Storms and Convective Discussion - 25th June 2019 onwards

[Thunder and Lightning]

Trend of stuff warming up at the beginning of July?

[Summer Sun]

Day 1 Convective Outlook

VALID 06:00 UTC Wed 26 Jun 2019 - 05:59 UTC Thu 27 Jun 2019

ISSUED 18:23 UTC Wed 26 Jun 2019

ISSUED BY: Dan

UPDATE 18:22 UTC 

Latest data suggests the risk of elevated thunderstorms affecting parts of SW Ireland later tonight has increased - as such a SLGT has been introduced. First wave of thunderstorms currently ongoing over the Celtic Sea is expected to pass to the south and/or weaken on approach, but the main interest is with a second round of elevated thunderstorms that will likely develop later this evening - perhaps also close to the Scilly Isles - will then head northwest towards Munster later in the night. Though it must be stressed the majority of activity will likely stay just offshore to the south

Upper ridge will expand across western Europe on Wednesday, while an upper vortex pivots westwards to the west of Biscay. The net result is advection of a high Theta-W airmass from France, across the Channel Islands and out to the Celtic Sea. Weak impulses running northwards from the English Channel into southern England may produce some showery bursts of rain from high-based elevated convection during Wednesday daytime. Lightning risk is considered quite low.

By late afternoon into the evening, an environment with very steep lapse rates and significant CAPE (1,500 - 2,000 J/kg) will evolve across the Celtic Sea, engaging with the left exit of a strong southerly jet to the west of Biscay. Model guidance is in reasonable agreement for a cluster of potentially very active elevated thunderstorms to develop during this timeframe, expanding in coverage as they drift west-northwestwards on the leading edge of this instability plume over open waters to the south of Ireland. Depending on the exact track, these may pass close to SW Ireland on Wednesday night - and upgrades may be required if trends suggest a heightened chance of reaching SW Ireland, especially late in the night.

http://www.convectiveweather.co.uk/forecast.php?date=2019-06-26

[Stuart]

day 2 Convective Outlook

VALID 06:00 UTC Thu 27 Jun 2019 - 05:59 UTC Fri 28 Jun 2019

ISSUED 19:48 UTC Wed 26 Jun 2019

ISSUED BY: Dan

Upper ridge continues to dominate across much of western Europe on Thursday, with an upper vortex continuing to spin over the Atlantic well to the west of Biscay. A corridor of significant CAPE will exist between these two systems (1,500 - 2,000 J/kg), stretching from northern France - Channel Islands - Cornwall - SW Ireland, as hot air between 700-900mb is advected northwestwards atop a cool boundary layer. As a result, there will be a sharp low-level temperature inversion, and also very steep mid-level lapse rates.

 

Subtle impulses running northwestwards in the strong southeasterly flow aloft will aid the development of elevated thunderstorms at various times over the Atlantic and Celtic Sea through this forecast period. Most activity will be offshore to the west and south of Ireland, but may drift over southwestern parts of Munster - primarily during Thursday morning. The strongest cells may produce some hail (along with heavy rain). Some uncertainty exists over how quickly the steering flow will veer more southerly, but elevated thunderstorms could return to SW Ireland during the early hours of Friday (but low confidence at present, with most NWP guidance generally keeping this round of activity offshore). 

 

http://www.convectiveweather.co.uk/forecast.php?date=2019-06-27&fbclid=IwAR35J7-SDR1XtLnGsFTpeZajXeCWZahc13JigsrmfnooBXMiKuwQSCYijis

Edited June 26, 2019 by Stuart

[Raindrops]

Curse that SE wind and jet-stream, back to staring at models for Fri/Sat. Thank you Stuart and Summer Sun for the forecast :).

[Flash bang flash bang etc]

Looks like that Biscay cell wants to check out Cornwall

[Raindrops]

25 minutes ago, Flash bang flash bang etc said:

Looks like that Biscay cell wants to check out Cornwall

Wish it would come check out my area, but I doubt it will make the 300+ mile journey ha.

 

My Daughter turned 19 today, the last night storm we had she was 4 years old....yeah it's a long time coming now. 

[ancientsolar]

Odd question.. being so many 100s of miles away, but  I wonder if the lightning is distantly visible from cornwall to the Bay of Biscay

[Raindrops]

13 minutes ago, ancientsolar said:

Odd question.. being so many 100s of miles away, but  I wonder if the lightning is distantly visible from cornwall to the Bay of Biscay

I don't know to be honest, my best long view was 30 miles away....but this Topic might help you out a bit https://www.netweather.tv/forum/topic/84844-how-far-away-can-you-actually-observe-lightning/

[East_England_Stormchaser91]

43 minutes ago, ancientsolar said:

Odd question.. being so many 100s of miles away, but  I wonder if the lightning is distantly visible from cornwall to the Bay of Biscay

Unimpeded views across the sea, providing its crystal clear, I’d say 200 miles you could make it out. 

