Storms and Convective Discussion - 20th April 2019 onwards

[Dreckly]

As a newbie I found this definition of CAPE very informative reading https://www.essl.org/cwg/res/zagreb2014/session1/Putsay_Session_1.pdf

[Bangers & Flash]

Certainly an exciting week of weather and model-watching ahead.

Intrigued by the forecasts published by Convective Weather,  the Met Office and PJB over on UKWW for this area (NW England) for tomorrow and early Monday and keeping a close eye on any updates.

Good luck everyone - look forward to reading updates and seeing photos/videos as the week progresses.

[ChezWeather]

Updated risk map from PJB (UKWW)

[Bangers & Flash]

Update from Convective Weather for Monday too, narrowing down the slight risks: https://www.convectiveweather.co.uk/forecast.php?date=2019-06-24

Day 3 Convective Outlook

VALID 06:00 UTC Mon 24 Jun 2019 - 05:59 UTC Tue 25 Jun 2019

ISSUED 20:58 UTC Sat 22 Jun 2019

ISSUED BY: Dan

On Monday morning, elevated thunderstorms may be ongoing across parts of Ireland across the Irish Sea to northern England, along the rear side of the frontal rain. This will continue to lift northwards into southern and eastern Scotland and out across the North Sea as the day progresses.

In its wake, a second shortwave impulse will arrive by late morning or the afternoon, and so a second round of thunderstorms is possible, particularly over northern England - but possibly some areas farther south too, depending on the timing/phasing of this shortwave. At a glance, forecast profiles look capped to surface-based convection, and so it is quite likely much of this activity will be elevated. That said, isolated surface-based convection cannot be ruled out, especially where initially elevated convection can root within the boundary layer. The environment is likely to be well-sheared, with both reasonable speed and directional shear present, enabling cell organisation. Hail and flash flooding may be problematic. This potential may be somewhat contaminated by hints of some frontal (dynamic) precipitation running up from the south at times too.

Scattered showers and a few thunderstorms will also be possible over parts of Northern Ireland and the Republic of Ireland on Monday afternoon / early evening in the post-frontal environment - although here, with closer proximity to the upper low, the environment will be less-sheared and so "pulse type" convection is most favoured.

On Monday evening, a shortwave over Biscay combined with isentropic upglide as a renewed pulse of very warm, moist low-level air advects north/northeastward will result in another round of elevated thunderstorms, though this time the steering flow will tend to drift these towards SE England and eastern parts of East Anglia. There has been fairly uniform agreement amongst model guidance for the track of these to shift farther to the east than earlier signals, and should this trend continue then it is possible the majority of thunderstorms could skirt to the east of England entirely.

This extended outlook provides an overview of the most likely forecast evolution during this forecast period - destabilising plume events are often fraught with uncertainty, and it is very likely certain aspects of the forecast will change as the event draws closer. 

[Mapantz]

convective weather's SLGT for the SE is pretty much a match with the UKV.

[ChezWeather]

Hi Res precip models are now in range of tomorrows event

AROME has storms moving N/NE during evening hours

Followed by a larger mass of precip forming further North during the night

 

Edited June 22, 2019 by ChezWeather

[ChezWeather]

  EURO kicking things off alot further South

NetWx SR has storms over N Wales in the evening

Followed by more widespread storms moving N/NE through the night

[TJS1998Tom]

8 minutes ago, ChezWeather said:

Hi Res precip models are now in range of tomorrows event

AROME has storms moving N/NE during evening hours

Followed by a larger mass of precip forming further North during the night

 

 Really hope we get some of these, or maybe even some elevated lightning from nearby storms

[Zak M]

30 minutes ago, ChezWeather said:

 

If this pulls off, then my goodness I will be a happy guy.

[Flash bang flash bang etc]

1 minute ago, zmstorm said:

If this pulls off, then my goodness I will be a happy guy.

That would be AWESOME

[Cheshire Freeze]

I must say, compared to a few days ago, this spell is looking really really underwhelming from a storm perspective now. That flow from the N Sea looks to dampen the fun and games.

Even worse, it looks like the Azores HP will nose in after. We all know what that means- convection MIA.

Why is it so hard to get a proper thundery plume??

[Mapantz]

5 minutes ago, CreweCold said:

I must say, compared to a few days ago, this spell is looking really really underwhelming from a storm perspective now. That flow from the N Sea looks to dampen the fun and games.

Even worse, it looks like the Azores HP will nose in after. We all know what that means- convection MIA.

Why is it so hard to get a proper thundery plume??

If I had a choice to teleport to your location or stay here and wait for a storm, i'd be prepping my tardis. 

[Flash bang flash bang etc]

9 minutes ago, CreweCold said:

I must say, compared to a few days ago, this spell is looking really really underwhelming from a storm perspective now. That flow from the N Sea looks to dampen the fun and games.

Even worse, it looks like the Azores HP will nose in after. We all know what that means- convection MIA.

Why is it so hard to get a proper thundery plume??

