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Historical Base Velocity


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Hello,

 

I am wondering if anyone would know a site where I am able to find archived data for base velocity maps from last year in my area.  I need one from the 21st of  August 2014, as I am trying to locate what I think was a tornado on this, and the rotation would be easier to find on that because, as I have checked the historical radar, it is difficult to find as this was a High Precipitation Supercell.  I have been all over the NOAA site.  I requested information in the form of a bunch of code but I am TOO DUMB to figure out how to convert it to, say, .KMZ files.  Any help would be much appreciated.

Thanks, 

 

Andy

 

P.S.  The station I use is State College, PA if that makes any difference.

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  • 2 weeks later...

You'll need some sort of software that allows you to view this data.  Either GR2 or GR3.  The former is better but more expensive.  Level II data is higher resolution, and the raw files display automatically in this viewer, whereas a few extra steps of conversion are required to convert them to Level III so they can be displayed by GR3.  They run about $250/$80, respectively, but you can also get a 21-day free trial if you just want to use it for this one instance.

 

Though I'll also say that you probably won't be able to prove the existence of a tornado from just base velocity.  Plenty of mesocyclones don't produce tornadoes.  If the NWS has any reason to suspect a tornado, they'll perform a survey and publicly release their findings.  If they didn't do that for this case, it probably wasn't a tornado.

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Hard to tell if it's actually a tornado or some really convincing scud.  The fact that it looks like it's emanating from a wall cloud makes me lean tornado.  What time was this?  And what place?

 

I assume you showed NWS CTP back in August?  If they ruled it isn't, then it probably isn't worth pursuing, imo.

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If my iPhone is correct, it was 4:29 pm. That is when the video I took was apparently. I don't know if it accounts for daylight savings or not. Also, I thought you had to be a trained weather spotter to report tornadoes.

Also yes, that is what made me think it was a tornado. It looked like it was attached to a wall cloud and it would make sense because about a half hour before the base rolled over the mountains from the north (heading about 118 degrees SE) and the warning ended soon after, but it seemed to keep its appearance on radar, etc. I wish I could upload the video of it to here. I did not report it at the time because i did not know if I should, or who to talk to about it. It also disappeared very soon after. Sorry this is kind of long.

As to where it was, it looked to be near the south mountains. These are about eleven miles away. Using the bearing I got, I went to the radar map and looked for where a line of that bearing intersected with the radar echo of the storm. It looked in a remote area. I am not sure.

Thanks for the help,

Andy

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Here's a gif I made of the 0.5 deg tilt BV from KCCX (State College) from 4:18 to 4:36 p.m.  Definitely a supercell and the mesocyclone is pretty well-defined on radar, especially for that range.

 

It certainly looks like you might actually have a tornado there!  I apologize for my skepticism.

 

Regarding the spotter/not a spotter question: I'd guess that the NWS takes spotters a bit more seriously, but since you have a picture, that's a moot point.  I would definitely email someone at NWS PBZ with the pic and a brief explanation. (Assuming you're in Jefferson County, you're actually in Pittsburgh's warning area.)  Whoever is in charge of StormData at that office would probably be very happy to be able to add that image/story.

 

8-21-14_NW_PA_TOR.gif

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It seems like the site should be back up by Monday- that's what they said for the site.  I got some orders from several days ago but I can't seem to figure out what to do with them.  I also am at a hotel so if I tried to download all the files it wouldn't go so well.

 

But the search continues!!

 

Oh my.  

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  • 10 months later...

Hello all, 

Here I am nearly a year later and I finally figured out how to use GRlevel3 and get archived data.  I looked over the reflectivity, base velocity, and the storm relative velocity (if anyone could educate me on the difference with those last two I would be very thankful) and there is a red and green intersection in that area at the time I filmed it (there was a file for exactly 4:29). I am not sure how to upload an image on my computer on here, but I can see if I can figure that out.  

Thanks

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