Climatology of Long-Track Tornadoes

A 40-year climatology (1979–2018) is presented for long-track tornadoes in the United States using the Storm Prediction Center tornado database. Path length (PL) stratification thresholds are defined using characteristics of supercell storm evolution, and are categorized as: all (ALL), PL >0 mi or 0 km; short (S), PL <30 mi or 48.3 km; long (L), [30, 60) mi or [48.3, 96.6) km; very long (V), [60, 90) mi or [96.6, 144.8) km; extremely long (X), PL ≥90 mi or 144.8 km; and long-track sum (LVX), PL ≥30 mi or 48.3 km. Results show LVX tornadoes: a) made up <1% of all tornadoes; b) occurred east of the Rocky Mountains; c) were generally wider; d) caused disproportionate numbers of deaths and injuries; e) typically had damage ratings ≥F/EF2 (peak F/EF3); f) occurred more often with more deaths and injuries in the Southeast than in the Midwest or Great Plains; g) had larger area scale and Destruction Potential Index; h) occurred mostly in April and May versus May and June for S tornadoes; i) occurred primarily from midafternoon to early evening; j) had a peak formation hour at 1600 local solar time (also true for ALL S, V and X), though L tornadoes had a peak and secondary peak at 1800 and 1500, respectively; k) were less common during nighttime than S tornadoes; l) were more frequent during nighttime in the Southeast than nighttime in the Midwest or Great Plains; and m) occurred more often with tornado outbreaks.