24th Conference on Severe Local Storms

P12.7

A synoptic climatology of high impact events in the county warning area of the National Weather Service Forecast Office in Charleston, South Carolina

Frank Alsheimer, NOAA/NWSFO, North Charleston, SC; and J. Jelsema, B. L. Lindner, J. Johnson, D. Timmons, and T. Rolfson

A synoptic climatology of the patterns associated with high impact weather events was created for the county warning area (CWA) of the National Oceanic and Atmospheric Administraion's (NOAA) National Weather Service (NWS) office in Charleston, SC (CHS). The CWA area includes southern South Carolina and north coastal Georgia. Events included in the study, taken between 1950 and 2006, were days with extreme heat (maximum temperature above 38 C (100 F)), days with extreme cold (maximum temperature below 0 C (32 F)) and the occurrence of strong tornadoes (EF2+), large hail (1.75 inch+), snow (1 inch or greater snow), and hurricane landfalls. Dates for the significant tornado and hail events were culled from the NCDC Storm Event database. The NWS's XMACIS database was used to determine dates of excessive heat and cold as well as winter precipitation. Finally, the historical hurricane track database hosted by NOAA's Coastal Services Center (CSC), based on data from the National Hurricane Center (NHC), was used to determine the dates of hurricane landfall along the coastline from Darien, Georgia northward to the South Carolina/North Carolina border. The dates for each type of event were then used to create mean and anomaly composites of 250, 300, 500, 700, 850, and 925 hPa heights, temperatures, and vector winds. Mean sea level pressure and mean and anomaly surface wind vector charts were also created.

Some of the more significant results from the composites, especially in the anomaly fields, will be shown on the accompanying poster. Precursor signals in the fields and event types up to 3 days prior to the event will be identified. The use of the results as a training tool for new forecasters to the area will also be mentioned.

Finally, a recent real-time case study will be displayed highlighting the potential future use of the study results in an operational environment. Specifically, the poster will highlight the potential use of the composites in determining the mode of severe weather expected for an event within the CHS CWA.

extended abstract  Extended Abstract (2.5M)

Poster Session 12, Severe Weather Climatology Posters
Thursday, 30 October 2008, 3:00 PM-4:30 PM, Madison Ballroom

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