On February 21–23, 1998, a devastating tornado outbreak affected portions of the Southeastern United States, primarily the U.S. state of Florida. Sometimes known as the Night of the Tornadoes, it was the deadliest tornado event in Florida history. In all, 15 tornadoes touched down, one of which was long lived and tracked for nearly 40 miles (64 km). Affecting mainly the Interstate 4 (I-4) corridor of Central Florida, including the Greater Orlando area, the tornadoes—among the strongest ever recorded in Florida—produced near-violent damage, killed 42 people, and caused 259 injuries.

One of the tornadoes was initially rated an F4 on the Fujita scale—among only two others officially so designated in the State of Florida, in 1958 and 1966—but was subsequently downgraded to a high-end F3; with 25 fatalities, most of which occurred in and near Kissimmee, this tornado featured the deadliest single-tornado death toll in Florida history, the previous such record being 17 on March 31, 1962. Two other F3s and a couple of additional strong tornadoes occurred over portions of Central Florida during the outbreak, killing an additional 17 people and injuring 109 others.

As the most intense activity of the outbreak occurred after sunset, concentrated either shortly prior to or after midnight, and affected densely populated portions of the I-4 corridor, including numerous mobile home and recreational vehicle (RV) parks, many sleeping residents became casualties; of the 42 deaths, 40 occurred in manufactured housing or trailers, including 15 at the Morningside Acres mobile home park and eight at the Ponderosa RV Park, both of which were located in Kissimmee.^{[2][3][4][nb 2][nb 3][nb 4]}

On February 22, 1998, data from both NEXRAD and weather satellites indicated that a bow echo and associated outflow boundary bisected portions of the Florida Panhandle and northernmost peninsular Florida, including the First Coast. Along the boundary, a vigorous squall line with embedded supercells—the initial nexus of severe weather—developed over the eastern Gulf of Mexico and headed eastward, toward the Tampa Bay Area. Ahead of the squall line, a retreating warm front coincided with robust atmospheric instability due to diurnal heating. By 7:00 p.m. EST, a low-pressure area near Mobile, Alabama, was linked to a cold front that extended southward, just off the west coast of Florida, while a trough in the middle to upper troposphere generated a strong subtropical jet maximum of up to 140 kn (160 mph; 260 km/h). This upper-level jet streak intersected a strengthening low-level wind field, with winds locally in excess of 50 kn (58 mph; 93 km/h) just above the surface, and thereby yielded conducive conditions to tornadogenesis.^[17][18][19]

During the evening and the overnight hours of February 22–23, 1998, this volatile environment—known to be common in the El Niño phase of the El Niño–Southern Oscillation (ENSO) during the Florida dry season (November 1 – April 30)—eventually produced seven tornadoes between about 11:00 p.m. EST on February 22 and 2:30 am. EST on the following morning. During El Niño the jet stream is typically stronger and displaced southward near or over Florida during meteorological winter and spring, thereby augmenting the likelihood of significant severe weather and tornado activity. During February 1998 one of the strongest El Niño episodes on record was ongoing, rivaling a similar episode in 1982–3 that had also contributed to elevated tornado activity over Florida. By October 1997, the National Weather Service (NWS) in Melbourne, Florida, highlighted the potential for enhanced severe weather over the coming months due to El Niño.^{[20][21][22][23]}

By 6:00 am. EST (11:00 UTC) on February 22, the Storm Prediction Center (SPC) had issued a convective outlook for day one indicating a moderate risk of severe thunderstorms capable of producing tornadoes over portions of North and Central Florida. At 11:55 am. EST (16:55 UTC), the NWS in Melbourne also issued a Hazardous Weather Outlook (HWO) highlighting a "significant" threat of tornadoes, hail, and destructive winds. By 1:44 pm. EST (18:44 UTC), the SPC issued its first tornado watch covering portions of the threatened area in Central Florida. Numerous, long-lived supercells with persistent mesocyclones would eventually evolve during the evening and track generally east-northeastward or northeastward over Central Florida, generating tornadoes that killed 42 people and seriously injured at least 259 others, making the outbreak the deadliest in Florida's history, surpassing another that killed 17 people on March 31, 1962, in Santa Rosa County.^{[24][25][26][27][28][29]}

• List of North American tornadoes and tornado outbreaks
• 2007 Groundhog Day tornado outbreak