How El Niño Affects the Southeastern United States: Winter Storms, Flooding, and Tornado Risk

Published: July 16, 2026 · 9 min read

The Jet Stream Connection

The mechanism that brings El Niño's effects to the Southeastern US is the same one that affects California: a southward-shifted, strengthened subtropical jet stream. But the consequence is different. While California gets atmospheric rivers hitting the coast, the Southeast gets a more persistent storm track stretching from Texas through the Gulf states to the Carolinas and up the Atlantic seaboard.

During strong El Niño events, the polar and subtropical jet streams merge over the southern tier of the US. This creates a single, powerful storm track that funnels Pacific moisture across the Gulf of Mexico and into the Southeast. The result: frequent winter storms that can last 2-3 days, dropping heavy rain measured in inches rather than fractions.

The 1997-98 El Niño winter produced particularly dramatic results. Florida received 150-200% of normal winter rainfall. Georgia and the Carolinas were similarly drenched. The 2015-16 event was wetter than normal across much of the region, though not as extreme. The 2023-24 El Niño — a weaker event — still produced a 45% increase in February rainfall in Atlanta compared to the 30-year average.

Flooding and Storm Damage

For the Southeast, El Niño's most direct physical threat is flooding. The combination of persistent heavy rain, already saturated soils from successive storms, and the terrain of the coastal plain (flat, slow-draining) creates conditions where even moderate rainfall can produce significant flooding.

Florida is the most exposed state in the region. The Florida peninsula's low elevation and high water table mean that heavy winter rains have nowhere to go. During the 1997-98 El Niño, Florida experienced widespread flooding that caused over $1 billion in damage. The Suwannee, Peace, and St. Johns rivers all exceeded flood stage for weeks. More recently, the 2015-16 El Niño brought flooding to the Tampa Bay area and the Florida Panhandle.

Florida also faces an El Niño-specific coastal flooding risk. The same warm-water expansion that raises sea levels in California affects Florida too. During strong El Niño winters, sea levels along the Florida Gulf Coast are typically 3-6 inches above baseline. Combine that with the seasonal king tides and El Niño's enhanced storm activity, and the result is more frequent and more severe coastal flooding in vulnerable areas like Miami Beach, Fort Lauderdale, and St. Petersburg.

The Gulf Coast from Louisiana to the Florida Panhandle faces a compound threat: El Niño's enhanced rainfall combined with the region's subsiding coastal wetlands and inadequate drainage infrastructure. New Orleans, Mobile, and Pensacola all face elevated flood risk during strong El Niño winters.

Tornado Outbreaks

One of El Niño's lesser-known effects on the Southeast is an elevated tornado risk during the winter and early spring. The same strengthened jet stream that steers storms across the region creates more favorable conditions for tornado formation: stronger wind shear at different altitudes, combined with warm, moist air from the Gulf of Mexico.

The 1997-98 El Niño produced one of the most devastating tornado outbreaks in Florida's history in February 1998. A series of tornadoes across central Florida killed 42 people and destroyed over 2,000 homes. The 2015-16 El Niño contributed to an unusually active winter tornado season across the Southeast, with over 50 tornadoes in January-February 2016 alone. The 2023-24 El Niño was associated with the deadly Rolling Fork, Mississippi tornado in March 2023 and a widespread outbreak across the Southeast in January 2024.

The mechanism is clear: during El Niño, the mean position of the subtropical jet stream creates a zone of enhanced wind shear across the Southeast from January through March. This period — normally the quiet season for tornadoes — sees elevated activity. The traditional tornado season (March-May) also tends to be more active during El Niño years, though the connection is weaker than the January-March signal.

Agriculture: Delays and Benefits

The Southeast's agricultural sector has a complex relationship with El Niño winters. The primary cash crops — cotton, peanuts, soybeans, corn, and tobacco — are planted in the spring (April-May). A wet winter delays field preparation and planting, compressing the growing window.

Georgia and Alabama's cotton and peanut production are particularly affected. During the 2015-16 El Niño, the wet winter and spring delayed cotton planting by 2-3 weeks across much of Georgia. The delay pushed the harvest later into the fall, increasing exposure to early frost and reducing fiber quality.

On the positive side, El Niño winters replenish soil moisture after dry summers. The Southeast experienced periodic drought in recent La Niña years, and El Niño provides the recharge that allows agriculture to recover. For the 2026-27 season, the water supply benefit could be substantial if the preceding summer is dry.

2026-27 Winter Outlook

For the very strong El Niño forecast, the Southeast should prepare for a wet winter (December 2026 - February 2027) with above-normal rainfall across the entire region. The Florida Peninsula and the Gulf Coast are likely to see the most significant rainfall anomalies. Tornado activity during January-March 2027 may be elevated. Coastal flooding risk is higher than normal due to elevated sea levels and frequent storm events.

See El Niño Winter 2026-2027: What to Expect Around the World for the broader winter outlook.

Explore more at the El Niño Guide — comprehensive climate science explained.