Storms and Convective discussion - November 2023 onwards

[Metwatch]

3 hours ago, cyclonic happiness said:

The Hinckley hailstorm!   

 

Incredible day and seeing through all the videos, if only I could have better memory of it!

The positively charged lightning ahead of the storm likely coming out of the anvil is spectacular! Paper on it below too:

Weather - 2013 - Clark - A severe hailstorm across the English Midlands on 28 June 2012.pdf

Edited December 17, 2023 by Metwatch

[A Face like Thunder]

28th June 2012, 'Thunder Thursday' and Newcastle was badly affected as well, see YouTube clips from the city, including the Tyne bridge being hit by lightning. 

[The Tall Weatherman]

I have highlighted some very interesting videos from this event including the full chase and the Sleaford tornado.

 

[Robert1981]

4 hours ago, The Tall Weatherman said:

I have highlighted some very interesting videos from this event including the full chase and the Sleaford tornado.

 

Great videos thanks for posting them loved watching them

[Sprites]

The radar has started the Xmas drinks early.

 

[Metwatch]

31 minutes ago, Sprites said:

The radar has started the Xmas drinks early.

 

 

 

[Sprites]

1 hour ago, Metwatch said:

 

 

I doubt all that purple freezing-rain is likely, temps are mostly above freezing. 

[WeatherArc]

Hi all, while we've been in the offseason for major convective activity i've been looking back at a few past notable severe thunderstorm/tornado events within the Uk, one of them being the July 28th 2005 Birmingham EF2/T4 tornado.

Recently environment data from the day of the event has been added to the tornado archive site, makes for some very interesting viewing.

At 500mb a trough was swinging in, note the enhanced flow in the exit region. Lots of Divergence aloft across both England and France. Although im not sure this divergence aided with the Birmingham event  its very likely the forcing allowed storms to fire across the open warm sector (France and southern/eastern England) leading to another supercell being reported near Cambridge/Lincolnshire and tornadoes in central France. The 500mb flow  out of the south east was around 40kts, sufficient speed shear for supercells.

Looking at the 850mb map things start to get interesting, a surface low had formed just off the north coast of Cornwall/South west coast of Pembrokeshire, this surface low would track to the north east during the day. A low level jet was present however the strongest flow was concentrated along the south coast (40kts) Birmingham was interestingly mostly removed from this flow with the LLJ being around 25kts. I usually think if the LLJ is under 30kts storms will struggle with tornadogenesis unless other factors can aid it, this is exactly what happened here.  

During the day a warm front extending east from the low would push northwards, at the time the tornado formed at around 2:30pm UTC this warm front was just north of Birmingham, this warm front was key to the severe weather setup, we know the boundaries of warm fronts concentrate low level rotation and aid cells with tornadogenesis.

This type of setup certainly wouldn't be amiss within the United States, especially during the winter months. 

A cold front was also present although very slow moving and difficult to make out.

Met Office FAX chart from the morning of the event. 

Looking at thermodynamics temperatures in the warm sector were widely around 23-25 degrees, this combined with dew points of around 17 degrees resulted in sbCAPE values of around 1000-2000 j/kg, more than sufficient for severe thunderstorms. As Birmingham was closer to the warm front and had been north of it for much of the morning stratiform clouds had tempered surface temps, this resulted in sbCAPE being around 700-1300 j/jg, although this was less than the cape further south it was still enough for storms to develop.

These cape values are very normal for summer, however its the hodographs for this event that stand out the most. 

Not often you see 600 j/kg+ of cape combined with clockwise curved, long and backed hodographs. Profile on the right is probably the most favorable one i've ever seen in the Uk for tornadoes, 150+ m2 of 0-1km SRH, 788 MLCAPE and favorable low level lapse rates (7.1c/km) interestingly mid and upper lapse rates are not favorable, some cells did struggle to get going within the warm sector, possibly due to this. The thing that stands out the most to me with that profile though is 3cape (145!) this large amount of instability in the lowest levels would of been able to very efficiently tilt and stretch any spin within storms, for context 3cape above 50 is considered enough for tornadogenesis. Also note the wind barbs on the profile, lots of veering with south easterlies turning to southerlies to westerlies with height. This veering allowed for good directional shear, the warm front would of also aided the low level shear, creating unusually favorable conditions for British tornadoes. 

