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Convective / Storm Risk Discussion - 21st June 2013 onwards


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Posted
  • Location: Eastbourne, East Sussex (work in Mid Sussex)
  • Location: Eastbourne, East Sussex (work in Mid Sussex)

    Please use this thread to discuss your general thoughts and post your data on the potential for upcoming convective events.

     

    Specific threads for days of high chance and activity will be opened as the information becomes more probable, like this for tomorrow:

     

    http://forum.netweather.tv/topic/77020-thunderstorm-potential-and-activity-for-wednesday-19th-june-2013/

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    Posted
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)

    Netweather Storm Forecast for Today: http://www.netweather.tv/index.cgi?action=convective;sess=

     

    NMM High-Res model showing CAPE building across SE England and E Anglia this afternoon and evening, probably in response to humid air and some sunshine breaking through, so potential for some home-grown storms developing here and also some storms imported from the near continent arriving overnight.

     

    Also some scattered showers and isolated storms possible further north and west across England and Wales.

     

     

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    Posted
  • Location: Eastbourne, East Sussex (work in Mid Sussex)
  • Location: Eastbourne, East Sussex (work in Mid Sussex)

    Here's what ESTOFEX have for the cross-over period through today up until tomorrow morning:

     

    Posted Image

     
    SYNOPSIS
     
    A plume of very steep lapse rates has been advected over western part of Europe between two major synoptic-scale features: a deep trough centered over Iberia and a large ridge over the Central Mediterranean and Central Europe. This is confirmed by most of the sounding measurements from the area. A wavy frontal boundary stretches around the warm sector with 850 hPa temperatures exceeding 20°C. Such pattern will remain mostly quasi-stationary during the forecast period without any major changes in the position of the main frontal zones. Surrounding the ridge a belt of strong flow is observed with windspeeds between 20 - 40 m/s at 500 hPa.
     
    Steep mid-level lapse rates atop moist boundary layer are expected to contribute to the development of moderate to high CAPE values over a large area. However, strong capping and lack of strong "forcing" will likely prevent explosive or widespread growth of deep moist convection apart from a few locations and this makes the forecast quite challenging

     

    ... BENELUX, Northeastern France, Central and Northern Germany ...
     
    A very isolated convection is possible along the warm front in the environment of very steep lapse rates and moderate to strong vertical wind shear. In such conditions, supercells are possible, capable of (very) large hail and severe wind gusts. Questionable, very uncertain initiation precludes higher level issuance attm.

     

     

     

    post-6667-0-48557400-1371539590_thumb.pn

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    Posted
  • Location: Eastbourne, East Sussex (work in Mid Sussex)
  • Location: Eastbourne, East Sussex (work in Mid Sussex)

    UKASF:

     

    Slight

     
    Forecaster: Dan
    Last Updated: 2013-06-18 00:32:00
    Valid: 2013-06-18 00:00:00 - 2013-06-18 23:59:00
     

    Posted Image

     

    Synopsis:
     
    Iberia trough becomes a cut-off low, with slight upper ridging over southern Britain. Moisture advection continues to nudge northwards through Tuesday, behind a surface warm front, although a tongue of drier/cooler air will advect across SW/CS England for a time, suppressing convection chances here by the afternoon.
    Discussion:
     
    As the front edge of a plume, characterised by high ThetaE/ThetaW, continues to advect northwards along the warm frontal boundary, further elevated convection is expected in almost any part of the SLGT area, with the potential for sporadic lightning and locally heavy rain. Activity will continue across the Midlands/Wales/East Anglia into southern portions of northern England by the afternoon, but with the lightning potential ever decreasing through the day as the frontal gradient weakens and instability reduces.
     
    Some models simulate surface-based convection development over Kent/Sussex/Essex late in the afternoon and into the evening in an environment of high CAPE (locally near 1000 J/kg), provided surface temperatures (resultant from insolation) reach the projected 23-25C. It is thought given the slack synoptic flow, local seabreeze convergence coupled with upslope flow may allow a thunderstorm or two to form, although exact locations will be difficult to ascertain at this stage. 30-40kts DLS would allow any isolated thunderstorms to remain fairly well-organised, with perhaps some reasonably-sized hail given instability present. Such convection is not a certainty, but a possibility that needs monitoring through Tuesday.
     
