Storms and Convective discussion - 25th July 2021 onwards

[Zak M]

A few snapshots from the video. One of the CGs almost made me s#@t my pants.

      

[Tn9]

good timelapse on this cam ..pescara italy ,starts off a nice day : -}

https://www.skylinewebcams.com/en/webcam/italia/abruzzo/pescara/pescara/timelapse.html" target="_blank"><img src="https://embed.skylinewebcams.com/img/1408.jpg" alt="Time-lapse Pescara"></a>

Edited August 28, 2021 by TN9

[Flash bang flash bang etc]

What are the chances this particular storm thread lasts well into 2023?

[Eagle Eye]

On 31/08/2021 at 15:04, Flash bang flash bang etc said:

What are the chances this particular storm thread lasts well into 2023?

You mean 2025

[Harry's House]

After 5 days of thunder in July, no thunder or lightning observed in August. Not experienced a thundery August for many years.

[dr weather]

There appear to be some sharp showers around the Isles of Scilly currently, with the Met Office's lightning radar having detected one or two strikes around 0700 in The Channel south of Devon.

Edited September 4, 2021 by dr weather

[Jamie M]

Never thought the most thundery month I'd have this year would be in May.

5 days in May, 2 days in June, 2 days in July, 1 day in August.

2/10 of those days were from storms from across the channel which is a change from the constant crossers that seem to happen here.

Can't dismiss the odd thundery squall through this autumn but not had one in a while!

Best shot from this year below:

 

[Badgers01]

September can be a good thundery month down here in the South…. Fingers crossed !

[Guest]

There is almost currently zero prospects of a decent thundery breakdown Wednesday, timing is all wrong, just the dreaded thundery showers at best.

[ChannelThunder]

On 05/09/2021 at 21:14, Alderc said:

There is almost currently zero prospects of a decent thundery breakdown Wednesday, timing is all wrong, just the dreaded thundery showers at best.

Been keeping an eye on it for a few days. Feels like a SLT might be issued (by CW) at the very most but certainly doesn't look like there'll be widespread disruptive cells. Currently 50/50 whether I even charge my camera batteries in hope!

[Chris Lea-Alex]

Confidence has increased regarding tomorrow's PVA lobe / theta-W mashup:

Day 2 Convective Outlook

VALID 06:00 UTC Tue 07 Sep 2021 - 05:59 UTC Wed 08 Sep 2021

ISSUED 20:56 UTC Mon 06 Sep 2021

ISSUED BY: Dan

An upper ridge initially over the UK/Ireland on Tuesday will slowly weaken and retreat eastwards, as an upper low west of Iberia lifts northwards. On the forward side, strengthening southeasterly flow aloft will encourage advection of a relatively high Theta-W tongue northwestwards during the overnight hours from France towards western English Channel / SW England / Celtic Sea / southern Ireland. With cooling aloft and some PVA as the upper low approaches, there is scope for some elevated deep convection to develop atop an elevated mixed layer in a rather narrow zone / instability axis that will shift northeastwards through the night. The instability axis is likely to move northwards at a reasonable pace across Ireland, but could remained anchored near or to the west of the Channel Islands during this period of interest.

Forecast profiles yield substantial CAPE from parcels lifted above the EML, with strong mid/upper flow in an environment with steep mid-level lapse rates - therefore, any deep convection that can develop has the potential to produce some very frequent lightning, but the biggest uncertainty is over the number of showers/thunderstorms that develop, and therefore coverage of lightning. Either way, in a broad sense there is scope for some elevated showers or thunderstorms to develop rather randomly within this zone through Tuesday evening and overnight into Wednesday. A blend of model guidance would imply the greatest activity may remain offshore over the Celtic Sea approaching southern Ireland, at least initially, with perhaps an uptick late in the night towards SW England and the Channel Islands further down the instability axis. Given the potential for some locally rather active thunderstorms, if confidence on specific areas increases a MDT may be introduced.

Convective Weather

WWW.CONVECTIVEWEATHER.CO.UK

---

Forecasting thunderstorms and severe convective weather across the British Isles and Ireland for up to the next 5 days.

 

[BrickFielder]

Multiple opportunities for Storms Wednesday and Thursday. Perhaps for the first time this year we have a storm threat where temperatures are above 25C with stronger updrafts possible as a result. Since this potential for storms is from a fairly sloppy low with individual features tricky to predict it is hard at this point to identify exactly where.

Models at the moment suggest that the South West on Wednesday afternoon could see some Storms. Indications are that these might be a bit elevated and surface instability is very marginal.

 

There is also a hint of elevated imports from the south for the South East and East Anglia in the early hours of Thursday.

 

Then on Thursday afternoon there is a chance of home grown storms for Wales and the Northern part of England.

 

Models are likely to get details wrong at this point and what we have is a Spanish plume like environment being slowly undercut by a moist maritime environment.  This is the type of environment where localized low level wind inflow from the south can create moderately severe Thunderstorms.

 

Too early at the moment to give any real details .

