-4 days too early in the predictions from 6 days ago which is a suspect what you are referring to.

[johnholmes]

12z ECM ensemble mean height anomalies for mid-month look a lot different to its last few days output.

 

EDM101-240.gif

 

 

Has the ECM picked up on a new trend?

 

NAEFS and NOAA say no for now....

naefs-0-0-240.png 814day.03.gif

I would tend to go with the NOAA output, providing, as it has been, fairly consistent over the past 3 days or so. The NAEFS I have less knowledge of its reliability but will probably include it on a regular basis from the autumn. We can then see how it matches up to the 500mb anomaly charts from NOAA, ECMWF-GFS. Who knows it may show better than they have over the past 3 years, on the other hand it may not be as reliable.?

the latest NOAA, remaining consistent in suggesting an upper trough is the main feature rather than an upper rdige in the uk area?

http://www.cpc.ncep.noaa.gov/products/predictions/814day/500mb.php

please note the dates for checking on it 14-20 June?

the 6-10 is valid for 12-16 June and suggests much the same?

Edited June 6, 2013 by johnholmes

[Geordiesnow]

some reasonably good trends this evening, yes it does look more and more likely there be some sort of break down next week(how quickly it breaks down is still a tad uncertain though) but the models have been hinting at heights lowering across Greenland and whilst this does not guarantee fine and settled weather, the chances of more fine and settled weather does increases though.

 

Plus if those heights build across Europe then another warm shot could be likely, 18Z shows this but it looks more cloudy, warm and wet but at least the models are hinting at a more normal summer weather pattern in general though. 

[bradymk]

take care as the ecm ens will in most cases, trend towards the theme of the op. the 00z run may well be different. it does, however, show that the forecast for week 2 remains quite elusive.

I think this point from BA is very true. In many cases, i always seem to find that the EC Ens regularly will follow a very similar pattern to the op for them to both change dramatically by the next output. Truth is, next weeks forecast is very tricky and i am sure plenty of changes will occur between now and then although there could well be a huge west/east split. We have the remains of TRS Andrea tracking towards us also. Also, been looking at July in recent days, interesting output and for those who saw my post last night, CFS is going consistently for higher heights over the UK. Will take a more in-depth look at other models and data soon. For now, lets hope the ECM is onto something regarding the return of the unfamiliar HP leading into next weekend. If i was a betting man though, i'd go with NOAA output at the moment only because of consistency last few days. If ECM delivers two runs like tonights tomorrow, i will be a happy man

[Steve C]

Thing is John you first mentioned the 6-15 day period as becoming unsettled...well....erm....about 6 days ago.

 

A bit unfair tbh. John, as far as I'm aware, mentions 70% accuracy, in his predictions. To pull him up on the 30%, 6 days after the prediction, is poor form imho.

Edited June 6, 2013 by Steve C

[mushymanrob]

Clutching at straws is what I see from various posts, ecm and gfs totally different at this stage, why on earth is the ecm to be correct this time??

 

the ecm has a better track record then the gfs... so its possibly the best model to get some idea of what might evolve. for eg look at the present conditions, the gfs repeatedly had us under +10c uppers by this weekend, the ecm didnt... the ecm was right.

 

not saying the ecm will be right, but its certainly an option to consider. it might be abit progressive with this anticyclonic regime, it was with the severe cold of spring...but it had picked up on a trend which evenetually delivered.

 

i dont think the gfs is that far away from the ecm, it just appears (skimming through quickly) that the gfs has high pressure close to our south/southeast instead of on top of us. it (the 00z) might be atlantic driven, but with higher pressure to the south, the track of the lows to our northwest, it wouldnt be too bad for the southern half of the country.

 

the options this morning post thursday appear to be a return to sunny and warm/very warm or remaining with the atlantic but not too cool, not too wet, not too cloudy (bright as opposed to dull) for a large part of southern/seastern uk.

[Frosty.]

The models are continuing to firm up on a breakdown to the current settled and very warm spell by the middle of next week with the eastern side of the uk being last to lose the fine weather but there has been a slight adjustment north of the main disruptive trough next week with the north of the uk likely to feel the change much more than southern england, indeed, it looks like weak ridging could rapidly return to the south within a day or two of the breakdown with the fine and warm weather returning after the briefest of interruptions but much more of a struggle for the likes of scotland & n.ireland to break out of the more unsettled regime. In the meantime, the lovely anticyclonic spell will continue for a while yet with very warm and sunny conditions persisting throughout the weekend and into the early part of next week but with a trough developing to the southwest ahead of the main atlantic low, unsettled weather is then likely to arrive in the southwest of the uk and spread up the western side and then across the north with the south and southeast of the uk perhaps escaping lightly in comparison.

