Model Output Discussion 31/03/14 onwards.

[Summer Sun]

It has to be said ECM looks very isolated this afternoon at t144 with GEM, GFS and UKMO all going against its pressure rise

 

 

UKMO doesn't develop the deep low to the west of Ireland like GFS, GEM & ECM instead it sends a 1000mb low towards the south

 

 

Hats off to ECM if it keeps the high later on but it wouldn't surprise me if it moves away from it given how isolated it looks

Edited May 7, 2014 by Summer Sun

[phil nw.]

Yes good agreement between UKMO and GFS out to T144 in keeping things unsettled and westerly.

It looks like the end of next week before there are signs of the jet going north as pressure starts to build over the south of the UK.

At least the GFS12z Op follows the 06z ens mean in it's timing for this.

[Panayiotis]

For the shorter term, im quite surprised that the Met havent given out any warnings out for rain across parts of the country especially the SW and north-west England:

Edited May 7, 2014 by Panayiotis

[049balt]

What a dramatic change, I feel that once this pattern gets established it might not change for some time.

[Cloud 10]

A large difference between the day 10 ensemble mean's from the 00z ECM and the 12z GFS,so

will be interesting to see if the 12z ECM flattens the pattern out a bit.

 

00z ecm..  12z gfs..

 

 

Talking of ensemble mean's,its interesting how the day 10 verification figures have plummeted 

over the last couple of weeks.

 

[IDO]

The GEFS are still no nearer sorting out week 2. You can see from the London ENS from D6 the scatter on both the 850s and pressure:

 

 

 

Looking at the individual members that scatter translates to a large spread of surface conditions by D10 onwards. A more amplified pattern remains the principle guidance but it looks like its back to 50/50 as to a UK high or a UK trough and each cluster has various solutions within that pattern.

 

ECM should be interesting but may not be much guidance just yet.

[Captain Shortwave]

ECM day 6

 

No comment required, fair to say it differs greatly from the other models 

[Summer Sun]

ECM isn't backing down from its pressure rise this evening

 

 

Unusual to see such big differences between ECM and UKMO at t144 ECM is certainly consistent at the moment doesn't mean it will be right of course considering how different it is to the rest I'll be amazed if its called next week right if it has then hats off to it

Edited May 7, 2014 by Summer Sun

[knocker]

The GFS has the upper ridge to the SE of the UK on the 17th and the trough to the west giving a low 300 odd miles SW of Cornwall and a high 1028mb in North Sea with a SE airstream over the UK. Haven't seen the ECM 500mb anomaly as yet.

 

 

[Cloud 10]

Very rare indeed to see this much difference between the Euro models at 144 hrs.

 

UKMO..  ECM..

[knocker]

Well the ECM isn't backing down on it's position at this stage. One suspects it all will boil down to where the upper ridge eventually plonks itself. At the moment it's much further west than the GFS.

Edited May 7, 2014 by knocker

[joggs]

Very intrigued at seeing which of the models have/will have the high modelled correctly

So hoping the ecm is bang on but with gfs and ukmo against it

Edited May 7, 2014 by joggs

[IDO]

Seems everywhere is pretty settled in 8-14 days time with above average heights everywhere in Europe:

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

Which means effectively ECM are the on the ball model for this evening.

 

Hi

 

The 6-10 day chart is the best comparison as that anomaly will compare with the 12z ECM op:  

 

This shows the AH trying to ridge towards the UK. Not as positive with a UK HP? Interestingly NOAA gave the "model of the day" as the GFS mean from the 0z.

 

Notes from the 8-14 days anomaly: "FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: ABOUT AVERAGE, 3 OUT OF 5, DUE

TO REASONABLE AGREEMENT AMONG TOOLS OFFSET SOMEWHAT BY UNCERTAINTY DUE TO

MODERATE TO LARGE ENSEMBLE SPREAD."

 

This is certainly inline with the GEFS from the 12z.

 

The 8-14 anomaly shown does not indicate a strong positive HP over the UK, and as it covers a seven day period it could be more representative of the spread slightly favoring a ridge closer to the UK; the signal weakened by the cluster of UK trough members. Not sure the 500 anomaly charts are a strong indicator of surface conditions for week 2 at the moment. No doubt Mr Holmes will clarify...

[phil nw.]

Yes the green thickness lines indicate the wave pattern as you describe I'm Dreaming..

An Atlantic trough just to our west with fronts to come east on occasions i dare say.Unsettled for another week or so i would think.

Notice some form of cut off low heading for the Azores later on the GFS run which doesn.t show on the ECM output.This results in a more straightforward build of heights across the UK.on the ECM Op.

http://www.wetterzentrale.de/pics/Rtavn1681.gif

http://www.wetterzentrale.de/pics/Recm1681.gif

 

A lot to be sorted yet but the GFS ens mean still looks encouraging for later in the month with that trend to shift the jet well north of the UK.

Edited May 7, 2014 by phil nw.

[Winter Cold]

Could this be another 'over amplification' error from ECM?  Im far from an expert but it dashed our hopes so many times in winter, im guessing summer weather patterns could also still cause it issues?

