Recognizing the Potential for Dangerous Nocturnal Fire Growth and its Implications on Fire Weather Products and Services (58)

Steven Pfaff, National Weather Service, Wilmington, NC

Joshua Weiss, National Weather Service

Richard Neuherz, National Weather Service

Terrence Lebo, National Weather Service



Numerical weather prediction tools currently available to forecasters are incapable of initializing relatively small-scale features, such as large fires, that can adversely modify the local environment to support rapid fire growth. As a result, fire weather forecasters must use caution when producing and relying on Spot Forecasts from the gridded output that does not recognize contributions from large fires, especially during the nighttime operational periods. This is especially true when the tendency of the models is to stabilize the boundary layer with the loss of diurnal heating and the absence of boundary layer warm air advection. In reality, large fires located where models depict stable conditions can significantly transform the local environment and lead to extreme fire behavior (EFB) at night. One example was the Highway 31 Fire in Horry County, SC on 22-23 April 2009 where significant atmospheric modification occurred and resulted in life-threatening, extreme nocturnal fire growth. Thus it is imperative that forecasters demonstrate the ability to diagnose the potential for nocturnal EFB through analysis of antecedent conditions, ventilation rate, visual observations, National Weather Service (NWS) Weather Surveillance Radar (WSR-88D) imagery, and atmospheric stability. This paper will provide fire weather forecasters with information about the factors that led to a period of dangerous nocturnal fire growth during the Highway 31 Horry County, SC fire, how to identify the potential for nocturnal EFB that may occur through the use of a decision tree, and resulting decision support implications for the 22-23 June 2011 Juniper Road fire in Pender County, NC.