Storm & Convective Discussion - 7th August Onwards

[Chris.R]

Newcastle METAR reports funnel cloud in the vicinity. 

[Flash bang flash bang etc]

1 hour ago, Windblade said:

I knew before even clicking on that link that I'd see the dreaded "Mini tornado" as the uk media continues to deny TORNADOS exist in this country.  "Mini" tornado my backside.

“The tornado-like cloud”

Arrrrarrg! just say ‘funnel cloud’ you gits

[Flash bang flash bang etc]

Despite attempts earlier to get a good pic from a very special vantage point in the centre of London - I only managed this

The rain was quite something

[Ǝssex Ǝasterly]

Just got sent this image from my cousin in london

What is it, a shelf or a wall cloud?

[Lauren]

That's what I can see from the other side out my window. It's a beast!

[LightningLover]

Bexhill has been experiencing some surprisingly persistent heavy convective rainfall for the past 2 hours or so, we must have had at least 13mm or more?

[Flash bang flash bang etc]

The weather is definately changeingnfor the better - convectively speaking - but it’s was still mainly pulse storms today - hoping for something more organised on Sunday - and I also won’t be stuck at work

[Thunderstruck]

Looks like I’ve missed some pretty good activity back at home - I’m down in Minehead for the weekend where we’ve had a grand total of nothing other than a heavy shower this morning. 

[Spikey M]

 

Just passed through Southend

[poseidon]

Quite spectacular cells embedded in the line South Essex. I also had a very interesting cell with pronounced gust front pass near my location.

   Gust front of large cell with intense rainfall.

Back of the line of storms, south Essex, There were really low cloud bases on these.

[Juanmoorchants]

Quite spectacular storm in Rayleigh 

[Summer Sun]

Day 2 Convective Outlook

VALID 06:00 UTC Sat 11 Aug 2018 - 05:59 UTC Sun 12 Aug 2018

ISSUED 20:15 UTC Fri 10 Aug 2018

ISSUED BY: Chris

A transient ridge of higher pressure will keep most of Britain dry through Saturday, however a warm front and following warm sector will overspread Ireland and southwestern parts of Britain by Saturday evening and overnight. Rain and the potential of some embedded elevated convection will bring a low end risk of a few lightning strikes as the cold front moves in during the early morning hours of Sunday.  At this stage the risk of lightning seems to be only around 10%. 

http://www.convectiveweather.co.uk/forecast.php?date=2018-08-11

[Weather-history]

Convective skies today

 

[Chris.R]

Sunday looks very interesting. Getting a good feeling about it. 35 kts of speed shear by midday as well. Steering wind good (backed at surface); CAPE good; trigger present. Juicy. 

[Windblade]

2 hours ago, poseidon said:

Quite spectacular cells embedded in the line South Essex. I also had a very interesting cell with pronounced gust front pass near my location.

   Gust front of large cell with intense rainfall.

Back of the line of storms, south Essex, There were really low cloud bases on these.

Lovely pics. Thanks for sharing.

[Summer Sun]

Day 1 Convective Outlook

VALID 06:00 UTC Sat 11 Aug 2018 - 05:59 UTC Sun 12 Aug 2018

ISSUED 10:06 UTC Sat 11 Aug 2018

ISSUED BY: Chris/Dan

 

UPDATE 10:06 UTC Cold front provides the focus for embedded mid-level instability release as strong upper forcing approaches from the SW, on the forward side of the main upper trough. While instability is fairly weak and profiles rather saturated, forcing may be sufficient to produce some sporadic lightning during Saturday night as the cold front continues to slide NE from the Celtic Sea into SW England and Wales; a low-end SLGT has been introduced to cover this potential

 

A transient ridge of higher pressure will keep most of Britain dry through Saturday, however a warm front and following warm sector will overspread Ireland and southwestern parts of Britain by Saturday evening and overnight. Rain and the potential of some embedded elevated convection will bring a low end risk of a few lightning strikes as the cold front moves in during the early morning hours of Sunday.  At this stage the risk of lightning seems to be only around 10%. 

http://www.convectiveweather.co.uk/forecast.php?date=2018-08-11

[Nick F]

Storm & Convective Forecast

Issued 2018-08-11 09:32:51
Valid: 11/08/2018 00z - 12/08/2018 00z

THUNDERSTORM OUTLOOK - SAT 11TH AUG 2018

Synopsis

An upper trough in the broad cyclonic westerly upper flow over N Atlantic will approach the west of Ireland today, a surface depression containing the remnants of ex-tropical storm Debby will also approach to west of Ireland while filling. A warm front will lift N across England and Wales today, with warm and moist southwesterly flow becoming unstable ahead or along cold front then following in from the west.

