Model Output Discussions 12z 03/05/2016

[coldcomfort]

13 minutes ago, Man With Beard said:

The desire for a second round of heat on Saturday has gathered pace quickly

Note some runs in there that keep it very hot for 3-4 days without a break. I'm pretty sure the hottest runs would see us up to 35C/36C. 

As it is, I expect the ECM would get close to 32C, the GFS would exceed 32C, and the GEM saves it for Saturday when it could reach 35C

No everyone lives in London though MWAB, for many the reality of the next 3 or 4 days is very different...chalk and cheese in fact.

[Man With Beard]

8 minutes ago, coldcomfort said:

No everyone lives in London though MWAB, for many the reality of the next 3 or 4 days is very different...chalk and cheese in fact.

The GEFS ensembles are not particularly hot for those living the other side of a line from Bristol Channel to the Humber. It's a close call though? I'm sure we've seen many an instance in recent years where the heat gets further north than forecast??

For sure, the GEM is an outlier but it does show the heat extending to 90% of the population of the UK. A few of these runs pop up in the GEFS and it seems to be a growing trend, so who knows?

The northern cold brigade will get their revenge on us southerners come winter, especially on me living on the south coast!! 

[Gordon Webb]

this hot spell can be broken down to 3 areas I think London and the SE most likely , midlands up to NW England possible especially the more S and E one travels NW England Northwards possible but less likely

that just about covers it I think

[Singularity]

This is a very challenging time for forecasters; the models are again displaying considerable ineptitude when it comes to how the periphery of a heat plume interacts with cooler air with respect to low pressure development.

On this occasion we have seen the low pressure development toned down, which has a two-fold effect; heat is not drawn as far or quickly north(west), so the plume has some intensity in terms of peak 850 hPa temps and does not look to get as far north(west) as we were being shown a number of days ago - but at the same time, the removal of the plume from the south and east has been slowed down, at least in the case of the GFS det. runs - the ECM det. runs have not been so hasty, but have made more of the breakdown when it's happened - this tendency most evident on yesterdays 12z before the considerable change of heart on this morning's 00z, which has meant that even this model has now delayed the removal of the hot weather from the SE corner.

There's still a lot to be resolved, most importantly for areas bordering The Southeast, which are right on the fence with respect to whether Thursday stays hot or turns cooler... and then we have the thunderstorm potential to sort out. No two runs have been consistent on this so far.

 

My eyes certainly widened at the sight of multiple 32*Cs on the GFS 00z 2m temp charts for the SE on Thursday. The obvious question is, what's the date record for 25th (and the days either side, for that matter)? 

[East_England_Stormchaser91]

A forecasters nightmare coming up over the next few days. We are at the point now of very fine lines of what could be very contrasting outcomes. A few hundred miles further northwest will enhance the heat and thunder potential for many more, however, a few hundred miles further east and we could well be seeing only the extreme southeast seeing any real heat and a Kent clipper scenario in terms of thunder. 

[stainesbloke]

25 minutes ago, East_England_Stormchaser91 said:

A forecasters nightmare coming up over the next few days. We are at the point now of very fine lines of what could be very contrasting outcomes. A few hundred miles further northwest will enhance the heat and thunder potential for many more, however, a few hundred miles further east and we could well be seeing only the extreme southeast seeing any real heat and a Kent clipper scenario in terms of thunder. 

Yep, forecasters must be scratching their heads a bit. The S and E have consistently been modelled to be hot however; the question is how far N and W the hot air will reach and where the thundery activity will be. Models are not showing a shift E as yet and hopefully that won't happen at all, rather the other way around and more importantly, a good BH weekend. Will be watching with interest!

Edited August 22, 2016 by stainesbloke

[A.J]

a few posts have been hidden, model output discussion only in here please

[Man With Beard]

Being a bit more UK-wide conscious...