Overall 6 tornadoes were reported in the Uk on the 28th July 2005, 2 in Birmingham 1 in Peterborough, 1 in Spalding, 1 in Melton Mowbray and 1 near Chesterfield, very active day of severe weather for Uk  standards, i believe large hail was also reported from the supercell in Cambridge, looking at the hodographs its no surprise, very long but with little to no curvature at the low levels. 2000 j/kg of cape also would of added to the active cells.  

Radar imagery for this event is unfortunately pretty nonexistent except for this one.

 

Despite this i have attempted to create a timeline of the event by using satellite imagery

The first cells fired at around 730 am close to Evesham likely due to breaks in the clouds (could also of been caused by warm air advection from the north moving warm front)  also indicating a cap wasn't present for this event, these initial showers were relatively weak although would develop over the next 3 hours as instability increased.

By around 930 the Evesham storm was well north of the warm front and had become elevated, it was likely sub severe for its entire life, primary cell development was held off by stratiform clouds covering most of the country.

Fast forward to midday, breaks in the cloud deck start to expand with surface heating underway, the breaks in the cloud allow for 4 small cells to develop in front of a dying thunderstorm near Bridgwater.

One of these cells in Gloucester rapidly develops into a supercell, moving north eastwards over Birmingham, this is likely where tornadogenesis occured as the cell was influenced by the increase of low level shear near the warm frontal boundary. 

Interestingly a cell fires to the storms south and very rapidly grows into another supercell, i wonder if the development of this cell had any affect on the tornadogenesis process, weve seen it countless times in the US where small cells fire and drift up/merge with a larger supercell causing its RFD to surge and initiating tornado development, shame we dont have anymore radar data.

Afterwards the two cells continue there north eastern track with the younger cell rapidly growing into a powerful supercell, although with the cells now north of the warm front they likely struggled to gain any severe characteristics and became elevated.  

 

 

As the day went on more cells began to fire as convective temperatures were breached and the warm sector became almost completely clear of clouds, look at those supercell anvils! Could seriously be looking at satellite for a severe weather event for the US. 

Another cell that caught my attention was the Peterborough cell forming at around 345pm in just 45 minutes it went from a small shower to a powerful looking supercell with likely severe weather, the two EF0 tornadoes very likely came from this cell. 

July 28th 2005 is one of the most high end convective severe weather days we have ever had in recent memory within this country, multiple supercells fired across a warm sector with both good instability and shear, i can only imagine what would of happened had there of been a cap during the morning hours and the 850mb winds had been stronger.

The Birmingham tornado tracked for 6.89 miles or 11.1 Kilometers, from Kings Heath to just north of the M6 in Erdington, causing 40 million pounds worth of damage. During its life the tornado went through multiple shapes, starting off as multiple vortex then becoming a wedge before finally roping out. Its peak width was 500m or 0.31 miles, lasting 20 minutes. 39 were injured. Somehow, amazingly there were absolutely no fatalities from a strong tornado moving through an extremely urbanized area. 

 

 

Some videos of the event 

(2mins 22 of this vid shows the multivortex stage of the tornado) 

I think the Birmingham tornado and the overall July 28th outbreak shows that we can get severe weather outbreaks within this country, it just takes the exact right combination of ingredients. There are also lots of similarities with severe events in the US with how that surface low was set up. Reminds me of a Cold-Core environment without the lower temperatures.

 

Lastly, the legendary Tim Marshall (senior meteorologist and surveyor who has helped analyse the damage of many major tornadoes such as 2013 Moore, 2011 Joplin,  2011 Super Outbreak, 1999 Moore and 1997 Jarrell) actually did a paper on this tornado, analysing the damage in depth and going over the meteorology, well worth a read. 

https://www.researchgate.net/publication/327022710_Birmingham_UK_Tornado_28_July_2005

Interestingly he notes that while houses in the UK are built very differently to the US (mainly the extensive use of brick) they performed in the exact same way as houses in the US when subjected to tornadic winds and offered little additional resistance. 

