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Storms and Convective Discussion - 20th April 2019 onwards


Supacell

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Posted
  • Location: Dorset
  • Weather Preferences: warehamwx.co.uk
  • Location: Dorset
8 minutes ago, MetWeather said:

Really annoyed that 12z isn't showing such a large severe outbreak across south-east on Thursday. I really feel like this event is just becoming more normal as the days go on. 

Thursday is months away in an evolving situation like this.

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Posted
  • Location: NW London
  • Weather Preferences: Convective Weather and Snow
  • Location: NW London
Just now, Mapantz said:

Thursday is months away in an evolving situation like this.

Yeah I know. I have been way to jumpy with this potential and therefore have had to many emotional mood swings. I need to stay calm and look at the facts.

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Posted
  • Location: Hoyland,barnsley,south yorkshire(134m asl)
  • Weather Preferences: severe storms,snow wind and ice
  • Location: Hoyland,barnsley,south yorkshire(134m asl)

A long way ooooooofffff!!!.....but....

this for next Saturday,off the scale,5000+j/kg!!!!

168-505UK.thumb.gif.00282cc06c4b56ffa5ff2c8b7ddfe619.gif174-505UK.thumb.gif.7aeeb6cf4e1cb28f09799470a2026469.gif

as for peeps moaning that nowt will happen through the week,you cannot judge that right now,we have a plume happening this week and things will go bang at some point,i hope it isn't my head against the wall lol.

 

Edited by Allseasons-si
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Posted
  • Location: Bexley (home), C London (work)
  • Weather Preferences: Thunderstorms
  • Location: Bexley (home), C London (work)

I’m going to be trying to get Friday off (at a friend’s but still in Kent) so these charts look positively awesome really. Key point here is there could be subtle tweaks and changes to the overall synoptic picture which make this irrelevant. Worth pointing out that while the models are now veering to keeping the plume just across the Channel, subtle changes back the other way see it surge back over the UK. 

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Posted
  • Location: NW London
  • Weather Preferences: Convective Weather and Snow
  • Location: NW London
2 minutes ago, Allseasons-si said:

A long way ooooooofffff!!!.....but....

this for next Saturday,off the scale,5000+j/kg!!!!

168-505UK.thumb.gif.00282cc06c4b56ffa5ff2c8b7ddfe619.gif168-505UK.thumb.gif.00282cc06c4b56ffa5ff2c8b7ddfe619.gif

as for peeps moaning that nowt will happen through the week,you cannot judge that right now,we have a plume happening this week and things will go bang at some point,i hope it isn't my head against the wall lol.

174-505UK.gif

Yeah but little shear, though over the top cape can mean storms can become severe. Though remember how far out that is. That's a lesson I had to learn many times.

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Posted
  • Location: NW London
  • Weather Preferences: Convective Weather and Snow
  • Location: NW London
Just now, Flash bang flash bang etc said:

Yeah I have been reading those every day, they are very good.

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Posted
  • Location: Hoyland,barnsley,south yorkshire(134m asl)
  • Weather Preferences: severe storms,snow wind and ice
  • Location: Hoyland,barnsley,south yorkshire(134m asl)
7 minutes ago, Mapantz said:

Thursday is months away in an evolving situation like this.

Yes exactly,peeps need to heed to this,that changes happen every day,swings on....

giphy.thumb.gif.0cdb6f4ba3e142e35e75917739ef6350.gif

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Posted
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield
  • Weather Preferences: Any Extreme
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield

Looks like a nail  in the coffin for tomorrow storm wise and also Tuesday if the GFS is correct and it does tend to overdo the cape. End of the week bonzo cape Thursday but no precipitation for the mainland and the same for Friday. Too far away anyway as there's been a huge drift he modelling.

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Posted
  • Location: Pemberton, Wigan, 54 M ASL. 53.53,-2.67
  • Weather Preferences: Winter - snow, Irish sea convection. Summer - thunderstorms, hot sunny days
  • Location: Pemberton, Wigan, 54 M ASL. 53.53,-2.67

 Just noticed GFS has underestimated current temperature by 7°C. That’s reliable then. 

