My take
Based on my knowledge and interpretation of the KUEX (Blue Hill NE WSR-88D) radar data, this is my best guess as to what phenomena hit the WX5TVS van.
First, it is clear that the main mesocyclone and possible large tornado passed about 2-3 miles to your NW and N, and that your van had an interaction along the leading edge of the RFD gust front.
Second, based on the velocity data above the 0.5 degree tilt at 002944 UTC, there is an anticyclonic Tornadic Vortex Signature with a delta-V exceeding 85 kts. This appears to pass just N of your location (within 1 mile). That anticyclonic vortex may have developed to the ground just after the 0.5 degree scan, since it appears in the next 0.5 degree scan just NE of Fairfield.
Third, there is an extreme RFD on the right (south) side of the low-level (LL) meso, with sampled ground relative winds at 115 kts at 700 feet above ground level (AGL).
My call:
You were definitely hit by a major RFD gust surge - probably as extreme as they get. The leading edge of the RFD was probably very turbulent, and no doubt there were probably multiple transient gustnado-like vortices that were just as strong as the RFD winds.
You might have also been hit by a developing anticyclonic tornado on the leading edge of the RFD surge, as indicated by the velocity data aloft. Video from the east looking toward your location would be helpful. Anyone?
You were not hit by the main cyclonic tornado of that storm, nor were you hit by a new tornado following a cycling of a new mesocyclone.
Other opinions are welcome. But in the end, glad you are alive!
Greg Stumpf