    Most models then simulate further elevated convection over the eastern English Channel and southern North Sea through the evening and overnight hours (beyond this forecast period), perhaps merging into an MCS-like feature by the end of the night and affecting Norfolk/Suffolk/Essex/Kent/East Sussex. More detail on this will be included in the forecast for Wednesday, assuming the potential remains by then. 

     

    post-6667-0-96944600-1371540048_thumb.jp

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    Posted
  • Location: Prague, Czech Republic and Staines, UK
  • Weather Preferences: Hot and sunny, thunderstorms, snow, fog, frost, squall lines
  • Location: Prague, Czech Republic and Staines, UK

    http://www.sat24.com/?ir=true&co=true&li=false

    Absolutely ridiculous amount of very heavy rain moving up from France.. The models don't want it to migrate any more North but I can't see it not moving into our shores..

    Yes, that's a serious amount of rain, it's even affecting eastern Spain! Unusual. Looks like its heading straight for the UK, it will probably move NW once it's over the Channel but I'm not expecting much in the way of thundery activity here. Too cool and cloudy :(
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    Posted
  • Location: Eastbourne, East Sussex (work in Mid Sussex)
  • Location: Eastbourne, East Sussex (work in Mid Sussex)

    Need I add any more to these pretty pictures????

     

    Posted Image

     

    Posted Image

     

    Posted Image

     

    Posted Image

    Posted Image

     

    A small corner of the SE with chances later, then we move on to tomorrow......

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    Posted
  • Location: Eastbourne, East Sussex (work in Mid Sussex)
  • Location: Eastbourne, East Sussex (work in Mid Sussex)

    NMM similar:

     

    post-6667-0-34461800-1371540708_thumb.pn post-6667-0-56446000-1371540709_thumb.pn

     

    post-6667-0-98622400-1371540710_thumb.pn post-6667-0-45497500-1371540712_thumb.pn

     

    post-6667-0-07220500-1371540715_thumb.pn  post-6667-0-72960100-1371540706_thumb.pn

     

     

     

     

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    Posted
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.
  • Weather Preferences: Snow and storms
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.

    NMM similar

    NMM suggests that a homegrown MCS forms over the south coast this evening and heads towards East Anglia by  early morning. Prior to that some home grown storms may also be set off further north during the afternoon. Tomorrow not looking as favourable now.

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    Posted
  • Location: Prague, Czech Republic and Staines, UK
  • Weather Preferences: Hot and sunny, thunderstorms, snow, fog, frost, squall lines
  • Location: Prague, Czech Republic and Staines, UK

    I'm not surprised by the big downgrades in thunderstorm risk, we need heat to kick things off. Sadly the sunny skies that would give this heat are well and truly absent.

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    Posted
  • Location: Bexley (home), C London (work)
  • Weather Preferences: Thunderstorms
  • Location: Bexley (home), C London (work)

    After lead like skies this morning, the Sun is starting to break through here in London. Hopefully will see some decent warming now.

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    Posted
  • Location: Eastbourne, East Sussex (work in Mid Sussex)
  • Location: Eastbourne, East Sussex (work in Mid Sussex)

    Currently:

     

    Posted Image

     

    Posted Image

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    Posted
  • Location: Bexley (home), C London (work)
  • Weather Preferences: Thunderstorms
  • Location: Bexley (home), C London (work)

    All in all its fairly tragic how non-eventful thinks are projected to be at this stage...first sense of pessimism I've had for a number of days in respect of this 'event'. 

     

    Still, must crack on so to speak.

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    Posted
  • Location: Nutley, East Sussex 120m ASL
  • Location: Nutley, East Sussex 120m ASL

    Here in the heart of East Sussex there are clear blue skies with some wispy clouds. The sun is heating things up very nicely

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    Posted
  • Location: Garvestone, Norfolk
  • Weather Preferences: Sunshine. And storms
  • Location: Garvestone, Norfolk

    NMM suggests that a homegrown MCS forms over the south coast this evening and heads towards East Anglia by  early morning. Prior to that some home grown storms may also be set off further north during the afternoon. Tomorrow not looking as favourable now.

