"Joe" wrote in message
...
I believe its TSSN and its only the intensity of the thunder/lightning
thats
noted?

-TSSN (light thunder) or +TSSN (heavy thunder) as thunder is given
priority
over snowfall (it has a higher synop code number)

someone correct me!

In METARs the ( +/-) refers to the intensity of the precipitation. However,
IIRC, SYNOP code 97 refers to the intensity of the thunder/lightning..

http://homepage.ntlworld.com/booty.w...o/uswfaq.htm#8
Gives more detail.

Jon.