Well most of Saturday here in Central NC was cool and damp here at the surface, but yet we still had severe weather and storms how this is so, well for those who want to know Ill explain.
At 12z(8am local) we had a backdoor front push all the way to the Charlotte metro/upstate SC with most of central NC in a cool surface stable wedge.
Also the 12z SPC sounding showed a cool layer of air at the surface but just above that about850mb(5000ft) there was warm moist unstable air.
Along with some weak CAPE but lapse rates from 700mb to 500mb were 7c/km cooling with height also dry air was noted in a deep layer as well. Water Vapor imagery at 11:30am showed a short wave in the mid west with an MCV at the surface.
also note the SE ridge overhead. Fast forward a bit in time and by 4pm we started seeing severe storms show up over KY/VA and TN.
by 4:40pm we started to see supercells break out in W/SW NC with tornado warnings out.(heres base reflectivity and Velocity from GSP SC radar.
while still at the surface for central NC(all but Charlotte metro where dewpnts were in the 60s and temps in the 70s, this served as a focus for storms to train along.
but still storms were on going over the cool stable wedge airmass over central NC.
Where heres some answers as to why and how. First RUC analysis showed a 500mb short wave passing by helping to get lift going and the storms.
Sfc temps were in the 50s to upper 40s.
Along with the short wave and steep mid level lapse rates that produced a lot of lightning but also remember the 12z Greensboro sounding showed warm temps and good moisture at 850mb well heres a product called Theta-E all it is, is temp and dewpoint combined and the higher Theta-E the more unstable heres what we look at around 6/7pm.
Also Lifted index above the surface here very low and unstable
All and all this was a good severe weather event to learn something from and study for future setups hope you enjoyed.
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