Model Output Discussion 18Z 18/6/13 onwards

[Summer Sun]

Makes a nice change to see this....

http://www.meteo.psu.edu/~fxg1/ECMWF_12z/test8.gif

pretty sure its been mentioned before not sure if these are updated over the weekend??,il post them anyway....

http://www.cpc.ncep.noaa.gov/products/predictions/610day/610day.03.gif

http://www.cpc.ncep.noaa.gov/products/predictions/814day/814day.03.gif

maybe this year we will get a half decent summer,tbh so far this June im well happy with whats been offered,the first 10 days (here in south wales) were perfect,and it has not been too bad at all the last 19 days

 

Sorry to sound dumb but where is the UK on those charts?

[Polar Maritime]

Sorry to sound dumb but where is the UK on those charts?

 

2pm

[Summer Sun]

2pm

 

Thanks I see us now I guess red is high pressure and blue is low

[Frosty.]

Sorry to sound dumb but where is the UK on those charts?

top right hand corner

[DTHFCJ]

Sorry to sound dumb but where is the UK on those charts?

your far from dumb Summer Sun...turn your head left so your touching your left shoulder with your ear,or 2oclock like Polar Maritime says....

[Captain Shortwave]

Makes a nice change to see this....

http://www.meteo.psu.edu/~fxg1/ECMWF_12z/test8.gif

 

If these charts were drawn by a person called Damien I would advise everyone who lives in the south east to evacuated immediately 

Serious note the settled spell start on the 5th July still looks on the cards, good times

[Summer Sun]

top right hand corner

 

 

your far from dumb Summer Sun...turn your head left so your touching your left shoulder with your ear,or 2oclock like Polar Maritime says....

 

 

Thanks guys found us now

 

[DTHFCJ]

Thanks I see us now I guess red is high pressure and blue is low

Summer Sun,John Holmes is your man ref to the charts i posted....i dont pretend to be an expert on these charts,but from what i can see from them..they appear to be positive for us in good old blighty

im going to do some research on them to learn some more...

 

having done some research,im still none the wiser ref red=high pressure,blue=low...il leave it in the capable hands of John Holmes ......they are anomalies so im assuming high and low?..looking at them last summer all i ever saw was blue over us most of the time

Edited June 29, 2013 by BALE1

[Milhouse]

Cross model agreement for a settled end to the coming week. Next weekend could be very warm and summery but we will have to wait and see.

 

Before that we have a pleasant few days to come but different in terms of temperature with tomorrow likely to see widespread 23c+, but Monday will see most parts stuck in the mid to high teens with an annoying finger of 0c upper temperatures stretching down from the north towards the UK. Dry to start on Tuesday before low pressure moves in to herald an unsettled spell midweek before high pressure is shown to rapidly move north later on. Thats how it looks at the moment.

[Tony27]

And for you Newbies T+96 is at the realm of semi reliable output from the models,,,,  

a very sensible post, i just got back home, i don't sit on my computer all day looking at charts, and i saw the ECM and yes it looks nice but the nice charts are still from T144 onwards, despite what some may say something can stop this heatwave from happening, all we can do is hope for the best and be patient yet again

Edited June 29, 2013 by Tony27

[Captain Shortwave]

Ensemble mean charts for Friday 5th July

ECM

 

GFS

 

Not much else to say, both ensembles build heights through the UK from this point onwards.

Whilst caution must be given for any heatwave, there is overwhelming evidence suggesting height pressure will build at the end of the week bring much more settled conditions.

I would add this pattern set up is backed by the background signals and also is a much more common and reliable set up compared to the likes of a blocking high during the winter. If this verifies for example the GFS would have picked this up ten days away and run it through to T0 with very little alteration of the broad pattern.

Edited June 29, 2013 by Captain shortwave

[Tony27]

a nice ECM ensemble mean, if these charts are still showing on Wednesday then i will be feeling confident, now is not the time to crack open the bubbly, i will enjoy the weather tomorrow it looks like it will be the nicest day of the year so far here at 24c with sun, hopefully the cloud coming in from the Northwest holds off till very late

Edited June 29, 2013 by Tony27

[Summer Sun]

ECM ensemble shows the high isn't leaving anytime soon once / if it build's

 

 

Edited June 29, 2013 by Summer Sun

[bluearmy]

nice to see the upper trough on an axis way to our west and centred where it should be for some decent summery weather nw europe.  naefs week 2 shows a decent mean jet in the eastern canada/s greenland area on the 00z run (repeated on the 12z). thats good news. little sign on the ecm 10 day suite of any return to the trough.  the spreads seem to show that the mobility on height variances are drifting ever north such that the southern half of the uk at least should remain settled out to mid month at least.  thats the message from the 12z's but the 00z could show a different nuance beyond the 10th.

[johnholmes]

Thanks I see us now I guess red is high pressure and blue is low

 

nope

red shows +ve height anomalies at 500mb and blue show -ve height anomalies

Summer Sun,John Holmes is your man ref to the charts i posted....i dont pretend to be an expert on these charts,but from what i can see from them..they appear to be positive for us in good old blighty

im going to do some research on them to learn some more...