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11 minutes ago, The PIT said:

Looks like a nail  in the coffin for tomorrow storm wise and also Tuesday if the GFS is correct and it does tend to overdo the cape. End of the week bonzo cape Thursday but no precipitation for the mainland and the same for Friday. Too far away anyway as there's been a huge drift he modelling.

Worth noting that Tony Gilbert over on UKWW is, in his words, 'taking a step back' as the models are far from resolving the thundery activity from Sunday with current outlooks by agencies not in line. 

It'll be interesting to see how things update over the next 24 hours.

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Posted
  • Location: Taunton, Somerset.
  • Weather Preferences: Thunderstorms, high teens to low 20's,sunny and convective
  • Location: Taunton, Somerset.
4 minutes ago, Onding said:

Worth noting that Tony Gilbert over on UKWW is, in his words, 'taking a step back' as the models are far from resolving the thundery activity from Sunday with current outlooks by agencies not in line. 

It'll be interesting to see how things update over the next 24 hours.

yes i also read that.just a waiting game now.

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Posted
  • Location: Godalming
  • Weather Preferences: Plumes and streamers
  • Location: Godalming

People need to remember that tomorrow daytime/afternoon was always a marginal thing - nobody ever suggested any significant chance for widespread storms during daylight hours.

That’s not to say it can’t happen - as potentially the right ingredients are there, but the likelihood is more for small thundery showers.

The second opportunity for tomorrow is in the evening hours and overnight. While this is still not completely guarenteed to be a ball-lightning fest, there is a reasonable expectation that elevated storms will break out in the unstable air. This instability is elevated, and will rely on MUCAPE (not SBCAPE), which means you don’t need to give up hope if models have seemingly overplayed or downgraded their CAPE figures.

MUCAPE takes measurements from layers of the atmosphere above any inversions that may be present - which tomorrow looks highly likely. The recorded values differ from those where energy is derived from measurements taken from ground level (or 100mb).

MUCAPE values are often considered to return reliable guidance on the energy available for nocturnal storms - so tomorrow this seems pertinent.

It’s all still dependant on other factors too, with the biggest storm risk moving NEly through the midlands. These storms potentially becoming quite electrically active as they engage air from the plume.

Don’t hang your hat just yet on either peg - we’ve got 24 hours to go and anything could happen.

(At least there’s a good chance I’ll get to watch the England game tomo without getting FOMS )

Discaimer: I’m still learning so please correct me if I’m getting anything wrong here

Edited by Flash bang flash bang etc
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Posted
  • Location: Siston, Bristol 70m ASL
  • Location: Siston, Bristol 70m ASL

As long as we have potential that is good enough for me iv'e seen enough plume events to see it doesn't always go to plan but the uncertainty makes it the more exciting!

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Posted
  • Location: Pemberton, Wigan, 54 M ASL. 53.53,-2.67
  • Weather Preferences: Winter - snow, Irish sea convection. Summer - thunderstorms, hot sunny days
  • Location: Pemberton, Wigan, 54 M ASL. 53.53,-2.67

Is MUCAPE equal to MLCAPE when there is no SBCAPE? That’s what I always thought.

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Posted
  • Location: spalding, sth lincs
  • Location: spalding, sth lincs

evening all, going by the latest bbc forecast we seem to be to far east here with regard storm activity this comming week, but as others have said the potential is still there, fingers crossed.

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Posted
  • Location: Pemberton, Wigan, 54 M ASL. 53.53,-2.67
  • Weather Preferences: Winter - snow, Irish sea convection. Summer - thunderstorms, hot sunny days
  • Location: Pemberton, Wigan, 54 M ASL. 53.53,-2.67

Just found an interesting discussion on the differences between MUCAPE and MLCAPE. This suggests to me we should be looking at the MUCAPE rather than the MLCAPE for elevated convection. 

https://www.americanwx.com/bb/topic/44136-difference-between-mlcape-and-mucape/

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Posted
  • Location: Godalming
  • Weather Preferences: Plumes and streamers
  • Location: Godalming
17 minutes ago, Chris.R said:

Is MUCAPE equal to MLCAPE when there is no SBCAPE? That’s what I always thought.

