Storms and Convective discussion - June 2023

[TwisterGirl81]

Exeter average rainfall in June is 2.12 inches so 53.8mm, we’ve barely had  5mm so for this month, keeping everything crossed we get a very heavy bout of rain soon 

[alexisj9]

11 minutes ago, Steel City Skies said:

I'd be surprised if stuff clipping the SE would have a huge effect right through later on tomorrow, no? 

It's going to head north to you, it probably is part of your event.

[camturbo]

7 minutes ago, mike5900 said:

Showers now forming Lyme bay.

Yep I just seen that very much doubt it will spark up but might get some welcome wet stuff 

[LeeRoyxD]

 Please make it across! I feel like it hasn't rained for 2 months in Seaford and let alone a good storm!! 

[Azazel]

Really need stuff to start firing in that massive gap 

[ChezWeather]

4 hours ago, Jo-anne said:

As I've said before I'm terrified of storms and with it saying we are expecting them for a few days could you knowledgeable lot let me know roughly when they would be for my area ie. Overnight or morning or afternoon if you can and don't mind, on the map I'm the blue pin I'm below @ChezWeather and a few of more of you, you all are really helping me stay calmer longer knowing where its coming. Thank you ☺ 

If storms are coming, I'll be in this thread posting

[Me & angel fiance]

24 minutes ago, ChannelThunder said:

Yeah, Blitz is best, particularly their live map version: https://map.blitzortung.org/#5.82/50.972/-0.759

You don't need the app, that page works great on mobile browser.

That's great and thank you.. Between that and the NW one I stay.. with everything crossed for an overnight storm but not too bad as long a manage one one the next 24 hours I'll be happy

[ChannelThunder]

Anyone living between Hastings and Dungeness seem very well placed for that channel storm to make landfall possibly around midnight.

[Southern Storm]

I decided to take a drive to Barton on sea clifftop, very calm, hardly a breath of wind, calm before the storm maybe. 

 mid level instability passing over my location also

[Mapantz]

Sunday in to Monday: 

[LeeRoyxD]

We seriously need rain down here  

[Jamie M]

 

Day 2 Convective Outlook

VALID 06:00 UTC Sun 18 Jun 2023 - 05:59 UTC Mon 19 Jun 2023

ISSUED 21:20 UTC Sat 17 Jun 2023

ISSUED BY: Dan

A broad upper low will remain to the west of Ireland on Sunday, with a relatively high Theta-W airmass (>16C at 850hPa) covering much of the British Isles. A shortwave trough migrating northwards on the eastern flank of the upper low may provide the focus for scattered elevated showers or thunderstorms across parts of northern and eastern England on Sunday morning, the focus then shifting to W/SW Scotland by the afternoon. In its wake, a humid airmass persists (dewpoints 17-19C) which, coupled with subtle forcing aloft, could still generate semi-random elevated showers/thunderstorms throughout the morning and early afternoon, this perhaps most likely (but far from guaranteed) over East Anglia/SE England. Depending on the extent of this activity (and associated cloud cover/rain-cooled air), this may have ramifications as to how the rest of the day evolves. Otherwise, fairly extensive high cloud is anticipated across much of England and Wales, but sufficiently thin/broken in places to allow a degree of surface heating through the day. Forecast soundings suggest near-surface temperatures of 21-22C will be required to erode SBCIN, and so given the moist boundary layer it seems plausible scattered showers may develop fairly readily with CAM guidance indicating initiation over the Midlands and southern England from around 11-13z onwards. A weak surface low is expected to develop and slowly deepen over central England during the afternoon, with increasing low-level convergence in the vicinity also aiding forced ascent. 

