Eagle Eye

Theoretically yes but if its moving too fast then considering it'll be decaying by then, it'll recover maybe but will also miss a lot of the Midlands. Just depends on the speed at which it can use the CAPE.

Looks like a lot has been used up. Significantly losing steam now but still think some more random storms will pop up in places without storm taken energy.

Thats near where some of my family lives.

Don't know if this has been shared before. Sam from UK weather chase in Devon.

Reminds me of the London Supercell from a few years ago in terms of lightning intensity. Here's the video I'm thinking of.

Wouldn't be that surprised. The CAPE lingers for quite a while over us. Just depends how much has been used up already as that's modelled poorly typically. Good sign then. Only thing that could stop it is it becoming too slow and lags behind the moisture tongue leaving. At some point that will probably happen and it will turn into a very messy cluster. Couldn't tell you when that would happen though. The storm is averaging just under 150 strikes a minute for the last 20 minutes. Even if it starts running out of steam, will be a while before people turn their cameras off.

Roughly using the storms track is 1500+ J/KG of MUCAPE into the night hours. 1,300 ish J/KG of MUCAPE just south of where it could be around 1-2 am. sShould have enough Theta-W to be able to transition to elevated if it isn't already. Pretty much the same environment it's in now.

Yes. Also, worked out the average minutely strike using all the UK and Ireland's storms in the past 2 hours. It's just under 250 a minute on average (30,000 strikes in the last 2 hours).

Blitzortung has it at 160 a minute with the storm at it's recent peak.

Hovering around a strike every second and a half with the new storm. Don't know about recent but UKV had this new storm forming late evening on some of its runs and travelled far. This one could go right into the night possibly. Scratch that, over a strike a second now.

About 100,000 strikes for us and the North Sea today if you take off the French storms. Me and Jay had a fair amount of that in a high risk but also I think had Sheffield where my grandparents live and they see the forecast but that had a very noticeable gap in it.

Absolutely beautiful. Looks like a mesocycline but can't tell exactly. If it is then that's one of the most beautiful UK mesocyclones I've seen.

Watch out for these. Clear slot below them, good for inflow and hail production. Potential may be a Supercell that forms here.

Yes it's probably over. Shortwave trough has passed you now. Might get a weak straggling storm with any CAPE left over but unlikely. It's also not even 5PM yet, we're only about halfway through if the models are correct.

I think north of you has definetely seen a return of those 90s storms you all talk about..

Ha ha ha. Alright, I'll go with you on that forecast.

Told you all with my forecast, the southern storm will be the strongest. Given best inflow and less restricted moisture and low-level vorticity. Absolutely not surprised that a Supercell happened. Not much here but cool looking skies. Will upload pictures later.

Yeah, Arnside Pier is about to get battered by the looks of it. Never mind, just realised where it is.