 

having done some research,im still none the wiser ref red=high pressure,blue=low...il leave it in the capable hands of John Holmes ......they are anomalies so im assuming high and low?..looking at them last summer all i ever saw was blue over us most of the time

see my last post explaining what the colours mean

 

without wanting to sound as if I am talking down to anyone, it really is a good idea to read up about using them, what they show etc. As a simple guide just use the lines NOT the colours, the lines are the contours, isobars if you like, at 500mb.

If anyone wants a more detailed explanation please pm me and I will do my best to try and explain. Maybe do a pdf and put it in the more leisurely thread so folk can find it easily?

Edited June 29, 2013 by johnholmes

[DTHFCJ]

nope

red shows +ve height anomalies at 500mb and blue show -ve height anomalies

see my last post explaining what the colours mean

 

without wanting to sound as if I am talking down to anyone, it really is a good idea to read up about using them, what they show etc. As a simple guide just use the lines NOT the colours, the lines are the contours, isobars if you like, at 500mb.

If anyone wants a more detailed explanation please pm me and I will do my best to try and explain. Maybe do a pdf and put it in the more leisurely thread so folk can find it easily?

Thanks John il leave you in peace now but i will pm you tomorrow to try to understand better,thanks for your time it seems i have been miss reading these completely

[snowking]

nope

red shows +ve height anomalies at 500mb and blue show -ve height anomalies

 

 

without wanting to sound as if I am talking down to anyone, it really is a good idea to read up about using them, what they show etc. As a simple guide just use the lines NOT the colours, the lines are the contours, isobars if you like, at 500mb.

If anyone wants a more detailed explanation please pm me and I will do my best to try and explain. Maybe do a pdf and put it in the more leisurely thread so folk can find it easily?

 

Might be a good idea just to do a quick illustration to clear this one up (I do understand it is confusing with the difference between heights and SLP - getting your head around the different pressure layers of the troposphere is one of the most tricky things to do, but its essential for more expansive forecasting)

 

So, heres a couple of basics, the sort of things that I used to take a look at when I only had a chance to glance quickly at the models. I have made some markings on the below image - the latest height anomaly projection from the ECMWF

 

 

As John has said, ignore the colours for now - follow the lines! (Again its tricky to get your head around, but don't automatically assume that the higher heights (reds) will always lead to high pressure, and vice versa with blues). By the lines, we are talking about the "horizontal" black lines, which are indicated by the green arrows drawn.

 

If anyone can think back to GCSE Maths (or possibly even physics), think of these in terms of a Sine wave. When they point up, they are a peak (or in meteorological terms, a ridge) and when they point down, they are a trough.

 

You might have heard that term trough used a fair bit on here - ridges and troughs are what make up the Longwave Pattern across the Northern (and Southern - though we rarely focus on this) hemisphere. By this, we mean that the weather all around the globe follows a series of ridges (areas of high pressure) and troughs (areas of low pressure).

 

We can identify such areas on the annotated chart above. I have shown a ridge (in the blue box) forecast across the UK - taken in current context, in around 8-10 days time, the current ECMWF suggestion is of ridging across the UK. How can we tell it is a ridge? Because those black bars are pointing towards the north pole.

 

I have also identified a trough (in the yellow box), which would indicate an area of 'troughing' - essentially, an area (or collection) of low pressure. We can tell its a trough because the black lines are facing towards the equator.

 

So, its a case of looking for ridges (black lines facing poleward) for the chance of more settled conditions, and troughs (black lines facing equator-ward) for unsettled conditions. 

 

It gets a lot more complex than that - we can start looking for closed ridges/troughs, and in the winter, we also look at certain colours of the black lines indicating where the 528DAM line (considered a good measure of the 'snow line' under most circumstances) is. But we'll worry about that another day.

 

In the meantime, when looking at height anomaly charts, look for ridges for potential settled spells, and troughs for potential unsettled spells, in the vicinity of the UK

 

SK

Edited June 29, 2013 by snowking

[Frosty.]

More very nice charts to start the day, now from T+120 hours onwards the anticyclone builds the fine spell from the south and eventually all parts of the uk become warm and settled, very warm in the south, a taste of things to come today in the east and south midlands, southeast england & east anglia with 26 or 27c likely which will make it one of the warmest days of the year so far, I think we will be seeing temperatures more frequently into the mid to high 70's to low 80's in around a weeks time onwards.

Edited June 30, 2013 by Frosty039

[johnholmes]

Might be a good idea just to do a quick illustration to clear this one up (I do understand it is confusing with the difference between heights and SLP - getting your head around the different pressure layers of the troposphere is one of the most tricky things to do, but its essential for more expansive forecasting)

 

So, heres a couple of basics, the sort of things that I used to take a look at when I only had a chance to glance quickly at the models. I have made some markings on the below image - the latest height anomaly projection from the ECMWF

 

Height-Anomalies.gif

 

As John has said, ignore the colours for now - follow the lines! (Again its tricky to get your head around, but don't automatically assume that the higher heights (reds) will always lead to high pressure, and vice versa with blues). By the lines, we are talking about the "horizontal" black lines, which are indicated by the green arrows drawn.