Later in the afternoon a more robust vorticity lobe, emanating from NW Iberia early in the morning, will approach southern England and the synoptic scale ascent associated with this will encourage thunderstorms to grow upscale during the late afternoon and evening hours, initially into an MCS across the East Midlands and western East Anglia, but eventually a larger mass of heavy rain over northern England later in the evening. Forecast profiles appear very moist, yielding rather tall but skinny CAPE, which coupled with PWAT 30-40mm and approximately one third of the convective cloud in the >0C layer contributing to efficient warm rain processes, suggests the potential for significant rainfall accumulations - perhaps locally in excess of 40mm in 1 hour. A SVR was issued primarily for the risk of flash flooding (especially where multiple cells train/backbuild over the same area), and to a lesser extent for isolated ≥2cm hail given a favourable kinematic environment for updraft/downdraft separation and cell organisation, this perhaps most pronounced across the north and east Midlands into East Anglia where the low-level winds will be most backed on the north/northeast flank of the surface low. These areas will also have a slightly higher chance of an isolated tornado given substantial low-level directional wind shear and progressively lowering cloud bases through the afternoon.

 

A trailing line of thunderstorms may affect other parts of East Anglia/SE England during the evening hours, linked to a substantial bowing segment that is expected to form over NE France - although much of the lightning activity associated with this feature may remain over France/English Channel.

 

Elsewhere, numerous showers and thunderstorms are likely to develop across Ireland once again, likely already feeding into southern coastal counties in the morning and expanding in coverage further inland/to the northwest with time, where the environment will be supportive of 1,000 J/kg MLCAPE and 15-25kts effective bulk shear. A SVR was introduced here for the risk of isolated large hail 2-3cm in diameter and local surface water flooding. 

 

Additional showers/thunderstorms are also likely during the afternoon and evening hours over mid/north Wales, NW England, W and SW Scotland, before these eventually merge into the broader area of heavy rain developing over northern England during the evening/night. Ahead of this feature, it is possible a few elevated showers/thunderstorms could develop over the North Sea and feed into eastern Scotland during the late evening, but confidence on much in the way of lightning with this activity precludes higher threat levels at this stage. Finally, during the overnight period a scattering of showers may feed into Wales and SW England from the Celtic/Irish Seas, perhaps producing the odd isolated lightning strike.

[Sprites]

Quite a bit of Accas around, not sure if it's trying to develop further, could be something home grown in the next hour or so. 

[Gordon Webb]

Day 2 Convective Outlook

VALID 06:00 UTC Sun 18 Jun 2023 - 05:59 UTC Mon 19 Jun 2023

ISSUED 21:14 UTC Sat 17 Jun 2023

ISSUED BY: Dan

A broad upper low will remain to the west of Ireland on Sunday, with a relatively high Theta-W airmass (>16C at 850hPa) covering much of the British Isles. A shortwave trough migrating northwards on the eastern flank of the upper low may provide the focus for scattered elevated showers or thunderstorms across parts of northern and eastern England on Sunday morning, the focus then shifting to W/SW Scotland by the afternoon. In its wake, a humid airmass persists (dewpoints 17-19C) which, coupled with subtle forcing aloft, could still generate semi-random elevated showers/thunderstorms throughout the morning and early afternoon, this perhaps most likely (but far from guaranteed) over East Anglia/SE England. Otherwise, fairly extensive high cloud is anticipated across much of England and Wales, but sufficiently thin/broken in places to allow a degree of surface heating through the day. Forecast soundings suggest near-surface temperatures of 21-22C will be required to erode SBCIN, and so given the moist boundary layer it seems plausible scattered showers may develop fairly readily with CAM guidance indicating initiation over the Midlands and southern England from around 11-13z onwards. A weak surface low is expected to develop and slowly deepen over central England during the afternoon, with increasing low-level convergence in the vicinity also aiding forced ascent. 

