Storm & Convective Discussion - SPANISH PLUME - 30/06/15 onwards

[pip22]

Shows how fast things can develop today at 9.05am... netweather extra 5 minute radar was totally clear around Lancaster, by 9.20 a small discreet storm has blown up and is producing the goods....

A first storm in Lancashire. Nice.

[Nick F]

Here's the latest Netweather storm outlook for today and tomorrow:

 

Storm & Convective Forecast

Issued 2015-07-01 08:23:59

 

Valid: 01/07/2015 0600z to 03/07/2015 0600z

 

CONVECTIVE/STORM OUTLOOK - ISSUED 1ST JULY 2015

 

Synopsis

Hot and humid plume continues to advect north across Britain during Wednesday between slow-moving upper trough to the west and highly-amplified omega ridge over the Mediterranean and central Europe. Hot humid airmass and elevated mixed layer will create large amounts of convective energy (CAPE) across the UK today, this energy most likely to released into thunderstorms, perhaps severe, across northern and western Britain today as pressure/height falls and surface convergence occur here. Storms, perhaps severe continue north across N England and Scotland overnight, before clearing NE Scotland by dawn as cold front moves in from the west. Further S and ahead of the cold front ... an new area of storms are indicated by most models to arrive from the S/SW across S/SE England by dawn, only slowly clearing as the cold front clears into the afternoon.

 

-------------------------------------------------------------------------------------------------------------------------------------------------------------------

 

DAY 1 CONVECTIVE OUTLOOK - WEDS 1ST JULY

 

... SW ENGLAND, WALES, MIDLANDS, N ENGLAND, N IRELAND and SCOTLAND ...

 

An area of elevated thunderstorms will push north across SW England, Wales, perhaps the W Midlands this morning and eventually NW England, as an Elevated Mixed Layer (EML) plume axis, characterised by steep lapse rates, pushes north here and destabilises as a dry air intrusion, visible on WV imagery, and associated vorticity max pushes north from western France. There is a risk of hail, torrential rain, gusty winds and frequent cloud-to-ground lightning  from these storms.

Home-grown storms are also likely to develop this afternoon and evening within the hot and humid airmass across the UK, particularly northern England northwards. The plume advecting north will be characterised by dew points of 16-18C, which will yield up to 1500-2000 j/kg SCAPE beneath the EML spreading north characterised by steep lapse rates. Falling heights and pressure from the W and SW, cooler 500mb temps towards northern areas, dry air intrusion and associated vort max pushing north and sea breeze convergence favour more widespread storms development across N Wales, N England and Scotland this afternoon and evening. Strenghtening southerly flow aloft and backed SEly flow towards the surface will result in 40-50 knts of DL shear, which will be enough for organised storm developent. Bowing line segements and perhaps 1 or 2 supercells appear likely the main storm mode, with a risk of producing the full-range of severe risks. Large hail, damaging wind gusts and torrential rain leading to flash flooding may accompany storms. Also, veering winds with height and backed sfc winds - particularly east of Pennines and east of Scotland favour strong Storm-relative Helicity SREH in the boundary layer, so if storms form or can become surface-based - there is also a risk of one or two tornadoes over the areas mentioned. Therefore, have issued a MODERATE risk for NE England and E Scotland. These storms may merge and form and MCS before clearing NE Scotland by dawn.

 

... ELSEWHERE ...

 

The highest risk of thunderstorms will be from the Midlands north and also to the west on Wednesday, but there is a risk of one or two isolated thunderstorms developing further south across central southern England  triggered by high afternoon temps. Also a risk later on into the overnight period of storms pushing over the Channel from France into southern/SE  England by dawn, with a risk of hail, gusty winds and torrential rain - so have introduced a MARGINAL risk for now. Otherwise, other areas are covered by a general thunderstorm area for now.

 

---------------------------------------------------------------------------------------------------------------------------------------------------

 

DAY 2 CONVECTIVE OUTLOOK - THURS 2ND JULY

 

 

 

... S/SE ENGLAND, E MIDLANDS and E ANGLIA ...

 

As mentioned in Day 1 outlook, thunderstorms, mainly elevated, are indicated by most models to spread NE from the English Cannel/N France across S and SE England Thursday morning, as plume destabilised ahead of cold front further west. UKMO indicates storms arriving by 6am across far S/SE England before spreading N/NE across E Midlands and E Anglia during the morning and early afternoon, before the cold front clears east introducing drier and fresher conditions from the west later in the afternoon. 40-50 knts of DL shear will be sufficient for multicell clusters or line segments given time of day and elevated nature of storms, capable of producing hail, torrential rain leading to flash flooding, marginally strong gusty winds and frequent cloud-to-ground lightning. A marginal risk is maintained here from the Day 1 outlook.

