Convective / Storm Discussion Thread - 31st May 2017 onwards

[Flash bang flash bang etc]

Really looks / feels like a storm could be on its way - acas and what look like small turkeys here...

[matt111]

Bit more cloud here now.

[Harry]

Hardly a reliable tool, but the train is extremely warm and sticky this evening. Clearly the humidity is on the up, which combined with observations of AcCas, should be promising.

However, MUCAPE (NMM) during the night is confined to the far SE so I look likely to be outside any realistic chance.

 

[Neilsouth]

I thought we had some great strikes the other day, but O M G! Check these out

https://www.lightningmaps.org/?lang=en#m=sat;r=0;t=3;s=200;o=0;b=;n=0;y=45.51;x=9.4411;z=9;d=2;dl=2;dc=0;

[Summer Sun]

Some thunderstorms tomorrow afternoon for some central and southern parts

[Flash bang flash bang etc]

Just now, Summer Sun said:

Some thunderstorms tomorrow afternoon for some central and southern parts

But appearently they are likely to be sporadic and messy :-(

[wimblettben]

55 minutes ago, Flash bang flash bang etc said:

I've noticed a lot of stuff appearing in here which - being very petty I know - should really be in the Euro storms thread.

Just so it stays on topic for those looking at potential UK storms, whenever they may be...

Yes I agree with this too!

Its getting confusing in here at the moment with all of these european posts.

Edited June 26, 2017 by wimblettben

[alexisj9]

45 minutes ago, Harry said:

Hardly a reliable tool, but the train is extremely warm and sticky this evening. Clearly the humidity is on the up, which combined with observations of AcCas, should be promising.

However, MUCAPE (NMM) during the night is confined to the far SE so I look likely to be outside any realistic chance.

 

I thought the storms were for tomorrow.

[Flash bang flash bang etc]

5 minutes ago, alexisj9 said:

I thought the storms were for tomorrow.

It's as if all the storm forecasters have gone off on holiday - i'm sure there's an outside chance of a rumble later on but nobody's letting on

[Windblade]

Really haven't been expecting anything today. Tomorrow looks more favourable for an outside chance of a late evening french import. I'm not too hopeful, but lets wait and see - you never know.

Edited June 26, 2017 by Windblade

[East_England_Stormchaser91]

July and August need to shape up. I hate to be a misery, but this year really has been terrible for many! I've not seen one visible lightning strike yet this year, and that is saying something in these parts. 

[Nick F]

SE England and E Anglia could see some thunderstorms from tomorrow evening, as a plume of warm and humid air spreads out of N France across SE UK and likely destabilises through differential thermal advection as cold air overruns aloft of the plume from the west and also some isentropic upglide on the northern edge of the plume above cooler boundary layer airmass flowing from the NE. GFS not really indicating much CAPE, but often struggles to simulate elevated convection IMO.

PWAT Tues 18z

Fax charts for tomorrow noon and 00z Weds show a trough across the SE, 12z ECMWF ppn charts show some very heavy (likely convective) rainfall for SE UK.

As often in these set-ups though, it's usually the eastern side of such a mass of convective / heavy rainfall that sees all the thunderstorms activity - so may turn out that the far SE gets the  storms in the end.

But, as always, will be a case of seeing how it evolves through nowcasting. BBC forecast seems keen on a risk of storms across much of the SE and north of London too, but we know these can be out of kilter too, such is the difficulty of forecasting storms in the UK - compared to with continental climates of U.S.A, mainland Europe!

Will get out a storm forecast shortly, could be some weakly electrified showers across Wales, SW England too in the afternoon, ahead/along of the cold front across the west. Also some post-frontal heavy showers and storms for EIRE and N. Ireland in the afternoon, as colder Pm air arriving steepens lapse rates.

 

Edited June 26, 2017 by Nick F

[Chris.R]

 Oh great, stuck in the middle with nothing again. Is it going to be one of those years? 

[Summer Sun]

Day 2 Convective Outlook

VALID 06:00 UTC Tue 27 Jun 2017 - 05:59 UTC Wed 28 Jun 2017

ISSUED 21:00 UTC Mon 26 Jun 2017

ISSUED BY: Dan

Atlantic upper trough will dig south towards Iberia on Tuesday, strong northwesterly jet on its western flank but rather weak return southerly flow on its forward side. Broad upper flow is anticyclonic across the British Isles for much of the day, but higher WBPT airmass will begin to advect northwards from France as the flow backs. Falling heights Tuesday afternoon and evening will promote some destabilisation of this airmass, but in a rather messy fashion with pulses of showery precipitation drifting north from France into southern Britain - majority of NWP guidance suggest these pulses will be largely dynamic (vs convective). Forecast profiles also exhibit saturated mid-levels with only marginal instability at best. That said, some embedded lightning cannot be ruled out, but point probabilities remain very low.

The bulk of any noteworthy instability will likely remain over the nearby Continent, with perhaps a slightly better chance of some lightning close to coasts of Kent/Sussex and East Anglia late Tuesday afternoon into the evening/night, but confidence is not particularly high - no SLGT issued for now. 

Elsewhere, behind the main frontal rain some insolation combined with cool air aloft will generate some instability across Northern Ireland, with scope for a few heavy showers or thunderstorms here. In general conditions remain too marginal to upgrade to SLGT for now. Some surface-based convection will also be possible over SW England for a time in the afternoon too.

http://www.convectiveweather.co.uk/forecast.php?date=2017-06-27

[wimblettben]

The convective forecasts on here are not looking very promising compared to the mainstream forecasts.

