The fire weather observer must obtain as much information as possible from all available sources to insure an accurate LAL observation. A single thunderstorm must be confirmed in the rating area. The clouds mostly produce virga, but light rain will occasionally reach the ground.
Lightning is very infrequent.
Thunderstorms are few, but two to three must occue within the observation area. Light to moderate rain will reach the ground, and lightning is infrequent. Thunderstorms are scattered, but more than three must occur within the observation area. Moderate rain is commonly produced, and lightning is frequent. 5 Towering cumulus and thunderstorms are numerous.