Storms and Convective Discussion - 25th June 2019 onwards

[Lu.]

16 minutes ago, Flash bang flash bang etc said:

Direction of storms might work in your favour, sliding ENE parallel with the M3 - possibly even more eastwardly than that.

Always a good track for our area 

Time will tell.

Will radar watching tommorow as the IOW always seems to kill the storm or split it. Willing to travel due to being on annual leave so will keep an eye out on what people expect tommorow

So far Ventusky is showing some good signs of life all across the south

[Zak M]

1 minute ago, Flash bang flash bang etc said:

At a fairly short time frame this should cheer a few people up

I highly doubt that there will be storms over Ireland and Western Wales in the morning. There is a lot of humidity around there although not much in terms of CAPE. There will probably just be sporadic lightning strikes.

[Mapantz]

Not convinced by the author of that warning map. The UKV doesn't show anything spectacular on Friday evening - in the purple box. If anything, early Saturday looks better for areas slightly above the purple box.

[Raindrops]

Looks like I need to rise from the dead early in the morning as convection may start from 9am onwards, I'm not found of early/late afternoon storms.

 

Edit:update

Ah thank you Met Eireann, puts a smile on my face.

Rain will become widespread and heavy Friday morning, with some localized spot flooding and thundery downpours. Brighter conditions with showers will follow into southern areas by afternoon and extend north eastwards through the course of the day. The showers will be heavy and possibly accompanied by hail, with further thunderstorms developing in many areas. Some localized spot flooding along with some hazardous driving conditions likely through the course of the afternoon and evening. Top temperatures of 18 to 22 degrees generally, but 16 or 17 degrees in the north and northwest. Moderate southeasterly winds will veer southwesterly as the rain clears and increase fresh to strong and gusty over Munster and Leinster during the afternoon.

I do wish they would put out Thunderstorm warnings for the Counties but that will probably come 1-2hrs before anything happens..or while it's happening, which is a little to late by then.

Edited July 18, 2019 by Raindrops

[TJS1998Tom]

22 minutes ago, Raindrops said:

Looks like I need to rise from the dead early in the morning as convection may start from 9am onwards, I'm not found of early/late afternoon storms.

 

Edit:update

Ah thank you Met Eireann, puts a smile on my face.

Rain will become widespread and heavy Friday morning, with some localized spot flooding and thundery downpours. Brighter conditions with showers will follow into southern areas by afternoon and extend north eastwards through the course of the day. The showers will be heavy and possibly accompanied by hail, with further thunderstorms developing in many areas. Some localized spot flooding along with some hazardous driving conditions likely through the course of the afternoon and evening. Top temperatures of 18 to 22 degrees generally, but 16 or 17 degrees in the north and northwest. Moderate southeasterly winds will veer southwesterly as the rain clears and increase fresh to strong and gusty over Munster and Leinster during the afternoon.

I do wish they would put out Thunderstorm warnings for the Counties but that will probably come 1-2hrs before anything happens..or while it's happening, which is a little to late by then.

I imagine Met Office tomorrow may put an extra warning elsewhere such as other areas in the South perhaps like Kent

[Summer Sun]

Day 2 Convective Outlook

VALID 06:00 UTC Fri 19 Jul 2019 - 05:59 UTC Sat 20 Jul 2019

ISSUED 20:14 UTC Thu 18 Jul 2019

ISSUED BY: Dan

A broad upper trough will linger to the northwest of the British Isles on Friday, with strong southwesterly flow aloft on its forward side. A pronounced shortwave will approach the Celtic Sea late in the afternoon, swinging across Ireland during the evening and England/Wales overnight. This forecast period is rather messy, and so pinning down the local detail is rather tricky and nowcasting will play a key role.

... S IRELAND / CELTIC SEA / SW WALES: MORNING ...

A complex pattern will evolve during Friday, as a rather elongated and slack surface low drifts northeast across Ireland towards SW Scotland / NW England during the forecast period. Embedded elevated convection with some sporadic lightning is possible first thing on Friday morning over the Celtic Sea / S Ireland / SW Wales, but any lightning will tend to reduce with time as the intensity weakens during the morning hours.

... IRELAND: AFTERNOON / EVENING ...

