End of the week & weekend storm risk

[Paul]

Just an error

 

[Frosty hollows]

5 minutes ago, Greenday said:

 

Just to add if I may, the last few convective days have been within a weak sheared environment. This means that storms can fire and intensify rapidly however the updraft, usually at the rear of a storm sucking in moisture and heat is quickly cut off by the cold air downdraft at the front of the cell. Giving storms a pulse like effect. Intensifying and then decaying within a short timeframe. The fuel is basically cut off by the downdraft. However get some strong shear in the mix, the storm then tilts seperating the updraft from the downdraft, the updraft can continue to fuel the storms getting more and more intense. Get both strong speed shear and directional shear, storms can begin to rotate with the presence of a mesocyclone. These storms become supercells. Not only can they last for hours, they can in turn produce strong tornados, giant hail, strong RFD (rear flank downdraft) and strong winds.

Thant's great!Thanks guys for taking the time to explain a bit more to me without being patronising or overly technical. Can anyone recommend good sites where I can learn a bit more without being totally blinded by science?

 

[Ben Sainsbury]

With GFS 12z rolling out, definitely seeing some well-developed surface based storms across South/West Midlands, Wales and NW England over the coming days. Initially we should see a couple of weakly electrified elevated storms across the SW Coast later tomorrow spreading into West Wales. From experience elevated storms often die down as they move further inland. We love to see a home-grown MCS!

[William Grimsley]

1 minute ago, Ben Sainsbury said:

With GFS 12z rolling out, definitely seeing some well-developed surface based storms across South/West Midlands, Wales and NW England over the coming days. Initially we should see a couple of weakly electrified elevated storms across the SW Coast later tomorrow spreading into West Wales. From experience elevated storms often die down as they move further inland. We love to see a home-grown MCS!

Home-grown MCS! LOL! That's quite unlikely to happen to say how dry the air will be further north and east. I think you may be in the "no go zone", too far east for anything elevated and too far west for anything surface based, that's just my opinion.

Edited May 5, 2016 by William Grimsley

[Ben Sainsbury]

5 minutes ago, William Grimsley said:

Home-grown MCS! LOL! That's quite unlikely to happen to say how dry the air will be further north and east. I think you may be in the "no go zone", too far east for anything elevated and too far west for anything surface based, that's just my opinion.

Oh I am too ambitious! Hehe... The Bristol Shield that is!

[Convective]

7 minutes ago, William Grimsley said:

Home-grown MCS! LOL! That's quite unlikely to happen to say how dry the air will be further north and east. I think you may be in the "no go zone", too far east for anything elevated and too far west for anything surface based, that's just my opinion.

Dewpoints only a few degrees behind the air temperatures both at the surface and also the 850hPa mark as well as humidities around the 80% mark upwards seem rich enough for some decent storms!

Precipitable water charts showing some 30+mm over parts during Saturday too, so plenty to fall from the sky.

Edited May 5, 2016 by Convective

[Wilxy]

4 minutes ago, William Grimsley said:

Home-grown MCS! LOL! That's quite unlikely to happen to say how dry the air will be further north and east, I think you may be in the "no go zone", too far east for anything elevated and too far west for anything surface based, that's just my opinion.

you don't get sarcasm William no one actually thinks that in fact in my opinion the risk isn't great I'm more confident on the showers inland than elevated stuff at the moment.

[William Grimsley]

I wish everyone would stop discounting the south west, this happened in 2014 and we got some of the best thunderstorms that Summer... Obviously, you didn't read my status, Tom. I knew it was sarcastic.

[Wilxy]

Just now, William Grimsley said:

I wish everyone would stop discounting the south west, this happened in 2014 and we got some of the best thunderstorms that Summer... Obviously, you didn't read my status, Tom. I knew it was sarcastic.

Don't worry I will try and order you a MCS!!!

[William Grimsley]

Just now, tomjwlx said:

Don't worry I will try and order you a MCS!!!

Wouldn't say it's impossible!

[Wilxy]

Just now, William Grimsley said:

Wouldn't say it's impossible!

Wait and see what happens after tomorrow its all about now casting! 

[Convective]

1 minute ago, William Grimsley said:

I wish everyone would stop discounting the south west, this happened in 2014 and we got some of the best thunderstorms that Summer... Obviously, you didn't read my status, Tom. I knew it was sarcastic.

Nobody is discounting anything just yet, William!

Even this close to the start of the event, its too close to say where will and where won't get storms. A plume cannot be predicted, and even nowcasting is no good. At this stage, people are simply relying on what the charts are showing. When forecasts begin to emerge, we can get a clearer idea, but don't worry, no one is discounting anywhere at this stage  

[William Grimsley]

Just now, tomjwlx said:

Wait and see what happens after tomorrow its all about now casting! 

To be honest, weather always is because none of it is ever what the models say...

[William Grimsley]

2 minutes ago, Convective said:

Nobody is discounting anything just yet, William!

Even this close to the start of the event, its too close to say where will and where won't get storms. A plume cannot be predicted, and even nowcasting is no good. At this stage, people are simply relying on what the charts are showing. When forecasts begin to emerge, we can get a clearer idea, but don't worry, no one is discounting anywhere at this stage  

It's interesting you say that. @Mapantz and @ajpoolshark have said different...

[William Grimsley]

On Sat24, there's something unstable looking moving in towards the Cornwall area now...

Looks like a mix of Altocumulus and Altocumulus Castellanus cloud to me. Any thoughts?

