The Bordeaux radar is currently providing an impressive view at the wildfire ongoing west of the city:

Doppler radar doesn't show rotation here, but instead shows an intense precipitation core with a divergence signature. This very strongly suggests a downburst to me. Just on the German side of the border it also produced a lot of wind damage: www.facebook.com/permalink.ph...

Actually it's not so uncommon to see this in hailstorms on C-band radars, since C-bands show lower RhoHV in hail than S-bands. Here's an example from 2 days ago:

I've finally had the time to work on something I was quite looking forward to: volumetric rendering of the polarimetric RGB. In this example you can see a deep TDS, with a large debris ejection occurring from the storm's top after a violent tornado hit Washington (IL) in November 2013.

Radar at least doesn't show a low-level rotation signature. Regarding reflectivity: The storm's core was quite attenuated by the storm in front of it, so you can better see it on the second higher-elevation scan.

Impressive tornadic debris fallout signature over Illinois yesterday. In this RGB cross-section you can nicely follow the lifting of debris from ground to overshooting top, and then the fallout downstream of the updraft.

It was not exactly an impressive storm that produced it!

After concluding yesterday that there are really too many dealiasing failures with German data currently, I increased the size of the window that determines how many neighbouring velocities are used in estimating the correct velocity. This seems an improvement, though dealiasing errors will remain.

Finally a closer look at when the circulation was over land, including a look at dual-pol variables through the RGB. It's possible that some debris was detected, but it's not a very coherent signature, and at least part of the low CC comes from ground clutter.

A loop:

Well... that was an interesting signature last night near the Fossalon radar in NE Italy @federicopavan.bsky.social . It tracked mostly over sea, but hit a small section of land as well, so I'm curious whether some damage reports come from there. The circulation wasn't that strong though.

Another useful check is that for temporal and vertical consistency. In this video below you can see a lack of such consistencies for this particular signature. The real rotation signature to the south is clearly more consistent, although it seems not completely free from dealiasing failures.

Good question. One of the main things to look for, is sudden jumps in velocities from one region to another. In this video you can see that velocities jump ~15-20 m/s between the 2 incorrectly dealiased regions and their surroundings. This is much larger than typical gradients in their surroundings.

The most pronounced rotation signature here is caused by a dealiasing failure in both the inbound and outbound velocities, so it should be ignored. But centered just west of Bad Driburg is a broader circulation associated with the hook echo, and that still looked pretty potent (but a bit broad) then

It has been producing more low-level circulations since this, but they have been pretty broad and weak, although the one at the second radar image briefly looked a bit more potent. But overall tornado risk seems to have decreased, although a brief tornado might still occur.

Currently looking less organised than earlier, but it could restrengthen.

Powerfull supercell with serious tornado potential in Germany currently. Radar-derived hodograph supports tornado potential, more so than model forecasts suggested.

On my way home now, after spending the past 2 weeks on chasing in the US with 2 friends. Saw some great supercells and 2 brief funnels or tornadoes. Some phone pictures while waiting at the airport (with not the best foreground on photo 4...):

I'm still very curious about what was detected with this earlier cycle over Cascina Malpaga. It was not ground clutter, as it wasn't present at surrounding times. It also originated from the ground, since reflectivity is highest there. And some manual dealiasing learns that there was a couplet.

It was not from the first cycle though, with what I thought was a TDS. It was from the second cycle, where the RGB shows a larger green region related to hail. Here I don't see something that I would call a TDS.

The likely TDS, with green colors in the hook. Green indicates low CC with low ZDR, as would be expected for tornadic debris. Velocity is sadly not that usable due to being mono-PRF with low Nyquist velocity.

I think we just got 1 or 2 tornadoes in northern Italy from this supercell. It had a hook for 2 time intervals, and during the first interval it seemed to have a TDS (in reply).

Less than 60 dBZ can do it if these hailstones are falling only sparsely. At the reported location of the hailstone we didn't see more than 56 dBZ.

This news begs of course for another 3D view. This time of a storm that had a very impressive BWER, or well.. it was actually only bounded on the sides and not so much at the top. What this storm also nicely shows is that you don't need very high dBZ for huge hail.

A corresponding cross-section with beam altitude estimates:

Yesterday's giant hail producing supercell in Texas didn't feature a BWER or very impressive echo overhang prior to producing this hail. But something that does stand out is how tall the hail core is, with 73 dBZ measured at 13 km altitude!

A look at yesterday's impressive train of RM supercells over northern Texas, which also produced up to giant hail:

A 3D view of the impressive LM supercell over Missouri yesterday with giant hail. Besides the impressive hail core itself with reflectivity up to 75 dBZ, we can see a large area with echo overhang and a bit of a BWER, indicative of large and strong updraft. Slanted hail core indicates strong shear.

A beautiful cell split occurred in northern Texas last evening: