Convective Storm/Discussion thread - 16/07/16 onwards

[Supacell]

A shiny new thread as we head into the second half of July and the mid point of the summer.

What a summer it has been. We started the summer with a lot of thunderstorms as June came in with a bang. Unfortunately as June came to a close and we moved into July the temperatures dropped and so did the storm risk. The most thundery early June I can remember has been balanced by the poorest early July I can remember. This looks like it is all set to change though as temperatures rise and summer returns. 
Temperatures are already rising across the south and this building warmth and humidity will spread northwards through the early part of the coming week, with the heat likely peaking on Tuesday. The first 30c is very likely this week. The increasing heat and humidity also looks likely, on current modelling, to culminate in the possibility of some dramatic thunderstorms.

The thoughts of Weather09 in the previous thread provide a good view of what we could expect from current modelling, seen on page 140 of the thread. The very high CAPE values being modeled for Tuesday are unlikely to be realised with strong ridging. It is currently late Tuesday night into Wednesday the period of interest (subject to change of course). Pin pointing an area to be at risk at this range is pointless.

I am thinking this thread is going to get busy with lots of excitement, forecasts and thoughts regarding what is likely to happen, even what you are hoping will happen. I am hoping it will be busy with lots of reports of thunderstorms and convective activity by the middle of this week and beyond. I think most of us would not want to see it fill up with "why do I always miss out", "nothing here", "wishing for no storms" or other moaning posts that should be in the correct moaning thread like the one below.

Good luck to all those that want a storm. 

A chart showing MLCAPE for early Wednesday, just to get the excitement flowing

 

 

Edited July 16, 2016 by Supacell

[Summer Sun]

Vicious storms possible Tuesday night and into Wednesday on the week ahead forecast with Alex

Exact locations ect hard to pin down at this range

[William Grimsley]

2 minutes ago, Summer Sun said:

Vicious storms possible Tuesday night and into Wednesday on the week ahead forecast with Alex

Exact locations ect hard to pin down at this range

Nice shot for your location, I would predict that thunderstorms will be most intense in southern areas before becoming thundery rain or just heavy rain as they move northward.

[Harry]

Not entirely sure what to make of GFS' circa 1,000 J/Kg CAPE at 03z Wednesday morning....

[weather09]

52 minutes ago, Harry said:

Not entirely sure what to make of GFS' circa 1,000 J/Kg CAPE at 03z Wednesday morning....

Those are quite realistic values when you consider just how much warmth and moisture there is likely to be at low-levels. Moisture-rich air mass surging north and east from Tuesday evening, and will take a while for c30C heat having built up during the day to weaken.  

Latest GFS/ECM outputs continue to break out thunderstorms and MCS(s) somewhere roughly over SW/W onward toward Midlands, transferring N and E during Weds morning as 500mb heights erode and forcing aloft arrives with approach of upper trough. Reasonable increase in mid-level winds generates decent deep layer shear for low-end severe convective episode - frequent CG lightning, possibly large hail and strong convective downdraft winds.  

In other words, a morning very much like June 28 2012.  That last part isn't meaning to be merely a ramp- the conditions during period in question look rather similar to that day, and the regions that look likely to be affected, and expected track of storms, also look similar.  

[Harry]

19 minutes ago, weather09 said:

Those are quite realistic values when you consider just how much warmth and moisture there is likely to be at low-levels. Moisture-rich air mass surging north and east from Tuesday evening, and will take a while for c30C heat having built up during the day to weaken.  

Latest GFS/ECM outputs continue to break out thunderstorms and MCS(s) somewhere roughly over SW/W onward toward Midlands, transferring N and E during Weds morning as 500mb heights erode and forcing aloft arrives with approach of upper trough. Reasonable increase in mid-level winds generates decent deep layer shear for low-end severe convective episode - frequent CG lightning, possibly large hail and strong convective downdraft winds.  

In other words, a morning very much like June 28 2012.  That last part isn't meaning to be merely a ramp- the conditions during period in question look rather similar to that day, and the regions that look likely to be affected, and expected track of storms, also look similar.  

Indeed - not a common thing by any stretch...a very interesting (and highly unpredictable I would suggest) period coming up in the next few days.

Its quite oppressively warm this evening and this is merely a foreword at what the next few days will bring! Bring it on

[A.J]

1 hour ago, weather09 said:

Those are quite realistic values when you consider just how much warmth and moisture there is likely to be at low-levels. Moisture-rich air mass surging north and east from Tuesday evening, and will take a while for c30C heat having built up during the day to weaken.  

Latest GFS/ECM outputs continue to break out thunderstorms and MCS(s) somewhere roughly over SW/W onward toward Midlands, transferring N and E during Weds morning as 500mb heights erode and forcing aloft arrives with approach of upper trough. Reasonable increase in mid-level winds generates decent deep layer shear for low-end severe convective episode - frequent CG lightning, possibly large hail and strong convective downdraft winds.  

