Lightning activity level

Lightning activity level (LAL) is a scale that describes degrees and types of lightning activity. Values are labeled 1–6.^[1]

Lightning Activity Levels
Level	Description
1	No thunderstorms
2	Isolated thunderstorms. Lightning is very infrequent, 1–5 cloud-to-ground strikes in a five-minute period.
3	Widely scattered thunderstorms. Lightning is infrequent, 6–10 cloud-to-ground strikes in a five-minute period.
4	Scattered thunderstorms. Lightning is frequent, 11–15 cloud-to-ground strikes in a 5-minute period.
5	Numerous thunderstorms. Lightning is frequent and intense, greater than 15 cloud-to-ground strikes in a five-minute period.
6	Dry lightning (same as LAL 3 but without rain). This type of lightning has the potential for starting fires, and is normally highlighted in fire weather forecasts with a red flag warning.

References

Meteorological data and variables

General	Adiabatic processes Advection Buoyancy Lapse rate Lightning Surface solar radiation Surface weather analysis Visibility Vorticity Wind Wind shear

Condensation	Cloud Cloud condensation nuclei (CCN) Fog Convective condensation level (CCL) Lifted condensation level (LCL) Precipitation Water vapor

Convection	Convective available potential energy (CAPE) Convective inhibition (CIN) Convective instability Convective momentum transport Convective temperature (T_c) Equilibrium level (EL) Free convective layer (FCL) Helicity K Index Level of free convection (LFC) Lifted index (LI) Maximum parcel level (MPL) Bulk Richardson number (BRN)

Temperature	Dew point (T_d) Dew point depression Dry-bulb temperature Equivalent temperature (T_e) Forest fire weather index Haines Index Heat index Humidex Humidity Relative humidity (RH) Mixing ratio Potential temperature (θ) Equivalent potential temperature (θ_e) Sea surface temperature (SST) Thermodynamic temperature Vapor pressure Virtual temperature Wet-bulb temperature Wet-bulb potential temperature Wind chill

Pressure	Atmospheric pressure Baroclinity Barotropicity Pressure gradient Pressure-gradient force (PGF)

General

Electromagnetism

ELF/VLF emissions	Radio atmospherics Whistlers Chorus Hiss

Optical emissions	Transient luminous events Upper-atmospheric lightning Sprites St. Elmo's fire Ball lightning

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