Mobile Mesonet Data

[Waylon K]

I wanted to ask, do we think something like mobile mesonet data, including data gathered from things like the Dominator, will ever be used in the rating of tornadoes? I only ask as I know windspeed is the main denominator between categories, though I understand that for accuracy, research-grade instruments must be at certain heights etc... Im just curious.

 

[Randy Jennings]

Probably not. They don't even use data from highly calibrated instruments used by field research teams in EF ratings now. Until they do that I see no chance of them using chaser obtained data. From The Enhanced Fujita Scale (EF Scale):

"*** IMPORTANT NOTE ABOUT EF SCALE WINDS: The EF scale still is a set of wind estimates (not measurements) based on damage. Its uses three-second gusts estimated at the point of damage based on a judgment of 8 levels of damage to the 28 indicators listed below. These estimates vary with height and exposure. Important: The 3 second gust is not the same wind as in standard surface observations. Standard measurements are taken by weather stations in open exposures, using a directly measured, "one minute mile" speed."

 

[Waylon K]

Why do they choose to use estimated winds rather than recorded when available? do you know?

 

[Randy Jennings]

1) It's always been that way, 2) measurements are not always available, 3) some say allowing measurements would pollute the dataset and make it impossible to compare events and change over time, and 4) it would be almost impossible to standardize the measurements (i.e. 3 m above ground in the tornadic circulation, 2.4 meters above ground .25 miles away in the inflow region, etc).

At it's root The EF scale is a damage scale - not a wind speed one. I said that once in the presence of the legendary Dr. Chuck Doswell and he corrected me. Dr. Doswell's argument was that damage is a proxy for wind speed and damage is just a proxy to get to wind speed. I highly respect his thoughts on this. I do however think that if it looks like a fish and smells like a fish, it likely is a fish. Bottom line is while efforts to revise the EF scale have been underway for some time, I would be surprised if they include measured winds speeds anytime soon.

 

[Waylon K]

Ah, ok, thank you.