Chase Log: June 06th, 2007
Click on any of the SPC products below (Convective Outlooks, Watches, or MCDs) to see the SPC's "Severe Thunderstorm Events" page pertaining to this event.
Total Distance: 1063 miles
Target Area: Kearney, NE
Chase Area: NE of Broken Bow, NE
Maximum SPC Risk category: Moderate
Watches:
Mesoscale Discussions (MCDs):
An extremely strong upper-level trough was forecast to move across the northern US, inducing bomb cyclogenesis across the northern Plains. The 975mb low was strong for any time of year in this part of the country and nearly unprecedented for June. Very strong shear profiles existed east of a dryline that extended from far southwestern South Dakota to the Texas Panhandle, with widespread >400 0-3km SRH present by late afternoon. Unfortunately, a stalled frontal boundary that persisted through the previous 5 days across the southern Plains, along with several well-organized MCS episodes through deep south Texas, resulted in marginal moisture return in the warm sector. With very warm temperatures aloft (e.g. -6C at 500mb and 14-15C at 700mb), the 56-63F Tds just weren't enough to overcome the cap, despite strong instability. It's not often that we see shear profiles as strong as was seen over a very large warm sector, so it was a shame to see the event largely bust. Another day of moisture return would have likely yielded a very significant tornado outbreak, most likely the largest since at least May 4th, 2003. That, however, is just conjecture.
We did deploy for ~10 minutes as a squall line moved in from the west, a line that developed from a rapidly-moving outflow boundary that developed from previous high-based convection across the NE panhandle. A single tornadic supercell did produce a relatively long-lived tornado (20-30 minutes) in far southwestern SD, but that was too far for us.
