Model Output Discussion - 1st July Onwards 18z--->

[Frosty.]

The Gfs 12z looks great for 4 days from Thursday with high pressure bringing lots of sunshine and increasingly warm as the HP migrates to the east and then we import continental heat, the weekend in particular looks glorious with very warm / hot weather and anything unsettled restricted to brushing across the far north, hope this is a new trend to lengthen the fine spell...nice end to the run too.

[knocker]

A quick look at the GFS 12 ops anomalies just out of interest.

 

On Sunday the trough and ridge located as expected and after that the trough migrates east and commences a fandango with the trough to the NE. Meanwhile back at the ranch HP is building mid Atlantic with a cutoff low to the SW of it (Omega block). This ends up with a general area of HP over the Atlantic with centres east and west. This setup would be acceptable

Charts weatherbell

Edited July 5, 2015 by knocker

[bluearmy]

A quick look at the GFS 12 ops anomalies just out of interest.

 

On Sunday the trough and ridge located as expected and after that the trough migrates east and commences a fandango with the trough to the NE. Meanwhile back at the ranch HP is building mid Atlantic with a cutoff low to the SW of it (Omega block). This ends up with a general area of HP over the Atlantic with centres east and west. This setup would be acceptable

Charts weatherbell

Given the recent extended anomolys, that op T300 is very unlikely with its sharp upper trough to our South.

[knocker]

Given the recent extended anomolys, that op T300 is very unlikely with its sharp upper trough to our South.

 

Granted, I wasn't really making a serious suggestion, but the GEFS is losing the trough as has previously been suggested.

Edited July 5, 2015 by knocker

[Methuselah]

Agreed, knocker...

 

But, would you concede that, within the GFS's rich tapestry of meteorological diversity, that its most extenuating difficulty (as of now, of course - no-one knows what'll transpire on the morrow) is how it handles the boundary layer between warmer-than-average air to our south and the colder-than-average airmass away to the northwest?

 

Putting that in English: the devil is in the detail?

[Summer Sun]

An encouraging end to ECM this evening with high pressure and warmer air coming back into play

 

[Frosty.]

I like the Ecm 12z this evening even though it's more progressive than the gfs 12z regarding next weekend but the benefit on this run is a warmer and more settled spell through the first half of the following week which the gfs doesn't have, the Azores high then ridges in again towards the end of the run. All in all, I'm pleased with the 12z output, the upcoming cool northerly plunge doesn't penetrate into the south and west and in any case is shunted away to the north east during wednesday with thurs/fri looking increasingly dry, sunny and much warmer by Friday, still warm in the south and east on Saturday.

Edited July 5, 2015 by Frosty.

[knocker]

Agreed, knocker...

 

But, would you concede that, within the GFS's rich tapestry of meteorological diversity, that its most extenuating difficulty (as of now, of course - no-one knows what'll transpire on the morrow) is how it handles the boundary layer between warmer-than-average air to our south and the colder-than-average airmass away to the northwest?

 

Putting that in English: the devil is in the detail?

 

Of course Ed. But I'm hoping for a scenario that loses the trough and allows more extensive movement of the HP north, doing away with pulses of very hot air but allowing warm conditions to spread further north thus allowing everybody to enjoy some great summer weather. Not impossible I feel.

[Man With Beard]

Musical chairs is how I'd sum up the output today. First, ECM moves to a more undulating pattern and looks ready to bring in summer from T96, apart from a brief pause around T144. However, the NOAA, which suggested further opportunities for heat yesterday, has now gone flatter in its 8-14 day outlook (though less so in 6-10 day). This one looks like it will run a bit. Must say the odds on good weather extending further through the UK from D7 onwards are looking better tonight than they have for a couple of days. And the Thurs-Sat spell of warm sunshine still looking reasonably likely, with a few slight variances

[summer blizzard]

Models a little more settled tonight however still largely average out to day 10 in my opinion bar the plume although it looks a bit watered down.

Both Euro and GFS end up with the Azores High to the west of the UK.