[Norfolk Sheep]

1 hour ago, Nick F said:

SE England and E Anglia could see some thunderstorms from tomorrow evening, as a plume of warm and humid air spreads out of N France across SE UK and likely destabilises through differential thermal advection as cold air overruns aloft of the plume from the west and also some isentropic upglide on the northern edge of the plume above cooler boundary layer airmass flowing from the NE. GFS not really indicating much CAPE, but often struggles to simulate elevated convection IMO.

PWAT Tues 18z

Fax charts for tomorrow noon and 00z Weds show a trough across the SE, 12z ECMWF ppn charts show some very heavy (likely convective) rainfall for SE UK.

As often in these set-ups though, it's usually the eastern side of such a mass of convective / heavy rainfall that sees all the thunderstorms activity - so may turn out that the far SE gets the  storms in the end.

But, as always, will be a case of seeing how it evolves through nowcasting. BBC forecast seems keen on a risk of storms across much of the SE and north of London too, but we know these can be out of kilter too, such is the difficulty of forecasting storms in the UK - compared to with continental climates of U.S.A, mainland Europe!

Will get out a storm forecast shortly, could be some weakly electrified showers across Wales, SW England too in the afternoon, ahead/along of the cold front across the west. Also some post-frontal heavy showers and storms for EIRE and N. Ireland in the afternoon, as colder Pm air arriving steepens lapse rates.

 

Nick you might want to alter the date on the convective forecast to June  

[Nick F]

As promised ...

Storm & Convective Forecast

Issued 2017-06-26 21:56:14
Valid: 27/06/2017 06z to 28/06/2017 06z

CONVECTIVE / STORM FORECAST - TUESDAY 27TH JUNE 2017

Synopsis

A negatively-tilted upper trough over the far N Atlantic extends SE into Iberia during Tuesday, with an increasingly cyclonic and strengthening SWly flow aloft of the UK, while at the surface a shallow area of low pressure will slide SE across Ireland – associated warm front will move north across northern UK with and increasingly warm and humid airmass spreading north out of France across SE UK, as surface winds back here ahead of slow-moving cold front lying N-S through the Irish Sea.

… SE UK …

Warm and moist airmass is forecast to spread N across SE UK during Tuesday, as surface flow begins back ahead of approaching trough from the west. Surface heating in any cloud breaks late morning into the afternoon may trigger a few isolated heavy and perhaps thundery downpours. Then ECMWF and AROME models break out an area of heavy rainfall and perhaps isolated embedded thunderstorms across Brittany and Normandy late morning, before spreading N across SE England during the afternoon and evening, timing between models varies. This heavy rainfall and possible elevated convection develops on the NW edge of high WBPT (Wet bulb potential temp) plume across mainland Europe, probably due to engagement of cooling aloft as upper trough approaches from the west and also isentropic uplift of the warm conveyor above cooler/drier NEly surface flow over SE UK. Possible isolated embedded elevated t-storms spreading N across the Channel across SE UK within area of heavy rainfall developing and spreading N may pose a risk of localised flooding, given PWAT (Precipitable Water) values of 33-36mm. This heavy rain and embedded storms continuing overnight into Wednesday morning, with a continued risk of localised flooding. Have issued a MARGINAL risk for risk of flooding.

… SW ENGLAND + WALES …

Surface convergence and orographic uplift of increasingly moist airmass ahead of slow-moving cold front lying N-S through Irish Sea may support some isolated weakly electrified thunderstorms during the afternoon, as diurnal heating increases in any sunny spells, however, this is largely dependent on any cloud breaks to allow temperatures to rise sufficiently to trigger convection.

… EIRE + N. IRELAND …

Cool post frontal airmass to west of cold front will be characterised by steep lapse rates as colder air moves aloft above heated surface in any sunny spells – supporting heavy showers and isolated thunderstorms in the afternoon. Any heavy showers/storms may produce hail and gusty winds.

Issued by: Nick Finnis

http://www.netweather.tv/index.cgi?action=convective;sess=

Edited June 26, 2017 by Nick F

[Nick F]

1 minute ago, Norfolk Sheep said:

Nick you might want to alter the date on the convective forecast to June  

Cheers, least someone's still awake

[Cheshire Freeze]

1 hour ago, Chris.R said:

 Oh great, stuck in the middle with nothing again. Is it going to be one of those years? 

Was just thinking the same. One third of summer almost gone and not a single rumble. In fact almost 12 months have gone by since the last one!

[Flash bang flash bang etc]

General consensus appears to be the potential for lightning across Kent - except for Estofex who don't think there will Ben imports.

As long as it waits until after 6pm I'm happy with a bit of flash bang flash bang before bed. Count me in

Edited June 26, 2017 by Flash bang flash bang etc
I don't know why they are importing Ben - but I would rather they import storms. No idea what happened there

[Another Kent clipper]

I'm in east Sussex tomorrow daytime but heading back home to Manchester on Wednesday morning.  We've not picked an area to stay in tomorrow night.  Any suggestions for some belated birthday lightning opportunities?

[wimblettben]

Not as much talk of thunder on this mornings forecasts, just heavy outbreaks of rain for the afternoon.

The sky does have a slight unstable look to it though at the moment.

[NO LONGER POSTING]

Regardless if it's thundery or not, looks to be some torrential rain for the south 

[LightningLover]

Good morning! Looking at latest forecasts the rain today will be pretty heavy in my location, throughout today and into tonight. I am looking at Blitzortung.org, and there has already been some sporadic lightning in the channel, hopefully a sign for later today! 

[Windblade]

Ok, so things are actually looking a lot more positive today. Looks as though we could get some homegrown storms in the afternoon as well as a chance at some imports this evening if I've read the forecast correctly.