 

... EIRE, N IRELAND ...

 

GFS indicates 400-700 j/kg CAPE across the above areas in the afternoon, so scattered heavy shower and a few thunderstorms appear likely, though with less warmth and humidity and weak DL shear, no severe weather is anticipated.

Edited July 1, 2015 by Nick F

[Summer Sun]

Showers breaking out in the south west as we speak

 

[Darren Bown]

Wow, good to see storms in Lancaster, though I now fear that I may be too far south.

[Snow free zone]

Small storm moving in from the Irish sea here, thunder heard a few mins ago.  I'm between Carnforth and Kendal in S.Cumbria.

[sn0wman]

 

Here's the latest Netweather storm outlook for today and tomorrow:

 

Storm & Convective Forecast

Issued 2015-07-01 08:23:59

 

Valid: 01/07/2015 0600z to 03/07/2015 0600z

 

CONVECTIVE/STORM OUTLOOK - ISSUED 1ST JULY 2015

 

Synopsis

Hot and humid plume continues to advect north across Britain during Wednesday between slow-moving upper trough to the west and highly-amplified omega ridge over the Mediterranean and central Europe. Hot humid airmass and elevated mixed layer will create large amounts of convective energy (CAPE) across the UK today, this energy most likely to released into thunderstorms, perhaps severe, across northern and western Britain today as pressure/height falls and surface convergence occur here. Storms, perhaps severe continue north across N England and Scotland overnight, before clearing NE Scotland by dawn as cold front moves in from the west. Further S and ahead of the cold front ... an new area of storms are indicated by most models to arrive from the S/SW across S/SE England by dawn, only slowly clearing as the cold front clears into the afternoon.

 

-------------------------------------------------------------------------------------------------------------------------------------------------------------------

 

DAY 1 CONVECTIVE OUTLOOK - WEDS 1ST JULY

 

... SW ENGLAND, WALES, MIDLANDS, N ENGLAND, N IRELAND and SCOTLAND ...

 

An area of elevated thunderstorms will push north across SW England, Wales, perhaps the W Midlands this morning and eventually NW England, as an Elevated Mixed Layer (EML) plume axis, characterised by steep lapse rates, pushes north here and destabilises as a dry air intrusion, visible on WV imagery, and associated vorticity max pushes north from western France. There is a risk of hail, torrential rain, gusty winds and frequent cloud-to-ground lightning  from these storms.

Home-grown storms are also likely to develop this afternoon and evening within the hot and humid airmass across the UK, particularly northern England northwards. The plume advecting north will be characterised by dew points of 16-18C, which will yield up to 1500-2000 j/kg SCAPE beneath the EML spreading north characterised by steep lapse rates. Falling heights and pressure from the W and SW, cooler 500mb temps towards northern areas, dry air intrusion and associated vort max pushing north and sea breeze convergence favour more widespread storms development across N Wales, N England and Scotland this afternoon and evening. Strenghtening southerly flow aloft and backed SEly flow towards the surface will result in 40-50 knts of DL shear, which will be enough for organised storm developent. Bowing line segements and perhaps 1 or 2 supercells appear likely the main storm mode, with a risk of producing the full-range of severe risks. Large hail, damaging wind gusts and torrential rain leading to flash flooding may accompany storms. Also, veering winds with height and backed sfc winds - particularly east of Pennines and east of Scotland favour strong Storm-relative Helicity SREH in the boundary layer, so if storms form or can become surface-based - there is also a risk of one or two tornadoes over the areas mentioned. Therefore, have issued a MODERATE risk for NE England and E Scotland. These storms may merge and form and MCS before clearing NE Scotland by dawn.

 

... ELSEWHERE ...

 

The highest risk of thunderstorms will be from the Midlands north and also to the west on Wednesday, but there is a risk of one or two isolated thunderstorms developing further south across central southern England  triggered by high afternoon temps. Also a risk later on into the overnight period of storms pushing over the Channel from France into southern/SE  England by dawn, with a risk of hail, gusty winds and torrential rain - so have introduced a MARGINAL risk for now. Otherwise, other areas are covered by a general thunderstorm area for now.

 

---------------------------------------------------------------------------------------------------------------------------------------------------

 

DAY 2 CONVECTIVE OUTLOOK - THURS 2ND JULY

 

 

 

... S/SE ENGLAND, E MIDLANDS and E ANGLIA ...

