Looking for good hail radar days

[rdale]

I'm trying to hunt down good hailers last year, primarily when the radar was in the new sevwx VCP so 4.1-ish minute updates are available. If you know of large hail not terribly far from a radarsite last year, can you post the date / location? I'm putting together some demo imagery to present at some of the sevwx conferences.

- Rob

 

[Karen Politte]

Are you looking for TBSS (triple-body scatter spike) representations??

I have one sitting on the laptop which is pretty good from KS last year I think....

KR

 

[Aaron Kennedy]

Be careful... the archived VCP 12 data I have seen has some major issues with reflectivity data near radar with tilts from 1.4-8 degrees or so. The good news is it is easy to spot; you have these crazy digital spot looking rings within 25km or so.

Example:

I'd suggest checking out the NCDC Storm Event database... do a search for 2-4" hail and find some dates. Then pull the radar data from HAS.

Aaron

 

[rdale]

I'll take it - but I'm primarily looking to use GRLevel2 to track the path of the extreme reflectivity in the core. A few of us playing around with the 3D side of GRL2 have made some interesting observations, but I want more data (and the faster scanning of VCP12) to get a better handle.

- Rob

 

[Aaron Kennedy]

Keep in mind reflectivity is a poor estimator of hail... especially size since hail falls within the Mie scattering regime. Reflectivity factor is based on Reyleigh scatterers where the diameter of the hydrometeors is much smaller than the wavelength of the radiation. That said, Arthur Witt found hail was 100% likely in returns of I believe 60dBZ during Vortex, but this was hail of all assorted sizes.


Aaron

 

[Kiel Ortega]

I'll take it - but I'm primarily looking to use GRLevel2 to track the path of the extreme reflectivity in the core. A few of us playing around with the 3D side of GRL2 have made some interesting observations, but I want more data (and the faster scanning of VCP12) to get a better handle.

- Rob

I'll sum up my project I've been working on the last year at the lab (our conf paper is available http://ams.confex.com/ams/pdfpapers/104885.pdf I've seen some things with the reflectivity core and hail reports. A short summary:
---the maximum elevated reflectivity core usually occurs upstream of where any maximum hail reports (if available) occur
---through playing in WDSS, you can do fun traces of the hail core around a meso...it's fun to watch, but doesn't do much in the way of helping diagnose hail.
---low level reflectivity doesn't appear to be the best way to judge whether there was hail, let alone severe hail, at a point. This is from fall trajectories, radar distance issues and inaccurate reporting of hail
---using Storm Data as a scientific verification dataset is a bad idea (but it's all we have to do a large dataset experiment)

In my opinion is that a multi-sensor and hybrid cell-/grid-based hail diagnosis algorithms need to be used to diagnose hail until dual-pol radar comes operational.