Model Output Discussions 12z 03/05/2016

[Man With Beard]

Stalling, stalling, stalling ... the Atlantic is making even slower progress on tonight's 12Zs so far. The Scandi High is looking stronger on all runs by Wednesday, which now more realistically could be hot away from the south west, as many of these runs do not clear the warm away by then. The GEM is hotter for Monday too. 

[bradymk]

On 10 August 2016 at 01:37, bradythemole said:

Much better from GFS 18z. Slightly slower breakdown of the hot weather next week with warmer uppers and these also lasting longer than on earliers ECM run. Hopefully a trend in this direction from 00z ECM. Think the heat will probably last from Monday until late Wednesday for most. 

Keep an eye out for high pressure possibly building in again from the south west/south late next week after the breakdown mid-week too

obviously a downgrade on the heat last couple of days which is a shame but a nice few summery days to come weekend and early next week. My post above from couple of days ago about high pressure moving in from south west late next week. Still think this the most likely outcome after a breakdown mid week, although this probably only transient once again and better the further west.

Edited August 11, 2016 by bradythemole

[Frosty.]

Well this is better from the Gfs 12z with the plume extending by an extra day, plenty of sunshine and then thunderstorms followed by a very pleasant anticyclonic low res..this is better than the 6z. The first half of next week looks very summery.

[cheese]

Hm.. towards the end of the run the high pressure isn't as favourably placed as it is on the 06z, but it's still pleasant enough with high pressure dominating - no doubt some pleasant sunny late summer days to enjoy. 

[Frosty.]

The GEFS 12z mean shows a summery first half to next week with +10 / +15 T850's on all 3 days, tuesday being the hottest day with plenty of sunshine and an increasing chance of thunderstorms late tues and overnight into wednesday and further ahead the Azores high is very influential with warm anticyclonic conditions predominating.

[The PIT]

Thankfully the plume doesn't last very long and a chance of a thundery breakdown fingers crossed. Deep FI has a return to perfect summer weather fresh low twenties so good sleeping weatehr and pleasant and warm in the day.

[Matthew.]

Yes the GFS once again pushing high pressure over the Uk later next week. Going by the law of averages we will surely see proper anti cyclonic weather soon.

Edited August 11, 2016 by Matthew Wilson

[Havaturkali]

[Man With Beard]

The latest installment for Wednesday:

  

A lot of warmth still around then

You can see that the GEFS still has some runs reaching the magic 20C 850s mark over the UK - the op, believe it or not, is actually on the cooler side - these are the ensembles for E Sussex

 

The precip chart for GFS shows that front trying to cross the country - anything ahead of it will be hot (maxes close to 30C in favoured spots if the front doesn't make it). The best precip chart I have for ECM is Wednesday 00am - hard to see but looks like the rain is well back

    

It's going to be a T24 job working out what will happen with that, we've situations like these at T144 where the front doesn't even make the SW by T0, or where the front has cleared the east coast.

Now onto the thundery stuff - actually Tuesday evening looks the tastiest on GFS, but Wednesday also has a chance. I suspect other outputs may differ

  

[knocker]

The ecm this evening. Saturday is the transition day from low pressure to the north of Scotland with a WNW airflow over the most of the UK, with showers and quite cool in Scotland and the north, to high Pressure moving from the south west to an HP cell over the UK by Sunday 12z.

The story from then until 18z Wednesday is of the high pressure moving slowly NE with fronts pushing slowly in from the west. This evolution continues to introduce a brief period of WAA and Tuesday is quite warm with temps 28C-30C below a line Liverpool to the Wash. By Weds 18z the fronts have arrived with thundery outbreaks over much of the UK and localised rain could be substantial although still quite warm in parts of the south and east reaching 26C-28C.

The front then swivels but is slow to clear and is still lying across Scotland and N. England 12z on Friday having introduced cooler air behind it.

 

Edited August 11, 2016 by knocker

[Gordon Webb]

after the last 3 days and the model changes I hope people don't fall into the trap of expecting high temps and big storms after what is only one run as these models can be fickle to put it politely might be all change tomorrow and back to a non event

[cheese]

@Man With Beard

42 minutes ago, Man With Beard said:

The latest installment for Wednesday

The precip chart for GFS shows that front trying to cross the country - anything ahead of it will be hot (maxes close to 30C in favoured spots if the front doesn't make it). The best precip chart I have for ECM is Wednesday 00am - hard to see but looks like the rain is well back

    

  

These charts remind me very much of 20th July this year. The rain was never as widespread as the GFS was going for. The day started off sunny and warm, it clouded over around lunchtime, we had a few drops of rain, then the sun came out again and it reached 27C. Could be similar.

