Climatology and Synoptic Evolution of Major Forest Fire Events Over the Northeast U.S.

Abstract

This study presents a spatial and temporal climatology of major wildfires (>100 acres burned) in the Northeast U.S from 1999 to 2009 and the meteorological conditions associated with these events. About 59% of the wildfire events in this region occur in April and May, with &sim76% of all wildfires over the higher elevation (> 1000 m) regions of the Northeast occurring in these months, while &sim53% occur in the Appalachian lee and the coastal plain. The other 41% of wildfires occur in the summer, fall and early spring months. The synoptic flow patterns associated with Northeast wildfires were classified using the North American Regional Reanalysis (NARR). The most common synoptic pattern in the Appalachian high terrain region is a surface high pressure centered over the northern Appalachians (&sim46% of events). For the coastal plain fire events, the most common pattern (&sim46%) is an anticyclone extending southward from southeastern Canada and Great Lakes to the Northeast. Trajectories show that the pre-high pattern shows the greatest subsidence, greatest decrease in relative humidity, and greatest increase in temperature. Terrain sensitivity studies show that there is a 1&degC to 2&degC increase in temperature and a 0%-8% decrease in RH when there is a southwesterly flow downsloping event over the NEUS.