DivShear Cloverleaf

Just wanted to note that it was impressive to see the DivShear show the cloverleaf product associated with the strong circulation around 1221 UTC in this QLCS event.

Flash

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AzShear & Damage

Example of where AzShear indicated a threat even though V data indicated minimal threat. Reports of wind damage within AzShear highlighted area.

 

-Oppenheimer

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Torp adding value over ProbSvr

Doing a comparison of Torp to ProbSevere, I found Torp to be superior on the tornado that occurred northwest of LWX as ProbSevere Tor probability never reached about 35% while Torp had values well above 50% for this identified object. It is nice to see a new tool like this that can improve on the older ProbSvr model.

Flash

MRMS RALA upper left, MRMS Refl at -10C upper right, 0-2km AGL low level rotation tracks lower left
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All four products

Both AzShear and DiVshear highlighting tornadic area quite well, and coincides great with Z and V data. Good example of high warning confidence “nudgers”.

 

-Oppenheimer

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Interesting AzShear/DivShear Features Leading up to Tornadogenesis

This line of thunderstorms split into 3 main line segments by 1150-1200Z. These line breaks are one of the nudgers/confidence builders in the QLCS tornado warning process. You can see convergence along the UDCZ and a few areas of weak rotation beginning to form along the southern flanks of each of those line segments.

KLWX 4 Panel of Z/V/SRM/CC at 1157Z

As things started to look interesting in the reflectivity/velocity images, increasing values of DivShear and AzShear led to a couple TORP 30-40% objects being created on the southern end of a couple of those line segments (a sign that we need to keep a close eye on the radar  for possible tornadogenesis).

KLWX AzShear Product shown at 1157Z.
KLWX DivShear product shown at 1154Z.

 

And ultimately, TORP tornado probabilities increased to ~95% right around the time wind/tornado damage started to be reported all across the city of Leesburg, Virginia (~1220Z). You can also see somewhat of that clover-type shape/look in the DivShear product ususally indicative of tornadic circulations.

KLWX DivShear and TORP Products at 1221Z.

Kilometers

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Double TORP objects close to radar with QLCS

TORP created a second object (95%) on the same circulation from the same radar (LWX). The original object maintained a 75%. This caused confusion, and led to a lack of trend on the new, 95% object.

TORP with two objects on the same circulation, from the same radar.

 

-Nimbus

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Two Torp Objects

Two TORP objects were created for this tornado-warned storm. Interestingly, the higher percentage object was new and did not have a trackable history, but the (slightly) lower percent object showed a rapid increase. -Sidney Crosby

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1210 AzShear and TORP

Images show an AzShear maximum in southwestern Loudoun County colocated with a TORP object showing increasing probabilities over time. This coincides with surging reflectivities and broad circulation. -Sidney Crosby

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