Convective Storm/Discussion thread - 02/09/16 onwards

[Mapantz]

I was just having a look at the FAX chart- what a mish-mash that is for tomorrow night/Friday morning!

It probably won't work out exactly like the chart below, but it sure puts emphasis on some very large rain totals for some areas.

[Allseasons-Si]

Well,i have just watched the last five clips for the first time and f@@king wow,how much lightning

pick the bones out of part 3

the rest will have to wait until tomorrow.

[Harry]

6 minutes ago, Mapantz said:

I was just having a look at the FAX chart- what a mish-mash that is for tomorrow night/Friday morning!

It probably won't work out exactly like the chart below, but it sure puts emphasis on some very large rain totals for some areas.

Trying to think of the last time we got slammed by two cold fronts from opposite directions...In fact I can't remember of a single occasion. What it does mean is one seriously awesome CZ with a warm humid sandwich of air in the middle.

[Ben Sainsbury]

Just now, Harry said:

Trying to think of the last time we got slammed by two cold fronts from opposite directions...In fact I can't remember of a single occasion. What it does mean is one seriously awesome CZ with a warm humid sandwich of air in the middle.

Must be incredibly hard to forecast I cannot imagine! Hopefully will bring us some surprises!

[Harry]

Unfortunately I've had nothing to contribute in terms of photos/vids over the past few days other than blue skies and sweat patches lol.

However, what appeared in the sky a short while ago was pretty gorgeous...twilight mackerel sky  Not come out anything as nice as it looked to the naked eye unfortunately

[Harry]

13 minutes ago, Allseasons-si said:

Well,i have just watched the last five clips for the first time and f@@king wow,how much lightning

pick the bones out of part 3

the rest will have to wait until tomorrow.

Gorgeous, stunning, awesome, amazeballs and any other superlative there is!

[Allseasons-Si]

4 minutes ago, Harry said:

Gorgeous, stunning, awesome, amazeballs and any other superlative there is!

Speechless,gobsmacked and totally surprised at how good this storm was and i was just on the edge of it,it was one of the best storms(for lightning)that i have ever seen,it even bet July the 3rd last year now looking back at all the clips

hopefully more to come tomorrow evening.

[Flash bang flash bang etc]

15 minutes ago, Harry said:

Unfortunately I've had nothing to contribute in terms of photos/vids over the past few days other than blue skies and sweat patches lol.

However, what appeared in the sky a short while ago was pretty gorgeous...twilight mackerel sky  Not come out anything as nice as it looked to the naked eye unfortunately

Saw this late night too over us. Dunno if you saw that elevated storm them at went up the channel. It was about 3am tho!

loads of lightning in it and I was hoping to see the atmos flashes as it was such a clear night but alas no

but the blanket of tiny high level clouds was really nice to look at :-)

[Ben Sainsbury]

I did not see this coming...

Day 2 Convective Outlook

VALID 06:00 UTC Thu 15 Sep 2016 - 05:59 UTC Fri 16 Sep 2016

ISSUED 20:54 UTC Wed 14 Sep 2016

ISSUED BY: Dan

Elevated convection over the English Channel and environs on Thursday morning should gradually weaken with time - however, there is some uncertainty as to how far north precipitation (and more importantly the cloud shield) may extend, and this may have some impacts on evening developments if cloud clearance is too slow. Some sporadic/isolated lightning from embedded medium-level instability release will also be possible in Northern Ireland / western Scotland from showery bursts of rain.

 

The upper pattern on Thursday will gradually become more progressive as an Atlantic upper trough approaches from the west, causing the cut-off low over Biscay to nudge eastwards across France, while elongating - and this process may be responsible for the advection of some elevated convection into parts of SE England and coastal East Anglia on Thursday night. 

 

Elsewhere, capping will persist for much of the day. That said, strong heating and increasing low-level wind convergence, as the surface low over Brest peninsula migrates NNE to southern England by evening, may provide sufficient forcing for scattered thunderstorms to develop late afternoon into Thursday evening, particularly across the W Country / Cen S England NE to the south Midlands. Forecast profiles are quite dry, and so initial convection may struggle to develop at first, but should any storms form then the biggest concern will be local flash flooding given PWAT in the mid-high 30s mm and slow storm motion. Gusty winds and hail to 1.5cm in diameter will also be possible, which falls just shy of our SVR criteria, hence no SVR issued at this stage. CAPE values near 1,000 Jkg-1 and steep mid-level lapse rates (although these gradually weakening (in a relative sense) through the evening) suggest lightning will be quite prolific in the most active storms.

 

During the evening and night, the approaching Atlantic front will likely increase low-level convergence and provide some forced ascent, with perhaps an increase in coverage of showery precipitation in a N-S zone (highlighted by the elongated SLGT), only slowly migrating eastwards. 200-400 Jkg-1 MLCAPE overnight suggests that some occasional lightning will be possible with this activity, albeit in a rather sporadic nature, and likely to not be as frequent as initial surface-based storms on Thursday evening.