Change of plan It's probably going to be quiet for a bit now, compared to tomorrow morning, so here's the discussion. Convective Outlook A trough ahead of a low pressure system will advance throughout part of the country during Sunday late morning and afternoon. Initially, there are weakening storms in the SW and perhaps south Wales moving north during the early hours. As those weaken they move towards northern Wales where daytime heating followed by a large pressure difference with height along an area of increased moisture convergence near the surface, is likely to force strong storms during the late morning hours in northern Wales, moving ENE and expanding as the low-level convergence also expands. This could then be followed by more storms behind the main system but those will likely be weaker in nature due to the initial storms uptake of CAPE. The residing moisture and instability from the weakening storms trough system, increases with daytime heating and low-level convergence. This increases hydrolapse rates along with the parcel vs environmental temperature difference. This is especially true for the mid-levels as there is potential for a surface inversion induced CIN weakening the amount of available surface CAPE. So, the LCL will be slightly lifted but the mid-level CAPE is very abundant. The surface inversion is the main increase for hydrolapse rates forcing because it means that post inversion, the relative saturation change to what is immediately below it, is tilted at a 90 degree angle at the difference in fluid flow layers. With the more laminar flow being the main area of using up of energy. Surface energy won’t be used as much, however, the storm could be enough on itself to cool the air below it through cool rains (in my mind, that is how storms in the tropics fall from elevated to surface based) and there is scope for this to change from elevated to surface based, with soundings contaminated by a storm having a weaker surface inversion. Storms can modify their local environment and a slight drop in temperature would be enough to change whether it’s elevated or surface based. If it can change from laminar flow to viscous flow, then the storm can change to being more shaped by the marked increase in low-level convergence and vorticity with a strong inflow layer and SVC. That significantly increases the chances of a persistent mesocyclone being born from almost zero to a fairly good chance of a Supercell. However, the transition would have to happen very quickly, as it looks likely to turn into a form of an MCS, with good downwards momentum for fairly strong wind gusts. That, along with extreme rainfall rates with the tropical moisture. However, even if it does upscale due to forcing, there should still be enough low-level vorticity and 3CAPE crossover in areas to form a brief isolated tornado. With 200+ J/KG of 3CAPE and extreme low-level vorticity fields in some areas, some funnel clouds or a weak tornado could potentially form. Especially on the northern side, with good attempts at veering on a backing vorticity field-3CAPE crossover area. However, the low-level vorticity field on the south side should be the strongest with the sharp rising air, so assuming 3CAPE is at least close to what it is modelled on the northern edge, then the southern edge should theoretically be slightly more favourable with a more favourable hodograph. The northern hodograph has a weaker critical angle and the low-level vorticity is less available because despite better 3CAPE, the MLCAPE is much weaker overall on a sounding I picked out. The SVC is tilted opposite to cell movement, so storm motion will be to recycle cells within the MCS, rather than keeping the same cell, so there should be bursts of change of strength if an MCS forms. This also means that the SVC and inflow are working the best they can with the very non-Supercellular and more squall favourable hodograph. However, that does still mean that the spin potential on the northern side will be rather weak due to the quickness to recycle cells. If the energy was more on the northern side, it would be much more of a chance to form a tornado. The southern part of the MCS, has a larger critical angle, increasing the usage of the low-level vorticity field and maximising the SVC available. So, when you look further in-depth, it is slightly more favourable of an area for a potential weak tornado than the northern mode. That assumes that cells are given enough time to shift the capping below them which would also weaken their severe potential, due to decreasing their dewpoint which is an important factor for determining severe potential. The southern side of the potential MCS, which may break up and rejoin together at times if it does form, looks to be in a line sort of ESE from mid-northern Wales to Lincolnshire. The northern edge is modelled to initially start in northern Wales and expand as it moves east up to Sunderland if the Swiss 4X4 is right. The Swiss-EZ4 has it similar with the northern side but the southern side only reaches Sheffield and moves ENE from there, with a few weaker storms south of it. The Icon-D2 lacks much of a trigger and only has isolated storms. The AROME is much more confusing with several rounds but generally is close to the Swiss 4X4. The UKV also tends to agree with the Swiss 4X4 but is slightly more south with the south side of the MCS/broken MCS. There is the potential for a Supercell within the MCS as well, those are typically located on the southern side if there is one and I would definitely look out for that potential with the MCS assuming that it does form. There is the potential for multiple rounds. With tall storms at past 12KM potentially sending out gravity waves. However, there is also the high level of MLCAPE and some very buoyant air. However, the initial storms look to have quite strong ECAPE and so could use up most of the energy themselves but scenarios like this can be very messy. With multiple potential PV lobes and potential for more than 2500 J/KG of MLCAPE in some areas on some of the models. Which is very strong for the UK. This also comes with strong DLS at 40+ knots. So, I wouldn’t be surprised if we saw an initial MCS followed by a mess of storms. There’s lots of buoyancy in the UK storms and with large LLLR’s, it’s a hail producing environment. The modelled large inflow strength, plus the very large inflow layer suggests a very rare atmospheric profile for UK CAPE. DCAPE is low in some of the strongest inflow layer and MLCAPE modelled areas but the initial envrionment is so good that the small percentage of updraft speed intake should still be enough for hail larger than 2-2.5 inches being possible. Large ECAPE if storms can be Supercellular and surface-based given the EL’s could allow for the analogue hail of 3.65 inches to be reached. However, the downwards momentum being quite weak suggests to me that 3 inches is the actual maximum but depends on how modelling trends. Most likely scenario is that we see a non-Supercellular storm become surface-based for a while produce 1.5-2.5 inch hail for a time and that exact value depends on how much ECAPE a non-Supercellular storm can get from this environment. This would most likely occur on the south side with the inflowing momentum inducing showers. So, if I was a chaser I would probably aim for the southern side of the system. The timing of these storms looks to be late morning and moving across the UK into the late evening, followrd by a trail of storms overnight on some models. There might also be another area of weaker convergence from Somerset area and north that moves across through to just west of Peterborough overnight and up to just north of Sheffield according to the AROME. However, other models just have general scattered showers and thunderstorms at this time. Ireland is a lot more easier to forecast. With a stream of storms, especially through central parts of Ireland but not particularly strong compared to the UK’s one but very well modelled. From late morning and lasting into the night hours but weakening as it gets further into the night. There are no particular severe potential factors with this due to limited shearing, however there is the potential for flooding due to the amount of showers and storms that some places could get. In Ireland, 25-35mm of rainfall could fall in some places due to the amount of storms potentially forming. In the UK, the severe risks are up to 3 inch hail bus more likely up to 1.5-2.5 inch hail. That alongside 35-55mm of rain potentially falling within the space of just over an hour, currently modelled on the southern side of the system with the most low-level moisture advection reaching the storms. There may also be a brief tornado in the UK along with the potential for a Supercell. This appears to occur on the jet streak region but very close the jet streak exit region, so forcing should be less of an issue than it has been before. Along with a very tilted jet stream providing a constant feed of near tropical like moisture.