 

If anyone can think back to GCSE Maths (or possibly even physics), think of these in terms of a Sine wave. When they point up, they are a peak (or in meteorological terms, a ridge) and when they point down, they are a trough.

 

You might have heard that term trough used a fair bit on here - ridges and troughs are what make up the Longwave Pattern across the Northern (and Southern - though we rarely focus on this) hemisphere. By this, we mean that the weather all around the globe follows a series of ridges (areas of high pressure) and troughs (areas of low pressure).

 

We can identify such areas on the annotated chart above. I have shown a ridge (in the blue box) forecast across the UK - taken in current context, in around 8-10 days time, the current ECMWF suggestion is of ridging across the UK. How can we tell it is a ridge? Because those black bars are pointing towards the north pole.

 

I have also identified a trough (in the yellow box), which would indicate an area of 'troughing' - essentially, an area (or collection) of low pressure. We can tell its a trough because the black lines are facing towards the equator.

 

So, its a case of looking for ridges (black lines facing poleward) for the chance of more settled conditions, and troughs (black lines facing equator-ward) for unsettled conditions. 

 

It gets a lot more complex than that - we can start looking for closed ridges/troughs, and in the winter, we also look at certain colours of the black lines indicating where the 528DAM line (considered a good measure of the 'snow line' under most circumstances) is. But we'll worry about that another day.

 

In the meantime, when looking at height anomaly charts, look for ridges for potential settled spells, and troughs for potential unsettled spells, in the vicinity of the UK

 

SK

 

 

thanks SK that, I think, may save me doing my explanation. If anyone still wants more help then please pm me and I can then do a pdf post as I suggested before. Just take it slowly, read up about the subject, ask questions, you will slowly learn how to use them. They do NOT give the detail, so small scale features may not show up and even when experienced on what to look for these may sometimes not be evident at first. Also remember that it is the upper air pattern that dictates what happens at the surface not the other way round.

In meteorology it has always been less difficult to predict the upper air pattern than to get the surface features correct. Getting the right amount of moisture is often the key to correct surface predictions and that is still the most difficult part of forecasting. The 500mb anomaly charts are dry hence less difficult to get nearer the actual upper air pattern at 6-15 day time ranges. Beyond 15 days and even an upper air pattern without moisture in it becomes more and more difficult to get right. I had once thought of doing checks on GFS 500mb charts to see how accurate they were beyond 240-300 but have never found the time.

Edited June 30, 2013 by johnholmes

[shaky]

An absolute peach of an ecmwf!!!my word how ive longed for charts like that to show up consistently!

[mushymanrob]

nope

red shows +ve height anomalies at 500mb and blue show -ve height anomalies

 

 

but doesnt that also suggest that where theres a high/low anomaly surface pressure would be higher/lower then expected?

 

well, signes are good that there might well be the first proper countrywide hot spell for 7 long years friday onwards. all models agree, as do the anomaly charts.... looking good after a changable, miserable, mid week period.

[johnholmes]

but doesnt that also suggest that where theres a high/low anomaly surface pressure would be higher/lower then expected?

 

well, signes are good that there might well be the first proper countrywide hot spell for 7 long years friday onwards. all models agree, as do the anomaly charts.... looking good after a changable, miserable, mid week period.

 

usually but not always and quite often not just where either the ridge shows or the +ve anomaly shows either, same with low pressure at the surface and the high level feature. So great care is always needed in trying to decide just what the surface pattern will be. A forecaster will be using all their knowledge of meteorology to see how the model is dealing with the various parameters at the various heights as well as what it shows at the surface. You often see on here folk asking why UK Met Fax shows such and such when the model has this or that. You can often get a fair idea just by 'reading' the model(s) but the machine/human mix is almost always the most accurate as far as it goes to T+120. Beyond that then the forecasters' interpretation of model outputs will again usually be superior to the model on its own.

[Captain Shortwave]

Beautiful day expect for those in the south east with temperatures of 26 degrees predicted, perhaps higher in favoured spots. Given wind direction spots like Lowestoft could reach the highest temperatures today.

From tomorrow onwards it's average conditions till the end of the week with some rain, but also some reasonable weather with the southern half of the country never seeing too much rainfall. Then it looks like the weather will settle down as the Azores high comes into play more building through the UK giving fine and warm conditions with the potential for very warm or hot weather to develop, especially if it progressed like the ECM run this morning.

Edit - yet again the ecm ens has high pressure parked right over us

Edited June 30, 2013 by Captain shortwave

[nitro_deluxe]

Indeed. Nothing bar a few flies in the proverbial ointment, before HP takes control again. Temps responding accordingly.

[Gustywind]

The ECM is an impressive high pressure dominated run and would give most a sunny, dry and increasingly warm weekend, although being picky the 850s aren't that impressive away from the south west until Monday 8th, when they rise above 10c for most if England and Wales. Being picky if prefer the warmer values to arrive earlier as opposed to the following working week when I'll be stuck at work all day.