 

The exact positioning of the zone of wind convergence, and hence greatest thunderstorm potential, is subject to a little doubt and hence the MDT may need adjusting slightly as conditions become clearer through the day on Thursday.

[stainesbloke]

Some great videos being posted of impressive lightning storms, reminds me of storms I used to get back in the 80's and 90's. Tomorrow looks interesting, unusual synoptics and some hot humid air in the mix....glad I have a day off work in case anything occurs in my area.

Edited September 14, 2016 by stainesbloke

[Allseasons-Si]

A question

when i looked back at the clips of the storm,i noticed that the focus was dipping in and out of focus,is this because the focus is set on automatic?

would it be better filming on manual focus?

this cam is fairly new so some teething issues,not sure if i can film on manual focus though

the cam is a Sony cyber shot dsc hx60

thanks.

 

 

[viking_smb]

17 minutes ago, Ben Sainsbury said:

I did not see this coming...

Day 2 Convective Outlook

VALID 06:00 UTC Thu 15 Sep 2016 - 05:59 UTC Fri 16 Sep 2016

ISSUED 20:54 UTC Wed 14 Sep 2016

ISSUED BY: Dan

Elevated convection over the English Channel and environs on Thursday morning should gradually weaken with time - however, there is some uncertainty as to how far north precipitation (and more importantly the cloud shield) may extend, and this may have some impacts on evening developments if cloud clearance is too slow. Some sporadic/isolated lightning from embedded medium-level instability release will also be possible in Northern Ireland / western Scotland from showery bursts of rain.

 

The upper pattern on Thursday will gradually become more progressive as an Atlantic upper trough approaches from the west, causing the cut-off low over Biscay to nudge eastwards across France, while elongating - and this process may be responsible for the advection of some elevated convection into parts of SE England and coastal East Anglia on Thursday night. 

 

Elsewhere, capping will persist for much of the day. That said, strong heating and increasing low-level wind convergence, as the surface low over Brest peninsula migrates NNE to southern England by evening, may provide sufficient forcing for scattered thunderstorms to develop late afternoon into Thursday evening, particularly across the W Country / Cen S England NE to the south Midlands. Forecast profiles are quite dry, and so initial convection may struggle to develop at first, but should any storms form then the biggest concern will be local flash flooding given PWAT in the mid-high 30s mm and slow storm motion. Gusty winds and hail to 1.5cm in diameter will also be possible, which falls just shy of our SVR criteria, hence no SVR issued at this stage. CAPE values near 1,000 Jkg-1 and steep mid-level lapse rates (although these gradually weakening (in a relative sense) through the evening) suggest lightning will be quite prolific in the most active storms.

 

During the evening and night, the approaching Atlantic front will likely increase low-level convergence and provide some forced ascent, with perhaps an increase in coverage of showery precipitation in a N-S zone (highlighted by the elongated SLGT), only slowly migrating eastwards. 200-400 Jkg-1 MLCAPE overnight suggests that some occasional lightning will be possible with this activity, albeit in a rather sporadic nature, and likely to not be as frequent as initial surface-based storms on Thursday evening.

 

The exact positioning of the zone of wind convergence, and hence greatest thunderstorm potential, is subject to a little doubt and hence the MDT may need adjusting slightly as conditions become clearer through the day on Thursday.

it's not often we are in the MDT warning area... hope it doesn't materialise as I have to be at a important inspection for sea cadets and it is outside, so will be annoyed if I get soaked esp as I will be in ceremonial uniform.

Edited September 14, 2016 by viking_smb

[ThundersnowDays]

That MDT warning for once is over me

[Harry]

23 minutes ago, Flash bang flash bang etc said:

Saw this late night too over us. Dunno if you saw that elevated storm them at went up the channel. It was about 3am tho!

loads of lightning in it and I was hoping to see the atmos flashes as it was such a clear night but alas no

but the blanket of tiny high level clouds was really nice to look at :-)

No I didn't sadly - I was spark out at 3am. I have my fingers crossed for tomorrow night/Friday. I'm working in Bedford on Friday - knowing my luck I'll drive away from potential and pass the CF before it fires lol. 

[Guest]

5 minutes ago, Allseasons-si said:

A question

when i looked back at the clips of the storm,i noticed that the focus was dipping in and out of focus,is this because the focus is set on automatic?

would it be better filming on manual focus?

this cam is fairly new so some teething issues,not sure if i can film on manual focus though

the cam is a Sony cyber shot dsc hx60

thanks.

 

 

I had the same issue at times and was on low battery so didn't want to faff about with modes and wear the battery down further. I have a Sony RX100.

If I go out tomorrow to film I'll be definitely going on manual focus.

[Southern Storm]

8 minutes ago, Allseasons-si said:

A question

when i looked back at the clips of the storm,i noticed that the focus was dipping in and out of focus,is this because the focus is set on automatic?

would it be better filming on manual focus?

this cam is fairly new so some teething issues,not sure if i can film on manual focus though

the cam is a Sony cyber shot dsc hx60

thanks.

 

 

Yes you are spot on! You video is still amazing though, absolutely fantastic storm, you are a lucky chap.