Later in the afternoon a more robust vorticity lobe, emanating from NW Iberia early in the morning, will approach southern England and the synoptic scale ascent associated with this will encourage thunderstorms to grow upscale during the late afternoon and evening hours, initially into an MCS across the East Midlands and western East Anglia, but eventually a larger mass of heavy rain over northern England later in the evening. Forecast profiles appear very moist, yielding rather tall but skinny CAPE, which coupled with PWAT 30-40mm and approximately one third of the convective cloud in the >0C layer contributing to efficient warm rain processes, suggests the potential for significant rainfall accumulations - perhaps locally in excess of 40mm in 1 hour. A SVR was issued primarily for the risk of flash flooding (especially where multiple cells train/backbuild over the same area), and to a lesser extent for isolated ≥2cm hail given a favourable kinematic environment for updraft/downdraft separation and cell organisation, this perhaps most pronounced across the north and east Midlands into East Anglia where the low-level winds will be most backed on the north/northeast flank of the surface low. These areas will also have a slightly higher chance of an isolated tornado given substantial low-level directional wind shear and progressively lowering cloud bases through the afternoon.

 

A trailing line of thunderstorms may affect other parts of East Anglia/SE England during the evening hours, linked to a substantial bowing segment that is expected to form over NE France - although much of the lightning activity associated with this feature may remain over France/English Channel.

 

Elsewhere, numerous showers and thunderstorms are likely to develop across Ireland once again, likely already feeding into southern coastal counties in the morning and expanding in coverage further inland/to the northwest with time, where the environment will be supportive of 1,000 J/kg MLCAPE and 15-25kts effective bulk shear. A SVR was introduced here for the risk of isolated large hail 2-3cm in diameter and local surface water flooding. 

 

Additional showers/thunderstorms are also likely during the afternoon and evening hours over mid/north Wales, NW England, W and SW Scotland, before these eventually merge into the broader area of heavy rain developing over northern England during the evening/night. Ahead of this feature, it is possible a few elevated showers/thunderstorms could develop over the North Sea and feed into eastern Scotland during the late evening, but confidence on much in the way of lightning with this activity precludes higher threat levels at this stage. Finally, during the overnight period a scattering of showers may feed into Wales and SW England from the Celtic/Irish Seas, perhaps producing the odd isolated lightning strike.

 

edit - seems already posted but map 4 posts above might be accurate reading this forecast and E midlands Eastwards seems best Tomorrow

Edited June 17, 2023 by Gordon Webb

[cheese]

I must admit I’m really surprised none of these warnings include at least South Yorkshire in the moderate area. 

Edited June 17, 2023 by cheese

[LeeRoyxD]

starting to hear distant rumbles now! it's spreading out a bit more to the west now also 

[Allseasons-Si]

A new cell has developed west of the main cell in the channel,also there are little cells popping up all over the shop.

Edited June 17, 2023 by Allseasons-si
typo

[Sam jackson88]

on my second monitor im watching reed timmer in the dominator start his chase today on youtube so radar on one screen and reed on another

 

[tomp456]

wondering if I should go to the beach for a lightning show in the channel, or am I too far west?

[matt111]

1 minute ago, Sam jackson88 said:

on my second monitor im watching reed timmer in the dominator start his chase today on youtube so radar on one screen and reed on another

 

Me too

Not expecting much here but I can live in hope. 

[Harry]

The trajectory of the Channel cell is bang on for us if it can keep going…

[Sam jackson88]

Just now, matt111 said:

Me too

Not expecting much here but I can live in hope. 

just got gifted a sub to reed timmers chanel and i always watch him, its what got me into weather and radar watching

 

[Nantes storm factory]

6 minutes ago, Allseasons-si said:

A new cell has developed west of the main cell in the channel,also there are little cells popping up all over the shop.

Let's hope they make a successful crossing across the Channel. 

[damianslaw]

Tomorrow could for some be very thundery and very wet. Here's hoping we see both!

[Guest]

10 minutes ago, cheese said:

I must admit I’m really surprised none of these warnings include at least South Yorkshire in the moderate area. 

Yes the CW one above seems a deliberate omission with the yellow zone literally bending round the southern side of the city/region. They know far more about the nuances of such a setup than me, so I'm wondering what influences their decision here as it seems to go completely against the hi-res model output, and other seasoned forecasters such as Paul Blight.

Very strange!

Edited June 17, 2023 by Steel City Skies