Convective Storm/Discussion thread - 11/06/16 onwards

[Harry]

10 minutes ago, Polar Maritime said:

Cape predictions for Thursday from the in-house Net/Wx hi res suite.

And GFS in isolation.

PM - that GFS in isolation is for next week, doh!  

[Polar Maritime]

18 minutes ago, Harry said:

PM - that GFS in isolation is for next week, doh!  

Yes H more coffee needed! Here we go.. GFS for 'Thursday' 

Edited June 21, 2016 by Polar Maritime

[Stormyking]

Im in one of those situations at the moment whether I stay on the Isle of Wight due to the fact this risk is extremely close and could so easily  be a sweet spot, or do me and my friend book a ferry and drive a bit further East, its so frustrating!

[weather09]

Met on board this morning with early warnings.  Things look like they've nudge a little east on this morning's outputs, but regardless of relatively narrow region at risk, conditions look favourable for low-end severe convective weather for far E/SE slice of the country during period of interest.  Shame a more wider area wasn't at risk.  

 

 

[Windblade]

Spotted some cirrus clouds as I came out the house this morning. - always a good sign. Took some pictures over the heath this morning which I've posted below, some interesting cloudscapes, looks like ac to me...

Edited June 21, 2016 by Windblade

[Windblade]

As for later this week, I'm hoping we get some decent mcs imports (seeing as this country seems incapable of brewing them anymore for whatever reason)!

[East_England_Stormchaser91]

Can see this one going down to the wire. Even as the event unfolds, there are different outcomes as to what is modelled even at 3-6 hours out. Thermal advection is a tricky one to get right. Remember estofex slapping a level 2 on northern France on the 3rd July last year and they got absolutely nothing whilst things exploded over the south coast and South Downs! 

[weather09]

Is a fine line between severe risk and no risk at all.  Models have initial NE'wrd advection of fairly high low-level moisture during Weds, but it's really post 00z Thursday that moisture increases further. Euro4 has sfc dewpoints to 17C already on Weds, so be interesting if it follows the GFS for 18-20C dewpoints for Thurs afternoon.  Certainly can see potential for some severe storms. Whether frontal boundary shifts further east though...

[A.J]

18-20C dewpoints!...not all that often we see those kind of figures in the UK.....i'm probably too far west on this occasion (slap bang between Bristol & Reading) but hope springs eternal! 

[East_England_Stormchaser91]

I'm on nights this week. But rest assured, I'll be chasing if these trends continue. Essex and Suffolk look like good bets at the moment. 

[Windblade]

Lets hope we get something here. As others have said its really on the line whether we'll see anything at the moment. Going to be watching the forecasts like crazy!

[Greeny]

For me I have a tinge of excitement just looking at the potential and actually seeing some strong DLS (Deep Layer Shear) forecast especially for Thursday currently. Low level convection visible here at the moment and nice and warm and a touch humid when the sun is out. Such a nice time of year

[weather09]

1 hour ago, ajpoolshark said:

18-20C dewpoints!...not all that often we see those kind of figures in the UK.....i'm probably too far west on this occasion (slap bang between Bristol & Reading) but hope springs eternal! 

06z Euro4 modeling 18-19C DPs for early Thursday across far E/SE. Strong June sunshine heating such a moist air mass will likely generate low-end moderate instability. Wise to be cautious of the risk in terms of likelihood given uncertainty in positioning of frontal boundary... things could still shift onto the mainland.  However, I don't there's much open to question regarding potential storm severity if all comes together.  

[Greeny]

7 minutes ago, weather09 said:

06z Euro4 modeling 18-19C DPs for early Thursday across far E/SE. Strong June sunshine heating such a moist air mass will likely generate low-end moderate instability. Wise to be cautious of the risk in terms of likelihood given uncertainty in positioning of frontal boundary... things could still shift onto the mainland.  However, I don't there's much open to question regarding potential storm severity if all comes together.  

