In the wake of an unprecedented fire season, it is imperative to develop methods for improving particular aspects of wildfire forecasting. These include timing and magnitude of low-level moisture variability and convergence, diurnal circulation characteristics (sea and land breezes), convection, precipitation and lightning initiation. Over 2300 fires scorched nearly a half million acres of Florida during the spring and early summer 1998 at a cost of over 500 million dollars. This study compares the conditions that attended a major outbreak period (20 June 1998) and a suppression period (10 June 1998) in order to identify features that may be useful in fire weather forecasts.

Satellite imagery and standard meteorological observations are used to determine the synoptic and mesoscale environments. Data from the National Lightning Data Network are mapped with fire characteristics (location, fuel type, acres burned, etc..) to develop a complete picture of the initiation and evolution of the fires.

Considerable contrasts are evident in the atmosphere between a day in which fires were suppressed and a day in which a dramatic expansion in the areal extent of fires occurred. The period of suppression was associated with passage of a significant trough and intrusion of subsident air over much of Florida. In comparison, the fire outbreak was characterized by adequate instability and moisture for convection, a light surface flows opposing sea breezes, and light winds aloft. This generated stationary convection and considerable lightning leading to initiation of fires particularly outside rain areas.