In other words, a morning very much like June 28 2012.  That last part isn't meaning to be merely a ramp- the conditions during period in question look rather similar to that day, and the regions that look likely to be affected, and expected track of storms, also look similar.  

and of absolutely no coincidence at all, I've just told the wife and kids to pack their bags, we're moving back to Staffordshire monday morning 

[William Grimsley]

2 hours ago, weather09 said:

Those are quite realistic values when you consider just how much warmth and moisture there is likely to be at low-levels. Moisture-rich air mass surging north and east from Tuesday evening, and will take a while for c30C heat having built up during the day to weaken.  

Latest GFS/ECM outputs continue to break out thunderstorms and MCS(s) somewhere roughly over SW/W onward toward Midlands, transferring N and E during Weds morning as 500mb heights erode and forcing aloft arrives with approach of upper trough. Reasonable increase in mid-level winds generates decent deep layer shear for low-end severe convective episode - frequent CG lightning, possibly large hail and strong convective downdraft winds.  

In other words, a morning very much like June 28 2012.  That last part isn't meaning to be merely a ramp- the conditions during period in question look rather similar to that day, and the regions that look likely to be affected, and expected track of storms, also look similar.  

Will be interesting to witness this MCS you're talking about, but not really sure if I should get excited about it, just yet.

[MattTarrant]

On 16/07/2016 at 22:54, William Grimsley said:

Will be interesting to witness this MCS you're talking about, but not really sure if I should get excited about it, just yet.

Shall hopefully be exciting, the change in heat from North Wales to here was a shock! 24 here today. GFS Cape gets be on my seat but it changes rapidly so not getting hopes up. 

[William Grimsley]

1 minute ago, MattTarrant said:

Shall hopefully be exciting, the change in heat from North Wales to here was a shock! 24 here today. GFS Cape gets be on my seat but it changes rapidly so not getting hopes up. 

Hello Matt, was wondering when you might be back. I agree lots of time for it to change, but thunderstorms look very likely now.

[MattTarrant]

On 16/07/2016 at 23:05, William Grimsley said:

Hello Matt, was wondering when you might be back. I agree lots of time for it to change, but thunderstorms look very likely now.

Yeah I agree, all factors seemingly in place for once. Just have to wait for closer forecasts for more confident placements. Is wind shear going to play any significant role in this likely breakdown Tuesday night?

[Cheshire Freeze]

GFS pushes the destabilisation further N&W....looks dicey for any action Midlands/further E on this run. Preferred the 12z solution personally

[Thundery wintry showers]

That's a concern- it showed up on a couple of yesterday's GFS runs as well, with central, southern and eastern England largely missing out and the north having just "thundery rain", i.e. frontal rain with the odd bit of thunder.  West Cornwall and west Wales would probably end up as the most thunder-hit areas.  For now UKMO and ECMWF still appear to have the main "trigger low" further east, which would cause a more widespread event across the mainland.

Edited July 16, 2016 by Thundery wintry showers

[William Grimsley]

We'll just have to wait and see!

[Costa Del Fal]

Bit frustrating to see some model runs have almost all of the precipitation Tuesday night in the Irish Sea; the GFS, NMM and Netweather hi res model. However a fair few models still have the low further east. Of course on the event itself, things can turn out markedly different but the latest Netweather hi res run 18z is a shift west with the low pressure again meaning even much of Wales could miss out on the action. The flipside is another hot day Wednesday which I am equally happy with. 

Still much time for change regarding the track of the low but so far, the potential for a very westerly favoured breakdown meaning E Ireland, IOM and W Scotland see the proper destabilisation of the plume. England may see almost nothing apart from the far SW perhaps i.e Cornwall and Isles of Scilly. But as said, a fair few models with the low further east and history would have it that slight eastward corrections would be expected although I may have expected that to begin a little somewhat by now though still 3 days to go.

[Cheshire Freeze]

3 hours ago, Costa Del Fal said:

Bit frustrating to see some model runs have almost all of the precipitation Tuesday night in the Irish Sea; the GFS, NMM and Netweather hi res model. However a fair few models still have the low further east. Of course on the event itself, things can turn out markedly different but the latest Netweather hi res run 18z is a shift west with the low pressure again meaning even much of Wales could miss out on the action. The flipside is another hot day Wednesday which I am equally happy with. 

Still much time for change regarding the track of the low but so far, the potential for a very westerly favoured breakdown meaning E Ireland, IOM and W Scotland see the proper destabilisation of the plume. England may see almost nothing apart from the far SW perhaps i.e Cornwall and Isles of Scilly. But as said, a fair few models with the low further east and history would have it that slight eastward corrections would be expected although I may have expected that to begin a little somewhat by now though still 3 days to go.

GFS 0z seems to have coloured the Irish Sea in with green crayon.....seriously though, this model run couldn't have placed that precipitation more accurately to cover the Irish Sea and IOM. Almost like the precipitation moulds around the sea/land boundary 

Soon after, Scotland cops it

 

[William Grimsley]

Now I'm getting worried, maybe we won't see anything. But, I'm not throwing the toys out of the pram just yet, I think we still have a very good chance down here, as I've always said models are pointless at this range.

