Generalelectrix

Morning all. Back in the office now, took me quite a while to read through all the posts, glad quite a couple in the forum got their fair share of frontal activity and that no major damage seems to have happened. To those who missed out: its not over yet. Hopefully the clouds will clear quickly behind the cold front, and with cold air aloft combined with diurnal heating should set off scattered and picturesque showers and small thunderstorms basically all over the post frontal areas of the UK. Just give Mr. Sun a short while to sort things, we are close to the 21st, where the sun will be at the highest in the sky at noon. Ralph Edit: Ajpoolshark and Chris K : You beat me to it

@ Dancerwithwings: This is a matter of nowcasting and watching the radar. If convection forms north of the system now crossing the Channel it will be outflow triggered and tapping into surface moisture on the south coast. However if the french storm system itself makes it across then the convection will be elevated. We have to wait a short while to see. Anyway, Have to head home from office, I am in Germany and its 3am, also a bit miffed that Im not in the UK and expect sizzling 3 days here without a hint of a storm, so good luck to all, stay safe and speak tomorrow Ralph

Thanks@panayiotis, my theory to this is basically the product of some long time observations we have made by Lake Constance, the question being that why in such pre-frontal situations is it that thunderstorms tend to fizzle out on the southern Swiss side, "jump" the lake and then regenerate into violent supercells or multicell clusters which wreak havoc on the northern side of the lake and into Bavaria. The only proper conclusion we have come across is that the blast of cold air from the collapsing thunder cell collects moisture ("lake effect" I think its called), and this causes substantial convective lifting on the northern shore. This is of course surface based. Was just wondering whether the outflow from the french cells can make it across a stretch like the British Channel and spawn further cells in the UK... Ralph

Thanks@all for the warm welcome here The outflow of the initial Nantes supercells seems to have created a very promising outflow boundary along which new cells are being triggered off northwards. This is basically like a mini cold front going north and is clearly visible on SAT24 Infrared. The boundary is the curved top of the white now mushroom shaped ex Nantes storms.(If someone from the Forum could post a grab off the SAT24 site would be much appreciated, have to get into downloading pics first) Shows how much instability is present, and also can speed up matters: If further cold outflow from the french storms makes it to the south coast and shifts under the pre frontal unstable airmass in the UK things may become interesting soon because we wont have to wait for the actual storms to arrive across the channel. Ralph

Hi@All. Just want to quickly introduce myself in the Forum after lurking for many years, My name is Ralph and I live 2 places: either in Germany in Constance (Lake Constance) or in Mytchett, Surrey. My job takes me back and forth between UK and Germany quite a couple of times every year. The outlook for the next hours looks more promising than anything thats been around this year, and the reason I posted is to answer a very valid question Buckster asked a short while ago, about why that Storm by Nantes split: The Nantes storm was a supercell and underwent a cell split into 2 supercell storms, the rotating updraft gets buckled upward like an inverted "U", separates at the top and then there are two separate updrafts, one rotating in a clockwise manner and number two anticlockwise. On the northern hemisphere the anticlockwise rotating supercell starts drifting off course to the right and is called a "right mover" The clockwise rotating "left mover" cell has to fight against the coriolis force, which eventually weakens it and it dies. Right movers are the cells to watch out for. Hope this helps. cheers Ralph Edit: sry, corrected rotation now, on post no107 by Stormeh the rotating updraft (meso) is clearly visible in the first pic, backlit by lightning.