Storm & Convective Discussion - 01/06/15 onwards

[NO LONGER POSTING]

All very interesting - I must say I'm still undecided about whether to be optimistic or pessimistic about tomorrow in truth. I've taken the day off now so I am free to roam as it were. I had planned to wait for storms around my location (06z to 12z) before darting east to the east Kent coast to await anything which fires around that location or moves in from the south/west. 

Regrettably however the models are keen not to develop anything over Kent, but rather take overnights area to the West of London and fire stuff north of London around noon and thereafter. 

 

That said, as BF rightly says, models tend not to be overly accurate and in my experience, Kent in particular often lacks in terms of charts in the CAPE department (possibly as a result of being entirely surrounded by water). This in turn often leads models to be reluctant to show any real storm risk or precip breaking out here. Experience shows however Kent certainly can fire storms and often boasts SBCAPE models are reluctant to show. 

 

I think for the time being I will keep to my plan, and hope we have more of a 28/06/11 day than what is currently modelled. 

 

Is it me or are those MLCAPE projections far higher than a normal plume event?

Good points.

Indeed the charts are a little odd to a normal plume event but, it's not really an established plume, the upper utmoshpere winds are all over the gaff with fronts moving left right and centre etc etc

Certainly some very tasty charts out there re tonight tomorrow some saying the fun starting around 9pm-12am tonight while others say the party starts around 3-6am others going for midday onwards and some saying the party won't even happen.

Nothing new then. Phahaha

[BlueHedgehog074]

Certainly some quite interesting clouds around at the moment - the sort of clouds that make you think a storm could be on it's way. Think this might be a form of Altocumulus Castellanus.

To be honest, don't really expect much here overnight and into tomorrow morning (although I probably wouldn't rule out the odd thundery shower or something). Those of you further East/South-East exposed to the warmer Southerly and South-Easterly flow ahead of the cooler air coming in from the West do look as though you'd have a better chance.

Considering the generally thunder-free year so far (though that would be dependent on where you are), would be nice to see a few odd rumbles, some flashes of lightning and some thundery downpours to get the Summer season started. What ever does happen in these next 24 hours or so, good luck!

Edited June 4, 2015 by DiagonalRedLine

[Pat Butcher]

No forecasts from ConvectiveWeather.co.uk (formerly UKASF) as yet...so that's Nick F away in the US, Estofex down and no UKASF...this will be the first significant plume event without any of those in place for quite some time.

 

I can't handle this lack of risk-based storm forecasting fix. Let's make our own.

[Mapantz]

Quite a shunt further East on this run..

[Karl83]

I can't handle this lack of risk-based storm forecasting fix. Let's make our own.

Ha ha - I think I just made it into the 'Lucky chump' zone!

Edited June 4, 2015 by Karl83

[William Grimsley]

Quite a shunt further East on this run..

Which run? NMM?

[Ben Sainsbury]

Which run? NMM?

The first GFS 12z runs are coming out about now so? I don't know.

[Mapantz]

Which run? NMM?

 

The GFS.

06Z compared to the 12Z..

 

 

Posted for discussion really, as i'll still be paying more attention to the radar later.

Edited June 4, 2015 by Mapantz

[NO LONGER POSTING]

Quite a shunt further East on this run..

As explained early this is expected in the 12z and 18z before the 00z pulls it back ,

[shaky]

hardly an eastward shift on the latest 12z run!!!besides now is the time to pay attention to the satellite and radar!!forget the nmm aswell!!!

[William Grimsley]

The GFS.

06Z compared to the 12Z..

 

viewimage (4).pngviewimage (5).png

 

Posted for discussion really, as i'll still be paying more attention to the radar later.

Yeah, radar watching is going to be key. But, I think I'm a little bit too far west here as most of the time is the case. But, I think the GFS right from a few days ago has kept an eastern favour whereas NMM still going for instability even over west Devon.

