EWP Blog

New TORP object showed rapidly increasing probabilities as it exits Orange County, which caught my attention to sparked further investigation. -Sidney Crosby

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

-Oppenheimer

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

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

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.

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).

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.

Kilometers

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.

-Nimbus

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

An interesting observation of Torp as a tightening and strong circulation moved just northwest of the LWX radar. Torp identified two separate objects (46% and 85%) on what appears to be the only circulation.

Flash

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

Enhancement of DivShear north of Culpeper grabbed my attention. Coincides with localized “bowing” of line segment and worth watching.  Object marker appeared around this area on the next scan. 

These next two images are from a scan or two later.  Object marker shifted north and DivShear seemed “messier”. Original concern may not have been warranted, based on this, but new area developing to south now is worth monitoring.

Update 3: Enhancement of DivShear and coinciding of strengthening Z resulting in me issuing an SVR. Decision to warn was made at 11:59z (warning eventually issued about  5 min later due to computer issues).

-Oppenheimer