... SW ENGLAND, WALES, IRELAND, IRISH SEA ...

Cloud and patchy rain will spread NE through the day across Wales and western England in warm sector, then through this evening a cold front will move in from the west. differential thermal advection as cooler air moves in aloft ahead of surface cold front and lift from the front itself will cause the warm and moist conveyor to destabilse mostly in the mid-levels upwards - supporting increasing elevated convection across the above areas this evening and into the night - with potential to bring isolated thunder and lightning and heavy downpours leading to localised flooding.

 

[alexisj9]

22 hours ago, The East has Ceased said:

Just got sent this image from my cousin in london

What is it, a shelf or a wall cloud?

A shelf which was in front of the squall.

[alexhawkins]

anything possible for this part of the country tonight and tommorow?

[Cheshire Freeze]

8 minutes ago, alexhawkins said:

anything possible for this part of the country tonight and tommorow?

I'm quite interested in tomorrow. The modelling is suggestive of possible convective activity through afternoon up through Wales, parts of the W Midlands and up into N England.

[Snowyowl9]

Tomorrow looks possible,well I missed a thundery shower yesterday as I wasn`t expecting any thunder and it was chilly as such and driving a tractor you can`t here anything, but did see the CB develop close by did think about stopping to got out too.

But just found that there was hail only nearby and a few rumbles,so I`ll book that down

Edited August 11, 2018 by Snowyowl9

[Mokidugway]

36 minutes ago, alexisj9 said:

A shelf which was in front of the squall.

Looks like some convergence cumulus  get them quite often here with occasional funnel clouds

[Snowyowl9]

Friday has given thundery showers on 3 days this year and once on a sunday different.

[Mokidugway]

We have drizzle  for a change , nice

[Summer Sun]

Day 2 Convective Outlook

VALID 06:00 UTC Sun 12 Aug 2018 - 05:59 UTC Mon 13 Aug 2018

ISSUED 19:39 UTC Sat 11 Aug 2018

ISSUED BY: Dan

Broad upper trough will drift eastwards during Sunday, from the Celtic Sea and across southern England by Sunday night. Associated cold pool will steepen mid-level lapse rates, with SSTs and diurnal heating inland further adding instability. Several shortwaves will add forced ascent to the mix, with several areas of potential convective interest.

 

The first shortwave, on the forward side of the main upper trough lying from roughly Merseyside to Lyme Bay at 06z, will for a time encourage mid-level instability release along the cold front (mainly W Country to SW Midlands) - though saturated profiles suggest lightning activity may be rather limited. In either case, the shortwave will weaken and overrun, resulting with a decaying of precipitation along the cold front during Sunday morning.

A small upper disturbance may develop late morning over the W English Channel, inducing a wave along the cold front into Cen S England for the afternoon.

 

Elsewhere, the primary focus will be on airmass convection beneath a cold pool aloft as the upper trough slides eastwards. Low-level convergence and orographic forcing will play a key role in convective development, with numerous showers and a few scattered thunderstorms likely from SW England through Wales and into N England during the afternoon and evening hours. Slow storm motion and PWAT up to 35mm suggests local surface water flooding should be the main threat, though some small hail and gusty winds will be possible from the most intense cores. Low-level convergence and fairly low cloud bases may allow a few funnel clouds to form.

 

Falling heights / upper forcing may allow showers to persist well into the night across the Midlands and northern England, though questionable by this stage as to how much lightning activity will still exist. There is also scope for scattered showers / thunderstorms over N France to drift NE-wards towards SE England for a time on Sunday evening, as another shortwave slides across the area.

 

There should be an increase in shower / thunderstorm activity over the English Channel during the early hours of Monday, especially close to the coasts of southern England where showers may train over similar areas - hence the extension of the SLGT here.

 

http://www.convectiveweather.co.uk/forecast.php?date=2018-08-12