Storms and Convective discussion - May 2024

[viking_smb]

Noticed there are 2 warm fronts on the fax for 00z tonight which one will they form next to please?

 

 

Edited May 1 by viking_smb

[Alderc 2.0]

 ChannelThunder usually we end up being too far west and ending up in the wet mess part, ironic if we too far south this time.

[Shaunado]

Kent usually does very well when storms come in from the SE. Maybe the worst of the rain will pass by to our west but hopefully a light show will emerge from the ripe conditions overhead! 

[ChannelThunder]

The undulatus this morning is quite something!

[Azazel]

I’ve done very well for night storms in May and September for the past couple of years now. Fingers crossed 

[Jamie M]

lol AROME still going mad, 3.2k CAPE over the Estuary 

[viking_smb]

 Jamie M

Im on lances thinking 

i think the vast marjority of the lightning will be on the south east coast 

[Eagle Eye]

 ChannelThunder

Similar here but I'm on thee bus and not facing right direction at the moment. Signs are beginning to get there now and it's ridiculously humid. 

Here's what the UKV 03Z says for CAPE. 

[daveinSB]

 Eagle Eye UKV and AROME now looking good for an area of storms that tap into the 1.5k+ cape in an around London, which suits me nicely.

Just a shame today is my last day of 2 weeks off work - I could be very very tired come Thursday morning - especially as my vantage point gives the best view to the SE and the tree surgeons have been getting busy

[GreyCrag]

[LightningLover]

 Eagle Eye That's pretty spectacular- ~2,400J/kg cape directly over East Sussex!

Edited May 1 by LightningLover
fat fingers

[LightningLover]

WRF-NMM also has over 2000J/kg CAPE spreading in from the southeast, so it's not just the AROME or the UKV!

[viking_smb]

By the looks of things i wont be affected till daytime tomorrow 

[lottiekent]

Not tonight’s risk, but a very active storm moving up the North Sea at the moment:

[Rush2019]

Met office yellow thunderstorm warning issued.

[lottiekent]

First warnings, SE:

UK weather warnings - Met Office

WWW.METOFFICE.GOV.UK

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Met Office UK weather warnings for rain, wind, snow, ice, fog, thunderstorm, lightning and extreme heat.

and SW:

UK weather warnings - Met Office

WWW.METOFFICE.GOV.UK

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Met Office UK weather warnings for rain, wind, snow, ice, fog, thunderstorm, lightning and extreme heat.

 

[Met4Cast]

AROME sampled Skew-T continues to signal  >2500J/KG of CAPE moving up into the SE area before expanding (and weakening) westwards with the shortwave trough. Assuming these values are realised we could be looking at a prolific lightning event tonight moving up into the southeast and extending northwest through CS England and perhaps even as far as Wales. 

I suspect the AROME is overcooking things slightly but regardless, potential for significant amounts of lightning tonight accompanying the likely torrential rainfall. Large hail looks to be a slightly higher likelihood compared with yesterdays thinking too, albeit probably reserved further southeast.

This really is an impressive setup for the time of year.

[AWD]

Always nice to see an early start to the storm season.  Let’s hope it’s the start of many future events.

[Mapantz]

Met Office warnings are at the lowest likelihood on the matrix.

[Met4Cast]

 Mapantz

Not surprising - Any rainfall will move through relatively quickly, storms are elevated so cloud-ground lightning strikes aren't really a concern and it's happening in the middle of the night so naturally the likelihood of impacts is quite low.

[Alderc 2.0]

 Mapantz  the dreaded yellow warning for thunderstorms - must of been under 30-40 of these last year. 

Some juicer air making its way over the channel, 17/14C in Manston currently. First time DP’s have been in the teens this year.

[Purplepixii]

 Rush2019

 

Also known fondly as the "Met Office kiss of death" 

[Paul]

@Nick F's storm forecast

Quote

Forecast Details

NW-SE elongated upper low sits across the far west of Europe on Wednesday – tending to extend towards the western Mediterreanean, with a surface low over the western Alps drifting north towards Benelux. A plume of higher wet-bulb potential temperatures (theta-w values of 14-16C) will continue to advect NW from central Europe and in across Britain over the next 24 hrs to the north of a warm front moving west across Britain.

Increased lift along the warm front as it reaches SW England and Wales, as increased forcing aloft arrives from France, will bring an area of locally heavy rainfall NW here this evening, perhaps with some isolated thunder & lightning. Further east, substantial destabilisation of the higher theta-w plume spreading WNW over Benelux and N France looks to occur during the afternoon and evening across northern France, as increased forcing aloft from falling heights from the southwest and falling surface pressure from low moving north occurs. High resolution models indicate this forcing engaging the plume and undercut of drier air from the NE at the surface generating an arcing area of thunderstorms across N France during the evening, which could produce large hail (3-5cm diameter) and flash-flooding  – before the storms then move N and NW towards SE England / E Anglia overnight. The thunderstorms will tend to be elevated above a stable drier surface flow from the NE, but tapping into MUCAPE of 1500 j/kg MUCAPE, as forecast by ECMWF & AROME. There is some uncertainty over the extent of thunderstorms when they arrive across SE England – however, given large CAPE values forecast – storms may produce isolated large hail (2-4cm diameter), intense rainfall leading to flash-flooding, frequent cloud-to-ground lightning and strong wind gusts. A severe area has been issued for the far SE of England.

A line of storms are forecast to continue NW and N across southern Britain in the early hours, perhaps reaching SE Wales and S Midlands before weakening. Some isolated lightning also possible further west across Ireland and S Wales along northern side of rainfall along warm front.

 

[Met4Cast]

 A plume of very warm theta-e 850hPa (>45C) will begin to destabilise along an occluded frontal wave associated with a broader upper trough sat across France/Belgium. Very high CAPE values in excess of >2000J/KG of CAPE look to be achieved by mid afternoon triggering rapid development of thunderstorms.

These are likely to become severe in nature across France and towards the Belgium border with the potential for large or very large hail & significant rainfall amounts. The frontal wave will continue backing westwards into the evening drawing the plume of air northwards and with that, the thunderstorms, helped along by a shortwave sat to the SW of the UK.

Thunderstorms will become increasing elevated above the 900mb level with a significant inversion developing. Frequent or very frequent lightning will push into the southeast of England extending into central southern England as the night progresses. Rough estimates place the highest risk between midnight and 3am Thursday morning with the risk getting later the further northwest you head.

Moderate wind shear suggests a small likelihood of large hail, particularly across the far SE closest to the highest instability. Sampled AROME soundings suggest CAPE in the region of 1500-2000J/KG just off the Kent coast with diminishing values the further north and west, albeit still enough to sustain on-going thunderstorm activity.

The greatest risk across the UK will be on the eastern extent of the rain band, model consensus is quite poor overall but the highest risk of thunderstorms & prolific lightning looks to be just east of the IoW across Kent, Sussex and extending northwest towards south London & the M4 corridor, perhaps extending into parts of the south Midlands later in the night although confidence on this is lower.

[LetItSnow]

Seeming to be on the borderline of the juicy area here tonight. I’ll be okay if we miss anything though I feel like there’ll be some light shows visible at the very least.