Faux Supercell? Interesting Radar Images

[Bob Hartig]

I captured these level 2 screen grabs of a storm northwest of the North Platte radar just a few minutes ago. The reflectivity images sure look convincing, but there was nothing in SRV or BV to suggest rotation, and the cloud tops (according to GR3, which I was also running) were only in the neighborhood of 10,000-15,000 feet. If it was in fact a supercell, it was a mighty low-topped one. The storm was headed northwest (which suggests cold core but makes the "hook" seem misplaced relative to the storm motion), and it dissipated within a few frames.

I thought the images were interesting enough to share.

 

[Jason Boggs]

I think it was just heavy sleet on radar.

 

[Bob Hartig]

Could well be. I have a hard time believing it was anything significant--just looked kinda cool.

 

[rdale]

I captured these level 2 screen grabs of a storm northwest of the North Platte radar just a few minutes ago.

Temps are in the mid-30's, obs are reporting snow, and the closest lightning is about 150 miles to the south. There's nothing "storm-ish" about those returns, you're just seeing mixed or wet frozen precip.

 

[Bob Hartig]

That's the other stuff I didn't bother to look at and no doubt should have. I was just intrigued by what I saw, grabbed it, and tossed it out here as a point of interest. You've heard of sheriff-nadoes? This is a "sheriff echo." Come on, let me off the hook!

 

[Jason Boggs]

Hey Bob, I'll go in with you here buddy! Man, isn't that a nice looking supercell on radar there? I bet there's a nice tornado on the ground with that one! rdale is crazy for thinking there is frozen precip with that!!!

Anyway, hope you have a great year of chasing Bob!

 

[Bob Hartig]

Hey Bob, I'll go in with you here buddy! Man, isn't that a nice looking supercell on radar there? I bet there's a nice tornado on the ground with that one! rdale is crazy for thinking there is frozen precip with that!!!

Anyway, hope you have a great year of chasing Bob!

I'm not sure whether to feel embarrassed as hell or laugh my arse off. I'll go with (C) both of the above. Besides, what the heck, there could have been a mile-wide snow wedge underneath that sucker. What was Rob thinking?

We're all about due for a decent year. Hope to bump into you out there in West Texas, bro.

 

[Jason Boggs]

I'm not sure whether to feel embarrassed as hell or laugh my arse off. I'll go with (C) both of the above. Besides, what the heck, there could have been a mile-wide snow wedge underneath that sucker. What was Rob thinking?

We're all about due for a decent year. Hope to bump into you out there in West Texas, bro.

Hey man, rain or snow, that sucker did look like a pretty good supercell. On the local news, the Met that I chase for did say that this was a sleet storm and not a supercell. That's the only reason I knew about it. Otherwise, I'd have freaked out if I saw that thing. It looked just like any normal supercell looks.

 

[rdale]

You must have been calling Ben Holcomb's Storm Chase Nowcasting Service while his GEMPAK machine was down

 

[Jeff Snyder]

The most interesting thing to me in these images is what appears to be pretty significant attenuation. At S-band (~10-11 cm wavelength, which includes the bands at which the WSR88Ds operate), attenuation through meteorological media tends to be relatively minor, only becoming noticeable/appreciable with long path-lengths through heavy precipitation; for example, attenuation looking "down" a squall line can be very significant. However, considering the area "down-radial" of the high reflectivity area is very muted (with greater down-radial Zh for azimuths either side of that higher echo), it looks like a case of significant (anomalously significant) attenuation. The only thing that makes me a bit questionable about that, however, is the "crispness" (i.e. characterized by strong gradients) in the Zh field for radials counterclockwise to those that pass through the reflectivity maximum (shown in the zoomed-in image). Judging from sfc obs and the reflectivity image, it looks like the precip type at the surface was melting snow [for example, Thedford ob is light rain with T=35F at 10pm CST, and interpolating the evening soundings from OAX and LBF for the Thedford area would support some potential for melting snow (looking at LBF) or perhaps some sleet (modifying OAX a little)], so the Zh is high likely as a result of giant, water-coated melting snowflakes or wet sleet. That doesn't explain, however, why attenuation appears to have been so significant. It's slightly possible that there actually were two NW-SE "bands" with a natural break in the precip to the NW of this high-Zh echo, but I find that more unlikely than severe attenuation.

 

[Ben Holcomb]

Technology meltdown.. Still need to pay bills.. you know how it is...