Edited September 7, 2021 by BrickFielder

[Summer Sun]

Day 1 Convective Outlook

VALID 06:00 UTC Tue 07 Sep 2021 - 05:59 UTC Wed 08 Sep 2021

ISSUED 06:27 UTC Tue 07 Sep 2021

ISSUED BY: Dan

An upper ridge initially over the UK/Ireland on Tuesday will slowly weaken and retreat eastwards, as an upper low west of Iberia lifts northwards. On the forward side, strengthening southeasterly flow aloft will encourage advection of a relatively high Theta-W tongue northwestwards during the overnight hours from France towards western English Channel / SW England / Celtic Sea / southern Ireland. With cooling aloft and some PVA as the upper low approaches, there is scope for some elevated deep convection to develop in a rather narrow zone / instability axis that will shift northeastwards through the night. The instability axis is likely to move northwards at a reasonable pace across the Celtic Sea and southern Ireland, but could remained anchored near or to the west of the Channel Islands during this period of interest.

Forecast profiles yield substantial CAPE from parcels lifted above the EML, with strong mid/upper flow in an environment with steep mid-level lapse rates - therefore, any deep convection that can develop has the potential to produce frequent lightning, but the biggest uncertainty is over the number of showers/thunderstorms that develop, and therefore coverage of lightning. Either way, in a broad sense there is scope for some elevated showers or thunderstorms to develop rather randomly within this zone through Tuesday evening and overnight into Wednesday. A blend of model guidance would imply the greatest activity may remain offshore over the Celtic Sea approaching southern Ireland, at least initially, with perhaps an uptick late in the night towards SW England and the Channel Islands further down the instability axis. Given the potential for some locally rather active thunderstorms, if confidence on specific areas increases a MDT may be introduced.

http://www.convectiveweather.co.uk/forecast.php?date=2021-09-07

 

[A Face like Thunder]

Yellow weather warnings for thunderstorms in a limited area tomorrow and more generally on Thursday.

[ChannelThunder]

Okay, the latest UKV looks really promising down here in the central south import-wise. Looks like I could be charging up those camera batteries after all 

[Aqbadger]

Nick gone early with the forecast tomorrow night. Looks promising...

[Flash bang flash bang etc]

literally looks great for tomorrow into Thursday overnight period across the Home Counties. How come there isn’t more of a fuss being made about this?

* THERE MIGHT BE A THUNDER ! *

[Petorious]

A very big storm heading north in Northern France at the moment, high lightning rates. This fills me with positivity, I am off work this week and have been enjoying the lovely weather and will hopefully be storm chasing tonight with a mate if it looks right.

[Guest]

Hmm, a smallish MCS has formed over north western France and is propagating NNE currently. A few amount of lightning activity however I’d expect lightning to wain as we start to approach diurnal minimum. tbh I’d expect lightning only to track to the east of the red arrow. SW Wales might be in with a decent shout. 

 

[Andy Bown]

Quick development off the South Devon coast. Shows the possibilities that lie ahead today.

[philglossop]

Sky has that pink look to it this morning in Plymouth City centre…

 

A few strikes out Start Point way already

[Eagle Eye]

@Alderc @Petorious

Alright I'll look at this to get the final decision on whether its a big storm to look at and the fact that it's 7am shows that there could be more or that's its going to fade. 

You know what I'm going for nowcasting. 

[Jamie M]

Few strikes offshore near Salcombe and one at Plymouth

[philglossop]

That Plymouth strike was right over my old house! 

[Gordon Webb]

Day 1 Convective Outlook

VALID 06:00 UTC Wed 08 Sep 2021 - 05:59 UTC Thu 09 Sep 2021

ISSUED 06:41 UTC Wed 08 Sep 2021

ISSUED BY: Dan

An upper low over the Celtic Sea will lift slowly northeastwards through Wednesday. On the leading edge, a narrow tongue of relatively high Theta-W will be the main focus for potential lightning activity along an instability axis, and this will gradually migrate northeastwards with time. Initially, the main focus will be over Ireland, SW England and the Channel Islands, moving eastwards across Cen S Eng and S Wales through the day and towards SE England / Midlands during the evening. There is a large amount of uncertainty as to how much lightning activity will occur vs just pockets of showery rain, and this adds difficulty in determining the threat levels to introduce and where.

Realistically, there could be a few odd lightning strikes almost anywhere from various pulses of showery rain during this forecast period. Current thinking is one cluster of heavy rain and elevated thunderstorms will affect the Channel Islands and SW England (especially Devon) during the morning, but possibly weakening (in terms of lightning) towards midday. Another wave may develop over northern France (initially surface-based potentially) and drift across the English Channel towards S / SE England during the afternoon and evening hours, but again perhaps weakening as it tracks further north - however, there could be an uptick of activity inland over the Home Counties late evening/overnight. Elsewhere, there is a small chance of isolated surface-based showers/thunderstorms developing over SW Midlands, SW England (especially N Devon/W Somerset), central Scotland and western Ireland - but in most cases this will be capped and heavily dependent on sufficient surface heating.

my opinion - not very hopeful for storm fans at least on widespread scale , bet they wish this was happening in June / July

Edited September 8, 2021 by Gordon Webb