• After witnessing the continued decrease of involvement in the SpotterNetwork staff in serving SN members with troubleshooting issues recently, I have unilaterally decided to terminate the relationship between SpotterNetwork's support and Stormtrack. I have witnessed multiple users unable to receive support weeks after initiating help threads on the forum. I find this lack of response from SpotterNetwork officials disappointing and a failure to hold up their end of the agreement that was made years ago, before I took over management of this site. In my opinion, having Stormtrack users sit and wait for so long to receive help on SpotterNetwork issues on the Stormtrack forums reflects poorly not only on SpotterNetwork, but on Stormtrack and (by association) me as well. Since the issue has not been satisfactorily addressed, I no longer wish for the Stormtrack forum to be associated with SpotterNetwork.

    I apologize to those who continue to have issues with the service and continue to see their issues left unaddressed. Please understand that the connection between ST and SN was put in place long before I had any say over it. But now that I am the "captain of this ship," it is within my right (nay, duty) to make adjustments as I see necessary. Ending this relationship is such an adjustment.

    For those who continue to need help, I recommend navigating a web browswer to SpotterNetwork's About page, and seeking the individuals listed on that page for all further inquiries about SpotterNetwork.

    From this moment forward, the SpotterNetwork sub-forum has been hidden/deleted and there will be no assurance that any SpotterNetwork issues brought up in any of Stormtrack's other sub-forums will be addressed. Do not rely on Stormtrack for help with SpotterNetwork issues.

    Sincerely, Jeff D.

Parameters for Doppler Indicated Tornado

Joined
Jan 11, 2006
Messages
372
Location
Winnipeg, Manitoba
I'm certain there are probably differences from one region to another, but what kinds of parameters are used to issue a tornado from Doppler data without any ground truth? Is the issuance of a tornado warning based solely on the triggering of WDSSII algorithms, or does a "judgment call" come into play for the radar operator?


John
VE4 JTH
 
Determining certain warnings are based on a wide variety of parameters. Where the storm is located (on a boundary, the type of air it is ingesting, etc.) I'd say that certain radar signatures, (TVS, mesocyclone indicator) are taken into account as well but they must be verified by the operator. Something important to remember about the algorithms is that they are computer algorithms and are subject to error.

I often check to see if that tornadogenesis signatures from the storm relative velocity exist. I don't know where I could find a link with that information.
 
Most think of the algorithms as 'dummy lights' or at least as a final gut check or a 'did you look at this' type of indicator. I don't think anyone really uses them as their warning triggers. The number one thing would be to look at the radar signature and evaluate the environment. Most of the science in the past 10 years has pointed to the conclusion of 'get a meso, get a low-level rotation, evaluate environment' type of mindset. So, the radar is part of that, then hand off to the environment.
 
I can tell you for sure that the standards, such as they are, vary greatly from office to office and maybe even from forecaster to forecaster in a given office. Out here in CT I've seen some storms get T-warned recently that would've just been laughed at had they occurred out on the Plains. I'm talking about blatantly obvious outflow dominant cells that didn't even have much in the way of a sustained couplet. At the time I figured these warnings must have been based on some kind of eyewitness report, however spurious, but the text just said it was doppler indicated with no mention of any spotter reports. Let's face it, the TVS algorithms are far from perfect, we all know this. Someone should tell those guys that a momentary TVS just doesn't really indicate all that much in the absence of any kind of sustained storm-scale rotation. I suspect most of these kind of dubious radar-indicated warnings are probably driven more by the "CYA" effect than anything else. No one at OKX seems to want to take any chances, not with the super-high population densities we have here in the Tri-State/NYC Metro areas. Ironically, the one recent storm that did actually produce a tornado in CT wasn't T-warned until 10 minutes after the tornado lifted. That cell did indeed exhibit classic sustained supercellular characteristics on radar, but it probably lacked a TVS at the time of the tornado and thus apparently wasn't warned. The bottom line seems to be that there are no hard and fast rules for doppler indicated warnings. It would appear that it's pretty much up to the forecaster on duty whether to warn or not.
 
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