AboutJason Expertise I know everything about weather. I am a 6-year trained Storm Chaser for Wired-WX Storm Chasing Services. Background in thermodynamics, global warming and cooling dynamics, advanced cellular thunderstorm dynamics, and diagram dynamics expert.
Experience Lead Storm Chaser: Organizations: Wired-WX and Member of National Weather Service/Skywarn Network
I am sure your familar with VIL and the hail index with being a stormchaser. I was trying to find errors associated with both of them that could lead to inaccurate measurement of hail. I know VIL and hail have no "real" correlation but could the values be overestimated or underestimated depending on the synoptic set up. For instance with weak vertical wind shear could we see VIL values being overdone with a lot of water falling in the column. Or even if it is not overdone could that lead to higher values not reflecting hail potential because of intense water loading.
Hail index is a measure of DBZ above the freezing level. And in my study I am finding out it is overdoing the max hail size a lot...what could some factors be to its inaccurracy or overestimation. If the vertical shear is weak wouldn't that show higher reflectivities above the freezing level.
Thanks for any input.
Answer Hello.
No radar is perfect. Few radars can even master the formula of Vertically Integrated Liquid known as VIL. Measuring the amount of precipitation in clouds is near impossible, because storms can strengthen or weaken at any time. VIL is very deceiving. Remember, VIL is only useful to help detect multi-cell and super-cell thunderstorms, otherwise it is just redundant.
Hail usually does not fall within the category of VIL. When VIL is measured within 20 miles of the radar, it is considered underestimated. VIL is overestimated when the radar shoots at all angles and is far away from its target. To finish my point and give you the answer you are looking for: VIL is less accurate for highly tilted storms and underestimated for tilted updrafts -- since the updraft of the hail core will tilt -- it tilts with respect to the vertical column of reflectivity. Therefore, reading VIL in hopes to predict hail is not a good idea, and will be redundant most of the time.
