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Julian 777

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Posts posted by Julian 777

    Convective/Storm Discussion Thread - 1st August onwards

    in Storms & Severe Weather

    Posted

    2 hours ago, wimblettben said:

    Was up till 3:00AM last night looking at heat lightning in the distance to the south.

    Judging by peoples posts on here from last night, I can't believe I was seeing lightning from storms at the coast as some of it was quite bright.

    Very odd!:cc_confused:

    I too was up till 4am in my case. Strange as through the afternoon quite a few Cb,s were moving over the South Coast from North to South but by night fall they seemed to stall at the French coast and head back to mid channel like a waving front..Wish I was on southern tip of IOW last night.:)

    • Like 2

    Convective/Storm Discussion Thread - 8th July onwards

    in Storms & Severe Weather

    Posted

    3 minutes ago, John Hodgson said:

    I'm going to heading back up to Yorkshire this week but i've pushed it back a day to Wednesday to give me the best chance of seeing storms.  Best case scenario would be decent overnight storms on Tuesday night down here and then by the time i get to Yorkshire on Wednesday, afternoon storms up there. 

    good luck ,hope it works out for you in both locations..At the moment at least its looking good.

    • Like 1

    Convective/Storm Discussion Thread - 8th July onwards

    in Storms & Severe Weather

    Posted

    1 minute ago, Nick F said:

    What makes you think that? Don't think there's any particular focus, will have to wait and see, GFS CAPE charts would suggest more energy aloft east of I.O.W., but as ever with storms in the UK, other than N France probably getting a lot of activity, as the norm, it's up in the air for now where the focus will be Tuesday night :)

    Just saw a BBC forecast that made me wonder if that was the case , but yes its a case of lightning radar on and enjoy watching things develop..lol

    Convective/Storm Discussion Thread - 8th July onwards

    in Storms & Severe Weather

    Posted

    11 minutes ago, Nick F said:

    Agree Brick, storms will be rooted above the boundary layer tomorrow night, can clearly see the warm nose at 900mb on the forecast skew-ts across S England. GFS painting some strong MLCAPE shifting north out of France Tuesday, probably due to the warm moist conveyor/theta-e plume spreading north overrun by an EML originating from SW Europe - creating steep mid-level lapse rates.

    So Tuesday we see the theta-e plume spread N out of France ahead of increasingly negatively tilted upper trough moving in from the west coming up against high pressure retreating east.

    gfsgif_thetae.thumb.gif.578ab39c56c4ecae4c16ab00e89a7cd0.gif

    MLCAPE increasing out of France Tuesday night, as lapse rates steepen with EML spreading N/NE over plume in low-to-mid levels

    gfsgif_cape.thumb.gif.68172c330d771fb8e05258649f970d74.gif

    Deep-layer shear increasing too, as mid-upper winds strengthen and veer S to SWly with height with approach of upper trough while backed SEly at the surface - so this will organise elevated convection into some storm clusters that may merge into one or two MCS with a threat of hail, torrential rain and frequent cloud-to-ground lightning.

    gfsgif_DLS.thumb.gif.48f8ea258ad0ef2e59d13cbaeba90265.gif

    Large scale ascent indicated by vertical velocity charts:, charts for winds aloft do show a shortwave moving NE, which is likely causing the ascent

    gfsgif_42-54.thumb.gif.9935d62fa8ba04b8d80b418a9e7624fa.gif

    Believe it or not, elevated strong storms, which are fuelled by large amounts of CAPE aloft, can be prolific lightning producers, particularly away from heavy rain cores - this is because electrical charges tend to dissipate through rainfall without a lightning strike (water being a good conductor) - whereas drier air the electrical charge building between the elevated base and ground has to overcome it with a lightning strike.

    Wouldn't take the precip charts too literally, but we may see elvated showers/storms develop initially over SW England tomorrow evening, before developing further east along N France/ E Channel and moving N across central-S and SE England Tuesday night, before spreading across Wales, Midlands, E Anglia during Wednesday morning, before reaching N England early afternoon and S Scotland later afternoon.

    Meanwhile, further south, heat and humidity could spark some home-grown storms, mainly north of M4/London (due to SWly flow into southern most counties having a drier more stable element). Deep layer shear does look fairly weak and there looks like a lack of any particularly focus or forcing other than increasing larger-scale ascent from approach of upper trough from the west. Nevertheless, though, strong heating and fairly strong SWLy flow aloft and decent CAPE may compensate .. to allow some linear clusters of locally strong storms with hail and torrential rain leading to flash-flooding the main threats.

    cape_w18z.thumb.png.c35f7396283784fc12619e9ca1fa2724.png

     

    Fingers-crossed we see some good lightning shows Tuesday night, these storms drifiting N on Weds morning and then some good home-grown surface based storms on Wednesday afternoon.

     

    wind_w15z.png

    Has the main focus of lightning tues night shifted slightly more favouring areas west of I.O.W.?   btw have downloaded your thunderstorm guide from a few years ago..Was VERY informative and interesting  Thanks for that..

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