Had 23C dewpoint temps everyday in Acapulco Mexico in August. I know what thats like I like it though just know theres potential for better storms when they are around and I saw a few when I was in Mexico too. All round great holiday for lovely hot and sunny weather with storms a lot of nights and the odd day! Fingers crossed for some to remain on UK soil. Wednesday is more certain, hoping Thursday will also deliver for some too.

Edited June 21, 2016 by Greeny

[Nick F]

Does look a bit SE UK-centric the storm risk over the next few days - some models (ECMWF/UKMO) confine the risk to Kent, Sussex, east Essex ... others further NW.

Actually tomorrow late afternoon, GFS builds some CAPE across SE/E Anglia tomorrow afternoon/evening as the warm sector that moved in is subjected to surface heating and also drier mid-level air moving aloft enhancing instability. So could see some home-grown thundery downpours develop.

 

GFS precip Weds 18z

UKMO precip weds 18z

We then see models develop a potential cluster of storms / possible MCS over Nern France and English Channel Wednesday night, as forcing for ascent of warm moist plume increases from the SW. Models differ to the NW extent of these storms as they track NE.

As I mentioned - ECM and UKMO furthest east:

ECM

UKMO

... HIRLAM looks best scenario

Once any overnight MCS clears the SE on Thursday morning, GFS hinting at the potential for surface-based storm development Thurs afternoon across SE England and E Anglia. GFS indicates PWAT values approaching 1.5 inches this moisture and surface heating yielding 500-1000 j/kg CAPE, mix in strong SWly jet and veering winds aloft - GFS indicates 50 knts of deep layer shear ... so potential for supercells capable of producing large hail and damaging wind gusts. Lightning wizard highlights a significant tornado parmeter too Thurs afternoon

 

Edited June 21, 2016 by Nick F

[DubWeatherAddict]

Looks juicy indeed for SE parts of the UK tomorrow. Very much dependent on how much surface heating can take place tho.

 

 

[Greeny]

Was looking at the significant tornado parameters a little while ago as well as supercell composite. Looking very interesting. Glad you added your forecast Nick cause wasn't so confident in adding that to the mix. NW skew-T isn't giving that much SRH but nearly 1000j/kg forecasting for Chelmsford (for Thursday that is).

Edited June 21, 2016 by Greeny

[Greeny]

Also showing significant tornado parameters for tomorrow..

Edited June 21, 2016 by Greeny

[Windblade]

Thanks for the forecast Nick, much appreciated as always. Its looking potentially good for my area over the next 48 hours but as always lets tread with caution on this one as I don't want to build myself up only to be let down with disappointment.

[Harry]

26 minutes ago, DubWeatherAddict said:

Looks juicy indeed for SE parts of the UK tomorrow. Very much dependent on how much surface heating can take place tho.

 

 

If it fills you with some degree of confidence, the above chart will almost certainly not be reliant on surface heating (certainly not here anyway). Where it occurs however is still very uncertain with some models suggesting it could miss all bar the extreme SE of the UK, others suggesting more of the SE quarter could be in with a chance.

Edited June 21, 2016 by Harry

[Methuselah]

We could be in for a few humdingers, if that comes off. Welcome to Royal Tunbridge Wells On-Sea!

[Polar Maritime]

Some lovely cloudscapes today here with long sunny spells.

[Windblade]

49 minutes ago, Greeny said:

Also showing significant tornado parameters for tomorrow..

I'd love to see a confirmed funnel cloud/tornado. I've seen two instances of what I think were very small beginnings of funnel clouds (very thin rope like clouds coming down from scud) but it was very hard to see on both occasions as they were quite far away from my position and only lasted less than ten seconds each so could have been just weird looking scud. One was years ago, the other was less than two weeks ago (and the storm did appear to be slowly rotating although it was dusk and hard to see how much). Both times to the north west of my house.

Edited June 21, 2016 by Windblade

[Azazel]

Kent clipper on the cards then. Definitely too far west here

[SteveB]

I might be reading it wrong, but there looks like an isolated risk for the West country & S/se Wales on those lightning wizard charts + the HIRAM chart Nick posted!