Edited July 5, 2015 by summer blizzard

[knocker]

The ECM anomaly tonight still retains the weakened trough just to the west whereas the GEFS is more bullish at getting rid but hey both agree in the ext period with pressure rises to the west/south west leading to a more settled HP analysis over the UK.

http://www.tropicaltidbits.com/

 

[Frosty.]

The GEM 12z compares favourably with the gfs/ecm this evening with high pressure building in after midweek with very warm continental air pushing north into the UK, the theme of the output today has been for a rinse and repeat summery pattern, especially for the south of the uk. It appears to me like the southern half of the uk in particular has lots of fine and warm / very warm and sometimes hot weather to look forward to in the weeks ahead with occasional very humid thundery outbreaks.

Edited July 5, 2015 by Frosty.

[damianslaw]

Models painting a very mixed pattern for the foreseeable - no sign of a protracted lengthy settled spell on the cards, which in my book is the hallmark of a good summer, not high temps which can easily be associated with an unsettled topsy turvy period just as we have seen these past few days.

 

Indeed quite a chilly outlook for the north with a dig of cool air from the NW mid week, a classic NW/SE split setting up with the SE holding on to respectable temps, mostly dry fine sunny weather, whereas the NW remains exposed to the vagaries of the atlantic and its associated cloud rain wind and disappointing temps, especially given the cold SST anomalies.

 

Later in the week signal for weak azores high ridging benefitting the SE the most as expected enabling an injection of warmer uppers again and temps entering the very warm category no doubt.

 

Hard to call what may happen thereafter, but may reckoning is for the trough to position itself just close enough to the west of us to prevent a plume of any sorts but will allow warm SW airflow to develop, which will mean mucky cloudy condition NW average temps, above average temps in south and east and mostly dry fine albeit rather hazy conditions, and humid for all.

 

In overview very typical standard conditions for the time of year for the foreseeable.

[knocker]

A very short overview of this morning's GFS.

 

With the general flow remaining in the westerly quadrant the whole run is dominated by the interplay of the warm air to the south and colder air to the north and the movement north and south of the boundary between the two. Thus no settled weather pattern and marked variations in temperature with unfortunately the north as usual being the loser. This can be shown by a snap thickness chart for the weekend which has been downgraded somewhat as the forecast depression track is a tad further south. The usual caveat that this is just one run, one model.

Charts weatherbell

 

[knocker]

Similar theme with the ECM but pushing the warm a tad further south.

[Gibby]

Hi everyone. Here is my latest report on the 00z Model Runs from GFS, UKMO,GEM, NAVGEM and ECM for today Monday July 6th 2015

 

" Sorry unable to provide links this morning"

 

The Latest Situation. A warm front is moving NE over the UK today followed by a complex cold front tonight. Tomorrow will see a showery and cooler WSW flow across the UK.

 

The 2 Week Forecast Headline Changeable with some rain at times but drier in the South and East with some warm spells.

 

The GFS Jet Stream Forecast shows the flow mostly blowing much to far South in the next few weeks. It's flow remains across the Uk this week veering NW as a trough translates East. then after a brief shift North it returns South across the UK next week in association with Low pressure close to Scotland.

 

The GFS Operational Run shows the pattern unchanged from recent days again this morning with some warm and dry conditions across the South at times as extensions of the Azores High cross close to Southern England only to be followed by brief Atlantic incursions of cooler air with thundery rain or showers at the transition point. The North closest to Low pressure off the Atlantic maintains largely changeable conditions with rain at times and here it will remain relatively cooler than conditions elsewhere.

 

The GFS Control Run is very similar in it's first week or so with the best of warmth and dry weather across the South while the North sees more changeable conditions on a Westerly breeze. Then later in Week 2 a pattern change is shown as High pressure builds through the Atlantic switching winds to a cool NW or even Northerly with a mix of sunshine and showers for all.

 

The GFS Clusters for the 14 Day point are almost universal in suggesting that a NW flow will be affecting the UK in 14 days time with Low pressure in varying degrees of proximity to the UK but most members showing cooler air flooding the UK from the NW with occasional rain or showers.

 

UKMO this morning looks quite good as we move towards and over next wekend as it builds a strong ridge NE from the Azores across Southern Britain restricting influence of Atlantic winds and fronts to the NW whereas the South becomes largely fine, warm and sunny next weekend.

