MrNooo

Surprised you all have + temps, weather station here showing -2.7C here, grass frost and car iced up. I hope we get to see some decent snow these next coming days/nights, it's been a bit of a "roller coaster". The Beeb don't seem too keen on it mind, hope they're wrong!!

Heavy snow here, a nice dusting, large flakes at a rate of knots.

Large sheet of dark cloud approaching here, temp currently 4.5C.

Regular thunder heard here now, last 5 mins.

Non stop thunder to be heard from the Swindon cell, can see a nice rainbow and the side of the Cu-nim, currently sat in the sunshine. it'll pass I suspect to the East of me.

Yes, large wall of cloud passed then all hell broke loose, looked very much like some form of mamatus type cloud behind the wall, then rain, very heavy, constant thunder and lightening, seems to have passed me now headed North.

Burst of VERY heavy rain and a few loud bangs and fireworks. regular lightning to the West of me and audible thunder, looks like it'll be a potentially long night!

Distant thunder and plenty of lightening, to the South of me.

Frequent flashes and the odd rumble South of here, had some light rain but nothing major, wind perked up also. Camera at the ready. Don't wish for any hail as it'll knacker my crop of Oil Seed Rape…!

Yes, it tipped it down here, walking the dog at the time, got soaked!! No thunder though, thought it might looking at the clouds.

Can see the lightning over Swindon, Marlborough Downs, seem to be firing off nicely!!

Very large storm passed here, currently over Cirencester, sky turned green. Plenty of rumbles of thunder but did not see any lightning although wasn't looking as inside.

Total cloud cover here, rain came through at 02.00am, wind did not seem too bad. Roll on Spring proper, had enough of the rain now!!

Wind really starting to ramp up here, hope all the tiles stay on the house!!! Stay safe everyone

Snowing heavily here, temp 3C, rain turned to snow event.

Very heavy hail shower here now, strong gusts after a fairly quiet morning, not a pleasant day to be out!

Calmed down markedly here in the last 15 mins, just some gentle rain against the windows. Stay safe all.

Torrid here now, last 5 mins especially, wind howling (exposed rural) rain lashing against the windows, roof leaking like a sieve!!!

John the only link I have is http://mwp.flightplanner.info/Beschreibengl.htm that shows a breaking wave. I do know that there was a lot of research done namely the Sierra Wave Project in the 50's and gather that a team of pilots have recently been assembled for another project starting next year (source Sailplane and Gliding) I have heard it spoken about whilst gliding up in Scotland (Portmoak, Scottish Gliding Centre) the consensus seemed to be that the upward going parcel of air goes past the 90 degrees and as a result topples, then creates rotor like turbulence, this seemed to be born out by my variometers showing the climb rate in excess of 1,200ft/min I did see 1,400ft/min prior to the wave breaking up (this was at FL15 or circa 15,000ft) when normally on a good day we would see anything from 200ft/min up to 1,000ft/min in typical hotspots. The turbulence was pretty horrific, airspeed going from zero, with the control stick limp in my hands to 80kts in a blink of an eye, I was glad I still had my straps done up tight or my head would have been through the canopy. It's pretty sobering when looking out at your long flappy wings and one is bent up 6-8ft while the other is bent down the same amount the other side. The wonders of Carbon fibre!!

I think the Lee waves are fairly easy to forecast, as a glider pilot I love them, but would say wave rotor is not very pleasant and sometimes bl##dy scary but this tends to be found lower down. Toppling waves, I think these are the worst from my experience (a glider is so small compared to a commercial jet so a jet may just fly straight through it?) I think it's when the top of a lee wave "topples" forward and breaks up creating serious rotor like turbulence, I had this happen whilst flying up in Scotland and can say it was the most frightening thing I think I've ever had to endure. How you would predict this type of event I don't know?