Sunday, 22 January 2012
Critical Sounding Parameters for Severe Pulse Thunderstorms in Coastal South Carolina
Hall E (New Orleans Convention Center )
WFO Charleston, SC (CHS) uses a convective checklist to help forecasters determine the convective threat for the day. A large number of atmospheric indices such as CAPE, BRN, shear, etc. are taken from the 12Z sounding, based both on the raw sounding data as well as data modified for the expected max temperature and associated dew point during peak heating. Values are then compared to typical values based on previous studies around the country, and convective cell type and severe threat are determined. While this has proved a decent first guess, there has never been a climatology of what those values are for Charleston, as well as what values represent what types of threats. While there are likely quite a few similarities to the studies from other offices that are currently used, there are also some differences due to the very warm and moist low levels that are common during the summer months in coastal South Carolina. This study created a climatology of those values, as well as departures from those values for days with severe weather reports, to compile a convective checklist tailored to WFO Charleston during Summer months. This produced a more effective forecasting tool to determine the severe weather threat for the warning area of WFO Charleston.