In the wake of any morning activity, provided sufficient cloud breaks occur over central and southern Ireland, a notably unstable airmass (600-1,000 J/kg CAPE) will be possible here by midday and through the afternoon hours given heating of a warm, moist low-level airmass. Wind convergence, local topography and a differential heating boundary may all contribute to the development of scattered thunderstorms during the afternoon and evening hours, in an environment with 30kts DLS and forced ascent on the leading edge of the approaching shortwave.

Hail up to 1.5cm in diameter and an isolated tornado cannot be ruled out, given locally backed surface winds to the northeast of the surface low. The exact location of the narrow corridor where low-level shear will be maximised (along the convergence zone) is a little uncertain, and heavily dependent on the shape / elongated nature of the surface low - and nowcasting will be essential for detecting this risk. The convergence zone will tend to extend across the Irish Sea towards NW England, and so scattered heavy showers and isolated thunderstorms will also be possible over these areas.

One main concern is the close proximity to the wrap-around occlusion and the potential therefore for cloud cover to limit the amount of insolation.

... ENGLAND / WALES: DAYTIME ...

Frontal rain will continue to drift northwards and eastwards, perhaps with isolated embedded lightning but the risk is considered relatively low. If any clearance can occur to allow some surface heating during the afternoon / evening, scattered showers may also develop - particularly along a zone of low-level convergence from the Severn Estuary to The Wash - and therefore pose somewhat of a lightning risk. Confidence is low, but a low-end SLGT has been issued.

... CS / SE ENGLAND / EAST ANGLIA: OVERNIGHT ...

On Friday night a renewed surge of very warm, moist low-level air will approach from Biscay, as the approaching shortwave encourages poleward warm advection. Showery bursts of rain will affect southern and southeastern England, with elements of embedded convection giving locally heavy rain and a few isolated lightning strikes. Confidence is low, but there could be a few better-organised thunderstorms developing over the English Channel and running NE-wards with time (more especially after midnight), either over or to the east of Kent/Sussex - hence the inclusion of a SLGT here.

http://www.convectiveweather.co.uk/forecast.php?date=2019-07-19

[Raindrops]

11 minutes ago, Summer Sun said:

Day 2 Convective Outlook

VALID 06:00 UTC Fri 19 Jul 2019 - 05:59 UTC Sat 20 Jul 2019

ISSUED 20:14 UTC Thu 18 Jul 2019

ISSUED BY: Dan

A broad upper trough will linger to the northwest of the British Isles on Friday, with strong southwesterly flow aloft on its forward side. A pronounced shortwave will approach the Celtic Sea late in the afternoon, swinging across Ireland during the evening and England/Wales overnight. This forecast period is rather messy, and so pinning down the local detail is rather tricky and nowcasting will play a key role.

... S IRELAND / CELTIC SEA / SW WALES: MORNING ...

A complex pattern will evolve during Friday, as a rather elongated and slack surface low drifts northeast across Ireland towards SW Scotland / NW England during the forecast period. Embedded elevated convection with some sporadic lightning is possible first thing on Friday morning over the Celtic Sea / S Ireland / SW Wales, but any lightning will tend to reduce with time as the intensity weakens during the morning hours.

... IRELAND: AFTERNOON / EVENING ...

In the wake of any morning activity, provided sufficient cloud breaks occur over central and southern Ireland, a notably unstable airmass (600-1,000 J/kg CAPE) will be possible here by midday and through the afternoon hours given heating of a warm, moist low-level airmass. Wind convergence, local topography and a differential heating boundary may all contribute to the development of scattered thunderstorms during the afternoon and evening hours, in an environment with 30kts DLS and forced ascent on the leading edge of the approaching shortwave.

Hail up to 1.5cm in diameter and an isolated tornado cannot be ruled out, given locally backed surface winds to the northeast of the surface low. The exact location of the narrow corridor where low-level shear will be maximised (along the convergence zone) is a little uncertain, and heavily dependent on the shape / elongated nature of the surface low - and nowcasting will be essential for detecting this risk. The convergence zone will tend to extend across the Irish Sea towards NW England, and so scattered heavy showers and isolated thunderstorms will also be possible over these areas.

One main concern is the close proximity to the wrap-around occlusion and the potential therefore for cloud cover to limit the amount of insolation.

... ENGLAND / WALES: DAYTIME ...

Frontal rain will continue to drift northwards and eastwards, perhaps with isolated embedded lightning but the risk is considered relatively low. If any clearance can occur to allow some surface heating during the afternoon / evening, scattered showers may also develop - particularly along a zone of low-level convergence from the Severn Estuary to The Wash - and therefore pose somewhat of a lightning risk. Confidence is low, but a low-end SLGT has been issued.

