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

[William Grimsley]

30 minutes ago, Ben Sainsbury said:

It's 5:30, we have 2 more hours+ of dirnual heating warm moist air...

Yes, but it's too late now, really can't see anything setting off now.

[Azazel]

30 minutes ago, Ben Sainsbury said:

Definite eastward shift on the current run, we see the warmth move through quicker during Wednesday, the mass of thunderstorms during tuesday night clipping more SW England and West Wales.

shift another 100 miles east pleaseeeee:D

[The PIT]

All shifted further north so thats us out of the firing line bar a few early showers. Plenty of time to change yet though.

[Flash bang flash bang etc]

9 minutes ago, William Grimsley said:

Yes, but it's too late now, really can't see anything setting off now.

I agree nothing looks likely at this point but the ingredients are actually all there for at least some heavy showers popping up, potentially.

900kj cape not to be sniffed at!

Showers I think most likely in Kent or Sussex - especially now we've got the sun out - but still close enough to be of interest if they do.

Very clear skies too, which means if anything were to develop it would be visible for quite a distance. Fingers crossed for something new unexpected, but there's plenty more excitement to come this week so no biggy if it's a no-show this evening...

[Staffordshire]

25 minutes ago, William Grimsley said:

Yes, but it's too late now, really can't see anything setting off now.

Although nothing is looking likely on this particular day, 6pm certainly isn't too late for anything to kick off

[weather09]

Not sure why some were expecting something to occur today... Stuck under strong ridge and subsiding air aloft, and little forcing elsewhere to set anything off. We'll see much more CAPE build during Tuesday when temperatures reach the upper 20s/low 30s, but that'll largely go to waste too given ridge aloft. 

[East_England_Stormchaser91]

27 minutes ago, Azazel said:

shift another 100 miles east pleaseeeee:D

Do think it will happen. Rarely seen events that have materialised further west than what was forecasted. Usually the biggest and most potent fireworks happen on the eastern periphery of a system that is heading north and east. 

Last year and the year before, this is exactly what happened. The night of July 17th 2014 the trough actually hit around 200+ miles or so further east than what was expected, and that was on a forecast on 6 hours prior to the event. 

Edited July 17, 2016 by East_England_Stormchaser91

[ChezWeather]

Can anyone summarise the current thoughts for Tues night into Wednesday?

Iv got limited internet access so bit difficult to check the models

[East_England_Stormchaser91]

4 minutes ago, ChezWeather said:

Can anyone summarise the current thoughts for Tues night into Wednesday?

Iv got limited internet access so bit difficult to check the models

I myself going by my own predictions would say that destabilisation of the plume over Wales and SW England will lead to storms breaking out around just before midnight and then conduct into a possible MCS heading from Devon/Cornwall and Wales trundling NNE up towards Midlands and Lincs by dawn. Other parts of NW England into Scotland inc. IOM I think will see some elevated storms dotted around. 

 

[Ben Sainsbury]

Yet another prediction from myself too, I would love to see a full scale MCS but whether this will be the case I'm not sure. Deep Layer Shear doesn't look anything amazing but is still decent, CAPE values I believe are quite high, tho I don't have access to ML Cape charts. Also SRH looks well over 300m^2s^2, so I believe any MCS or storm that may form could possibly have supercellular characteristics which large hail being a risk too. If an MCS does form, I believe again over Exeter/Cornwall, through Bristol Channel, East Wales, but will decay into thundery rain as it moves north as I don't believe that the MCS can be sustained. I may be wrong as I am very amateur!

If no MCS forms, without a doubt, strong thunderstorms are possible, poss 1 or 2 supercells with frequent lightning and large hail.

This isn't to over hype anyone or neccesarily a proper predictions I'm just basing what I have just said by the facts of the models.

Edited July 17, 2016 by Ben Sainsbury

[William Grimsley]

7 minutes ago, Ben Sainsbury said:

Yet another prediction from myself too, I would love to see a full scale MCS but whether this will be the case I'm not sure. Deep Layer Shear doesn't look anything amazing but is still decent, CAPE values I believe are quite high, tho I don't have access to ML Cape charts. Also SRH looks well over 300m^2s^2, so I believe any MCS or storm that may form could possibly have supercellular characteristics which large hail being a risk too. If an MCS does form, I believe again over Exeter/Cornwall, through Bristol Channel, East Wales, but will decay into thundery rain as it moves north as I don't believe that the MCS can be sustained. I may be wrong as I am very amateur!

That sounds a very good prediction to me not just because you included Exeter in there but actually makes sense. To be honest, I think the models are developing everything too far north, there's plenty of energy available as far south as Brittany northwards so we'll just have to see. Oh, and yes, I will be on the lookout for my Altocumulus Castellanus cloud tomorrow and Tuesday.

I'm thinking this could be very similar to the last MCS that hit this area on the 24th of June 2005.

Edited July 17, 2016 by William Grimsley

[Flash bang flash bang etc]

Still I think too far out for real predictions. Will wait until tomorrow afternoon and see what's developing by then.

i know an eastward shift would disappoint those in north Wales and Scotland - but I don't care I want storms :-D !!!!