 

So in summary, there is a risk of a few heavy showers in southern england today but most areas will be dry, sunny and very warm, a very warm and sunny weekend under high pressure plus next monday, but by tuesday the fine and summery weather will be across the east. I think this morning's Gem 00z best illustrates what I have said about the breakdown next week and then the subsequent recovery., the Gem 00z is also my pick of the models this morning.

Edited June 7, 2013 by Frosty039

[Gibby]

Good morning. Here is the report from the midnight output from GFS, UKMO, GEM, NAVGEM and ECM for today Friday June 7th 2013.All models support a period of fine and largely sunny weather over the UK for another 4-5 days as a weak ridge holds across the UK. A weak thundery disturbance is affecting my area today with the risk of a shower or thunderstorm later but this should move away West tonight. A few lighter showers could develop over the hills of the North and low cloud and mist will be a feature overnight moving in from the North Sea to affect Central and Eastern Counties through the early part of each day and it will generally become a little cooler and fresher.GFS then shows a trough crossing East towards midweek with a windy spell for the NW while the SE could see the rain turn thundery by Thursday. A ridge then crosses slowly East over next weekend giving a dry and brighter spell before cloud and rain affect NW areas later. Through FI the changeable pattern of weather persists with some rain or showers for all at times but with some good spells of dry and bright weather in between when on the operational it is shown to become very warm in the South from the 17th to the 20th. With pressure systems rolling in from the West outside of this period temperatures will be close to average for the most part and winds will predominate from between SW and NW.The GFS Ensembles show a different slant on the distribution of precipitation than recently with all areas seeing some rain soon after 11th. The South then sees a trend towards drier conditions while Northern locations remain more at risk of further rain. Uppers fall back towards average levels soon and leaving aside the very warm outlier stage of the operational later on most members maintain an average position through the run.The Jet Stream currently shows a weak arm to the NW decaying with a Meditteranean arm gradually doing so too. Later next week the flow settles stronger across the Atlantic and over the UK towards Scandinavia.UKMO shows a trough crossing slowly East across the UK towards the middle of next week with some rain, perhaps thundery for most. thereafter a change to cooler and fresher weather in a westerly breeze with scattered showers look likely for a day or so.GEM today shows a similar evolution through the midweek days of next week with a change to more changeable conditions thereafter with some rain at times but some drier spells too in temperatures returning to average levels.NAVGEM too shows a more changeable theme after a spell of rain midweek as pressure remains weakly low over the UK with rain at times and average temperatures.ECM finally shows a change to more unsettled conditions with rain at times as the Atlantic strengthens it's strangle hold over the UK. There would be some dry and bright spells behind the midweek rain, especially in the SE close to a ridge for a time before it becomes breezy and unsettled in association with Low pressure crossing East close to the North with troughs spreading cloud and rain followed by showers West to East over the UK next weekend in temperatures by then no better than average.In Summary last night's ECM operational which was not supported in it's ensembles was a wild card run and, has reverted to form this morning with a changeable and unsettled pattern developing from midweek. This is shared by most of the other output too but I feel that the worst of any unsettled weather will be more prevalent for the North and West while the South and East could see some good drier interludes between the rain bands when it could feel quite warm. However, it looks a little more likely this morning that the pleasant days of end to end blue skies some areas have experienced of late will be a thing of the past for the time being after the middle of next week.

[phil nw.]

Yes the latest T84hrs fax chart shows Monday as the probably the last day of widespread dry and fine weather with approaching fronts from the Atlantic on our doorstep.

 

 

The changeover day looks like Tuesday-confirmed by the Warks. ens.graph with the first sign of precipitation.

 

showing also that the GFS Op.was a warm run aganist the mean later on.

 

So as expected a fresher more westerly type of pattern seems likely later next week with the drier and brighter spells always more likely the further south and east.

One thing in that setup is that  there is always the chance of the Azores high ridging towards the UK at intervals pushing the fine weather across the whole country-certainly not a bad outlook and more typical of the UK Summer.

Edited June 7, 2013 by phil nw.

[johnholmes]

After seeing the NOAA 6-10 and 8-14 last evening and the morning issue from ECMWF-GFS today this is my summation on what they are indicating

Fri 7 june

Ec-gfs

Ec has almost no sign of any ridging/+ve indications and is largely a trough chart from hudsons bay across the atlantic into the uk area with closed upper low and a strongish wly flow for all uk apart from northern Scotland, much as last issue and the noaa output last evening

Gfs has a more buckled flow just e of uk with ridge/+ve heights showing again similar to yesterday

So we have two models showing unsettled as the main theme and one suggesting a mix of the two, unsettled nw and more settled se

and below the link to ECMWF-GFS

http://www.meteo.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

and below is the NOAA link

http://www.cpc.ncep.noaa.gov/products/predictions/610day/fxus06.html

On the basis of the above and the last 2-3 days I would be very surprised if we have ridge dominated weather for the majority of the UK in a weeks time?