... CS / SE ENGLAND / EAST ANGLIA: OVERNIGHT ...

On Friday night a renewed surge of very warm, moist low-level air will approach from Biscay, as the approaching shortwave encourages poleward warm advection. Showery bursts of rain will affect southern and southeastern England, with elements of embedded convection giving locally heavy rain and a few isolated lightning strikes. Confidence is low, but there could be a few better-organised thunderstorms developing over the English Channel and running NE-wards with time (more especially after midnight), either over or to the east of Kent/Sussex - hence the inclusion of a SLGT here.

http://www.convectiveweather.co.uk/forecast.php?date=2019-07-19

Sounds spot on to me, the cloud covering will be an issue from 06z-12z -_- , but after that maybe just maybe I might be lucky enough for afternoon/evening heating.

Image from wetterzentrale.de

[oliverek7]

We should turn to this eh? I know it’s 6 days away but just look at what could happen after all that heat and humidity builds, big explosions potentially! 

[Raindrops]

3 hours ago, zmstorm said:

I highly doubt that there will be storms over Ireland and Western Wales in the morning. There is a lot of humidity around there although not much in terms of CAPE. There will probably just be sporadic lightning strikes.

Storms here can be unpredictable, I remember a time when Met Eireann and Estofex or any forums didn't predict a somewhat sever storm back in 2007 I think, it caused flooding and power outages, 3 inches or more rain in less than 45mins. What a beautiful evening that was.

Wow my memory is good after all ha.

Read this News Irish News, it happened this date 11 years ago....oh crap.

Actually I just got a flash back, I recall Estofex updating a warning to Lvl 1.....after the Storm had hit and passed somewhat an hour later .

Edited July 18, 2019 by Raindrops

[Raindrops]

58 minutes ago, TJS1998Tom said:

I imagine Met Office tomorrow may put an extra warning elsewhere such as other areas in the South perhaps like Kent

Ah the Met Office is mostly one step ahead(as I have seen here on this forum)compared to Met Eireann, I'm not putting down Met Eireann they do a good job but they don't seem to concentrate on Thunderstorms for some bizarre reason , only in the past few months have they decided to integrate lightning strikes on the rainfall radar, but even that is to slow, hence the reason why I mostly use other sources for information ie Netweather, Wetterzentrale, Blitzortung.org ete etc.

[Flash bang flash bang etc]

I don’t see anywhere any mention of ‘frequent’ lightning or ‘organised’ storms - other than possibly for Kent later in the evening, so I would hazard a guess that it’s more likely to be thundery rain for most of the country, for most of the day.

As been mentioned already cloud cover could be quite an issue for the majority - providing underwhelming CAPE for a lot of areas in the risk zone - so as far as lightning is concerned I wouldn’t expect anything too remarkable.

Still, storms are storms and it’s better than what we usually get...  

Might Head out later tomorrow evening towards Box Hill depending on the behaviour of that warm sector in the south.

Radar watching for certain tomo

Edited July 18, 2019 by Flash bang flash bang etc

[Raindrops]

Storm Forecast ESTOFEX

Storm Forecast
Valid: Fri 19 Jul 2019 06:00 to Sat 20 Jul 2019 06:00 UTC
Issued: Thu 18 Jul 2019 20:59
Forecaster: PISTOTNIK

A level 1 is issued for Ireland and England mainly for excessive convective precipitation and tornadoes.

Level 1 areas are issued for various parts of central Europe, SE Europe, the Georgian and Russian Caucasus region and NW Russia mainly for excessive convective precipitation and to a lesser degree for large hail.

A level 1 is issued for the E Black Sea mainly for non-supercellular tornadoes (waterspouts).

SYNOPSIS
A broad, weak to moderate westerly flow stretches across Europe. Two mature cyclones are located between Iceland and Scotland and over NW Russia, respectively. The tails of their largely occluded frontal systems fan out into a main frontal zone that runs between 50 and 55N and sharpens somewhat to the west, where a frontal wave crosses Ireland and Scotland.
A subtropic high pressure systeme with very warm air covers the S half of Europe.

DISCUSSION
... Ireland and England ...