[Scorcher]

1 hour ago, cheese said:

@Man With Beard

These charts remind me very much of 20th July this year. The rain was never as widespread as the GFS was going for. The day started off sunny and warm, it clouded over around lunchtime, we had a few drops of rain, then the sun came out again and it reached 27C. Could be similar.

You took the words right out of my mouth...I remember Wednesday 20th well. We had lots of hazy sunshine for most of the day and it ended up warmer than expected at 27C.

This setup actually looks better than it did on that day.

[knocker]

Today

A marked contrast between an area SE of a line Lincoln to Bristol and the rest of the UK. Particularly western Scotland which will be very wet.

The GFS for the weekend and next week

Saturday not dissimilar to yesterday with the transition from a showery north westerly (specifically in the north) to high pressure edging NE to become centred over the UK by 18z on Sunday. Temps for the weekend a little below average north of the Watford gap on Saturday and around average on Sunday.

From then on the scenario is much as yesterday. The HP edges NE whilst the Atlantic fronts move in from the west. The latter duly arrive late Tuesday/early Wednesday bringing some thundery outbreaks and perhaps some significant localised rainfall. This scenario drags in some warmer air with perhaps 28C in some places in the south. on Tuesday and more widespread south and east of a line Humber to Shrewsbury on Wednesday.

The front(s) continue to travel NE and dissipate before the next shallow depression arrives on Friday.

Sidney was quite sanguine on hearing the news yesterday - even had a glint.

 

Edited August 12, 2016 by knocker

[Gordon Webb]

I'm just going to point out that when comparing next Tuesday / Wednesday with the 20th July that in London there will be almost 1 hour 26 minutes less daylight time on Tuesday then what there was then and 1 hour 29 minutes on Wednesday , now not really sure if it'll play any part in forecast weather but I think it's interesting to note anyway

Edited August 12, 2016 by Gordon Webb

[mb018538]

26 minutes ago, Gordon Webb said:

I'm just going to point out that when comparing next Tuesday / Wednesday with the 20th July that in London there will be almost 1 hour 26 minutes less daylight time on Tuesday then what there was then and 1 hour 29 minutes on Wednesday , now not really sure if it'll play any part in forecast weather but I think it's interesting to note anyway

I think we're past the point of peak heat now, regardless of the set up...in my book, you have all of July and the first week of August to tap into the peak of any summer heat, and after that as the days get shorter, the heat starts to drain back south with the cooler days starting to return up in the northern regions.

[Frosty.]

The Gfs 00z shows a nice warm up from the south after the weekend with temps well into the 20's celsius, wednesday is now the warmest day but with a higher risk of thunderstorms which rumble on into the night further east and the warmth hangs on in the south throughout next week but that isn't even the best news because high pressure and warmth dominate the rest of this meteorological summer!

So.. this weekend looks rather cool and a bit disappointing with a lot of cloud and some patchy rain and showers but with sunny spells too and the south is warmer, into the low 20's c, perhaps 24c in London but then temps rise nationwide through the first half of next week. I think the gfs is wrong about tuesday, I think 30c will be reached in the south.

[knocker]

The evolution of the ecm not that dissimilar to the GFS with the fronts arriving in the west by 06z Wednesday and the crossing the country with the distinct possibility of thundery outbreaks and some heavy localised rainfall. Still WAA as this evolution unfolds with temps 26C-28C south of a line north Wales to Norfolk (only 14C in NE Scotland) and a little warmer on Wednesday with possibly 30C in the East Midlands (16-18C in north east Scotland).where there could also be some nasty storms. Having said that it's far too far away to be considering detail such as that/

Edited August 12, 2016 by knocker

[Singularity]

Interesting how the configuration has been adjusted - the low pressure development where the warm and cool air meet is much, much weaker, while the high to our east now moves to our northeast more quickly. The combined effect is to reduce the extent to which a plume of heat is drawn north from the continent, but also to increase the staying power of whatever we do manage to import.

ECM is the most progressive of the 00z det. runs, while GFS and UKMO suggest that a small low from the subtropics might engage with the Atlantic jet a little while well west of the UK, resulting in a weak ridge building ahead of it and across the southern UK. With any luck that will hold on through the weekend - but there's a risk that the subtropical export drifts over the south at that time - one to keep an eye on.