 

Hopefully I will get my storm tomorrow night

 

I'm looking forward to your other videos when you post them.

 

Edited September 14, 2016 by Christchurch storm nut

[Flash bang flash bang etc]

1 minute ago, Harry said:

No I didn't sadly - I was spark out at 3am. I have my fingers crossed for tomorrow night/Friday. I'm working in Bedford on Friday - knowing my luck I'll drive away from potential and pass the CF before it fires lol. 

I wish you all the best - Friday it looks like we'll be getting mostly 'poor man's storms' of the pulse variety but tomorrow we might get our just desserts... :-D

[Thunderstruck]

In the SLGT. The next 2 days could be interesting...

[Allseasons-Si]

10 minutes ago, Christchurch storm nut said:

Yes you are spot on! You video is still amazing though, absolutely fantastic storm, you are a lucky chap.

 

Hopefully I will get my storm tomorrow night

 

I'm looking forward to your other videos when you post them.

 

Thanks buddy i will try that,i suppose if you set the manual focus on for taking pics,it should be the same for filming,i will give it a trial tomorrow

oh!,and part 4 is processing and i will post it shortly

hope you get some storms tomorrow.

2000 post's,yay

Edited September 14, 2016 by Allseasons-si

[Speedway Slider]

Is this purple stuff anaprop in the channel, or really compact, heavy rain....?

[Allseasons-Si]

Part 4

sorry for the noise from my daughter

i must of clocked over 100 strikes easily with this storm,maybe 200 plus

i still yet to capture stills from these clips and i suspect there will be quiet a few,i will have a dig tomorrow,goodnight chaps and lets hope we have some humdingers tomorrowlol.

 

[Chris K]

51 minutes ago, Ben Sainsbury said:

I did not see this coming...

Any storms should they develop will tease us by about 50 miles to our East/SE. You can bet your bottom dollar on it!

Edited September 14, 2016 by Chris K

[Nick F]

Netweather's official storm forecast for Thursday: http://www.netweather.tv/index.cgi?action=convective;sess=

Storm & Convective Forecast

Issued 2016-09-14 22:05:55

Valid: 15/09/16 00z to 16/09/16 00z

CONVECTIVE / STORM FORECAST - THURS 15TH-SEPT-2016

Synopsis

Quite a complex synoptic pattern evolves across the UK/NW Europe over the next 24 hours, an upper low over Biscay will gradually drift across western France while filling … while Atlantic upper trough approaches from the west. At the surface, a shallow low will drift north across the English Channel and in across southern England during Thursday. A slack warm and humid but unstable airmass across much of the UK will be capped across most areas, however, thunderstorms may develop across central parts of England by the evening ahead of cold front arriving in the west.

… S ENGLAND, MIDLANDS, E WALES, N ENGLAND …

A MCS moving N/NW over France tonight may eventually affect the Channel Islands, English Channel and low risk of affecting southern coastal counties of England overnight before gradually weakening during the first half of Thursday morning. Any elevated storms that make landfall over Channel Islands or south coast could bring a risk of localised flooding, frequent cloud-to-ground lightning and gusty winds.

Then during Thursday, despite GFS building up to 1000+ j/kg CAPE in the afternoon, as warm humid airmass is heated in the sunshine, this potentially unstable airmass will generally be capped. However, shallow surface low drifting north across southern England will likely induce breeze convergence in a N-S line from central S England through the Midlands and up towards N England. So along this zone sufficient lift may break the cap to allow isolated storms initially in the afternoon … before greater forcing for ascent arrives from the west in the evening as upper trough and surface cold front move in from the west … allowing storms to expand in coverage over SW and C S England, E Wales, The Midlands and N England.

Given weak winds aloft – storm motions will be fairly slow … combine this with PWAT (Precipitable Water) values of 30mm+, there is a risk that storms could produce large rainfall totals in a short space of time locally (25-30mm per/hr). Also, given large CAPE values, storms may also produce brief bouts of isolated large hail (2-3cm) and frequent cloud-to-ground lightning … before storm updrafts are cut-off by downdrafts in weakly sheared environment. Have issued a MARGINAL risk for severe weather across the SW/CS England, E Wales, MIDS and N England.

… E SCOTLAND …

There is also a more isolated risk of storms across eastern Scotland … as cold front/upper trough moves in from the west and creates forced ascent of warm and humid airmass. Any storms could produce localised flooding.

 

Issued by: Nick Finnis

 

Edited September 14, 2016 by Nick F

[Nick F]

38 minutes ago, Speedway Slider said:

Is this purple stuff anaprop in the channel, or really compact, heavy rain....?

Anaprop I'm afraid,often there, think it's ships!

Won't be staying up to see if that thundery rain / MCS over France makes it across the Channel tonight.

[ancientsolar]

time to get my cameras charged... before the potential discharge ... 

Was in Cardiff yesterday or was it Monday.. when the thunderstorms hit... beautiful!!! I haven't been following the weather properly for a while.. and only by chance I saw a weather watch tonight ^^