Storm & Convective Discussion 12z 21/7/14 ------>

[Harry]

Okay, I've started the thundersnow thread for anyone who wants to share their experiences of it:

 

http://forum.netweather.tv/topic/81155-thundersnow-events-in-the-uk/#entry3024562

 

Anyway back on to convection discussion. According to the GFS, it looks like this weekend is going to be quite quiet for thundery activity, with relatively stable air positioned over the UK. However, parts of Eastern and Southern Scotland may see some thundery showers on Sunday afternoon.

 

Thundersnow discussion....in August????

 

That's depressing

[Carl46Wrexham]

Thundersnow discussion....in August???? That's depressing

Not as depressing as this so called summer month is turning out to be...utter garbage sadly.

[Mapantz]

Not as depressing as this so called summer month is turning out to be...utter garbage sadly.

Nothing depressing about it here.Quite a rash of showers on the radar, they're further west than what the Euro 4 was showing yesterday, and more widespread than todays latest run.Good day for a time lapse.

[Harry]

Just saw a rather unexpected CG to my NW, nice rumble of thunder too in an enclosed glazed box.

 

How unexpected!

[Flash bang flash bang etc]

A big beautiful cumulus over london as I head out south on the train. Friece looking sky beneath.

The sky is so clear - looks great!

[Greeny]

A big beautiful cumulus over london as I head out south on the train. Friece looking sky beneath.The sky is so clear - looks great!

@torrouk tweeted that a small funnel was spotted over Westminster and to let them know if anyone saw it.Edit: at about 5ish Edited August 18, 2014 by Greenday

[Generalelectrix]

Hi@ all

Interesting convection today in the London area, am there right now and took a little time to observe a promising cell developing NE of Farnham. followed it a bit toward Elstead, it fizzled shortly afterwards. Too high based and flat topped, no deep convection there. Also a (local?) dry intrusion had taken a substantial bite out of the Cb halfway up. Small dry intrusions can aid convection by causing evaporative cooling on the outer side of the cloud but today was just too much....

 

Hope something happens while im in the UK

 

Cheers

 

Ralph

[Weather-history]

[Mokidugway]

@torrouk tweeted that a small funnel was spotted over Westminster and to let them know if anyone saw it. Probably caused by all that hot air rising from parliament !!....Edit: at about 5ish

[NL]

 

@torrouk tweeted that a small funnel was spotted over Westminster and to let them know if anyone saw it. Probably caused by all that hot air rising from parliament !!....Edit: at about 5ish

 

Ah.. so they're to blame for AGW...!!  Couple of strikes just to the south of my location within the last 10-15mins.

©Netweather 5min radar

[Greeny]

This is a picture that emerged from the brief funnel spotted over Westminster.

[DH764]

That was a surprise......its been quite cool all day but just had a nice little Storm over Middlesbrough .

A few bright flashes and some good rumbles...great end to the day ! 

[Cloud 10]

That was a surprise......its been quite cool all day but just had a nice little Storm over Middlesbrough .

A few bright flashes and some good rumbles...great end to the day ! 

 

 

Yes,very fortunate with that one.

 

[Flash bang flash bang etc]

@torrouk tweeted that a small funnel was spotted over Westminster and to let them know if anyone saw it.Edit: at about 5ish

I was staring right at the Westminster cell at about 5pm! but lots of things in the way from the train - ie. other trains.Was probably too far away to have seen it anyway but the cloud base looked like it was possibly funnel-worthy.

[Convective]

Real lively downpours here. Some light flash flooding looks a possibility. Roads were like rivers 10 minutes ago.

[Weather-history]

Pretty showery post midnight

[Weather-history]

Showers and rainbows this morning

[Neilsouth]

Not as depressing as this so called summer month is turning out to be...utter garbage sadly.

 

June was ok, July was a very humid month with great storms in some places... We don't always get an entire summer of heat ;p

[Weather-history]

[Greeny]

Could this be a plume trying to reach us at the end of the month? Can't get any further without it stepping in 12 hour intervals at the moment.

[Greeny]

Could this be a plume trying to reach us at the end of the month? Can't get any further without it stepping in 12 hour intervals at the moment.

GFS is forecasting a rise in temperature and dewpoint temperature from Tuesday next week. Before that the temperature rises in France. Hopefully it will do away with this early autumnal feel :-)

[mhielte]

GFS is forecasting a rise in temperature and dewpoint temperature from Tuesday next week. Before that the temperature rises in France. Hopefully it will do away with this early autumnal feel :-)

Before that though we have this...

 

No doubt coinciding with the rain sweeping across the country during the day. It'll feel pretty rotten out there!

 

What interests me is the potential for a few thundery showers developing after the main rain band clears north east. The energy is there and is more widespread than yesterdays 12z.

 

 

Of course it's a little far out and CAPE/LI charts aren't the only source of information for predicting this kind of thing, however we might as well seen as precip models this far out are largely academic. Looking at the above charts you could imagine the M4 corridor could do well, and parts of the southwest too, running into Wales and the West Midlands.

 

I think we're looking at pulse type storms should conditions stay favourable. After a warmer Tuesday temperatures take a nosedive again for the remainder of the week, limiting convective potential.

[Greeny]

Could this be a plume trying to reach us at the end of the month? Can't get any further without it stepping in 12 hour intervals at the moment.

 

 

Just 24 hours later it's gone from the quoted pictures to..

 

 

I haven't seen anything like that disappear so quickly before lol

 

Before that though we have this...

 

No doubt coinciding with the rain sweeping across the country during the day. It'll feel pretty rotten out there!

 

What interests me is the potential for a few thundery showers developing after the main rain band clears north east. The energy is there and is more widespread than yesterdays 12z.

 

 

Of course it's a little far out and CAPE/LI charts aren't the only source of information for predicting this kind of thing, however we might as well seen as precip models this far out are largely academic. Looking at the above charts you could imagine the M4 corridor could do well, and parts of the southwest too, running into Wales and the West Midlands.

 

I think we're looking at pulse type storms should conditions stay favourable. After a warmer Tuesday temperatures take a nosedive again for the remainder of the week, limiting convective potential.

 

I'm quite amazed to see a distinct change from GFS 24 hours later, it showed warmer temps from Tuesday for most of the week and now it doesn't, like you said just Tuesday, although dewpoint temps seem to stay up for longer so perhaps a bit more of a muggy feel to next week.

[Thermohaline Conveyor]

The disappearance of CAPE is down to the development of the low and the models trying to get to grips with where the low will track, what phasing the low will be in and how it will evolve ie. whether it will be a flabby low with a centre tracking through much of England and a slack pressure gradient running through W France or whether it will be a more intense feature with a stronger pressure gradient or another option is the development of a secondary low within the complex parent low which is what the GFS06Z  dataset was teasing us with.  It is simply too far out for any real resolution of this low feature at present but we may begin to see more consistency in the next few runs.  ECM-mean takes the centre of the low through Northern England a little further North than latest ECM and GFS operational guidance so plenty will chop and change.  Nevertheless no matter where the low tracks the environmental conditions will be favourable for some thundery activity some-where across England and Wales due to the simple fact that air will cool aloft and warm air will be passing through at the surface.  Ideally for more "severe convective" chances we would like to see the more Northerly track taking the centre across Scotland or N England with a stronger pressure gradient to the South of the low centre across England and Wales (stronger) jet streak and an increase in windshear.  Fingers crossed we get lucky.

[TonyH]

Some thundery showers breaking out this afternoon, particular over EA, potential for the East Midlands I should think too looking at that Notts cell,