We got to do a real-time case this afternoon. A fairly classic cold core aloft with steep lapse rates, a deep mixed layer and dewpoint depressions of 15F or greater. Based on cloud heights in the surface observations we’re probably looking at LCLs on the order of 5000-6000 ft AGL. Not terribly favorable for tornadoes, but perhaps a chance for the NMDA to shine before thermodynamics takes over with very strong downdrafts that might congeal into a cold pool.

At the left is coincident NTDA and NMDA detections coincident with a respectable kink in the convergence line. The 0.5 degree cut corresponds to an approximate height of just over 2000 ft AGL. The NMDA is triggered off the 0.5 to 1.3 degree cuts, even though there is still a weak couplet above this at 2.4 degrees (that’s probably just a bit below the AzShear threshold).

The right column is much later when the outflow has begun to outpace the convection. As seen in other cases, we see a lot more NMDA and NTDA detections overall, but the sliders are very helpful by allowing us to filter out the false detections (lower 20s percent chance threshold in this case for NTDA).

It should be noted that the ProbTor showing zero percent during this time and I think this has a lot to do with its awareness of the unfavorable thermodynamic environment.

-marfafront