September 9th was the second day of a 3-day active pattern over the northern Adriatic with supercells forming in NE Italy plains. Conditions were favourable, with a 40 kt SW mid-level jet and up to 1500 J/kg CAPE. A strengthening southeasterly low-level wind would acompany a shortwave passage in the evening, increasing shear and helicity.
I started my run late in the afternoon as the northern FVG plain became active. By the time I arrived, a huge HP elevated mess had developed with several embeded mesocyclones. Several elevated wall clouds, but nothing seriously impressive.
After watching this show for about half an hour just NW of Palmanova I met up with Marko Korošec outside Ruda. We waited for quite a while for new storms to form, but at about 19:30 the newly forming cluster in the Alps north of the plain started exploding with activity. We raced northward towards the lightning barrage, stopping north of Porpetto. Soon an isolated supercell formed.
The supercell rapidly developed impressive structure – a massive wall cloud and inflow tail, beaver tail and mesocyclone striations. The inflow was quite impressive at about 40 km/h sustained, blasting into the supercell. The entire supercell was rotating spectacularly.
The wall cloud passed right overhead, with some impressive rotation visible.
We opted to let this supercell pass for the next one, forming to the west. The second one never really developed and turned out to be the last of the evening. Not bad though.