The good and bad of Prob Tor/AzShear/Meso Detection Algorithms

The image below looks at 2 cells in central Oklahoma. The northern cell has a prob tor of 77%, but is falsely lightning up a shear zone with little chance of a tornado. The southern cell shows all the characteristics of a tornadic supercell, but has a prob tor of 37%. However, the southern cell is closer to producing a tornado (via live media).



Here's another image using KVNX instead of KTLX, and shows only the prob tor.



The two cells to the north have 90 and 91 percent, respectively, while the southern supercell has only 33 percent.
Not to pick on the prob severe product, the meso detection algorithms a similarly struggling. Below is a 4-panel showing the legacy mesocyclone alogrithm (upper left), the digital mesocylone algorithm (upper right), the low level AzShear (lower left), and the experimental meso algorithm (lower right).



All three detection algorithms are flagging the circulations as equally important, but an examination of the base data shows otherwise.

Thorcaster

ProbTor and AZ_Shear

ProbTOR showing rapid increase in tornado probability with AZ_Shear increase.  These time series trends are extremely valuable for trends when diagnosing storm intensity increasing/decreasing. 

- Jake Johnson

ProbTor Trends on Storm in State College CWA

While spinning up in the Philly CWA, noticed a persistent signal in the ProbTor values with a storm tracking through central Pennsylvania.

While we don't have the KCCX data at this point, you can see the persistent rotation on the MRMS Low-Level Rotation tracks.  At the time of this image at 1840Z, the ProbTor value peaked at 74%.

1840Z MRMS Display: ProbTor maxed at 74% (lower left panel). 

Here is a loop of the the storm over the last hour, with the trend up in ProbTor values.

Loop of MRMS data in State College CWA.  Notice the trends in the ProbTor values in the lower left hand image.

In addition, the ProbTor was above 20% for nearly an hour. 

-GOB

Another elevated probtor of 55 percent. Highest yet.

Prob TOR southwest Iowa

Prob tor of 40+% 10  minutes before pictures of tornadoes. Dropped to 10% at time of tornado occurence roughly. Tornado has lifted and prob tor down to about 10%

Benjamin

SevereProb

Some of the highest TorProbs we have seen northern storm had a Torprob of 53%. We warned on that storm even though no reports of tornadoes were reported. Based on both radar signatures and TorProb we felt it warranted a tornwarn.

Highest PROBTOR Prob seeing so far 53 percent

Highest ProbTor value so far with northern storm with 53 %. A Tor warning was issued several volume scan before it got to that level (tor issued with ProbTor at 46 %).