Discussion: Through the late morning/early afternoon, we are expected to see a drastic rise in CAPE possibly reaching anywhere between 500-1000J/KG possibly higher, across N England & S Scotland. This will allow the initiation of pulse-type storms to form, alongside a convergence zones which will help lift & force the showers to develop. As these storms develop, there general track will be heading N where further initiation will take place. These storms will not be long living however they may certainly pack a punch. Frequent lightning, the odd funnel cloud, intense rainfall can be expected within these showers. Deep layer shear looks to certainly be weak which would normally help these storms becoming long lasting, but this will not be case as Deep layer shear is expected to sit around (5kn - 15kn) which is definitely a low amount. Most lightning / storm activity will remain within the AOI zone, a few sporadic lightning strikes can be detected outside the AOI.
Technical discussion: Falling surface pressure and converging moisture should allow for a deep surface rooted warm Theta-E airmass to form over Scotland during Saturday afternoon. This allowing for 100+ J/KG of 3CAPE to form with a few pockets of lift helpful for thunderstorm formation. Weak saturation and strong low-level lapse-rates should favour lightning risks but given the weak deep-layer shear it'll likely be popcorn showers thst last a short time. Meaning that storms will have to take full advantage of the environment to realise their lightning risk. A large warm nose at the 700s level will take a lot to overcome and is a very possible bust risk because storms won't have long to overcome it before they can't support themselves. Especially as the lift is very low past the surface convergence. The strong low-level lapse-rates and near surface convection should allow for some hail formation though, perhaps up to half an inch. Especially given the weak shearing. However, that assumes a storm can get past that warm dry mid-level nose.