Currently, 0-6 km vertical wind shear is in the range of 40 - 70 kts and effective SRH approaches 200 J/kg across the entire domain of convection, which is certainly sufficient for supercells. SBCAPE is around 500 - 1500 J/kG where convection is currently occurring, and the convection is forming right along the strong cold front. Because of the lower quality of the moisture, LCLs are slightly high (~1.5 km AGL), so tornado threat may not be substantial, especially if cold front undercuts supercells.
Update (6:25 pm CDT):
Our first tornado warning has popped up in OK on the very nice looking supercell in the radar imagery shown below. This event is looking much more interesting.
The Peanut Gallery (9:58 pm CDT):
Well, there have been at least 4 tornado reports this evening, one out of the cell pictured above in OK and 3 in central MO associated with the line of supercells. One 2.75" hail report occurred with a tornadic storm in Pulaski County, MO. Apparently, the supercells were able to keep optimally far ahead of the cold frontal forcing boundary to sufficiently keep from being undercut by cold and stable low-level air, thus they were free to undergo tornadogenesis. Using the proximity sounding from SGF, the Bunkers right moving supercell index estimated that the storm motion of the supercells would be toward the east-southeast (100 deg) at 29 kts. Given some projection of motion away from the front along its normal heading, the relative speeds were apparently somewhat comparable. The strong cap may have prevented too much convection from forming along the front. Obviously the strong wind shear aided supercell development. A very interesting case that dispelled some of skepticism from earlier today.
No comments:
Post a Comment