Edited July 17, 2016 by Flash bang flash bang etc

[Summer Sun]

Current thoughts from the beeb from Wednesday

Don't take that as a given nowhere is immune from the storms

[A.J]

I'm going to make a big, bold and pretty accurate & in depth technical prediction as well based on model output, all the atmospheric parameters and general knowledge.....

 

 

 

It will stay bone dry without flash of any description here 

[William Grimsley]

@ajpoolshark, don't loose heart buddy, I'm sure we can both feel sympathy if it all goes up in flames!

[A.J]

Just now, William Grimsley said:

@ajpoolshark, don't loose heart buddy, I'm sure we can both feel sympathy if it all goes up in flames!

i'm not loosing heart me old mucka, simply going by all the current model output..............and there was an element of humour in my post 

[weather09]

Latest ECM keeping focus for storms over western and northern parts, with first round over NI and Scotland late Tues into Weds, then main round from SW/Wales early Weds, transferring north and east over northern England during the morning to early afternoon period:

This in agreement with GFS, so getting a slightly better handle on track of storms. Meso models over next day or two should make things somewhat clearer.

 

[William Grimsley]

@weather09, I hope that 2nd chart is after it's developed otherwise we're stuffed.

[Cheshire Freeze]

Looking at those ECM charts, might see something here by the skin of my teeth....won't hold my breath however. 

Even areas in the Midlands may get a decent light show however, given elevated nature- provided it kicks off during the early hours.

[Summer Sun]

Day 2 Convective Outlook

VALID 06:00 UTC Mon 18 Jul 2016 - 05:59 UTC Tue 19 Jul 2016

ISSUED 19:31 UTC Sun 17 Jul 2016

ISSUED BY: Dan

Upper ridging will build on Monday across the British Isles, but with a residual high WPBT airmass. Despite forecast profiles looking very dry, low-level convergence with surface temperatures 25-28C and dewpoints in the high teens Celsius may allow a couple of showers or thunderstorms to develop late afternoon / early evening, albeit fairly low confidence at this stage. PWAT in the mid-high 30s mm suggests local accumulations of 30-35mm is possible in a short space of time, despite reasonable motion to the NE, which may cause some local surface water issues. There is scope also for isolated deep convection elsewhere, such as Northern Ireland, S + NE Scotland, but confidence is too low for any threat levels for now.

There may also be some early ongoing elevated convection across portions of NE England on Monday morning, hence the extension of the LOW threat level northwards here to cover this risk. A plume of significant instability will eject NW-wards from France on Monday night, but with no real upper forcing is not expected to produce any deep convection at this time.

http://www.convectiveweather.co.uk/forecast.php?date=2016-07-18

[Harry]

Curious as to how this warm front tracking North during Tuesday night plays out. Currently the BBC not really modelling any precip off of it but you never know....

Conditions are seldom good in the UK for warm front triggered thunderstorms however given the instability present it just may well do the trick. The only time I've witnessed warm front thunderstorms was in the US and they were pretty incredible, along with (I think) September 2009 in Kent but that was more akin to a CZ straddling the warm front.

If there's one golden rule I've learned about plumes its to expect the unexpected - that is to say if you're sat under a few thousand MLCAPE do not be surprised to wake up to unexpected fireworks - which has been the case for me over the past couple of years.

[StormChaseUK]

I think July 2014 were warm front storms, overnight 2 nights in a row. Pretty incredible lightning.

[Chris.R]

 I'm going to get struck by lightning  in my tent I just know it. Better put lots of pegs in  in case of gust fronts and such. i'm very excited. 

[Spikecollie]

9 minutes ago, Chris.R said:

 I'm going to get struck by lightning  in my tent I just know it. Better put lots of pegs in  in case of gust fronts and such. i'm very excited. 

Please be careful! We had a nasty event in France in August 1999, during which people died, we had to evacuate our campsite due to flooding. We were happily watching the lightning and drifted off to sleep only to be woken by a torrent flowing under our tent.

You are unlikely to be "struck" in or around your tent, but be careful. Guy ropes and a good pitch will withstand pretty heavy winds...knowing that is when we just lie back and relax and enjoy the show - but do keep an eye out for any flood issues, check with the site warden if it looks uncertain.

There's something about being so close to the earth in a tent, and without the constraints of a building during a storm, that is utterly amazing...

[weather09]

Can't see a warm front moving north over the country Tues - 18z analysis showed a warm front over NI/Irish Sea, to be situated over N Scotland tomorrow midday, with parent sfc low out over the Atlantic.  Secondary sfc low(s) look to develop on the periphery to the S/SW late Tues - as upper trough and forcing aloft migrates eastward - which will track NE across the country bringing significant increase in low-level moisture and instability.  

GFS's sig. tornado/supercell parameter outputs look colourful for early Weds across regions of interest given considerable increase in winds and slight turn with height.  This together with plenty of moisture and instability and forcing for ascent with upper trough and shortwave disturbances aloft points to risk of severe convective weather.  Wales, N England and Scotland the main areas of interest atm.