[Summer Sun]

5 minutes ago, William Grimsley said:

Now I'm getting worried, maybe we won't see anything. But, I'm not throwing the toys out of the pram just yet, I think we still have a very good chance down here, as I've always said models are pointless at this range.

It looks a good deal fresher for your area on Wednesday you could really do with some storms on Tuesday whilst you still have the heat

[William Grimsley]

Just now, Summer Sun said:

It looks a good deal fresher for your area on Wednesday you could really do with some storms on Tuesday whilst you still have the heat

Potentially, but if the low is being forecast further west, then it may be warmer, to me that doesn't look fresh, still temperatures in the mid-20's...

[A.J]

7 minutes ago, William Grimsley said:

Now I'm getting worried, maybe we won't see anything. But, I'm not throwing the toys out of the pram just yet, I think we still have a very good chance down here, as I've always said models are pointless at this range.

models are pointless at T72?....A strange and wholly inaccurate statement IMHO,as it's normally at these kind of short to mid scale time scales the model output is at it's most accurate, or where you referring to the microscale realm of ppn charts? in which case I'd agree to a point.............Anyhoo's the FAX output & most model output looks underwhelming for the majority of England and Wales in terms of thundery activity at this stage....hot and sunny for a couple of days, but then a gradual breakdown in the heat with no real stormy breakdown for most.....still subject to change of course, and it better damn well change, as from an IMBY perspective, this is the worst spring/summer for thunderstorms I've ever experienced

[Nick F]

Risk of a few isolated heavy thundery showers developing across southern counties this afternoon looking at morning models, probably result of a sea breeze front developing inland as warmth builds inland and pressure falls to allow sea breeze to develop.

 

Does look like northern and western areas will be prime areas for storms as the breakdown starts from the west later on Tuesday. Thunderstorms  developing across EIRE, N. Ireland, NW England and SW England during Tuesday evening, before these storms rumble northeast across Scotland Tuesday night.

Thunderstorms ongoing or reveloping across northern and western areas on Wednesday, further south across Wales and SW England too, perhaps some  severe storms developing from SE Wales, NE across the Midlands to E and NE England too, looking at 00z ECMWF, as an area of low pressure moves NE along the cold front.

Detail subject to change at this range though.

Edited July 17, 2016 by Nick F

[William Grimsley]

Yes, models and particularly in detail precipitation charts aren't always the best bits of information to focus on at this range. What is happening is the charts are now starting to get confused and the runs are all over the place now, so the best thing is to just wait and see what occurs on the day. What did we do before charts? We just had to wait and see. Oh, well it may be the worst thunderstorm period for you, but certainly not down here. 

BBC still think so, at least they're still going with it.

"Warm and humid on Wednesday with a chance of early thunderstorms, but becoming fresher by Thursday with showers."

Gives me hope...

Edited July 17, 2016 by William Grimsley

[William Grimsley]

@Nick F, thanks for that brilliant forecast. If I read it correctly, is my area classed as being the "breeding ground" for these thunderstorms or would I still be too far south?

[A.J]

8 minutes ago, William Grimsley said:

Yes, models and particularly in detail precipitation charts aren't always the best bits of information to focus on at this range. What is happening is the charts are now starting to get confused and the runs are all over the place now, so the best thing is to just wait and see what occurs on the day. What did we do before charts? We just had to wait and see. Oh, well it may be the worst thunderstorm period for you, but certainly not down here. 

 indeed we did.................thing's haven't changed...lol...............re, this year, the weather patterns just haven't been right IMBY, for a good thundery breakdown here we're normally looking at a strong plume of moisture rich from the south with an active cold front encroaching from the atlantic at just the right time, this time things look to be considerably further west to be helpful here, but the glimmer of hope is that at T60-T72 small changes in weather patterns now can can much wider implications at said time scale......at least that what is says on the small print of my bottle of 'prozac for storm junkies'

[claret047]

39 minutes ago, ajpoolshark said:

models are pointless at T72?....A strange and wholly inaccurate statement IMHO,as it's normally at these kind of short to mid scale time scales the model output is at it's most accurate, or where you referring to the microscale realm of ppn charts? in which case I'd agree to a point.............Anyhoo's the FAX output & most model output looks underwhelming for the majority of England and Wales in terms of thundery activity at this stage....hot and sunny for a couple of days, but then a gradual breakdown in the heat with no real stormy breakdown for most.....still subject to change of course, and it better damn well change, as from an IMBY perspective, this is the worst spring/summer for thunderstorms I've ever experienced

Hi,

From a IMBY perspective here in Mid Essex, we have had more thunderstorms, or days I have heard thunder this year than I can recall for at least the last 5 years.

It is strange that there can be such differences within what is a relatively small country.

What are your thoughts on the southeast/East Anglia experiencing any thundery activity this coming week? to my untrained eye it does not appear to be too hopeful, with the main activity now thought to be further west than my location.

Kind Regards

Dave