I’m really not sure, there’s a chance I’ve got the two mixed up but I think MUCAPE takes calculations from a certain point and returns only the maximum value found.

Cant remember why

 

Edited by Flash bang flash bang etc
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Posted
  • Location: Godalming
  • Weather Preferences: Plumes and streamers
  • Location: Godalming
6 minutes ago, Chris.R said:

Just found an interesting discussion on the differences between MUCAPE and MLCAPE. This suggests to me we should be looking at the MUCAPE rather than the MLCAPE for elevated convection. 

https://www.americanwx.com/bb/topic/44136-difference-between-mlcape-and-mucape/

Ha! I read this earlier today in fact. Yes it seems to suggest MLCAPE values can be affected by unreliable readings at surface as you read values right through. Also I think inversions affect the reliability of the result

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Posted
  • Location: Pemberton, Wigan, 54 M ASL. 53.53,-2.67
  • Weather Preferences: Winter - snow, Irish sea convection. Summer - thunderstorms, hot sunny days
  • Location: Pemberton, Wigan, 54 M ASL. 53.53,-2.67
5 minutes ago, Flash bang flash bang etc said:

Ha! I read this earlier today in fact. Yes it seems to suggest MLCAPE values can be affected by unreliable readings at surface as you read values right through. Also I think inversions affect the reliability of the result

Here’s the key sentence.

Keep in mind that MUCAPE will lift parcels from anywhere in the sounding to find the one that is the most unstable, while MLCAPE is essentially surface-based CAPE, except that the "surface-based" parcel has the average conditions in the lowest ~100mb as opposed to the true "surface" values. 

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Posted
  • Location: Blackwood SE Wales
  • Location: Blackwood SE Wales

This Sunday-Tuesday set up reminds me of an Ex Hurricane from the USA.. I think in August, a few years ago. There is a little village (boscastle?) That got absolutely flooded by the amount of moisture that was picked up in the atlantic and dumped over the hills. - Yes it's less windy, but I believe the moisture battling the heat give some concern for a nasty situation. 

I would have considered a wide metoffice warning for torrential thundery downpours if anything. I think the term thunderstorm is patchy at best given the set up until later into the forecast. 

(ahh a few years ago I said, 2004 .. nearly half my life time ago )

 

Edited by ancientsolar
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Posted
  • Location: Pemberton, Wigan, 54 M ASL. 53.53,-2.67
  • Weather Preferences: Winter - snow, Irish sea convection. Summer - thunderstorms, hot sunny days
  • Location: Pemberton, Wigan, 54 M ASL. 53.53,-2.67
5 minutes ago, ancientsolar said:

This Sunday-Tuesday set up reminds me of an Ex Hurricane from the USA.. I think in August, a few years ago. There is a little village (boscastle?) That got absolutely flooded by the amount of moisture that was picked up in the atlantic and dumped over the hills. - Yes it's less windy, but I believe the moisture battling the heat give some concern for a nasty situation. 

I would have considered a wide metoffice warning for torrential thundery downpours if anything. I think the term thunderstorm is patchy at best given the set up until later into the forecast. 

 

 Yes it was 2004. Think it was dynamic rather than convective though; peninsula convergence zone; can’t really remember. 

Here we go

https://www.metoffice.gov.uk/weather/learn-about/weather/case-studies/boscastle

Edited by Chris.R
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Posted
  • Location: Dorset
  • Weather Preferences: warehamwx.co.uk
  • Location: Dorset

Latest UKV is rather disappointing for Monday night in to Tuesday. Quite a shift Eastward - Kent clipper style.

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Posted
  • Location: Godalming
  • Weather Preferences: Plumes and streamers
  • Location: Godalming

Wow a lot of negativity about the week ahead

We should wait until Monday morning to see what/where/if/how things have shaped up. From this stage a lot could or couldn’t happen

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