Lightning and severe weather warnings
Dear Tom,
Why are severe thunderstorm warnings are never issued for lightning?
Jim Froemke, Chicago
The National Weather Service issues a severe thunderstorm warning when it believes
a storm will produce winds of at least 58 m.p.h. and/or hail at least three-quarters
inch in diameter or larger. Lightning ground strikes are not severe thunderstorm
criteria.
Meteorologist Rusty Kapela at the Milwaukee NWS says, "Any convective cloud that
manages to generate one lightning bolt is, by definition, a thunderstorm. If lightning
were a criterion, even a weak thunderstorm such as a garden-variety thundershower
would require the issuance of a warning."
That would greatly diminish the effectiveness of the warnings. Kapela advises that
any thunderstorm should be considered severe with respect to lightning.