Me and Jay's best forecast so far this year in my opinion. Writing the discussion for tomorrow's one now but will save in case of any changes to make tomorrow morning so we won't use it yet. I'm trying to go into way more detail with this next week.

And me and Jay

He's retired from forecasting.

Here's my discussion for tomorrow. Working from 9 till 5 so best to put it here now even though Jay hasn't done the actual map yet. There are a couple different modes and timings with these potential storms. I'll start with the most likely but also has the smallest ceiling of potential. Ahead of a cold front, with fairly good DLS, showers and storms should form in Ireland and up into parts of western Scotland. These happen mainly throughout the afternoon in a stream along an area of 500-1,000 J/KG of MLCAPE along a tight PV lobe. With weak MLCIN and a fairly good trigger with PV lobe induced low-level convergence. This occurs with fairly high moisture and fairly weak saturation. So, all showers and some weak to moderate storms may well form. High LLLR's and strong 3CAPE (100+ J/KG) allows for some small severe hail to form, potentially around 1-1.25 inches. There is potential for locally 2,000+ J/KG of MUCAPE and combine that with the large inflow layer and you could suggest, strong updraft speed for strong downdraft speed, however, weak downwards momentum within storm soundings will mean that downwards momentum won't be a particularly high percentage of the updraft speed and with restricted inflow strength, so hail is still going to be restricted compared to updraft strength. Strong buoyancy will help the hail, however, there are a lot of anti-severe hail factors mentioned before that keep it from being a significant factor in anything other than increasing updraft width+speed but not necessarily much of the downwdraft speed for the hail size. Moving onto the Wales and the midlands-northern England part of the risk. There is quite strong capping in place and no real trigger. However, 2400+ J/KG of MUCAPE in places with widespread 1,000 J/KG of MUCAPE in an area of tropical moisture rates means that with fairly strong DLS, any low-level convergence available via localised orographic features or something like that, could spark a few severe isolated thunderstorms with a small chance of becoming a Supercell. Again, this happens in the afternoon and if storms can get going then it would be mid-afternoon initiation and into the late evening for storms. Good buoyancy with a large inflow layer and good sub zero CAPE suggests some 1.5 inch hail is possible. The hodograph isn't really your typical C shape with the inflow which is fairly strong but still leaning towards the moderate side and so the hail is still being restricted to about 1.5 inches. The inflow layer is large compared to recently but still relatively small compared to events larger than 1.5 inches. Storms could potentially reach past 12km cloud tops which is quite high compared to your everyday thunderstorms, hence why they could be quite severe. Finally, in the evening and overnight in the SW, some elevated thunderstorms could form. Not particularly large CAPE but good moisture and good modelling guidance suggests, these should happen. Previous events suggest some good lightning frequency potential as well. Here's the current idea that Jay has but he's waiting till tomorrow which is fair enough but I can't do; (black outline is area of interest for lightning and also in my opinion, the severe outline I would think of as well.).

Any difference in environmental temperature or pressure enough for it to become a front or a trough. A shortwave trough or any front. To be more specific, there are other ways for or to occur though, anything that works to make low-level convergence and upper-level divergence can work as a forcing. Something like a jet streak (just research, it's pretty simple) or PV lobes that I often over talk about. Along with moisture advection near the surface forcing moisture convergence. Then there's the most complicated gravity wave, which is rare here. Those are ones other to fronts and troughs that work.

Sorry about no forecast for today earlier. Absolutely shattered and Jay wasn't available to do the map. Proper professionals.