    Hmm, these overnight MCS usually mean a lot of cloud hanging around during the day, inhibiting any further developments.....

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    Posted
  • Location: Bexley (home), C London (work)
  • Weather Preferences: Thunderstorms
  • Location: Bexley (home), C London (work)

    MCS please!!!!!! Bank!!!! 

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    Posted
  • Location: Home - Hutton, Essex / Work - Camden Town, London
  • Weather Preferences: Hot Sun, Deep Snow, Convective Goodness, Anvil Crawlers
  • Location: Home - Hutton, Essex / Work - Camden Town, London

    Grey & Hoomid here already, Cape looking promising tomorrow, although not as high as forecast yesterday, shame I'll be in Cardiff where I think the risk is a bit of a swizz :(

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    Posted
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)

    http://www.sat24.com/?ir=true&co=true&li=false

     

     

    Absolutely ridiculous amount of very heavy rain moving up from France.. The models don't want it to migrate any more North but I can't see it not moving into our shores..

     

    Yes, that's a serious amount of rain, it's even affecting eastern Spain! Unusual. Looks like its heading straight for the UK, it will probably move NW once it's over the Channel but I'm not expecting much in the way of thundery activity here. Too cool and cloudy Posted Image

     

    That be the cold front to our S over France, could bring an MCS later today.

     

    post-1052-0-44880000-1371544655_thumb.gi

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    Posted
  • Location: Bexley (home), C London (work)
  • Weather Preferences: Thunderstorms
  • Location: Bexley (home), C London (work)

    That be the cold front to our S over France, could bring an MCS later today.

     

    Posted Imagefx00_tu06z.gif

     

    Fully appreciating the complexity of such a setup, how do you view the chances of that happening Nick?

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    Posted
  • Location: Eastbourne, East Sussex (work in Mid Sussex)
  • Location: Eastbourne, East Sussex (work in Mid Sussex)

    Blimey that's a very busy system going on there:

     

    Posted Image

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    Posted
  • Location: SE,London (Catford)
  • Location: SE,London (Catford)

    so maybe an average chance today??  bbc says NO all day tomorrow, but wet n horrible and thundery for thursday Posted Image ,, so that may turn out to be a damp and drizzzly then knowing our shores!! The skys well tell..

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    Posted
  • Location: Bexley (home), C London (work)
  • Weather Preferences: Thunderstorms
  • Location: Bexley (home), C London (work)

    so maybe an average chance today??  bbc says NO all day tomorrow, but wet n horrible and thundery for thursday Posted Image ,, so that may turn out to be a damp and drizzzly then knowing our shores!! The skys well tell..

     

    No no no that's not good news at all...I'm off tomorrow afternoon and was hoping to grab some developments :cray:

     

    Coast, all looking very frontal from that radar grab - I note the MCS' mixed in there, but am curious to see whether anything explosive develops over the continent which may come our way....eyes on the radars and satellite images

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    Posted
  • Location: Rochester, Kent
  • Location: Rochester, Kent
    NMM suggests that a homegrown MCS forms over the south coast this evening and heads towards East Anglia by  early morning. Prior to that some home grown storms may also be set off further north during the afternoon. Tomorrow not looking as favourable now.

     

    NAE going for imports,

     

    post-5986-0-23972000-1371546245_thumb.gipost-5986-0-51484500-1371546250_thumb.gipost-5986-0-97901300-1371546256_thumb.gi

     

    And then the SE corner has this to look forward to, tomorrow evening,

     

    post-5986-0-93085200-1371546306_thumb.gi

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    Posted
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)

    Fully appreciating the complexity of such a setup, how do you view the chances of that happening Nick?

     

    Notoriously fickle these plume set-ups, looks like we could end up with some thundery rain arriving across the SE/central S England late morning and into the afternoon, gliding N/NW along the cold front - which could kill off any chance of home-grown development. Just have to hope the convective system coming north out of France peps up and gets more electrically active as the day progresses, as we are in the usual late morning minimum for lightning activity.

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    Posted
  • Location: Newton-le-Willows, Warrington, Merseyside
  • Location: Newton-le-Willows, Warrington, Merseyside

    It's warm and sultry here, sun's been out all morning so far too. Getting lovely and warm.

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