[Generalelectrix]

Quote Brickfielder: "So all the ingredients are there in different places for a severe storm, they just don't quite come together on this modelling output"

 

Indeed, looking at wrf it seems to be only the south east half of the UK for the action and also that the event will take place in two phases. Dont hang me if I havent nailed it down correctly tomorrow but I would say that phase 1 is in the am hours, starting south of London, moving over the East of the city at around 9am and then skirting the coastline in a northeasterly direction eventually to move out over the North Sea.  Phase 2 should be the formation of convective activity just north of London at about 2 pm and moving via Cambridge in a more easterly direction. Ihe convective activity could possibly extend as far north as Hull in this instance. In both cases we should be expecting multicell storms. This means that Norwich for example could get action twice tomorrow, others lose out completely....

 

Thats my 5 cent to the forecast, but dont bet on it  

 

Regards

 

Ralph

 

@ Davethedog  

Edited June 4, 2015 by Generalelectrix

[Rain123]

All the alto- cumulus has dissapeared  completely. It's a bit hit and miss if surrey be in with a chance tomorrow.

[William Grimsley]

All the alto- cumulus has dissapeared  completely. It's a bit hit and miss if surrey be in with a chance tomorrow.

Ac Cas normally comes in in the morning in great amounts and then dissapears several hours before storms move in.

[Mapantz]

[A.J]

Ac Cas normally comes in in the morning in great amounts and then dissapears several hours before storms move in.

For elevated plume type storms this is actually incorrect as it's the mid level cloud (ac cas) that tower into thunderstorms

[William Grimsley]

For elevated plume type storms this is actually incorrect as it's the mid level cloud (ac cas) that tower into thunderstorms

I suppose so. I mean that was evident today as Ac Cas did move in to the east of here and towered into TCU. So, are you basically saying that now all the Ac Cas has gone, there won't be any storms? :?

[A.J]

I suppose so. I mean that was evident today as Ac Cas did move in to the east of here and towered into TCU. So, are you basically saying that now all the Ac Cas has gone, there won't be any storms? :?

no, I'm saying nothing like that William....rather the Ac Cas that's been floating around today is an indicator of some marginal instability in the mid-levels...the plume hasn't 'engaged' as such yet, so not enough instability to trigger elevated thunderstorms, as you've probably noticed, the Ac Cas hasn't been 'clean' as such, there's been a lot of regular Ac around which is indictive of the current marginal instability....the mid-levels will start to destabilize overnight

[William Grimsley]

no, I'm saying nothing like that William....rather the Ac Cas that's been floating around today is an indicator of some marginal instability in the mid-levels...the plume hasn't 'engaged' as such yet, so not enough instability to trigger elevated thunderstorms, as you've probably noticed, the Ac Cas hasn't been 'clean' as such, there's been a lot of regular Ac around which is indictive of the current marginal instability....the mid-levels will start to destabilize overnight

Ohh right, I see. Yeah, lots of it has been messy. I don't think I have much chance here anyway. I'm too far west by the looks of things.

[davehsug]

I wouldn't take alt cas as any sort of guide. There's plenty of that around here and we certainly won't be joining in any fun.

[A.J]

Ohh right, I see. Yeah, lots of it has been messy. I don't think I have much chance here anyway. I'm too far west by the looks of things.

yep, there's a weak warm front (pushing up over southern counties) that has caused the marginal instability.....FAX chart output show's this front straddling southern counties....This front will lift up north/north eastwards, and it's behind this front where the plume lies......have a look at brickfielder's excellent post a couple of pages back

[Dami]

I have 'liked'  ESTOFEX  on facebook and they have posted a chart, with a level2 warning, sadly not for the uk. (mainly north of france)

[East_England_Stormchaser91]

Ac Cas is a good precursor, but it's the cumulonimbus that deliver the goods! Hopefully someone gets a decent night show tonight and early hours of the morning leading onto a spectacular Friday.

[Mapantz]

I have 'liked'  ESTOFEX  on facebook and they have posted a chart, with a level2 warning, sadly not for the uk. (mainly north of france)

Well spotted!

[Supacell]

I am going to head out tonight and travel SE in the hope of seeing some lightning displays. I envisage quite a lot of lightning overnight but not a lot of rain. Basically the perfect recipe for getting some lightning shots.

 

By first light tomorrow storms are likely to gain intensity with regards to rain and this could give a soggy and active morning to areas across East Anglia and the SE give or take 50 miles or so each way. Unfortunately I think by this time tomorrow it will be Benelux and the North Sea getting the action. It's an exciting 24 hours ahead though.