Jim Steenburgh and collaborators have written a paper on lake-effect snowstorms over the Great Salt Lake. In that paper, they develop a climatology of 16 well-defined events over the last 5 years (see their Table 1).

Of the 16 lake-effect snowbands, three of those bands produced cloud-to-ground lightning as detected by the National Lightning Detection Network (courtesy of Gary Huffines and Richard Orville, Texas A&M). I compiled the proximity soundings (Salt Lake City) for each event.

[CLICK TO ENLARGE.]
The green lines are the three temperature profiles where CG lightning was observed during lake-effect snowstorms (LTG). The white lines are the remaining soundings occurring during lake-effect snowstorms with no lightning (NO LTG).

I constructed a similar plot for the dewpoint temperatures.

Note that the LTG soundings are warmer and moister in the lower troposphere than the NO LTG soundings. In fact, every LTG sounding has a warmer surface and 700 hPa temperature than all the NO LTG soundings. There appears to be no difference between the two groups (LTG and NO LTG) for the lower-tropospheric lapse rate, as measured by the surface-700-hPa temperature.

The Great-Salt-Lake temperatures (courtesy of Scott Halvorson, University of Utah) for the LTG cases were 13.5, 14.0, and 18.0 deg C. For the NO LTG cases, they were 2.0-12.0 deg C.

Two similar plots for lake-effect snowstorms in Buffalo, derived from a series of dates listed in Moore and Orville (1990, Monthly Weather Review), can be seen here (temperature) and here (dewpoint).

That warm lower tropospheres favor lightning doesn't hold all the time. Here is an example (courtesy of Jim LaDue, Operational Support Facility) of a temperature and dewpoint sounding taken 3 hours before two positive cloud-to-ground strokes recorded by the NLDN. Note that it is nearly -20 C at the surface!

These results are in agreement with those of Holle and Cortinas (1998). In particular, their Fig. 2 shows that the number of reports of thunder is greater at Salt Lake City and Buffalo for surface temperatures greater than 0 degrees C.

MacGorman and Rust (1998, 292) summarize their review of lightning in winter storms with, ``we are aware of no thorough scientific investigation of causal relationships between the electrical state of winter storms and their snowfall. Extensive tests to evaluate the proposed hypotheses concerning possible links between lightning and the mesoscale and synoptic scale meteorology associated with winter storms have yet to be performed.'' I hope that this research provides some evidence towards understanding the synoptic-scale environment for lightning in winter storms. Hopefully, this work will also lead to operational criteria for forecasting wintertime lightning.

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