Monster Medford OK meso & tornadoes 5/10/10

My wife Shawna, her son Zach, and I intercepted the large supercell near Medford OK last Monday (5/10/10). As a rule, I don't chase storms going 50+ mph, but we decided to try it, given the high-end potential tornado environment (see significant tornado probability mesoanalysis graphic for 20z, 2nd image above, an experimental product that Bill Togstad in Minneapolis and I have been working on). We were prepared for very fast storm motions, probably giving us only a few minutes of intercept time.

There were many chasers on the Wakita-Medford storm, but we managed to avoid most of the crowds (and all the road "drama" south of Wakita) by pulling off on a county road 5 miles north of Medford and letting the dangerous storm come toward us. As it emerged from the haze and broken low clouds near Medford around 3:50 pm, the mesocyclone at first appeared to be rain-wrapped, but then we could begin to see features behind the rain curtains, including a narrow tornado on the north side of the meso (see 3rd image above, please excuse the poor video quality). We were using WxWorx due to some internet problems, and Threat Net was indicating that the meso would pass just to our northwest. Not so! It quickly became apparent that the storm was moving more rightward/eastward, and that we needed to move south FAST, out of the path.

It was unnerving to see a meso that large coming toward us at nearly 60 mph (a mile a minute!), and the pressure drop with the fast movement was causing our ears to "pop", the first time I remember experiencing this with an approaching mesocyclone. As we blasted south, the first tornado dissipated, and a larger one formed near the center of the meso, with rain and dust curtains moving around it. In fact, thoughout much of the meso, what appeared to be wispy "spin ups" and brief condensation columns were also occurring, causing us to wonder if much of the mesocyclone might actually be a very wide lower-end "tornado" a mile or more across, with more intense vortices moving around inside it (see 4th image above). There's certainly no clear-cut answer to that. Regardless, we needed to get out of the way.

As the larger cone tornado within the meso sped toward us (see 1st image above), we cleared the path of the meso and RFD winds to the south, and pulled over just north of Medford. Looking back to our north, the tornado(es) were no longer visible, as rain and hazy sunlight obscured our view (chasers farther east reported seeing only a rain-wrapped meso at this point). Looking to our west, we noticed an anti-cyclonic wall cloud and circulation on the trailing gust front (a feature not that uncommon), whch produced a very brief spin up beneath a small condensation funnel aloft (not shown). With the incredibly fast storm motion, our chase was over in only minutes, and Shawna's son Zach had videotaped his first tornado(es).

The last graphic above is a schematic and approximated path of this large fast-moving mesocyclone (several miles across), one of the largest and fastest I've ever seen. Despite the damage path from near Wakita OK to east of Arkansas City KS, it was great to hear that there were no deaths or serious injuries from this dangerous supercell.

For those on Facebook, additional video captures are under Shawna Davies' photo folder titled "5-10-10 Medford OK meso /tornadoes".

- Jon Davies 5/15/10