Minutes of the November 15, 2004 Meeting
Smoky Mountain AMS Chapter


Everyone met at O'Charleys in Morristown around 6:15 PM. After dinner, the meeting commenced at the National Weather Service (WFO MRX) around 8 PM. George Mathews (the new Meteorologist-in-Charge) introduced himself and mentioned a few words about upcoming activities with the NWS. Stephen Parker (Science and Operations Officer at WFO MRX) then spoke on "A Climatology of Synoptic Conditions which produced Significant Tornadoes across the Southern Appalachian Region" (can be found at http://www.srh.noaa.gov/mrx/research/tornclim/tornadoclim.htm):

"A 54 year climatology (1950-2003) of significant tornado events across the southern Appalachian region was compiled in order to examine the similarities and differences in the synoptic patterns and their relationship to the large-scale terrain features. Composite maps and individual surface and upper-air charts closest to the time of tornado occurrences were examined for this study. Sounding parameters were not examined due to the lack of a representative sounding in the region. Most tornado events were found to have occurred on the southern and western sides of the southern Appalachians, while far fewer events occurred on the eastern side. The peak season for significant tornadoes was during the spring on all three sides. However, a secondary maximum occurred during November and December (only on the southern and western sides) with November events typically associated with multiple tornadoes. Most summer events occurred across the western side, and were associated with west to northwest 500 hPa flow.

Surface charts revealed that most events occurred near a pre-frontal trough, especially across the southern and eastern sides. Events associated with cold fronts occurred mainly on the western side, but were nearly absent on the eastern side. All stationary front events occurred at night, while the events with pre-frontal troughs and troughs north of a low occurred primarily during the day. Of those events associated with pre-frontal troughs on the western side, most occurred either west of or on the Cumberland Plateau, with very few in the Great Tennessee Valley. This same result was seen with the two outbreak events associated with pre-frontal troughs on the western side, where the tornado tracks occurred primarily on or just west of the Cumberland Plateau with few or none in the Great Tennessee Valley.

For all significant tornado events, surface dewpoints were typically between 14 and 21 0C (58 and 70 0F) with most between 16 and 19 0C (60 and 66 0F). At 850 hPa, temperatures were typically between 13 and 18 0C with dewpoints typically between 10 and 15 0C. Most events were associated with southwest 500 hPa flow ahead of a neutral-tilted trough (although outbreak events were typically near positive-tilted troughs). However, west to northwest flow dominated during the summer months and produced most of the tornado events in the mountains. Most of the tornado events were located near a 300 or 250 hPa jet streak and most occurred on the right side, with a even split between the entrance and exit regions."

Howard Waldron then spoke briefly about some recent interesting severe weather phenomena in our area, including the Seymour "tornado-look-a-like".


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