AzShear and Radar Artifacts

AzShear showed an interesting streak of both cyclonic and anit-cyclonic shear exactly down radial from the radar KDVN at 2025z. Just looking at that, it look like an artifact from the base velocity data down radial from the radar.

Looking at the reflectivity and velocity data, the issue seems to be beam blocking to the northwest of KDVN causing the erroneous AzShear values. Good to see that TORP is not influenced by this artifact.

-Stormy Surge

LP Supercell Tornado in Calhoun County, IA

A LP supercell produced a tornado in Calhoun County, IA, on the radar scan shown in a very low Z region with little rotation evident on velocity. TORP got as high as 43% but did not have a notable quick increase as recent tornadic storms did. AzShear increased but with a quick, minimal jump. This is a tough case and, considering that the TORP ingests radar data, without a defined signature on radar it will be tough for TORP to detect anything either. -newt

TORP Vs. ProbTor Example

During the slow portion of our CWA being in three tornado watches (for a much longer time than one might think), we noticed a TORP object along a meager looking meso. Probabilities were relatively low sitting around 25% which we tended to agree with due to the lack of promising features among base radar products. And then we decided to entertain a look at the ProbTor model and found an estimate of 58% for the same meso. This was clearly blowing the probabilities out of the water and TORP was able to give us confidence in disregarding ProbTor’s input in this case.

Probability trends for TORP remained low for it’s detection of this mesocyclone.
ProbTor model ran a much higher probability than TORP for this mesocyclone.

It’s nice to see even just one example of TORP trumping the aged ProbTor model.

-Wx Warlock

TOR OAX

Not obvious on radar, and likely an EF0, but small probs on AZ shear at time of report. I would not have warned on this and probably would not have warned, but probably would have after the fact given the persistent of similar signal in AZ shear data – Wildcat

Environmental Data

Along with radar data, near-storm environmental conditions are an integral part of the  warning decision, so including it in the TORP display would be very useful to warning forecasters.  Contoured plan view data of  MUCAPE, MLCIN, 0-1 km helicity, etc should be added to the “Weather Related Overlays” to tell if storms are moving into more/less favorable environments. Some other environmental data items that could be added to the list of graphed data trends: DCAPE, 0-6 km shear, 0-3 km helicity, Other forecasters will have their own preferences for what environmental parameters to include.

Posted by Rigel