Five severe convective cells over North Texas from three separate dates were
examined to determine what three dimensional, or “total” lightning data can add to the
understanding of a convective cell’s intensity, propagation, and severe weather potential.
Total lightning data were obtained from Vaisala Inc.’s Dallas/Fort Worth (D/FW)
Lightning Detection and Ranging (LDAR) network. Radar data from two Weather
Surveillance Radar – 1988 Doppler (WSR-88D) sites were used for position data and
information regarding the intensity and kinematic properties of each cell.
Total lightning products used by the National Weather Service Forecast Office in
Fort Worth, Texas were compared to total lightning flash rate; a quantity that has been
shown to be correlated to changes in cell intensity inferred from other sources, such as
radar and satellite data. These products, specifically flash extent density (FED) were
also compared to CG flash rate and radar derived measures from the WSR-88D sites.
The results of this work show that FED and total flash rate are well correlated,
with an average Pearson correlation value of 0.73, indicating that previous total flash rate
results may also apply to FED. Lightning hooks, holes, and notches in FED displays
indicated likely updraft regions, while appendages were observed to develop prior to deviant motion with two supercells. These results, combined with a greater update
frequency provided a useful complement to radar data in the warning decision process.
FED jumps were observed prior to several severe weather reports, indicating that total
lightning activity may be related to updraft strength as found in past studies. However,
FED jumps were sometimes observed without any associated severe event. More work
is clearly needed to define what FED changes are of most importance in the short-term
prediction of storm severity. The usefulness of the total lightning data on these dates
was dependant upon LDAR network status and distance of the cell from the network
center.
The results of this study suggest that combining total flash rate trends with visual
displays of FED provides the greatest added benefit to forecasters in maintaining
situational awareness during warning operations.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2874 |
| Date | 15 May 2009 |
| Creators | McKinney, Christopher Michael |
| Contributors | Carey, Lawrence D., Orville, Richard E. |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | electronic, application/pdf, born digital |
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