I think it was the northern edge of the trough that was at fault - it seemed to break off and move through NW Norfolk leaving the top of the remaining trough to pass me and TWS.
Yes, could be an interesting dessert after the main course earlier! Having added some overlays on the NW radar, there seem to be ideal conditions - lapse rates, CAPE and LI all good, not much inhibition either. Only negative is lack of wind shear.
Great photos Harry, what a treat! To think that's the sort of thing that probably 99% of Londoners won't have noticed, because people almost never seem to look up!
Back now - late luch and then distracted by other matters.
Fairly impressive storm passed to the SE of us - first thunder heard at 14:27, heavy rain and some bright lightning flashes observed (from my vantage point I was unable to see whether they were CG or IC. A lot of turbulent clouds still hanging around and the occasional faint rumble heard still.
Looking back now on this post, I cringe at my own ignorance when I asked such an elementary question! :o All I can say to defend myself is that I was unaware of the context of John's explanation.
Getting very dark again - our end of the trough has rotated and is now coming from the West/SouthWest. Saw a flicker of lightning to my NW a minute ago, but didn't hear thunder as I'm listening to the Internet coverage of the Test Match on TMS.
That red blob that was heading straight for me has faded, thankfully - I was terrified of storms as a kid, and, though I'm fascinated by them now, I still don't like them right overhead.
It's moved up through Norfolk to the East of Norwich - over the Broads and now to the coast, but there's a longer cell or group of cells drifting NE up from W. Suffolk/S. Cambs way.