Tornado outbreak of November 21–23, 1992
The Tornado outbreak of November 1992, sometimes referred to as The Widespread Outbreak, was a devastating and large three-day outbreak of tornadoes that struck the Eastern and Midwestern United States on November 21–23. This exceptionally long-lived and geographically large outbreak produced 95 tornadoes over a 41-hour period, making it one of the longest-lasting and largest outbreaks ever recorded in the US, and published studies of the outbreak have indicated the possibility of even more tornadoes. There were 26 fatalities, 641 injuries, and over $300 million in damage.
Meteorological synopsis
On November 21, 1992, a very strong cold-core low was located over southeastern New Mexico; in nearby El Paso, mid-level temperatures of were recorded. Rounding the base of this feature was an jet streak. At the surface and in the lower levels of the atmosphere, low pressure was becoming established across western Texas. Strong wind flow in advance of these features led to the northward transport of warm, moist air from the Gulf of Mexico and into the Southern United States. The cold-core low progressed northeastward from western Texas toward the eastern Great Lakes region as the tornado outbreak unfolded. Areas of low pressure at and just above the surface followed similar tracks, with the associated low-level jet advancing across most of the Gulf Coast region and eventually along the Atlantic Coast. A preceding system had left a weak cold front stretching from Texas to Michigan on November 21, and in fact, forecasters initially questioned whether moisture would be sufficient for an organized severe weather event across Texas the following day. However, continued southerly flow advanced dewpoints in excess of across central and southern portions of the state, and the cold front soon surged northward as a warm front instead. Convective available potential energy values, though modest, still reached 1,000 J/kg across southern Texas. This moist and unstable environment, combined with very strong wind shear, promoted the development of an intense squall line and isolated supercells ahead of it, contributing to multiple tornadoes in the Greater Houston area on the afternoon of November 21. As the squall line spread eastward the next day, an intense low-level jet contributed to provide favorable wind profiles, abundant moisture, and a sufficiently unstable airmass. As such, the line of thunderstorms maintained vigor as it moved eastward across the Gulf Coast, while discrete supercells continued to form to its east. The same general environment persisted into the Mid-Atlantic early on November 23. This severe weather setup contributed to dozens of tornadoes during that time, many of which were significant and deadly.Farther north, a secondary concentration of tornadoes developed across the Ohio River Valley, resulting in the most damaging late-season tornado outbreak at the time there. Environmental conditions were more comparable to a widespread springtime event instead of a late season event.