If you’re in Cornwall, I’d definitely attempt a lookout for a short while, you may see the odd flicker, even possibly reflecting off any high clouds. 

Oh and another good thing to look out for given being far away from the storm, would indeed be sprites. These are red bursts/spurts of atmospheric lightning up to 50 miles above a storm. 

As above, it was actually me that created a thread for it!  

Edited June 26, 2019 by East_England_Stormchaser91

[Raindrops]

The storm system over Bay of Biscay is rather nice, I like the plume effect it's showing by spreading outwards, it is banking left (heading west towards southwest of Ireland) and the cells are far apart, I can see about 7 clusters, The cluster on the far right might actually be view-able (if that's a word ha) from Cornwall if....IF it makes it. Some new cells are popping up behind the main Thunderstorm system but my guess is they to will bank left.

Please take note I am no expert, I'm just guessing from my own knowledge.

Edited June 27, 2019 by Raindrops
added text

[Raindrops]

Storms are dying but stable, will they pick up electrical activity when the sun rises? Who knows?....stay tuned. I'm joking, I could be sleeping by then.

 

Storms are still heading NW towards the Celtic Sea, from the Bay of Biscay. Seems to only now be three active clusters,

Edited June 27, 2019 by Raindrops

[TJS1998Tom]

Looks like a bit of Cape around on Saturday evening. Could be good if there was anything to trigger it

[Raindrops]

27 minutes ago, TJS1998Tom said:

Looks like a bit of Cape around on Saturday evening. Could be good if there was anything to trigger it

Cold front coming in the from the East, I don't think it will make it that far SE of UK, the best so far are Northern Ireland the west coast of Ireland and maybe West Scotland....maybe I did say maybe...also yes there's a but, but homegrown storms over the SW of UK is a possibility.

Can I set a reminder? Please take note I am no expert, I'm just guessing from my own knowledge.

Edited June 27, 2019 by Raindrops

[Chris.R]

 If you were to just look at the CAPE/LI on WRF for my location then you would say Saturday looks epic but it just doesn’t look like being released.  Having said that it does want to break out some convective precip by evening as the cold front approaches and the CIN drops.  

Think there may be a few surprises yet. 

[Flash bang flash bang etc]

This hot spell is about as surprising as an old shoe

[Flash bang flash bang etc]

There’s some potential on the horizon:

Edited June 27, 2019 by Flash bang flash bang etc

[TJS1998Tom]

Picked up even more now. Hopefully some good homegrown but after recent days taking it with a pinch of salt 

[BrickFielder]

I am watching Saturday closely for the potential for elevated storms. Looking at the Forecast SkewT's then we can see a huge CAP preventing boundary convection, but above that there is some potential for convection to initiate  (The instability looks to be mostly elevated rather than surface based). What I am looking for is signs of a 700hPa Jet ahead of the front which could initiate storms. Upper level instability more often that not is not released without a significant trigger and I am just not really seeing it at the moment. If some troughs occur ahead of the cold front  (fax chart -- Northern areas) then  there might be some possibilities.

It should be noted that the CPC blocking charts are somewhat different to what modelling solutions are suggesting so confidence that models have a proper handle on the evolution synoptic conditions is somewhat limited. Best wait till closer to the time.

 

[StormChaseUK]

3 hours ago, TJS1998Tom said:

Picked up even more now. Hopefully some good homegrown but after recent days taking it with a pinch of salt 

Saturday requires a surface temp of 43C to trigger off any storms so unlikely.

[Chris.R]

15 minutes ago, StormChaseUK said:

Saturday requires a surface temp of 43C to trigger off any storms so unlikely.

 For surface based ones yes but elevated ones we probably just need something like a pre-frontal trough. 

[thunderhead 2005]

The Convective inhibition (CIN) seems higher than available cape will this be an issue also?

[Chris.R]

8 minutes ago, thunderhead 2005 said:

The Convective inhibition (CIN) seems higher than available cape will this be an issue also?

 Yes. You can basically subtract the CIN from the SBCAPE and if you’re left with a negative number then you can say that nothing will initiate. 

[Flash bang flash bang etc]

Essentially the mathematics and science is there to tell us that we won’t get any storms.

Basically this heatwave is pointless  

[thunderhead 2005]

16 minutes ago, Flash bang flash bang etc said:

Essentially the mathematics and science is there to tell us that we won’t get any storms.

Basically this heatwave is pointless  

pretty much i miss the 90s, massive heat wave then a big storm. 

[IanR]

55 minutes ago, Flash bang flash bang etc said:

Essentially the mathematics and science is there to tell us that we won’t get any storms.

Basically this heatwave is pointless  

Its getting common to get a heatwave without any storms at the end now,  cant see anything happening on saturday,  bbc graphics did show some showery activity in the middle of the irish sea , pushing into southern scotland  . I suspect this will be the case , its happened a few times over recent years where the activity is over the northern irish sea