Identification of side-door/back-door cold fronts for fire weather forecasting applications

The objective of this presentation is to demonstrate the ability of a mesoscale numerical weather prediction model (MM5) to resolve side-door/back-door (SDBD) cold fronts in the northeastern United States for the purpose of forecasting their potential impact on wildland fires. We employ the MM5 to simulate two SDBD cold front cases: 22 April 1987 and 14 May 2004. This presentation focuses on the phenomenological aspects of SDBD cold fronts and relates these aspects to operational fire-weather and fire-behavior parameters.

Using the output from these simulations, we assess the ability of the model to resolve the structure of SDBD cold fronts and their pre- and post-frontal environments. Pre- and post-frontal environmental characteristics are discussed in terms of their potential impact on fire-weather parameters from the perspective of both traditional fire-weather ingredients (i.e., warm, dry, windy; temperature, relative humidity, and wind velocity) and diagnostics and indices that detect mesoscale boundaries relevant to fire-weather interactions (e.g., mixed layer depth, ventilation index, surface potential temperature gradients).

This study illustrates the potential for variations in fire-sensitive parameters to impact wildfires during the climatologically favorable season for SDBD fronts over the northeastern United States. These results also can be employed to help assess the potential impact of sea-breeze fronts, synoptic-scale cold fronts, and other surface-based mesoscale boundaries on wildland fires.