Edited June 7, 2013 by johnholmes

[Frosty.]

This morning's Ecm 00z ensemble mean is encouraging, especially for the south & east with a northwest-southeast split developing beyond the brief unsettled blip around the middle of next week, the northwest of the uk looks like becoming most unsettled and cooler but the further away to the south and east you are, the drier, brighter and warmer it is then likely to become once again, so the ecm 00z ens mean is much better than the ecm 0z operational run, there is a good chance for a steady recovery soon after the current fine and very warm spell ends by next wednesday, the east and southeast holding on to the fine dry weather for longest and soon getting it back again.

[William of Walworth]

I'm liking the more Northerly track of the LP in that ECM modelling.  Leaves room for some hope (for those further South at least), that the breakdown might prove limited and temporary?

[Milhouse]

The ECM has been showing low pressure to crash through next week for several days, only for some runs to show high pressure holding firm such as last nights 12z. The broad theme remains a return to westerlies with low pressure closest to Scotland and high pressure closest to SE England.

 

The warmth should edge further over to the east coast on Monday

 

[Milhouse]

Tuesday on the 6z has low pressure nibbling away at the high with rain getting into Ireland and western coasts of England and Wales. Remaning dry and warm elsewhere with the best temperatures to be found in northern England. The eastwards progress of low pressure looks quite limited on this run.

 

[Bottesford]

Any thoughts on the low cloud potential tonight/tomorrow morning? 

BBC says it'll roll in tonight and be a cloudy start tomorrow. This will really impair heating my yard for a bbq later pushing it over the edge into too cold to bother.

Anything in the model output that would help in knowing where or how extensive it will be? I'm not sure what data to look at - if indeed it is available.

[Milhouse]

By Wednesday the weakening band of rain has pushed through and we are in a  southwesterly regime of fairly dry conditions and average temperatures. High Pressure building into France which could deliver something warm for the UK as the run progresses.

 

[AWD]

Any thoughts on the low cloud potential tonight/tomorrow morning? BBC says it'll roll in tonight and be a cloudy start tomorrow. This will really impair heating my yard for a bbq later pushing it over the edge into too cold to bother.Anything in the model output that would help in knowing where or how extensive it will be? I'm not sure what data to look at - if indeed it is available.

FWIW the High Res NAE model show predominantly sunny skies for most tomorrow with any low cloud restricted to the extreme east coast;Temperatures not as high as they were forecast a few days ago though, with high teens and very low 20c's likely for most of us;Whether that's warm enough for you or not is down to your personal preference.

[Weather Boy]

I'm liking the more Northerly track of the LP in that ECM modelling.  Leaves room for some hope (for those further South at least), that the breakdown might prove limited and temporary?

 

The general impression that I have been getting pretty much since the fine spell started is that the breakdown should not be full scale and it should be limited to showers, especially in the south-eastern quarter of the UK.

 

No charts to back up what I'm saying as it's just the impression gleaned from the models generally over the last week or so.  I have seen little to support the notion that we will have a full-scale breakdown with mobile, very unsettled and wet weather.

 

So, I think that at this point I'd yes, there is reason to hope that, especially those of us in my quarter of the country.

[gottolovethisweather]

Any thoughts on the low cloud potential tonight/tomorrow morning? 

BBC says it'll roll in tonight and be a cloudy start tomorrow. This will really impair heating my yard for a bbq later pushing it over the edge into too cold to bother.

Anything in the model output that would help in knowing where or how extensive it will be? I'm not sure what data to look at - if indeed it is available.

 

I've PM'd you Bottes and well done AWD, you is on the ball again.  

[Bottesford]

Thanks AWD - sounds like we should be ok but pity those on the east coast. So long as the sun charges the brickwork up in the morning it'll re-radiate it in the shady late afternoon/evenings and feel warm enough. If the sun doesn't come out till later we'll need 21c+ air temps to avoid the chill which look unlikely.

Really should look at my nw-extra more shouldn't I!

[snowmadchrisuk]

Well the Hottest day of the Year has been ruined in the SW by the Cloud from that disturbance to the South , This is likely to only increase through the day as it all heads West over night. However tomorrow the South West looks likely to be in one of the best places for sunshine ... There after following the Midweek Breakdown a ridge builds , but lower pressures bringing Thundery rain to the SW. This is shown well on the chart below for Thursday . 12 deg in the SW into the 20's elsewhere .