[Gordon Webb]

3 minutes ago, knocker said:

The evolution of the ecm not that dissimilar to the GFS with the fronts arriving in the west by 06z Wednesday and the crossing the country with the distinct possibility of thundery outbreaks and some heavy localised rainfall. Still WAA as this evolution unfolds with temps 26C-28C south of a line north Wales to Norfolk (only 14C in NE Scotland) and a little warmer on Wednesday with possibly 30C in the East Midlands.where there could also be some nasty storms. Having said that it's far too far away to be considering detail such as that/

I've seen setups like this in the past with fronts moving W to E with hot weather ahead of it and forecasts of nasty weather which come to nothing , if you like storms then breakdowns from the south are the way to go but there becoming fewer as the years go by it seems , still this is 5 days away front may speed up or slow down during that time

[Man With Beard]

1 hour ago, Gordon Webb said:

I'm just going to point out that when comparing next Tuesday / Wednesday with the 20th July that in London there will be almost 1 hour 26 minutes less daylight time on Tuesday then what there was then and 1 hour 29 minutes on Wednesday , now not really sure if it'll play any part in forecast weather but I think it's interesting to note anyway

I think that is a factor when trying to keep the hottest weather over the UK - in July we could pretty much sustain it but now we need a constant continuation of the hot feed - which is why a slight change in flow in charts between Monday and now mean we're looking at uppers of 16/17C rather than 20/21C.

Still the charts remain hot for Tuesday and increasingly Wednesday across all charts - once again, models seem to have been overestimating the ability of the Atlantic against a block directly to the east - so perhaps 30C on Tuesday around Bristol, and 30C on Wednesday in London, I'm guessing - if these charts were to verify. 

But do I now suspect a trend to keep it very warm across especially eastern parts for the entire week? The cooler air of the Atlantic failing to make much impression on upper air by Thursday.

Of course, a change in the charts earlier lead to changes later, and the failure of the Atlantic to get through encourages more high pressure to approach to uk from the SW by the end of the weekend. The GEFS is full of high-pressure dominated charts by T240 - though worth mentally knocking off 300 miles to the northern extent of the highs to be on the safe side!

[Man With Beard]

The Icelandic ECM charts now appear to show next Wednesday as being hot pretty much nationwide, with just the SW, Wales and N Ireland under the influence of encroaching fronts by then. Still, things will change further

  

[stodge]

Morning all

Another day, another set of output and as I look out to the end of next week and beyond the signs for a reasonable end to summer especially in the south but much of Britain looking good and just the very tiniest of hints the Bank Holiday could be settled as well but we've been led up the garden path by promises of heat this week so a very long way to go yet.

Starting with GEM this morning and the 00Z OP at T+216:

The quite large and deep Atlantic LP (for the time of year) is ambling toward the British Isles and throwing up a ridge of HP in front of it so a reasonable outlook - dry, warm and sunny but with cloud starting to encroach from the west later.

ECM at the same time:

Very different with HP to the north and west and a shallow area of LP over the south-east so rain and showers, perhaps thundery, for southern and eastern areas but fine elsewhere and the Atlantic seemingly moribund.

Last but not least the GFS 00Z OP at the same time:

Pretty straightforward - apart from some cloud and drizzle over the western isles, that looks dry though possibly quite cloudy in some northern and western areas but more sunshine further east and warm to very warm.

The ENS at this point is very anticyclonic - some have the HP over the British Isles, some have it ridging down from the NE - about an even split. The GLOSEA signal for HP to the North East hasn't quite come off but it's still appearing regularly in the ENS so it's not to be discounted and even if it doesn't affect us directly a stronger block to the east or north east will, as others have noted, hold up the eastward movement of any Atlantic systems and provide the opportunity for the importation of hot continental air from the south. Indeed, what fans of heat don't want is the HP to sit right on top of the British Isles as while that would provide settled, dry and warm conditions it cuts off access to the really hot air over Europe.

[snowprincesspboro]

19 hours ago, Man With Beard said:

Snow princess - just saw your post, sorry I'm going to be straight up I really don't have a clue what the weather will be like next weekend, I feel that the UK is stuck between two areas of settled weather and it's a lottery right now whether we will join in or not! I doubt it will be hot though.

Perhaps if you give details of your journey some others might chip in!

thankyou for that, know its defo no easy to pinpoint exacts lol, defo wasnt expecting a solid forecast haha, just a rough idea, seriously hoping for a storm or 2 thou. leaving peterborough mid afternoon fri 19th, driving to folkestone (tunnel) towards paris, on towards lyon, monaco, montpellier, through to andorra, through the pyranees and on to barcelona, final destination tarragona. gonna be fun, weve decided on the convertible for the tunnel as sure its gonna be hot by the time we hit southern france and northern spain. thanks for your help man with beard  

[knocker]

The EPS anomaly has some transient ridging around the 21st-24th but post that the pattern flattens out to a westerly flow with LP to the NW and HP to the SW which is a not unfamiliar story. Of course the usual caveat of the detail dependent on the phasing of the aforementioned. Temps around average in the 6-10 day period.

Just to add the  latest EC32 mean plays out a similar scenario until the first week of September.

Edited August 12, 2016 by knocker