Eagle Eye

Yeah. Sheesh.

Ooo ooo guys in the south. I've got another storm opportunity to chase, only this one has a big chance of totally busting for everyone. You in?

Using light paintings to try and get a good idea of the structure. On the back edge of the storm. Seems a mean back structure. Almost looks Supeecellular but that just looks like outflow winds happening to be on the back side.

Lots of lightning still going on but in a tricky spot to catch at the moment. Here's some stuff from earlier as well. These next 3, seperate strikes.

I had shotgun positive CG thunder earlier that turned all the power out. Wasn't videoing at the time though.

Totally normal night.

Quite possibly. Also check the stuff behind it.

The channel storm appears to be turning more northern now.

I saw a flash about a minute ago, possibly.

Mostly a Kent clipper unless it expands north which it could well do. Might be more around 2am tomorrow is my hope as well. There is a more northerly flow it's about to hit that could take it further into Kent.

Finished work potentially just in time.

The stuff north of Caen...

Almost every import is late initiation. There is some signs of instability post warm front as well.

The later the initiation, the better for me. Still at work atm.

Dont use models from now on. Best to start using the radar as the event evolves. New model runs won't be that much more accurate and will keep chopping and changing. Having said that, I just looked at the models and yeah it's mostly the same as earlier with slight changes which aren't trends in either direction massively. Now comes the point where the event overperforms or underperforms depending on sub-gride scale interactions.

Convective Outlook On Friday. Initially, a line of showers and storms may form in the morning across the western coasts of the UK. It weakens as it moves east but may pick up in the SE. Then overnight, strong storms with frequent lightning could ride the east coast area, along a sliding Theta-E airmass. The morning showers and storms in the west coast will form rapidly but quite quickly lose energy as they move northeast. The line appears to be tilted SE with a few in the channel and moving into the south coast. They have a severe status potential for wind gusts and rain right along the west coast. With the wind gusts coming from the downwards energy from the storms. Whilst not particularly large, may be enough to force strong wind gusts. Along with strong moisture, for surface flooding from torrential rainfall. The wind gusts restricted to the coast due to this being the area of best forcing for downwards momentum transfer between laminar and viscous flow which is more forced by the coast rather than inland. This occurs mid to late morning along an area of PBL Theta-W airmass that can hold elevated thunderstorms if need be. So earlier in the morning than usual, is initiation time it appears. Steepening low-level parcel temperatures in recent forecasts have increased 3CAPE to post severe levels (50+ J/KG) and lowered the LCL. That increases ECAPE hence the uptrend in strength recently. Mid-level hydrolapse rates are now more akin to storm activity than thundery rain with high mid-level hydrolapse rates. The rapid loss of dewpoint and decreasing moisture advection with height is helpful for lightning activity. Eventually, the showers and storms forced into a line will weaken but will pickup again along the south coast with re invigorated forcing. Then there may be some random popup storms, especially in the SE during the day. This is before the evening and overnight. This is where a Theta-E mass advection occurs with a developing strong PV lobe. Mainly in the south, SE and up to the mid eastern coast where some tropical like Theta-E airmass temperatures can advect. A surface inversion holds off most of the surface energy and surface buoyancy at bay, however, the energy beyond the surface m inversion is strong and can tap into a strong Theta-W airmass. This has strong saturation but very tall EL's with 35,000+ feet storm heights and DLS supporting it. So with the direction of shearing, along the PV lobe, a squall line or an MCS will likely form. Moving NNE with frequent lightning likely given the amount of energy and the height that its stretched over. These might form over the channel or the south coast and move NNE. Slowly, initiation should change further east with a couple rounds of initiation with such a pool of energy and high PBL Theta-W air in the channel and the south and east. With such strong forcing for the DCAPE, severe squally wind gusts are possible along with frequent lightning and surface flooding. Some small hail may occur given the potential for pre-MCS Supercells ,which would make the most of the sub-zero CAPE available and the hodo is favourable. Buoyancy isn't particularly favourable at the surface but at cloud height is particularly unstable. So some 0.75 inch hail may be possible. However, a Supercell pre-MCS would only happen if the MCS meets the tropopause and sends out gravity waves and strengthens any cumulus fields pre-MCS which could then break through the capping. A tornado may be possible given the larger inflow layer in recent forecasts allowing for high SVC intake at layers. However, the lifted LCL will likely mean that the tornadic potential is limited and most energy will be transferred in outflow winds despite the low-level vorticity fields available, the mid-level vorticity will naturally be different due to the change to laminar flow less favourable for the atmospheric instability pattern needed for tornadic formation. Viscous flow appears much more favourable for small-scale rotation. There is significant LLS available so if something can latch onto a surface feature along the warm front then a tornado may still form. However, warm fronts tend to have high surface capping and be more renound for their hail and wind gusts capabilities In Ireland, there's a local increase in CAPE to 400+ J/KG during the overnight hours which may form some storms. These have the potential for during wind gusts and surface flooding in the night hours.