 

The Fax Charts endorse the raw data well today with a ccoler pahse of NW winds and showers midweek giving way to warmer conditions late in the week and into next weekend with High pressure lying close to the SE with a warm front travelling NE over the NW with a little rain and humidity rising everywhere.

 

GEM today keeps the current pattern going over it's 10 day span with High pressure always close to the SE or South and winds blowing from a West or SW point across the North and NW with occasional rain. A lot of rather warm and humid weather looks likely on this run across the South with just a very occasional interruption of rain on troughs crossing from the West, all this after a brief cooler and showery blip in this coming midweek period.

 

NAVGEM maintains the status quo of current weather pattern with Westerly winds and occasional troughs delivering showers and some rain at times with some fine and warmer interludes in the South especially later in the period.

 

ECM today sits on the changeable fence with occasional troughs crossing East in the otherwise Westerly wind delivering occasional rain in the South and more frequently in the North. This run does take a more GFS Control Run stance of switching winds to a cooler NW or North flow late in the run as pressure builds North through the Atlantic.

 

The ECM 10 Day Mean Chart from last evening shows slack Westerly winds and occasional rain across the UK with temperatures bordering above average especially in the South.

 

The Verification Statistics of GFS, UKMO and ECM. This morning's verification statistics show ECM leading the way at 3 days with 96.0 pts followed by UKMO at 95.1 pts and GFS at 94.7 pts. At 5 days ECM is stll king at 85.2 pts followed by GFS at 82.1 and UKMO at 81.9 pts. Then at 8 Days ECM still leads at 48.8 pts over GFS's 46.2 pts. Finally at Day 10 ECM leads GFS at 30.3 pts to 26.9 pts from GFS.

 

My Thoughts Once again today there seems little difference in the overall patterning of conditions over and around the British Isles over the coming weeks. The main thrust of the Jet Stream remains too far South to allow continental heat to move back over the UK in any meaningful fashion and while conditions will be far from bad in any one place any significant warmth and sunshine still looks rather brief and fleeting as Atlantic fronts move East to dislodge it quite quickly after it's arrival. As is usual in a Westerly flow South will always be best and there could be quite a lot of pleasant weather for much of the time but areas further North will have to pick and choose the best days as here Atlantic winds will bring more frequent bands of rain and showers at times. There is a something of a shift in some of the longer term output to build pressure across the Atlantic through the second week which would result in a shift of winds to a cooler NW or Northerly quarter for all. This is highlighted well in this morning's GFS Clusters, the GFS Control Run and the ECM operational today and while yet it is still too far out to call we need to keep an eye on this trend in future runs. In the meantime it's business as usual with the North/South divide remaining in place for some while yet and while it may not be high summer in the true sense of the word conditions could be far worse and I'm sure there will be some decent fine weather to be had for all regions in the coming two weeks but more especially in the South.

[Summer Sun]

UKMO shows high pressure over the UK at the end of the week bringing us a settled day on Friday

 

 

Saturday sees the low slipping away with low pressure trying to push in over Scotland and Northern Ireland the risk of some showers here, but the further south and SE you go the drier, brighter and warmer its likely to be

 

 

By Sunday the high is pushing back in from the south west, so remaining mainly dry in the south with any rain / showers confined to the far north and west and largely warm and sunny in the south

 

[mushymanrob]

.... its all looking very 'normal' or 'average' to me. a mobile westerly pattern, unsettled but with nicer days. no washout, no heatwave (proper one lasting more then 3 days). and as knocker reminds us, better in the southeast, poorer in the northwest.

[Man With Beard]

Studying the models this morning, and I'm now thinking the UK might go below average in the period around D10 away from the southern counties, although most areas may keep predominately dry and sunny conditions.

 

The culprit is the trough to our North-East and a developing ridge in the mid-Atlantic - the trough to the NE has been lurking on the models for a while, it gives us a short bite this week but I suspect it will return to give us a harder bite next week.

 

GFS and ECM ens mean charts are in agreement out to D10 on this feature - note the greens to our north and east:

 

The charts show signs of a ridge developing mid-Atlantic, meaning air is forced down to us from a NWly direction.