Just wait and see how things pan out. Remember a small change tomo can spell a bigger shift as the week progresses

[Flash bang flash bang etc]

Is it safe to say tomorrow night will be more akin to a briskly moving thundery squall, than an MCS?

[ancientsolar]

might not be very relevant , but there is already a thunderstorm in the Atlantic , surely.. must be hard to squeeze a thunderstorm that far out in the atlantic.. and it's coming towards us? probably will die.. but the ingredients must be something special?

[Flash bang flash bang etc]

22 minutes ago, ancientsolar said:

might not be very relevant , but there is already a thunderstorm in the Atlantic , surely.. must be hard to squeeze a thunderstorm that far out in the atlantic.. and it's coming towards us? probably will die.. but the ingredients must be something special?

The Azores low making itself known on the approach, perhaps?

[Chris.R]

 Still above 17°C here. Already having trouble sleeping and it’s not even started yet supposedly. 

[Flash bang flash bang etc]

30 minutes ago, Chris.R said:

 Still above 17°C here. Already having trouble sleeping and it’s not even started yet supposedly. 

Quite cold here, was even thinking of putting the bed heater on

[TJS1998Tom]

An interesting line there 

[Met.]

Me mutha was getting a bit worried about thunderstorms tomorrow. We're going to walk in the park, and she doesn't want to be caught in lightning. i tried to explain that there's more chance of a tree falling on our heads than even seeing lightning around here!!!! 

[ChezWeather]

Update from Convective Weather, now with large MDT zone 

http://www.convectiveweather.co.uk/forecast.php?date=2019-06-23

Day 1 Convective Outlook

VALID 06:00 UTC Sun 23 Jun 2019 - 05:59 UTC Mon 24 Jun 2019

ISSUED 06:39 UTC Sun 23 Jun 2019

ISSUED BY: Dan

Longwave trough will linger over the Atlantic close to western Europe on Sunday, the southerly flow on its forward flank encouraging advection of a high Theta-W airmass.

Ahead of this, an isolated heavy shower / thunderstorm is possible during Sunday afternoon / early evening in a zone from Cen S England / S + W Midlands / Wales. However, despite profiles exhibiting reasonable speed and directional shear to aid organisation, one or more warm noses may significantly restrict cloud depth and so the risk of lightning is treated with quite a low probability for now. It is more likely that outbreaks of largely dynamic rain will be falling from medium-level cloud over Wales / Midlands, associated with the warm front slowly lifting northward. A few showers are also likely in N and W Scotland, but limited in depth and so the lightning risk is considered quite low.

Main thunderstorm interest is during Sunday night. By Sunday evening, frontal rain will likely already be affecting parts of SW England, Wales, W Midlands and Ireland. A lead shortwave impulse in the strong southerly flow aloft will aid ascent, coupled with isentropic upglide. CAPE values of 500-1,000 J/kg are expected, this instability being released through the course of the night. 

In a semi-random fashion, scattered elevated thunderstorms will develop, although there is considerable uncertainty over exactly where and when, hence a very broad SLGT area. We suspect much of the thunderstorm activity will be primarily focussed along two main Theta-E ridges. This would suggest one round over the East Midlands / Lincs / Yorks, and into NE England later in the night - this may also extend into parts of East Anglia for a time, depending on how quickly the plume destabilises (the earlier, the more widespread the risk is before moving offshore).

A second area of interest would then be Wales, perhaps the W Midlands, moving NW-wards across the Irish Sea towards eastern Ireland - perhaps expanding across to NW England later in the night. Given the magnitude of CAPE/shear, lightning will tend to be very frequent with any thunderstorms that do develop, accompanied by the threat of hail, gusty winds and locally very heavy rain.

Given the large uncertainty about storm placement at present, it is difficult to highlight specific areas for a MDT. We have issued one where there is better multi-model consensus, but it is acknowledged that scattered thunderstorms will develop elsewhere as well. We will continue to monitor trends throughout the day, and may issue further updates if necessary.

 

[Azazel]

This really is giving the experts a headache so I commend their time and effort combing through all the models to try and make sense of it.

Doesn’t look good for my area down south at all anymore so I’ve got a horrible feeling this summer’s total thunder days will remain at one clap from a distant shower. Pinning my hopes on next Saturday now and hoping it all goes out with a bang and doesn’t just devolve into drizzle like has been so often the case in recent years. 

[P-M]

Well I've got me fingers and toes crossed. In Washington I'm covered under the slight and literally just outside of the moderate. If storms develop as close as that moderate zone then it's not much of a push for my neck of the woods. Either way some potential interest for many this evening as long as storms initiate! 

 

Happy hunting / radar tracking! 

[NO LONGER POSTING]

All getting very messy...I am sure some will see some storms but for now I wouldn't focus much energy on models or forecasts.. Instead try gauge rough areas then radar watch :?

[Thunder and Lightning]

All the models just keep pushing main severe risk further and further back, now its Saturday and I feel like it will never happen. The UK weather is terrible.