Storms and convective discussion - 18th June 2020 onwards

[summer blizzard]

I noticed GFS has been showing storms for F1 on Sunday, what are the chances from you guys.

[Zak M]

24 minutes ago, summer blizzard said:

I noticed GFS has been showing storms for F1 on Sunday, what are the chances from you guys.

The WRF-NMM has picked this up in its previous runs but the UKV currently isn't having any of it. We will get a clear picture of what will happen on that day in a few days time I think.

[TJS1998Tom]

On 04/08/2020 at 20:55, Josh Rubio said:

How long until they break out further north and west, just like they did last time?

For once I hope they're further West lol, mainly as that's where I'll be next week. No doubt Lincolnshire will get good storms when I'm not there  

[TJS1998Tom]

Few days yet but certainly liking the looks of this so far 

[Superstormuk]

2 hours ago, TJS1998Tom said:

Few days yet but certainly liking the looks of this so far 

I see that the classic anti-storm dome is active over the south.

[ChannelThunder]

27 minutes ago, Superstormuk said:

I see that the classic anti-storm dome is active over the south.

The dome has performed exceptionally well this year! God it'd better be broken within the next week for the sanity of us all!

[Harry]

23 minutes ago, Lance M said:

The dome has performed exceptionally well this year! God it'd better be broken within the next week for the sanity of us all!

Echo those sentiments @Lance M - been a good 8 years or so since I’ve experienced such a cruddy year for storms. I seem to recall 2007-2012 being particularly quiet (notwithstanding El Brumo in 2012 which my area missed entirely) but since then every year has produced some goods.

The hot humid air is currently creeping in here, albeit tempered by the frontal cloud that’s hovering overhead. I’m more hopeful this time round than last week’s heat (or indeed previous warmer/hot spells this year) but mindful of the fact that if the forecast low pressure systems are slightly further east, we could very well (into next week) fall on the cooler more stable N/W edge of the low, rather than the hot humid E flank.

All to play for but with reasonable optimism to be had at this stage I think, especially as we are potentially looking at a few days of potential rather than a 2-3 hour window.

 

[Justin1705]

So. Here we are again. Probably for one of the last times this storm season(anything severly convective). The english channel is coming up to its max temp, its gained 1c in the last week to 17.1c. August OPTIMUM is 18.3, that co incides well for the chance of possibly multiple rounds of storms from the south as we have the hot and humid air for the forseable. Most people here see august as the worst for storms. Its right, however if conditions are right. Then we can actually get severe Tstorms in august. The reason i posted channel temps is that, even last weeks storms, channel was 1c lower, every chance before that it would've been lower.

 

The reason i post this is that, it bodes well for surival or french imports or explosive action we can and have seen in the channel before.

Therefore imo we have the best chance all summer over the next 2 weeks, to see some widespread action.

 

of course i know sea temp is just 1 factor many others, but its one i see has only been increasing. And is forecasted as i say to peak mid august, and as i see for the time being will correlate with hot humid air. Fingers corssed for southerners !!

Edited August 6, 2020 by Justin1705

[StormLoser]

I was idly perusing the pressure charts from the MO and wondering if that slack low pressure could generate something. I'm guessing maybe not as there does not look enough instability in the whole set up?

But then I remembered the (nicely put) anti-storm dome.  How long have we experienced the Kent Clipper phenomenon, too?  In the 1980s I recall plume after plume from the south and the regular 11:00pm - 3:00am storms over the south east. And then they stopped.

Since then...apart from the very occasional exciting moment...it has been rubbish. So I'm not holding out much hope.   

[Mapantz]

The channel temperatures won't matter if elevated thunderstorms move up.

[Guest]

6 minutes ago, Mapantz said:

The channel temperatures won't matter if elevated thunderstorms move up.

Indeed, unusually with the airmass being so warm and humid storms could root relatively close to the boundary layer even over the channel. 

[Supacell]

You can get big thunderstorms in September. For example there were some awesome storms on 13th September 2016 in the northwest and then in the south on the 15-16th September 2016.

[MP-R]

4 minutes ago, Supacell said:

You can get big thunderstorms in September. For example there were some awesome storms on 13th September 2016 in the northwest and then in the south on the 15-16th September 2016.

Indeed! One of the most impressive lightning displays I’ve seen was in September... 2014.