 

Ensemble charts, of course, average things out a little, but more definition to the trough/ridge may allow air sourced from the Arctic Circle (driven by the Scandi trough) to reach us, for instance:

 

 

It's fair to say at this stage that there are still a few ensemble members that continue to push ridges through the pattern so that the UK remains on the warm side, but they are increasingly in the minority. The ECM De-Bilt ensembles show this up in the D8-15 range - a warmer cluster of runs, yes, but the majority of runs returning slightly depressed temperatures for mid-July (see bottom corner):

 

 

Although of course if De Bilt temperatures are lower, being 200-400 miles further west we could possibly be warmer than that, especially in SW of the UK. Indeed, should the mid-Atlantic ridge get established, southerly-facing coasts across Wales, the South and the South-West may see some excellent weather as the sun heats up the air as it travels across land.

 

Far from certain that this will be the eventual outcome - a very small lift in the trough further north would keep many parts in warm, settled conditions - but definitely a drift towards a NWly influence today. Plumes looking off the menu for a while, and the July CET likely to drop a bit.

 

EDIT: Of course, having taken a punt like that, the next model run was bound to do the opposite!!! The GFS 06Z shows what could happen if the Atlantic low exiting the US at T96 is slightly held-up - less interaction with the main Atlantic trough and a surge of heights ahead of it, leading to the chart below by T180 - nothing "below average" about this:

 

Edited July 6, 2015 by rjbw

[johnholmes]

An interesting item here that Gibby shows every day

The Verification Statistics of GFS, UKMO and ECM. This morning's verification statistics show ECM leading the way at 3 days with 96.0 pts followed by UKMO at 95.1 pts and GFS at 94.7 pts. At 5 days ECM is stll king at 85.2 pts followed by GFS at 82.1 and UKMO at 81.9 pts. Then at 8 Days ECM still leads at 48.8 pts over GFS's 46.2 pts. Finally at Day 10 ECM leads GFS at 30.3 pts to 26.9 pts from GFS.

 

It really does look as if the GFS update has made a considerable improvement to it. It still rarely beats EC but is doing at times with UK.

One other feature this shows is the that at 10 days neither of them are better than a 1 in 3 chance of being correct. To me that suggests that for we mere mortals without major computer access the anomaly charts, IF used carefully, will give much better guidance routinely. My statistics show that the overall weather pattern they predict is correct about 70%+ of the time? Put another way it is wrong about as often as EC-GFS is right!

[Polar Maritime]

Yes i have noticed that myself John re GFS since the update, Seems to be performing much better.

Edited July 6, 2015 by Polar Maritime

[Yarmy]

Yes i have noticed that myself John re GFS since the update, Seems to be performing much better.

 

Consistently out-performing the UKMO now:

 

 

I suspect the old prejudices against it will linger though, especially come winter.

[Summer Sun]

t144 from UKMO has the high a good deal further north giving more of the UK some fine dry weather

 

 

GFS on the other hand has the 1020mb line just clipping the far south

 

Edited July 6, 2015 by Summer Sun

[Winter Cold]

Evening

 

Its all just a bit 'meh' really isnt it looking forward. Distinctly average. One post on the 12zs so far by 8pm says it all really! You dont even have to look at the models normally to get a feel for things, the post count on this thread is the best measure of them all. Just a handfull of posts for the last few days.

 

 

GFS and ECM both showing changable condtions with the north going below average at times. Having a look at South Yorkshire below -

 

Temperatures arent anything special, high teens for the majority of the days right out to the last third of July so allowing for the undercooking we get then id say 20c at best. Some pretty chilly days showing infact with a mean of 15c and the run being optimistic at the end:

 

 

Mean pressure quite low aswell for the whole run so always the chance of rain or showers and the run is way above the mean towards the end. Its not looking dry thats for sure with quite a busy precip chart aswell:

 

  

 

 

So all in all not too great for July on todays outlook so we will need to keep an eye out for improvements. The UKMO is better but its been lost as of late and the verification stats posted earlier dont fill me with confidence that it knows what its doing!

[ANYWEATHER]

What a difference a week makes.....  Welcome to the Uk!!!    

Edited July 6, 2015 by ANYWEATHER