 

It used to be such a great model, and we relied upon it in past winters and it almost always proved correct, but the 'upgrade' last year seems to have done more harm than good to me! Are they planning a fix or patch at all? They must have noticed lol.

[damianslaw]

Reliable timeframe - unsettled with bands of rain and showers from the west in brisk winds and feeling quite chilly especially in the north particularly so over the weekend with winds turning to the NW.

 

GFS showing further trough development to our west next week killing off the chance of any build of heights from the SW, however, ECM is showing a build of strong heights from the azores high - these quickly building over the country next week ushering in a very warm settled outlook.

 

This time of year can see sudden swings from one extreme to another as the northern hemisphere moves into its summer state. Its a very difficult time of year to make forecasts, much more so than the late summer-autumn-winter period.

 

A warm settled spell in May is always a treat though - and can deliver the best the year can offer for sunny dry settled weather here in the Lake District and points further north and west.

[Summer Sun]

ECM ensemble continues to show high pressure building in next week with the 850's slowly rising

 

 

Something is going to give its just a matter of time one or maybe more of the models is wrong but which will it be

Edited May 7, 2014 by Summer Sun

[049balt]

Reliable timeframe - unsettled with bands of rain and showers from the west in brisk winds and feeling quite chilly especially in the north particularly so over the weekend with winds turning to the NW.

 

GFS showing further trough development to our west next week killing off the chance of any build of heights from the SW, however, ECM is showing a build of strong heights from the azores high - these quickly building over the country next week ushering in a very warm settled outlook.

 

This time of year can see sudden swings from one extreme to another as the northern hemisphere moves into its summer state. Its a very difficult time of year to make forecasts, much more so than the late summer-autumn-winter period.

 

A warm settled spell in May is always a treat though - and can deliver the best the year can offer for sunny dry settled weather here in the Lake District and points further north and west.

What a great post.

[knocker]

This I think is what is causing the contradiction between models at the moment.

Edited May 7, 2014 by knocker

[johnholmes]

 

 

This time of year can see sudden swings from one extreme to another as the northern hemisphere moves into its summer state. Its a very difficult time of year to make forecasts, much more so than the late summer-autumn-winter period.

 

 

a very true observation for any type of model over any time scale. It does also occur to some extent in the autumn change over and the input of hurricanes into the Atlantic is also another issue with all models.

[johnholmes]

 

 

The 8-14 anomaly shown does not indicate a strong positive HP over the UK, and as it covers a seven day period it could be more representative of the spread slightly favoring a ridge closer to the UK; the signal weakened by the cluster of UK trough members. Not sure the 500 anomaly charts are a strong indicator of surface conditions for week 2 at the moment. No doubt Mr Holmes will clarify...

not sure I can but the post from pj mystifies me in his interpretation of the NOAA 8-14 day chart?

[johnholmes]

Seems everywhere is pretty settled in 8-14 days time with above average heights everywhere in Europe:http://www.cpc.ncep.noaa.gov/products/predictions/814day/500mb.phpWhich means effectively ECM are the on the ball model for this evening.

how do you arrive at that conclusion, the anomaly heights, which is what I assume you are referring to show only very small +ve height anomalies over Europe, slightly higher over Scandinavia.

There is nothing in that one chart which I would use to arrive at your conclusion. What I do is keep an eye on several outputs for the 8-14 and also compare this with its 6-10 day outputs and at the same time the ECMWF-GFS 6-10 day upper air anomalies. When all 3 are consistent over several days and the 8-14 also fits in with that consistency then it is a fair assumption to take the upper air pattern as being likely to be what is being predicted.

Please don't think I am geting at you I am not but I do think that making forecasts from 1 chart is fraught with danger no matter what time scale we use. The upper air prediction is just that-upper air and trying to make a surface chart from them is always quite complex.

I posted not long ago, yesterday I think which Knocker commented on about sitting on the fence. The 6-10 day outlooks from the 3 main sources are coming round to the idea of the main trough around 30 west and +ve heights showing more generally in western Europe but one model (GFS) still is not keen on this idea at the 6-10 day time scale. Over 4 years of watching these charts I tend to believe NOAA more than GFS and probably slightly more than ECMWF version. However, I still prefer to see consistency over several days on ALL 3 and so far we do not have that.

Hope you feel that is some kind of answer to you' I'm dreaming..'?

Edited May 7, 2014 by johnholmes

[Frosty.]

Models are firming up on a big pattern change to summery weather as high pressure takes over by later next week onwards, and the met office are also saying it so there is an end in sight to the showery pattern..summer is arriving early this year. :-)

[Frosty.]

How long do the Met Office predict it lasting? My guess would be five to seven days, as that is usually about average for high pressure systems in the UK.

Right now I'm just pleased to see that the ecm 0z was definately on to something big, and with the met office support from mogreps too. As for duration, hopefully 10 days or more with warmer and warmer weather and lots of sun..BRING IT ON!

[knocker]

A quick glance at the GFS this morning.

 

Although it's altered it's position regarding the upper a wee bit it's still not playing the high pressure game. A brief flirtation with it on Friday but by Saturday this has sauntered off to the North Sea and cyclonic has edged in. By Sunday the UK is in a col. Low pressure to the SW and NE and high to the NW and SE. Time to throw the dice and await the ECM.