Spoke about this yesterday and nothing has really changed about it. Hail threat and tornadic threat aren't actually as big as they would seem. Shallow inflow so despite supportive hodo, hail growth is likely to be fairly stunted and current soundings continue to suggest poor hydrolapse rates though, the lapse-rates are decent. Given the mostly non-surface based element, buoyancy which is also important for hail size as with my mini paper a few weeks ago is probably going to be fairly limited. DCAPE is likely undermodelled though so wind gusts could be quite high. Look at dewpoint more than temperature for hail growth as well.

UKV 03Z continues to show it. Bit delayed on this run which is better for me because it means I might be able to catch it after work if the UKV is the model that is right here. Reminds me a bit of July 23rd 2019.

A trough pre-occluded front looks to arrive in the UK on Friday afternoon/evening which will likely advect with it a very strong Theta-E airmass with strong moist and warm air. The airmass with near tropical moisture potential appears to advect from northern France northwards then eastwards and at some point, the strongest 850's Theta-E could move into the SE at 60 degrees. For context, typical plumes of this year have been around 30's to 40's. It is a potentially ridiculously moist airmass with the moist airmass entrapment pre-longwave trough which is then pushed along towards us by the shortwave trough and released in hopefully a burst of energy. For context of how moist and tropical like this airmass is potentially going to be, the only places in Europe at the moment with that kind of moisture, is the typical Central Europe area from south France through northern Italy, the places you go for a proper summer thunderstorm. If we can get the moisture anywhere close to that, it would be incredible. Hydrolapse rates look pretty average but with elevated MLCAPE likely in excess of 1,000 J/KG and potentially more once all CAM's come into range, the hydrolyse rates don't necessarily matter as it's more typical of a Dixie Alley risk in the USA that you see such high hydrolyse rates. They've been useful for moisture transfer recently but with the surface and upper high building but being a humid high pressure, then it's no wonder that the hydrolapse rates are rather low with a quite highly saturated system al the way up. That kind of detail can be worried about closer to time as surface troughs may move faster than the upper trough moves and that can create localised strong hydrolapse rates. Initial thoughts for hail are that with the high temperatures and moisture laden airmass, the below zero CAPE is going to be stored rather high up in the atmosphere and so the low hydrolapse rates do contribute to the weaker hail discussion in this setup. Normally you would say that with that amount of excessive CAPE, that hail is almost a guarantee to be large however, it's not that kind of setup. Though the hodograph appears quite C shaped including inflow, I suspect that the inflow layer will be restricted and so the hail growth and updraft width will be rather weak I imagine. So hail is not really a given in this situation. Storms will be latching onto the high 850's Theta-W and won't be subject to surface flow features and unless there's a particularly tall topographic feature in a risk area, it won't make much of a difference. Also means that 3CAPE will be limited and so will Supercellular development with the forcing more being in a typical PV lobe band, helpful for MCS and squally forcing. Sort of also helped by the DCAPE being moderate on the GFS so squally wind gusts may occur with the downwards transfer of momentum and energy, limiting of hail growth if most of the DCAPE momentum is held in above zero temperatures. Though a tornado is possible given the fairly good SVC forecasted and the strong inflow even if I think that the actual layer will be restricted. However, the elevated nature of the storm makes it difficult for ECAPE to increase and also the storm to make much use of the low-level vorticity field. So a tornado cannot be ruled out but is unlikely despite the sounding I picked up having analogs at 83% tor. Post 12km EL's means that with forcing, this squall line potential has potential to be really mean and churning out lightning even more than your typical import over recent years. However, high saturation may dampen that risk and we're still quite a few days out and it almost definitely will change it's positioning on the forecasts. The DLS will help force some near tropopause development and we may see some further developments in gravity waves induced forcing in any cumulus fields. By the next day, a ridge starts building into the south and will likely last until early next week where that long wave trough might cause some trouble. It's not a guaranteed good storm or even a storm this Friday but it's the best chance we've had in a while.

Convective Outlook 600+ J/KG of SBCAPE with fairly decent lift allows for widespread showers with occasional thunder. Most lightning is likely to stay in the slight risk with strong lapse-rates and a small local increase in moisture suggests stronger storms capable of heavy rain and some small hail. Fairly weak DLS means that mostly pulse storms should form. So it seems like a pulse shower with sporadic lightning mainly in the slight risk.

Alrighty...

I think over forced and we end up with a pretty typical winter of people throwing toys out the pram before a short spell with lots of snow dumped in the one place no one in the model thread seems to live in the UK. El Nino is typically pretty good but not the it's as strings it will likely be.

WRF continues on the theme of bringing the storms to me roughly around the time I'm in work.

ECM at it again with 5000+ J/KG of MUCAPE in some areas.

The slight risk from earlier today still stands till 6am then the latest one uploaded kicks in. Here's the old slight risk