Convective / Storm Discussion - 28th July onwards 2013

[Jane Louise]

Hopefully my turn today . If not i'll see ya all in the NSC again. Good luck once again lol.

Edited July 28, 2013 by Jane Louise

[Darren Bown]

There were some joke predictions last night in this thread. We were told that NW England would probably record the least amount of rain, we were told that nowhere would record more than 15mm from this even though some stations had already had before the time of post was made. We were told it was going tits up before it even got started despite the models said it was going to get heavier as the night went on. Predictions not based on fact but based on how many toys were thrown out of the pram. I rather give 82 million to professionals than some of the tantrum, histrionics that were around yesterday evening.

I was the one who said NW England would get little rain, based on the radar at the time, but as the system rotated, it got very interesting last night. Looks like I slept through the worst of the rain last night to be left with much cooler air, and quite a gusty wind this morning!

[Supacell]

My forecast is on the last thread, essentially widespread thundery showers across the western half of the country today along with Ireland. Best chance for more intense storm activity across C+W Ireland, Wales, NW England and the NW Midlands - with storms possibly taking advantage of a small amount (20knts) of DLS and having more organisation across Wales.

 

If I was to pick a spot today it would be somewhere on the NE Wales/NW England border - that's a best guess only though

[Guest William Grimsley]

Lots of showers and thunderstorms around for Devon, today. Hopefully, Newton Poppleford sees some downpours!

Edited July 28, 2013 by William Grimsley

[Gord]

I thought the forecasts for here were spot on, although the timing was a bit out.

Looking forward to blustery thundery showers today. Are they going to quick moving or prolonged? Showers rattling through is one of my favourite types of weather. Love it when it's so changeable within a short space of time.

[Jane Louise]

Please, can we keep on topic regards todays potential rather than who was right or wrong with the forecasts yesterday.  Thanks 

[Weather-history]

Carlisle according to weatheronline has had 49mm in the last 6 hours.

Any campers in the Lake District got and are still getting a serious soaking.

[Jane Louise]

TORRO CONVECTIVE DISCUSSION 2013/008

 

A TORRO CONVECTIVE DISCUSSION has been issued at 22:45GMT on Saturday 27th July 2013

 

Valid from/until: 22:45 – 18:00GMT on Saturday 27th July/Sunday 28th July 2013 for the following regions of the United Kingdom & Eire:

 

SW England

 

S and parts of mid Wales

 

THREATS

 

Isolated tornadoes; wind gusts to 50mph; CG lightning; hail 10-20mm diameter

 

SYNOPSIS

 

Unstable south-westerly airflow will move into the area overnight and remain in place on Sunday. Overnight tonight, shear will be fairly weak so severe weather is unlikely. During Sunday, diurnal heating should allow for a few hundred J/Kg of CAPE to develop in a region characterised by increeasing vertical wind shear.

 

Further scattered showers and thunderstorms should develop during Sunday. Vertical shear is likely to increase through the day as an upper trough approaches from the south-west. The shear should be sufficient for some organised convection, mainly in the form of multicells and small lines, wind some marginally severe hail and wind gusts. However, some updraught rotation is possible, especially in the afternoon, and a low-end tornado risk appears likely. The activity may spread into parts of central southern England and the Midlands later, and into the evening. A watch may be needed through the day and into the evening if convection develops as expected.

 

Forecaster: RPK.

 

http://www.torro.org.uk/site/forecast.php

 

 

Edited July 28, 2013 by Jane Louise

[Jane Louise]

Okay, I can't seem to attach the map, best to pop over yourselves and take a look.

[ZONE 51]

Please, can we keep on topic regards todays potential rather than who was right or wrong with the forecasts yesterday.  Thanks 

There was 2 - 3 pages of anti-meto moaning (nothing personal ppl)

 

(can remove just needed to say it)

 

I tried to explain things in a sensible way to the posters who had a dig at the MO, not just because I am a fan of the Met O but because I understand why things change so often.

Edited July 28, 2013 by ElectricSnowStorm

[Captain Shortwave]

I think this is a northern and western day to be honest. East Wales into Northern England look like the best spots. South East looks likely to stay dry.

All about tomorrow for where I live with several troughs predicted to move west to east.

Good luck, at least the Flemish can't steal these storms 

[Darren Bown]

Seems to be a good risk today by most forecasts for storms this afternoon here. Only time will tell!