Edited May 5, 2016 by William Grimsley

[Stormyking]

Hmm I have been observing this situation all week and to be honest with the weekend now closing in, it still virtually impossible to say for sure where showers or storms are gonna be or how intense or weak they will be. From what I have seen, the highest potential (Surface based showers/storms) does appear to be from Bristol Northwards, such as West Midlands, Wales and the North West, especially Saturday and Sunday as there does also seem to be better instability around those areas.

As for the South/ South West or even the South East its a bit of a different situation, this is this the trickiest part, whilst I am confident that Elevated showers/storms will pop up, I am not confident on where. Tomorrow Night and into Saturday Evening, An area of showers has been consistently showing, but 1 run its further west, and then the next its further east, latest 12z pushes an area of showers towards the Dorset coast and parts of East Devon, and also a very pockety but intense area of showers just to the west of the IOW, then quickly dies through Saturday. 

Saturday Evening and overnight has been interesting me that bit more as its been consistently showing as well an intense but fairly small area of precipitation pushing up towards the South Coast, the latest run pushes it further East, Which shows to be affecting areas such As The Isle of Wight eastwards and moves towards Brighton/Eastbourne before quickly dying off. This will chop and change throughout the next 48 hours so even with this still my confidence is around 50-60%

Th problem with Elevated storms they are so so tricky to predict and point and they can just about pop up out of no where, ive seen so many times where even the highest resolution charts dont pick up anything what so ever and still has delivered. I think it would be foolish to discard places like the South East in these sort of set ups as things can still very easily change, even this close in..

Alot of this weekend too does also depend on wind shear too which i think will quite important.

Anything beyond Saturday i wouldnt like to judge as its still too far out.

[TropicThunder]

Well I will be in Northampton for a lot of the weekend, usually I think that would be a decent place to be for plumey setups but looks like it may be a bit too far east this time.

So my attention for now is on around this time tomorrow, radar watching to see if anything elevated starts heading this way from France!

[William Grimsley]

2 minutes ago, Stormyking said:

As for the South/ South West or even the South East its a bit of a different situation, this is this the trickiest part, whilst I am confident that Elevated showers/storms will pop up, I am not confident on where. Tomorrow Night and into Saturday Evening, An area of showers has been consistently showing, but 1 run its further west, and then the next its further east, latest 12z pushes an area of showers towards the Dorset coast and parts of East Devon, and also a very pockety but intense area of showers just to the west of the IOW, then quickly dies through Saturday. 

I knew it! Finally, we're going to get something (jinxes it instantaneously)!

[Stormyking]

Just now, William Grimsley said:

I knew it! Finally, we're going to get something (jinxes it instantaneously)!

If you read what I put, i havent said an exactly location, its all over the place, honestly mate there is a risk yes but its only a risk, i dont want you to get your hopes to high as it could end in tears, im not for one minute discarding anywhere, its so tricky to say where.

[William Grimsley]

Just now, Stormyking said:

If you read what I put, i havent said an exactly location, its all over the place, honestly mate there is a risk yes but its only a risk, i dont want you to get your hopes to high as it could end in tears, im not for one minute discarding anywhere, its so tricky to say where.

I know, I know, I know, I'm perfectly calm just slightly excited that's there going to be this "risk" around. Anyway, on a positive note, Cirrus Castellanus cloud is now visible to my SSE and WSW!

[Harry]

I agree with what has been said above, I'm really struggling to call this one.

With fronts out west and LP moving through, it is a good platform for unexpected trough features and CZs which could act as decent triggers for more organised storms. I think it was July 2014 when I along with many others were predicting a hot humid but dry night in the SE/E, with storms being reserved for the W portions, only to be woken at 2am by an active series of storms triggered by a trough that wasn't forecast anywhere.

While the conditions this weekend are not directly comparable to a July plume, instability is there and I do expect storms in places. Still favouring Midlands N and W'wards, but that doesn't preclude other areas (E/SE/S/SW) either from home growns or imports, particularly Sunday and into next week.

 

[A.J]

57 minutes ago, William Grimsley said:

It's interesting you say that. @Mapantz and @ajpoolshark have said different...

??.......the outputs 48-72 hours ago weren't exactly awe inspiring and I did make the point not to discount things as the outputs will chop and change as we get near to T0, so in essence, Convective's post is very similar to mine

 

...you mention about people discounting the SW....can't say I've really seen that, but to be absolutely frank, the shear amount of comments you make in terms of IMBYisms, it's, for me, a bit of a thread turn off...no offence intended, just a personal observation

[Cheshire Freeze]

10 minutes ago, ajpoolshark said:

??.......the outputs 48-72 hours ago weren't exactly awe inspiring and I did make the point not to discount things as the outputs will chop and change as we get near to T0, so in essence, Convective's post is very similar to mine

 

...you mention about people discounting the SW....can't say I've really seen that, but to be absolutely frank, the shear amount of comments you make in terms of IMBYisms, it's, for me, a bit of a thread turn off...no offence intended, just a personal observation

I have a thread induced headache

Edited May 5, 2016 by CreweCold

[A.J]

to be honest, taking one model in isolation, the GFS12z is uninspiring for the SW (Devon & Cornwall) over the next 72 hours, not a definite no-no but there is not much instability of note.... the best instability is further north and east, BANES, Wilts, Hants, Oxon, Gloucs and into Wales, the Midlands and northern England....but before I hung, drawn and quartered for saying that, it is one model run, and I'll be watching the other runs (in particular the hi-res one's) with interest as well as following the input from some of the well respected & knowledgeable posters 

[Greeny]

2 hours ago, William Grimsley said:

@Greenday, what do you think for us? I know you got it right last time (2014). XD

I'm taking a look now, certainly at first glance can't rule anyone out just yet. Looking at Friday through Saturday midday currently. It is nice when my predictions actually come to fruition.

Edited May 5, 2016 by Greenday