Model Output Discussion 18z 28/07/13

[Frosty.]

The Ecm 00z ensemble mean looks rather warm and cyclonic next week with a mixture of sunny periods and heavy, slow moving thundery showers with generally light winds, it shows a gradual warm up again early next week with high pressure to the east and a trough to the west of the uk, then a very slack sluggish and rather warm and muggy showery set up.

 

As for the near future, a peach of a day for england and wales tomorrow with lots of hot sunshine and a continental S'ly to SE'ly breeze with increasing humidity so it will be feeling very sultry as time goes on, scotland and n.ireland will be dull and wet tomorrow with temperatures between 18-20 celsius but for england and wales, more like 27-32c, 81-90f, the hottest weather across the southeast. On friday, a cold front slowly pushing from west to east with sunshine and showers for most of the uk and temps in the low 20's celsius but for the southeast & east anglia, hot and sultry with an increasing threat of heavy showers and thunderstorms with temperatures in the high 20's celsius. The weekend is an improving picture with a northwest-southeast split, the northwest of the uk having a breezy mix of sunshine and showers but better on sunday, the south and east mainly dry and warm with sunny spells and mid 20's celsius as pressure begins to rise, then slowly turning more showery next week with sunny periods and temperatures ranging from average to rather warm and muggy from northwest to southeast.

[Captain Shortwave]

Improvement for the start of next week on the GFS

 

Previous run

 

Even if the pattern does turn more zonal, better southwards digging of that trough to the west might give us another couple of warm/very warm days.

[shedhead]

Improvement for the start of next week on the GFS

 

Previous run

 

Even if the pattern does turn more zonal, better southwards digging of that trough to the west might give us another couple of warm/very warm days.

This often gets said in Winter CS, but it's probably better to compare the latest run with yesterdays 06, rather than comparing it with it's immediate predecessor.

 

As we know this time yesterday many of us got suckered into the 2nd plume idea as Nick alluded to earlier, not least because of it's solid ensemble support, but this run has dropped that idea altogether now and pretty much goes with the plan from the 00 outputs.

 

So in summary, briefly warm/very warm for many and hot for some. Cooler and fresher this weekend with temps close to average and a scattering of showers, perhaps becoming rather warm in many places for a time early next week, before probably turning cooler everywhere from midweek. Finally beyond that, still a good deal of uncertainty whether or not the Jet fires up and the pattern flattens, but I think that is a 60-40 yes as things currently stand.

 

 

Edited July 31, 2013 by shedhead

[Djdazzle]

This often gets said in Winter CS, but it's probably better to compare the latest run with yesterdays 06, rather than comparing it with it's immediate predecessor.

Why compare it with a chart that is 24 hours out of date? That makes no sense at all Shed. Last night, you compared the GFS 18z with the ECM 12z, so I think you're contradicting yourself again!

[Frosty.]

Why compare it with a chart that is 24 hours out of date? That makes no sense at all Shed. Last night, you compared the GFS 18z with the ECM 12z, so I think you're contradicting yourself again!

Actually, John Holmes in the past has said we should compare like for like and I think using the ensemble mean is a better guide for a more realistic picture and of course the 500 mb anomaly charts.

[Djdazzle]

Actually, John Holmes in the past has said we should compare like for like and I think using the ensemble mean is a better guide for a more realistic picture and of course the 500 mb anomaly charts.

I agree about the ensemble mean and anomaly charts. But for a model that runs for times a day such as GFS, it seems silly to compare the current run against something that is four runs behind.

[Frosty.]

 But for a model that runs for times a day such as GFS, it seems silly to compare the current run against something that is four runs behind.

it's just a rough guide, but I take a bit of notice of it for trends, like seeing if today's 6z is an upgrade on yesterday's 6z etc..

Edited July 31, 2013 by Frosty039

[Djdazzle]

Anyway the 6z seems to have reduced the strength of the eastward progression of the trough. Ensembles will be interesting, as will this evening's runs.

Edited July 31, 2013 by Djdazzle

[Radiating Dendrite]

Why compare it with a chart that is 24 hours out of date? That makes no sense at all Shed. Last night, you compared the GFS 18z with the ECM 12z, so I think you're contradicting yourself again!

 

Each run has different amounts of data entered.

 

I think this is why some advise to compare 12z against 12z etc as they are fed with same data sample.

[Captain Shortwave]

Actually, John Holmes in the past has said we should compare like for like and I think using the ensemble mean is a better guide for a more realistic picture and of course the 500 mb anomaly charts.

That is true, but I do like to observe the differences between the two recent runs, especially as the models have been on a slippery slope into zonality and this run at least tries to show some form of fightback. The run overall in high resolution is less progressive and also shows the deep trough over the pole having less of an influence as it doesn't get a far south so the jet is weaker.

[MP-R]

I would think the angle at which the jet is progged at would be the most important thing should it reinvigorate. Surely with a block of some sort over the continent, the jet would align itself on a SW-NE trajectory which would put us in a better place for more settled weather. A NW-SE angle would blast any sign of summer warmth well into Europe. 

 

Fortunately, as the onslaught of unsettled Atlantic weather is still out in FI, concentration should be on the reliable and at the moment everything is looking rather flimsy, with shallow highs and shallow lows which, depending on their track, could dictate how FI changes over time. As such, I'm not completely convinced by the sudden switch to more vigorous autumnal looking charts. I would not surprise me to see the jet pushed north with future runs.

[johnholmes]

I agree about the ensemble mean and anomaly charts. But for a model that runs for times a day such as GFS, it seems silly to compare the current run against something that is four runs behind.

