Greg Stumpf
EF5
Don't feel bad about knocking the algorithms, and we'll take all the constructive criticism we can use. As I said, these were initially developed over a decade ago, and we are continuously looking for ways to improve warning decision guidance. For example, what you describe above has been used to develop what we call our "intermediate hail diagnosis" products for WDSSII, and are available from NSSL's Google Earth WDSSII set-up. We're also pumping some of these multi-radar/ multi-sensor hail diagnostic grids into AWIPS at several WFOs (OUN, TSA, FWD), products like reflectivity on the 0C and -20C temperature altitudes, 50 dBZ Echo Top, and the difference in Height of the 50 dBZ Echo Top to the -20C level, along with gridded multi-radar POSH and MESH (same stuff available in GR2), and MESH swaths of various accumulation intervals. Temperature information is automatically updated from RUC 3D analysis grids.The typical stuff...height, extent, and intensity of reflectivity cores, etc. We've been using a chart put together by another office (their exact identity escapes me at the moment), that relates current freezing levels to the height of 50-55 dbz necessary for severe hail, and it has performed admirably for discriminating strong from severe, but that's just one tool, of course.
For the most part, we "calibrate" our size expectations with the first several hail reports we receive. I don't remember ever seeing anyone here look at the size estimations in SCAN, but then again, I don't remember seeing many people use SCAN. I don't want to slam the work you guys have done with the algorithms, far from it. The TVS algorithm performed very admirably during our 3/31 event, noticeably better than usual, in fact.
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More information and our thoughts on the topic are included in this paper.