Edited July 28, 2013 by Darren Bown

[ZONE 51]

Thought I'd put on the latest MetO Satellite image, there is a lot of heavy rain over northern England covering Scotland with the southern edge to Lancashire and North Yorkshire some of this rain is very heavy.

Heavy showers have got into the SW and Wales as I type these are moving in and developing, there is clear skies across much of the south and with day-time heating that would help get some active thundery downpours going across many parts of the UK and Ireland today.

 

(The white blobs of cloud into SW are the convective stuff and also down over Biscay/Brest)

Edited July 28, 2013 by ElectricSnowStorm

[staplehurst]

Apologies JL, just wanted to clarify a few things from yesterday as I didn't get the opportunity to last night...

 

 

I agree with those posters that say certain organisations were ramping up the thunderstorm potential in terms of it's coverage - it never (to me at least) looked like it would be a widespread affair, only isolated embedded cells with any significant thunderstorm potential being in the far southeast. That seemed to be the case back on Thursday, and remained so right up to the point. So I can understand that frustration to a certain point, but I did try and state many times in the past couple of days that some folk were going to be disappointed if they kept ramping this event up! 

 

In discussion with fellow colleague Ian Fergusson, it was clear that although the Met Office expected locally large rainfall totals, some of the high-res modelling actually left parts of the country very dry with little rainfall forecast for Saturday. This was most notably north of London in their modelling at the time, although given the complexity of the situation it was virtually impossible in advance to say 'yes these areas will hardly see any rain', but to that degree it's not surprising to see some places see very little in the way of rainfall. I sat at Dungeness for about 8 hours yesterday afternoon waiting for the storms to cross the Channel, and we had some pretty heavy rain for a time there with a lot of surface water collecting on roads etc.

 

With regards to the temperature forecasting for yesterday, naturally the NAE (which drives the BBC/Met Office graphics) had a lot of cloud and mid-level showers throughout much of the day for yesterday, before the heavier rain arrived during the afternoon. The combination of a general lack of these earlier showers and the later arrival of the rain meant much more sunshine across southern Britain than was forecast for the previous days, so it's only natural the temperatures were much higher than expected. Not necessarily an error with modelling the temperature, just the general local weather which in turn has an impact on how high the temperatures can go.

 

In terms of modelling, I feel a combination of UK4 and GFS did reasonably well, although the GFS is limited by it's horizontal resolution somewhat. In particular the CMC (Canadian Global Model) did best overall with consistency and placement in the days running up to this event. 

 

 

Quote from Thursday:

 

 

The main thing to note here is there will be a large mass of general frontal rain on the western flank of the plume (ie with no thunder). The thunderstorms themselves will be only on the eastern flank, and at the moment this only affects parts of Kent and Essex at best. Yes there will be some fairly widespread rain over East Anglia and the South East, but the bulk of it won't be thundery sadly...

However this is MCS forms (ie if it does track further west) there will still be a large area of just plain rain on the western periphery where the frontal boundary lies.

 

 

Yep the frontal wave looks set to remain on track to bring some quite heavy rain across CS/SE England and East Anglia, but again this is generally non-thundery with thunderstorms on the whole staying on the Continent, perhaps clipping parts of Kent, East Sussex and Essex for a time, and then some mid-level storms perhaps developing over East Anglia as the system exits into the North Sea (nothing new there then ha!)

 

 

 

Next couple of days has always had the better potential for more widespread scattered t-storms.

Edited July 28, 2013 by staplehurst

[The PIT]

Well I posted a load of rubbish last night when I got back from the pub. Don't post when drunk. If I offended anybody sorry.

Well more radar watching today and hopefully some storms.

Yesterdays rain came on strong around 3 ish with 21 mm of rain falling.

[Darren Bown]

It's a good 4c cooler than it has been the last few mornings. Quite a refreshing change!

[Jane Louise]

There was 2 - 3 pages of anti-meto moaning (nothing personal ppl)

 

(can remove just needed to say it)

 

I tried to explain things in a sensible way to the posters who had a dig at the MO, not just because I am a fan of the Met O but because I understand why things change so often.