I think anywhere south of a line from the Lake District up to the English/Scottish border on the east has a shouting chance of reaching 25C on Wednesday - anywhere south of line from the Bristol Channel to the Humber could top 30C (subject to local conditions e.g. proximity to the sea / onshore breeze / height above sea level). Little cloud, very light winds, decent upper level warmth. The "warm zone" may vary say, up to 100 miles yet, which of course could increase or decrease the zones. But I don't see this as a truly SE only event. The SE of course will be hottest, as it always is. But it's still beach weather for many. Scotland and N Ireland are the exceptions, unfortunately.

Quick look at the latest GEFS ensembles (which have done brilliantly for this week, unlike for last week!) - many runs still pushing the heat on northwards, like this one:

Ecm of course is still not that keen so to be held lightly, but I would say the GEFS has had the slight edge over the ECM ens IF current charts verify...

Edited August 22, 2016 by Man With Beard

[weirpig]

1 minute ago, Man With Beard said:

Being a bit more UK-wide conscious...

I think anywhere south of a line from the Lake District up to the English/Scottish border on the east has a shouting chance of reaching 25C on Wednesday - anywhere south of line from the Bristol Channel to the Humber could top 30C (subject to local conditions e.g. proximity to the sea / onshore breeze / height above sea level). Little cloud, very light winds, decent upper level warmth. The "warm zone" may vary say, up to 100 miles yet, which of course could increase or decrease the zones. But I don't see this as a truly SE only event. The SE of course will be hottest, as it always is. But it's still beach weather for many. Scotland and N Ireland are the exceptions, unfortunately.

Yep  quite a nice few days coming up.  I expect for my area  mid 20s  will be the order of the day  with perhaps the chance of a storm on Thursday  all in all not to shabby  however way out into the unreliable it does look like atlantic is in control

[Kentspur]

3 hours ago, Gordon Webb said:

this hot spell can be broken down to 3 areas I think London and the SE most likely , midlands up to NW England possible especially the more S and E one travels NW England Northwards possible but less likely

that just about covers it I think

Got to say us in NWKent/ SE London are extremely lucky as weve had a very good summer down here except for parts of June when ironically the norh west of the country had a bit of a heatwave. But seeing as I am more of a snow lover, when it gets to winter I am dying to.see some of the white stuff lay down here- we've had no snow for whats coming up for 4 years! but I know those up north will have plenty to get their revenge on us down here. I just have an inkling though that we could have a good one this winter as I cannot remember the last time we went this long without snow+ some of the other factors- QBO/ low solar activity etc. Plus the fact that we had a record breaking warm december last year which I doubt can be repeated

[Polar Maritime]

For tho's who missed AJ's post a page back.. Can we please stick to 'Model Output Discussion' only in here, Thanks.

[Captain Shortwave]

So looking again at the middle of the week and what will likely be the hottest part of the week.

      

So up to 30C tomorrow with prolonged sunny spells. Wednesday and Thursday still look hotter and interestingly Thursday is beginning to suggest that the heat could extend a little further north and west with a huge temperature contrast where the front sits bringing cool and wet conditions. Some stunning temperature predictions with 33/34C possible in the south east by Thursday if this pans out.

Regarding the weekend, the GFS does push another surge of heat from the continent late Friday and into Saturday, but there is a caveat which can be seen on the output, this brings a warm front with some decent instability which triggers some elevated showers and thunderstorms across southern England which move northwards during Saturday. This holds the temperatures down despite the higher 850s returning.

         

Huge uncertainty with this though, but it is worth noting this as this could be quite an event if it came off.

 

Edited August 22, 2016 by Captain Shortwave

[No Balls Like Snow Balls]

 

[Nouska]

@No Balls Like Snow Balls is this what you're trying to show? You need to embed whole tweet.

Edit maybe others can see just blank screen for me.

