ATMO 10/9 - Lightning

Current Weather:
- Hurricane Norton: SE Pacific headed for Baja then the moisture will head NE toward SE Arizona and SW New Mexico
- Chance of showers this weekend because of moisture moving in, but the trough pushing south from Canada will determine rain/no rain

Lightning:
- Cloud-Ground lightning is only 20% of lightning in a storm
- Most of lightning (80%) is intra-cloud lightning (from negative area to positive area)

Sequence of Events for Cloud to Ground Lightning:
- Charge separation in cloud; induction charge on ground
- Formation of a stepped leader; moves in surging steps toward the ground, the path is unpredictable
- When ~100 ft from ground, positive leaders surge upward from objects on ground
- When connection is made, lightning occurs (flow of electrons through lightning channel from cloud to ground)

Lighting Up:
- The lightning bolt lights up from the bottom because the electrons flow the fastest from the bottom where the connection is made and electrons upward start flowing, lightning up the bold from the bottom up

St. Elmo's Fire:
- Green/Blue positive leaders

Distance to Lightning:
- (Speed of Sound) X (Time to Hear Thunder)
- Example: (1 mile / 5 seconds) X (10 seconds) = 2 miles

Electric Field Measurement:
- Measures the strength of charge build-up
- When the strength gets to a certain threshold, a lightning strike is probable and a warning can be issued