Closed cold core 500mb low

[Kurt Silvey]

Looking at today’s 12z data,(1/1/06), would this setup fit into the C500L as defined by Jon Davies? There is a C500L over nw MO at -20c and a closed surface low located in ne MO. Could this have contributed to the tornado reports in east central MO overnight? And, do you think this setup could go on to produce today? I have just recently read Mr. Davies paper, and am trying to lean more about this setup, and how to identify it.

http://www.spc.noaa.gov/obswx/maps/500_060102_12.gif

http://www.spc.noaa.gov/obswx/maps/sfc_060102_12.gif

EDIT: Researching a little more: the C500L was probably located somewhere around KC last night, the warm front (focal point) was in se MO, and there were Td’s in the lower 60s. This places the C500L less than 200 nm from the reported tornado in Reynolds County. It would seem that this event may fit into Mr. Davies parameters. It will be interesting to see if this setup can produce again today, possibly in southern IN.

Edit2: After reviewing the current RUC model forecast, it appears that these lows (surface & C500L) will become more stacked and occluded as the day progresses, so I don’t believe we will see any more tornado production form this (C500L) setup.

 

[Jeff Snyder]

I don't think I'd call last night's setup a cold core setup. We typically speak of cold-core activity as seperate from warm-sector activity. Yes, the surface low was pretty close to the 500mb low, but, in this case, the proximity of the 500mb low just meant that the warm sector slid under colder 500mb temperatures to result in stronger instability. With a true cold-core setup, the activity usually develops outside what we would call the warm sector, in an area near an occluded front. With southerly flow across southern / central MO last night, I'd say that the strongest convection was warm-sector-type convection.

EDIT: I think some of the supercells developed immediately along the warm front.