Supercell tornadogenesis over complex terrain

A study was performed to investigate whether the complex topography of eastern New York and western Massachusetts modulated the low-level wind, temperature and moisture patterns in favor of tornadogenesis in selected regions on a day when the synoptic-scale environment was conducive for severe weather. Analysis of available scientific literature revealed that F3-F4 intensity tornadoes, although rare, occur in rough-terrain environments with some regularity, averaging one event every two years. The Great Burrington (GBR), Massachusetts tornado on 29 May 1995 is an event of this type. Analysis results of the GBR tornado suggest that terrain-channeled, low-level southerly flow in the Hudson Valley of eastern New York and the Housatonic Valley of western Massachusetts may have modulated tornadogenesis potential by strengthening the wind shear in the lower part of the atmosphere and by enabling warm, moist, and unstable air near the ground to surge northward.