Warm and very moist air is advected into Ireland and England in the warm sector of the frontal wave. Despite poor lapse rates, daytime heating will allow around 500 J/kg of CAPE over Ireland, while this buildup will be slower and weaker over England. Moderate to strong vertical wind shear (0-3 km: ~15 m/s, 0-1 km: ~10 m/s) overspreads the unstable air. Vertical wind profiles are strongly veering near the warm front with 0-3 km storm-relative helicity on the order of 200 m^2/s^2, before they straighten to some degree in the warm sector.
The rain shield of the warm front, which might already include a few embedded thunderstorms, will largely clear Ireland by 12 UTC and England by 15 UTC. Scattered thunderstorms will then initiate in the warm sector in the late morning to afternoon, aided by daytime heating, sea breeze fronts and strong synoptic lift ahead of a short-wave trough, and will organize into multicells and perhaps a few supercells. Possibly training storms and high precipitation efficiency in the very moist air could support some heavy rain events with a possibility of flooding. In addition, one or two tornadoes could spin up, especially if clearing skies and insolation follow soon after the warm front passage, while wind profiles are still most supportive. The hail and wind risk is limited by poor lapse rates and very moist air, though marginally large hail or a hail cover are not ruled out in case of a supercell.
Storms will gradually decay when they move offshore onto the North Sea. The cold front may push new rounds of (partly embedded and weakly electrified) convection SE-ward into S England and the Channel region overnight, but they will struggle to stay surface-based. The severe weather risk decreases overnight, though plentiful rain could still accumulate.

... Spain ...

Forecast models agree on patchy CAPE on the order of some hundred J/kg in the sea breeze and upvalley flow regimes that push deeply inland from the N and E coast and up the Ebro valley. These thermal circulations are opposed to the mid-level flow and therefore also feature enhanced 0-3 km shear around 15 m/s.
In the absence of synoptic lift, convective initiation is the critical issue. Any updraft will encounter strong entrainment of very dry air. The most likely scenario is that only a few struggling and short-lived evening storms will form. However, in case the capping inversion on top of the sea breezes and the entrainment can be overcome for a longer time, large hail and (dry) downbursts are possible.

... other continental thunderstorm areas ...

Quiescent synoptic conditions will allow some hundred J/kg of CAPE over wide sreas. Isolated to scattered, mostly daytime-driven storms are expected, especially over orographic features and along the occluding frontal system of the Russian cyclone.
Vertical wind shear is weak across low levels before it regionally rises to moderate values across the 0-6 km layer (e.g. around 10 m/s over Germany, the Czech Republic and Austria, parts of Romania, Turkey and Georgia and surroundings, and up to 15 m/s in the Russian warm sector). Most storms will therefore be single- or multicellular and pose a main risk of heavy rain. A few moderately large hail events are possible with the strongest pulse storms, especially in the regions with slightly enhanced shear mentioned above and over the Balkans, where the CAPE magnitude is highest. These regions wioth a combined heavy rain and hail risk are upgraded to a level 1.
The severe weather risk appears relatively highest in the warm sector of the Russian cyclone, but some doubts exist whether the 800-1500 J/kg CAPE suggested by ECMWF, ICON and GFS can indeed materialize. A possibility of too early, widespread initiation and a lack of foci for a higher concentration of severe weather events therefore preclude a level 2.

... E Black Sea ...

A shallow warm-core depression will likely allow some offshore convection, especially early in the forecast period. Low cloud bases and converging winds could allow a few non-supercellular tornadoes (waterspouts).

Edited July 18, 2019 by Raindrops

[Zak M]

Some lightning over south-western Wales currently.

Is it just me or does this precipitation look like a rocket that's flying west?

Edited July 19, 2019 by zmstorm

[Flash bang flash bang etc]

Just now, zmstorm said:

Is it just me or does this precipitation look like a rocket that's flying west?

What are you suggesting?

[Zak M]

Just now, Flash bang flash bang etc said:

What are you suggesting?

Well, it probably is just me then 

[Flash bang flash bang etc]

Looks like there’s a lot of cloud about but I am hopeful that quite a few people will see something today although it must be stressed the severe element seems to be missing today, as storms parameters are generally quite negligible.

Looks like the best chance for lightning would be later in the day over central England and some potential for things to spark up with a little more aggression over the SE around midnight.