Edited December 20, 2023 by WeatherArc

[WeatherArc]

July 28th 2005-Tornadoes and hail.

28th June 2012-Tornadoes and sig hail.

10th September 2023-Sig hail and sig wind. 

Weird how storms from some of the most significant weather days we've had over the last 23 years have tracked over the exact same area of Lincolnshire. Storm capital of England?

Also just occurred to me how low topped the 2005 storms were and how explosive this years september supercell was, likely to do with it having 3,500+ sbcape to feed off.

Anyways due to the lack of anything properly convective in either the Uk or USA i think ill go into some deep winter hibernation for a while  hope everyone here has a great christmas and new year! 

[Arnie Pie]

 A lovely couple of posts here @WeatherArc

As the storm moved into the SW of Brum it passed over Bartley Green/ Weoley Castle, where we lived at the time

I can remember the intense rain and lightning which caused some local flooding, before moving on to drop the tornado over ' the Balti Triangle' to the East

[Robert1981]

there is 100 lightining stikes so far within an hour in the southwest of cornwall and of southern lreland.

[viking_smb]

12 minutes ago, Robert1981 said:

there is 100 lightining stikes so far within an hour in the southwest of cornwall and of southern lreland.

its to do with the trough over warm SSTs, the strikes will die off once they hit land 

[Robert1981]

24 minutes ago, viking_smb said:

its to do with the trough over warm SSTs, the strikes will die off once they hit land 

Thanks for the information  

[viking_smb]

4 minutes ago, Robert1981 said:

Thanks for the information  

no problem  

[LeeKay/]

Well, well Estofex has gave a storm warning.

Its been windy and gusty at times here, a destroyed fence panel; with the bins dancing around.

Weak orange glow again after sunset. Must be the jetstream overhead optical phenomina.

Keep a eye on the squall line thats currently entering south Wales i think that was the reason for the forecast from Estofex Quote:

A level 2 was issued across parts of far SE-Ireland/NW-UK mainly for (extremely) severe wind gusts but also for a nocturnal tornado threat with a strong event possible.

A level 1 surrounds the level 2 with similar hazards but lower probabilities.

https://www.estofex.org/

 

[LeeKay/]

Update, i was wrong. The small squall dissipated.

Im sorry i was to early.

A few strikes to Mid Wales just now.

Main feature is now the much stronger squall to southern Ireland area bearing North East also giving off some lightning too.

Again, i could be wrong but worth keeping a eye on.

 

[Robert1981]

21 minutes ago, LeeKay/ said:

Update, i was wrong. The small squall dissipated.

Im sorry i was to early.

A few strikes to Mid Wales just now.

Main feature is now the much stronger squall to southern Ireland area bearing North East also giving off some lightning too.

Again, i could be wrong but worth keeping a eye on.

 

what map is that from at the bottom please ?

[Robert1981]

plenty of lightinging happening near north wales heading towards bangor and holyhead also a bit of lightining around lockbie.

[andy989]

Very decent unexpected thunderstorm here with frequent lightning 

[andy989]

This would explain the torrential hail and booming thunder we are having, look at the definition of that line 

[StingJet]

9 minutes ago, andy989 said:

Very decent unexpected thunderstorm here with frequent lightning 

likewise here too 

 

[Convective]

Very impressive for late December!

[andy989]

Well that was a nice treat. I didn’t look at the forecast/keep up with convective outlook last few days. Was this on the cards?

 

 

 

 

[Dangerous55019]

Holy cow that was a good rumble of thunder!!

Forked lightning as well!!

Just been out with the dog… I have to say that this is very unexpected, (but most welcome) for late December.

[LeeKay/]

Its a old habit for me i tend to look at all convective outlooks, day in day out what ever time of year.

Glad that lightning is showing but its the time to be very aware of wind gusts now possible 3 hours of peak activity now.