No it's fine.  The topic is locked now. There's always a lot of Met O bashing when their forecasts aren't spot on but we must remember all different forecasts try their best and not all are right. Thunderstorms are very hard to forecast just like snow! anyway I must keep on topic now lol

[Captain Shortwave]

 

Apologies JL, just wanted to clarify a few things from yesterday as I didn't get the opportunity to last night...

 

 

I agree with those posters that say certain organisations were ramping up the thunderstorm potential in terms of it's coverage - it never (to me at least) looked like it would be a widespread affair, only isolated embedded cells with any significant thunderstorm potential being in the far southeast. That seemed to be the case back on Thursday, and remained so right up to the point. So I can understand that frustration to a certain point, but I did try and state many times in the past couple of days that some folk were going to be disappointed if they kept ramping this event up! 

 

In discussion with fellow colleague Ian Fergusson, it was clear that although the Met Office expected locally large rainfall totals, some of the high-res modelling actually left parts of the country very dry with little rainfall forecast for Saturday. This was most notably north of London in their modelling at the time, although given the complexity of the situation it was virtually impossible in advance to say 'yes these areas will hardly see any rain', but to that degree it's not surprising to see some places see very little in the way of rainfall. I sat at Dungeness for about 8 hours yesterday afternoon waiting for the storms to cross the Channel, and we had some pretty heavy rain for a time there with a lot of surface water collecting on roads etc.

 

With regards to the temperature forecasting for yesterday, naturally the NAE (which drives the BBC/Met Office graphics) had a lot of cloud and mid-level showers throughout much of the day for yesterday, before the heavier rain arrived during the afternoon. The combination of a general lack of these earlier showers and the later arrival of the rain meant much more sunshine across southern Britain than was forecast for the previous days, so it's only natural the temperatures were much higher than expected. Not necessarily an error with modelling the temperature, just the general local weather which in turn has an impact on how high the temperatures can go.

 

In terms of modelling, I feel a combination of UK4 and GFS did reasonably well, although the GFS is limited by it's horizontal resolution somewhat. In particular the CMC (Canadian Global Model) did best overall with consistency and placement in the days running up to this event. 

 

 

Quote from Thursday:

 

 

 

 

 

Next couple of days has always had the better potential for more widespread scattered t-storms.

 

Fair enough, can we all agree and say that the NAE has had a complete shocker this week. If weather and temperature graphics are worked out by this model then its issues extend beyond yesterdays stormgate, for example predicted maximum temperatures for large areas of England were as much as 5-6 degrees lower than what those areas actually got.

Edited July 28, 2013 by Captain shortwave

[SarahWxm]

My forecast is on the last thread, essentially widespread thundery showers across the western half of the country today along with Ireland. Best chance for more intense storm activity across C+W Ireland, Wales, NW England and the NW Midlands - with storms possibly taking advantage of a small amount (20knts) of DLS and having more organisation across Wales.If I was to pick a spot today it would be somewhere on the NE Wales/NW England border - that's a best guess only though

So.... Are you saying Wrexham may actually have a chance of a storm today?? Lol Edited July 28, 2013 by SarahWxm

[Polar Maritime]

64.2mm of rain here overnight..

[Chris.R]

Well it was raining here all night up untill about 5 AM, getting progressivly lighter during the latter part of the night. Local weather station recorded around 15 MM.

Looking forward to this afternoon, I think i'm in a good playce here, as anything that develops on the welsh border should head my way asuming that we still have an SSW/NNE flow?

Nice to be in a good playce for a change!

[The PIT]

64.2mm of rain here overnight..

Sure only got 27mm here. Still Thundery in nature so I guess it's possible a large difference.

Quite amusing last night. The pub was so warm people were going outside to stand in the rain too cool down.

Any idea when ti should kick off today?

[Guest William Grimsley]

(The white blobs of cloud into SW are the convective stuff and also down over Biscay/Brest)

Yeah and those are heading towards SW England.

[Guest William Grimsley]

SW England

 

S and parts of mid Wales

 

THREATS

 

Isolated tornadoes; wind gusts to 50mph; CG lightning; hail 10-20mm diameter

WOW! Isolated tornadoes? You've gotta be kidding me!

[Cloudwatcher]

My subscription for NW Extra ran out yesterday and I'm too disillusioned to renew it. So of course we will have storms today!

 

Seriously though, can't see much happening round here today. Started off with the usual Cheshire mid-level white/grey murk that we've come to know and hate. Feeling cool too, much cooler than yesterday.