Rain (and the timing of it) seems to be the significant concern - could be quite tricky driving conditions about so ppl take care on the roads

[Azazel]

10 hours ago, Oliver Wyndham-lewis said:

We should turn to this eh? I know it’s 6 days away but just look at what could happen after all that heat and humidity builds, big explosions potentially! 

Yay another Kent event while the rest of us get nothing.

Looks like i'm in the firing line over the next 36 hours though I don't expect much from embedded convection - maybe the odd rumble but no structure etc.

[ancientsolar]

I have my video camera on charge, just in case something hits SE Wales in the next 30 mins... unfortunately my parrot has decided to start squawking

[Thunder and Lightning]

Hoping that the Estofex forecast will come to light. Hoping some surface heating could trigger something. Helicity values over 200 in my area by 1PM. Sun just poking through (which isn't supposed to happen) If this continues I might get something rather interesting!

[Raindrops]

Good Morning to all .

Met Eireann Warnings

DUBLIN WARNINGS
Status: Yellow
Rainfall warning for Ireland
Status Yellow - Rainfall warning for Ireland
Heavy thundery downpours will give high totals of rainfall in short spaces of time today/early tonight leading to localized spot flooding.

Valid: Friday 19 July 2019 06:00 to Saturday 20 July 2019 03:00

Issued: Friday 19 July 2019 06:00

NATIONAL WARNINGS
Status: Yellow
Rainfall warning for Ireland
Status Yellow - Rainfall warning for Ireland
Heavy thundery downpours will give high totals of rainfall in short spaces of time today/early tonight leading to localized spot flooding.

Valid: Friday 19 July 2019 06:00 to Saturday 20 July 2019 03:00

Hopefully after 12pm there will be some Orange warnings, lets wait and see what mother nature has in store.

Edited July 19, 2019 by Raindrops

[StormLoser]

I am....scratching my head. The Met Office have issued weather warnings of risks of storms in mostly Scotland for the next few days. Good luck folks there!

But...why none of their inane yellow warnings for the massive bulk of rain wandering through England north of London right now?  Surely that inundation must count for a risk of flooding?

I don't get the Met Orifice and their yellow warnings. They make no sense. Never have to me.   

[Mr Frost]

1 minute ago, StormLoser said:

I am....scratching my head. The Met Office have issued weather warnings of risks of storms in mostly Scotland for the next few days. Good luck folks there!

But...why none of their inane yellow warnings for the massive bulk of rain wandering through England north of London right now?  Surely that inundation must count for a risk of flooding?

I don't get the Met Orifice and their yellow warnings. They make no sense. Never have to me.   

Indeed - living in the West of Scotland I have never known so many thunderstorm risks/warnings for this area. (It has been almost on a weekly basis since mid June)

Risk of overnight thunderstorms - which is always the best kind! We shall see.

[Raindrops]

9 minutes ago, StormLoser said:

I am....scratching my head. The Met Office have issued weather warnings of risks of storms in mostly Scotland for the next few days. Good luck folks there!

But...why none of their inane yellow warnings for the massive bulk of rain wandering through England north of London right now?  Surely that inundation must count for a risk of flooding?

I don't get the Met Orifice and their yellow warnings. They make no sense. Never have to me.   

There was a warning for South Wales for rain, indeed there were some heavy downfalls showing on the radar, that time has come and passed. As for the rain heading towards north London it does seem to to be losing intensity also moving fast. If it was lingering/stalling then it would be problematic, but hey what do I know I live miles away haha.

[Thunder and Lightning]

3 minutes ago, Raindrops said:

There was a warning for South Wales for rain, indeed there were some heavy downfalls showing on the radar, that time has come and passed. As for the rain heading towards north London it does seem to to be losing intensity also moving fast. If it was lingering/stalling then it would be problematic, but hey what do I know I live miles away haha.

I'm a Londoner. I just set up time lapse but hoping the rain will pass soon because I want the more interesting weather to happen later.

[BrickFielder]

Quite a serious risk of a severe storm for parts of Ireland today with low level convergence and significant wind shear. Elsewhere cloud cover and lack of instability will most likely limit things. I am however watching a lobe of vorticity running along the front and approaching from the south west. This could affect Wales later on. The complicated frontal pattern it is tricky to call. We should probably keep an eye on Cumbria and the Scotish borders  as storms over Ireland drift that way later. on.

 

For tomorrow then there is a suggested risk on the modelling for convergence zones to set up in bands across the country. Winds will be uni directional and instability not that strong. Something to watch out for tomorrow.