 

Something like 10 years of looking at the models and for trends, that is say beyond 5-6 days ahead, then you will find that comparing like with like, 00-00, 12 to 12 etc, regardless of them being 24 hours apart, you will find that trend spotting has a better verification if you use the method I suggest. For nearer term, 1 to 5 day then yes the method you quote is usually better but it is still not a bad idea to see how each run is compared both to the last one and the last one at the same start time (24 hours earlier).

Edited July 31, 2013 by johnholmes

[Captain Shortwave]

The GFS mean gets the upper temperatures back up to 14C in the South East on Tuesday, at least a bit of hope for something beyond the rest of this week.

[shedhead]

The GFS mean gets the upper temperatures back up to 14C in the South East on Tuesday, at least a bit of hope for something beyond the rest of this week.

To be fair CS, there is just as much 5c over Rockall as there is 14 over Dover Harbour...

 

In general 850's look to be around 8-10c for most places, which given any sunshine should make it feel pretty warm at the surface, but things may be moving more from Rockall than Dover later in the week.

[Swave Snow]

To be fair CS, there is just as much 5c over Rockall as there is 14 over Dover Harbour...

 

In general 850's look to be around 8-10c for most places, which given any sunshine should make it feel pretty warm at the surface, but things may be moving more from Rockall than Dover later in the week.

 

 

I seriously hope not.  But i hear where you are all coming from sadly

[Captain Shortwave]

To be fair CS, there is just as much 5c over Rockall as there is 14 over Dover Harbour...

 

In general 850's look to be around 8-10c for most places, which given any sunshine should make it feel pretty warm at the surface, but things may be moving more from Rockall than Dover later in the week.

To be fair all I said there was at least a hope, nothing more. 

At least the warmth seekers are not resorting to the NAVGEM just yet, then we would be in trouble. 

Edited July 31, 2013 by Captain shortwave

[Yarmy]

To be fair all I said there was at least a hope, nothing more. 

At least the warmth seekers are not resorting to the NAVGEM just yet, then we would be in trouble. 

 And some hope is better than Rockall.

[shedhead]

To be fair all I said there was at least a hope, nothing more. 

At least the warmth seekers are not resorting to the NAVGEM just yet, then we would be in trouble. 

Even NAVGEM is no heatfest this morning for once, but it's not too bad. However it does look as if things would collapse from the WNW if it went beyond this 144hrs...which thankfully it doesn't!

 

[mushymanrob]

The anomaly charts, ECMWF-GFS both continue with the theme I posted last evening, that is of the trough becoming the main feature over the UK area. GFS is less keen than the EC version but they do now seem to support the NOAA idea.

link below

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

Just how changeable/unsettled it is likely to become as we get into August, or overall how much lower the temperatures are going to be compared to the past month is not really clear. That kind of detail is for the synoptic 2x and 4x daily outputs once they have settled into this idea of a change from the July pattern.

 

... as i feared a few days ago, IF the atlantic takes charge then itll possibly be here for a while, and reduce drastically the chances of any more heat. unfortunately for us heat lovers these charts would suggest the atlantic will win out and stay for at least the first half of august... we will just have to hope that predictions of pressure rise after tomorrows hot blip become a reality and we get more heat whilst we can.

 

im not one for september heat, in fact late august either... looks like i better enjoy tomorrow because that MIGHT well be the last hot day.

[Lincstim]

Any change with Saturday weather in north lincs?

By some miracle is it going to be dry ?

[Frosty.]

The Gfs 06z is filled with very decent summer weather for at least the southern half of the uk throughout the high resolution with mostly above average temperatures and pretty warm for most of the time with temperatures climbing into the mid to high 70's F and occasionally into the low 80's further south & east, compared to recent years it's very acceptable weather, a lot of dry and sunny weather and just some occasional heavy and thundery showers scattered around, most of the rain in the next 7-10 days is showery in nature and mostly across the northwest of the uk which is n.ireland and scotland, this is where the lions share of the unsettled weather will be but even up there it won't be a write off, there will also be some fine and warmer intervals between the showers and persistent rain. Beyond next week the 6z becomes very amplified with troughs swinging southeast from greenland/iceland and brings a cooler more generally unsettled pattern but that's still a long way off and might very well not even happen at all, some very nice temperatures here, this 6z run has similarities with the ecm 00z ens mean with a rather warm and very slack pattern which later shows signs of more amplification with the jet profile slowly tilting more towards northwest-southeast towards mid august but a lot will change between now and then as the weather will do what it wants anyway.

Edited July 31, 2013 by Frosty039

[summer blizzard]

While the long goodbye continues the ECWMF finally kills the warmth at day 6, supported seemingly by the UKMO.

 

[Gordon Webb]

Any change with Saturday weather in north lincs?By some miracle is it going to be dry ?

 

sunsune and showers looks the most likely at the minute and temps probably maxing somewhere in the low twenties but as you know with showers you may get one , loads or not any at all best to take a brolly just to be on the safe side

[Lincstim]

Thanks frosty,

Those rain charts for Saturday (@3pm) is that total rainfall for that day up to then?

I like the fact there is non around sunny scunny . (If this is the case)

Edited July 31, 2013 by Lincstim

[Frosty.]

Thanks frosty,

Those rain charts for Saturday (@3pm) is that total rainfall for that day up to then?

I like the fact there is non around sunny scunny . (If this is the case)

you will be unlucky to catch a shower, saturday looks decent across the southeastern half of the uk with temps in the mid 20's celsius, pretty nice I would say, even better on sunday.