 

As mentioned in Day 1 outlook, thunderstorms, mainly elevated, are indicated by most models to spread NE from the English Cannel/N France across S and SE England Thursday morning, as plume destabilised ahead of cold front further west. UKMO indicates storms arriving by 6am across far S/SE England before spreading N/NE across E Midlands and E Anglia during the morning and early afternoon, before the cold front clears east introducing drier and fresher conditions from the west later in the afternoon. 40-50 knts of DL shear will be sufficient for multicell clusters or line segments given time of day and elevated nature of storms, capable of producing hail, torrential rain leading to flash flooding, marginally strong gusty winds and frequent cloud-to-ground lightning. A marginal risk is maintained here from the Day 1 outlook.

 

... EIRE, N IRELAND ...

 

GFS indicates 400-700 j/kg CAPE across the above areas in the afternoon, so scattered heavy shower and a few thunderstorms appear likely, though with less warmth and humidity and weak DL shear, no severe weather is anticipated.

 

Amazing update - thanks very much for this! First time I've ever been under a moderate risk 

 

Just noticed the first proper storm forming north of Lancaster. And so it begins... 

[Jonathan Lang]

Towers coming up here already! Getting hotter seemingly by the minute

[alexisj9]

What is wrong with the channel killing everything that's trying to cross it!

It's not the channel it's cin, I'm literally watching clouds disintegrate here.

[Wilxy]

I think storms will start to break out north of the M4 soon bit like in winter when it snows north of M4.

[BA Baracus]

Hot, sultry and hazy in Leeds this morning.  A few clouds out west but nothing building nearby.

[pip22]

Its 10AM and its 26C already. Its getting hotter and the clouds are getting bigger.

[Mapantz]

Talking of clouds, there's a lot developing in the South, my sunshine was wiped out ages ago. It looks to be going that way further East than I was expecting...

[Liam J]

Lightning strikes being picked up to the SE of Cumbria already, kicking off early! Hope it doesn't cloud over too soon and prevent the heat building further, it's already 26.3c!

Edited July 1, 2015 by *Sub*Zero*

[SalopWatcher]

Not far south of me, but another area of storm activity just cropped up near Knighton/Craven Arms... keep coming north please! 

[tornadomanuk]

Have to say I'm a little dissappointed with regards to this mornings developments. It all started so well down here with numerous storms firing over the channel and making landfall from South Devon across to Lyme Bay. But unfortunately they lost all energy and has ended with some amazing cloudscapes and thats it I heard a couple of far off deep rumbles of thunder, but nothing materialised. Shame, but nevermind.

[StormChaseUK]

Not far south of me, but another area of storm activity just cropped up near Knighton/Craven Arms... keep coming north please! 

Here in Knighton at moment, had massive overhead crack of thunder.

[NO LONGER POSTING]

32 here now.. Astonishing 

[alexisj9]

32 here now.. Astonishing 

At 10:00 and they think the high will be 35, I'm thinking the record is going to be smashed, thank goodness I've moved to the coast.

[pip22]

32 here now.. Astonishing 

I think it could break the 2003 record. I might be wrong though.

Edited July 1, 2015 by pip22

[Chris K]

Have to say I'm a little dissappointed with regards to this mornings developments. It all started so well down here with numerous storms firing over the channel and making landfall from South Devon across to Lyme Bay. But unfortunately they lost all energy and has ended with some amazing cloudscapes and thats it I heard a couple of far off deep rumbles of thunder, but nothing materialised. Shame, but nevermind.

 

To be honest that was pretty much expected with storms weakening but then initiating further North again. Can't rule out isolated storms in the South though from the high heat. Looks like it may reach higher than forecast...

 

Looking forward to seeing some pictures later from those further North because i think that is the only chance I will see lightning today.

 

For my area, I am pinning my hopes on Friday evening....

[davechesh]

train of large cu rapidly growing east of A1 probs around doncaster

[Staffordshire]

32c already Jesus!

Regarding my positioning today... Pretty poor unfortunately but I think I'm gonna head north of I see some opportunity a bit later, however with that cell already in the NW it looks like it could be further N than forecast maybe?

[ChezWeather]

Possible cells developing over Lincolnshire 

 

And for anyone temperature watching, this is an interesting site http://www.wunderground.com/wundermap

[Summer of 95]

Here in Knighton at moment, had massive overhead crack of thunder.

That's more promising, come to me......

Disappointingly cloudy this morning so far, will need a storm to avoid today being a total bust...

[Dean E]

At 10:00 and they think the high will be 35, I'm thinking the record is going to be smashed, thank goodness I've moved to the coast.

Got to remember, medium level cloud left over from the storms my slow the rising temperatures!