Examination of Derecho Environments Using Proximity Soundings

Observed upper air soundings that occurred within 2 h and 167 km of derechos were collected and analyzed to document atmospheric stability and wind shear conditions associated with long-lived convective windstorms. Sixty-seven derechos, accompanied by 113 proximity soundings, were identified during the years 1983-93. Owing to the large variability of the synoptic-scale environments associated with derechos, each derecho was further divided into categories based on the strength of synoptic-scale forcing associated with each event.