An edit for @Summer Sun hurricane (cat 4 probably) 967mb at that point - bottoms out at 951mb. Tropical Tidbits better if you want to see close up for these features.

http://www.tropicaltidbits.com/analysis/models/

Edited August 22, 2016 by Nouska

[MR EXTREMES]

18 minutes ago, No Balls Like Snow Balls said:

 

my thoughts exactly plus very low solar output certainly can say this summer has had alot of northern blocking and the zonal train looks somewhat weaker i certainly expect this to continue for the mean time anyway.

anyway back to the models broadly speaking id be shocked if after this hot spell things may well slip into early autumn but not especially cyclonic zonal.

[The PIT]

Twop bites at the hot weather for England. Tuesday and Wednesday and another push on Saturday if it comes off. To close a contrasting month off it looks like a sudden cold outbreak to cancel the two days out. An air frost shown in Scotland on the 30th. Unlikely to pan out that way but it has been a month of contrasts. 

[Summer Sun]

Does anyone know what sort of pressure the low I've put an arrow next to would be?

GEM also has that low at the same time

[The PIT]

1 minute ago, Summer Sun said:

Does anyone know what sort of pressure the low I've put an arrow next to would be?

GEM also has that low at the same time

No idea the first ex hurricane to cross over this year. Going to be interesting how the GFS and ECM cope with it.

[Captain Shortwave]

Well the GFS clears the warm front sufficiently north on Saturday to given central/southern England a decent and very warm day, 30C possible in the south east again.

   

There could be some potent thunderstorms early on in the day like on other runs. Reasonable agreement too with the UKMO and GEM going for something similar.

   

Things return to near normal by Sunday with a mix of sunshine and showers, as mentioned above some cold low polar heights do seem to be flirting with sinking towards Scandinavia and hence give a colder option in the 7-10 day range potentially.

Before then three potentially hot days before cooling off a touch on Friday in the south, it still looks rather unsettled in the north but hopefully some brief drier and warmer periods mixed in.

[phil nw.]

Yes it's interesting to see the African heat plume continuing to pulse north right up to day 5 on the GFS before it's finally cutoff and pushed away east by the approaching Atlantic trough.

A tricky day to day forecast across the UK this week for where the boundary lies between the air masses.Weds.fax for instance

a wiggling weather front across us showing the ebb and flow of the temperature gradient.

It does look like we will lose the last of the heat plume by the week end though according to both GFS and UKMO op runs,much in line with day to day ens outputs.

Just looking ahead that developing Scandinavian  trough may well come into play as we enter Autumn

Flattening the Azores high bringing a cooler more changeable westerly pattern.

 

[Man With Beard]

EURO4 and GFS more or less on the same page at T48 - the ECM a degree or two less warm especially further NW. You'd have to back the EURO4 at this range? Bit tricky to read but I think I'm right.

(follow the lines/numbers, the colours don't correspond for some reason)

     

A fair amount of cloud around could peg the temps back, so 90F not a forgone conclusion in the SE, whilst areas in the north of England could do rather well if in the more broken cloud. Will have to wait for the day.

 

ECM is moving back towards the GFS for Saturday. Could be bangy.

  

[knocker]

1 hour ago, Summer Sun said:

Does anyone know what sort of pressure the low I've put an arrow next to would be?

GEM also has that low at the same time

955mb at T222

[Summer Sun]

ECM shows pressure rising from the south resulting in a northwesterly flow the south-west would see the best temps if this were the case

It's fair to say we have 2 completely different options as we move into the start of Autumn GFS goes for an autumnal start

Edited August 22, 2016 by Summer Sun

[Nouska]

2 hours ago, Summer Sun said:

Does anyone know what sort of pressure the low I've put an arrow next to would be?

GEM also has that low at the same time

ECM 934mb at 192....

..... and guess where that steering is going.

On 21/08/2016 at 15:17, MP-R said:

That's quite the autumn storm! Looks similar to the one on 11th-13th September 2011.

Ex hurricane Katia - a very similar path to what 90L will take as per current modelling.

Edited August 22, 2016 by Nouska

[ANYWEATHER]

Good Evening All. A Pluming Nightmare to forecast for the end of the week in any detail!!! Ecm and Gfs  show some likeness at this range!!! After that don't look,,,,,,,