[ChannelThunder]

I see the BBC Weather app has gone into its usual routine. I've got 17 odd hours of non-stop thundery showers forecast from 3pm on Weds 

[Zak M]

2 minutes ago, Lance M said:

I see the BBC Weather app has gone into its usual routine. I've got 17 odd hours of non-stop thundery showers forecast from 3pm on Weds 

Same here 

[Southern Storm]

Yes, I remember an awesome storm developed just off the coast of Blackpool, and that was during the last week of September 99/2000 not sure which year, but it was one of the best storms I have ever seen. 

What made it even more impressive was how it developed in perfectly clear skies, from almost nothing into one massive cell, it's still very clearly etched into my brain lol

Under the right conditions you can get some absolute beauties, even that late in the year, and in the coming week, there will be opportunities galore. 

 

[Jamie M]

Some eye candy before it all goes wrong. 

[Zak M]

PJB over on UKWeatherWorld has posted a good explanation of what to possibly expect next week:

"Good indications now for a surface & upper pattern to become established over NW Europe which would favour the development of Thunderstorms from Sunday through to Mid Week. A broad upper trough is likely to become quite slow moving to the west of the continent with a plume of very high 850mb temperatures to move north from Spain and France, Aloft however there will be areas of steeper or cooler mid level temperatures and 300-600mb shortwaves moving NE on the ascending side of the trough. At the surface High temperatures and areas of high Theta-w at 850mb are likely to be located in the South and SE for much of the period. Areas of elevated confluence and destabilisation are likely to take place during the period and i suspect quite difficult to forecast much more than 24 hrs ahead.

Forecasting this will be quite tricky

1. How much moisture there is and how dry the lower layers get, models can at times in the 4-5 day range over do the model precipitation.

2. ECMWF has tended to overdo CAPE values and the development of Thunderstorms in the previous model cycle. Will be interesting to see how this new model cycle performs in the next few days given its had enhancements to the models CAPE and convection processes.

3. GFS has trended west with the development of a more active thundery plume development during mid week as a more robust shortwave moves north and pressure falls at the surface over N France and English Channel. Movement and development of such shortwave detail is prone to sig forecast errors at this range

4. Potential is there for some intense thunderstorms to develop over NW Europe with development of a Mid level wind max over parts of Central & Southern Parts early next week and considerable directional and speed sheer aloft

5. day to day variations in the models are likely with precipitation being developed in the model widely over differing locations inter model and intra model."

Source: http://www.ukweatherworld.co.uk/forum/index.php?/topic/124384-convective-chat-august-2020/page__st__15

Edited August 6, 2020 by Zak M

[Cheshire Freeze]

GFS storm risk later Sunday-

[East_England_Stormchaser91]

1 hour ago, CreweCold said:

GFS storm risk later Sunday-

Fantastic opportunity for some real juicy corkers to crop up anywhere under that dome of 15c+ uppers. A whole variety of home grows and some imports too from France and the Low Countries. Something to look forward to again at last!! 

[NUT]

Wonder how many pages this thread could be at by say this time next week (at the moment it's 134) in all seriousness could be a very long few days for some from Sunday onwards. Summer might not have given much in the way of goods but looks increasingly likely that about to change in a very big way.....................

[Justin1705]

Sorry for the extensive uploads of screenshots. Ill keep quiet now and you wont get my 2 pence until the weekend.

I can see here that consistently for 2 runs now GFS has thrown out thunderstorms Saturday evening- into sunday. A day earlier; along with sunday/mondays risk. The screenshots are comparisons of the previous and current runs at similar times- along with precipitation. There is not to much difference which to me indicates  there is also a risk for widespread thunderstorms  saturday evening. Cape through the day but naturally there will be a Cap in place so it might not come of at all, bearing in mind that cape significantly reduced 18-21z

Edited August 6, 2020 by Justin1705

[Justin1705]

8 minutes ago, NUT said:

Wonder how many pages this thread could be at by say this time next week (at the moment it's 134) in all seriousness could be a very long few days for some from Sunday onwards. Summer might not have given much in the way of goods but looks increasingly likely that about to change in a very big way.....................

I Expect a new one soon, as it is going to be an active week. Up to the mods i guess

[The PIT]

Local met office forecast having none of it. Local Beeb forecast going crazy. It's a question of waiting and watching as storms could disappear from the forecast or on the day turn up in the wrong place.

[Chris.R]

looking good here from Sunday but no doubt it will be too far south or east again. Wish I had already moved to Huyton. Will be there from September.