Observations: one shelf cloud, one supercell, hail, and lightning
Distance: 300 miles
Time: 7 hours
Chase Team: Car 1 - Dean Narramore, Rob Warren, Rob Lee, and myself; Car 2 - Pete Argyle, Rob Graham, Kate Brown, and Becky Hewins
SPC Convective Outlook: Slight Risk (upgraded to Moderate) (Click to see SPC products, data, and storm reports)
Chase Setup: A rare late fall chase event. A deep trough situated above the western edge of the Plains promoted the formation of a surface low in South Dakota, with a cold front stretching from the low all the way down through northwest Oklahoma into the Texas Panhandle. With dewpoints in the upper 50s and CAPE of about 1000 J kg-1 in north central and south central Oklahoma, storms expected to fire all along and ahead of the cold front. Greatest mid-level lapse rates found in northeast Oklahoma/southwest Missouri, and greatest helicity values of over 350 m2 s-2 found in eastern Kansas and east central Oklahoma. Low-level shear looks sufficient for supercells, especially in north central and northeast Oklahoma into southwest Missouri and southeast Kansas, although primary threat may be large hail.
Chase Log: Unsure of the day's potential for tornadoes, we set off in the hopes of at least seeing some good late fall convection, lightning, and hail. We were not disappointed, as we did not have far to go before we saw a large supercell near Stillwater. The supercell was outflow dominant, though, so it had little chance of producing a tornado.
We did see an amazing shelf cloud, and had to run away from the storm three times as it barreled down on us with penny- to nickel-sized hail (there may have been a few quarters as well). Golfball-sized hail was reported in the area, but we missed it. We stopped at a gas station near I-35 near dark, for cover from yet another wave of hail and to watch the brilliant lightning show put on by the storm.
While at the gas station, I heard a lady tell the guy at the cash register about her bad day. That afternoon, she was watching the lightning at her nearby farm when her power got knocked out and then lightning struck her field and started a fire. The fire department came out to put the fire out, but had some difficulty when it started hailing. Then the tornado sirens went off. At least she didn't have to wind up dealing with a tornado, as the only tornado reported this day was in southwest Missouri.
This was a good day for us; we got just about what we expected - good storm structure, lightning, and hail. Couldn't ask for much better on my first November storm chase!