developing El – Early signs of a strengthening El Niño are emerging after La Niña faded. Scientists and forecasters say the shift could tilt 2026 summer and late-season weather across the U.S.—with the southern U.S. leaning wetter and the north and Pacific Northwest trending
For the third straight wave of uneasy forecasts, the ocean is giving weather watchers something to grab onto.
A developing El Niño in the Pacific is showing its earliest atmospheric fingerprints—shifts in pressure. wind patterns. and ocean temperatures that could start steering weather across the United States in the months ahead. Southern states may see wetter conditions, while the north could face warmer and drier stretches.
The concern for many meteorologists isn’t the word “El Niño” itself. It’s what comes next if early signals keep strengthening—especially the possibility that ocean heat stored in the western Pacific could continue migrating toward the central and eastern Pacific. resetting patterns for summer and beyond.
Forecasters have been warning for months about the potential for a strong—or even a “super El Niño”—as climate models continue to show a pattern that could rival some of the most intense events on record. The latest observations include warmer-than-normal sea surface temperatures and bursts of westerly winds that help push stored heat from the western Pacific toward the central and eastern Pacific.
Severe Weather Europe described the transition as a turning point for summer, and potentially, the remainder of this year. “The 2026 North American summer season is entering a critical transition phase,” Severe Weather Europe wrote. “Latest data confirms that a strong El Niño event is not only developing but is already showing early signs of its presence in the global atmospheric circulation. We are now witnessing the first detectable changes in pressure and temperature patterns across the United States and Canada.”.
If current trends continue, forecasters say the emerging El Niño pattern could influence the jet stream and shift seasonal weather across North America heading into late summer and fall—altering rainfall, temperatures, and storm tracks in different ways by region.
NOAA guidance points to a split across the country: a stronger. more active subtropical jet stream that can increase storm systems and rainfall potential in the southern U.S.; increased rainfall potential along the Gulf Coast and Florida. including a higher risk of heavy rain events and localized flooding; a tendency for wetter storm tracks across the southern tier of the U.S. from Texas to the Southeast.
In contrast, the northern U.S. and the Pacific Northwest are expected to tilt warmer and drier, with fewer storm systems tracking through the region.
The Atlantic hurricane outlook is also expected to diverge. El Niño is expected to lead to a more active hurricane season in the Pacific and a less active one in the Atlantic. NOAA-linked expectations point to suppressed Atlantic hurricane activity due to increased wind shear that disrupts storm formation.
Meteorologists caution that summer impacts are often subtle compared to winter patterns, when El Niño influence is strongest.
The sequence of what’s being watched helps explain why the timeline feels so tight: forecasters are tracking early atmospheric fingerprints now. then looking for how those changes reshape the jet stream later in summer—while hurricane guidance depends on whether the ocean-atmosphere coupling continues to strengthen.
On the hurricane side, the Pacific picture is leaning toward more activity if the signal holds.
A developing El Niño in the Pacific Ocean could tilt conditions toward a more active eastern and central Pacific hurricane season this year. Warming signal—if it continues to couple with the atmosphere—can reduce wind shear and support more frequent tropical cyclone development across the basin.
AccuWeather expects 17 to 22 named storms in the Eastern Pacific, along with 9 to 13 hurricanes and 4 to 8 major hurricanes this season. The forecast also calls for 6 to 9 direct impacts to Mexico and Central America—more than double the historical average. In the Central Pacific. which includes Hawaii. forecasters are calling for 4 to 7 named storms. 2 to 4 hurricanes and 1 to 3 major hurricanes. with 1 to 2 direct impacts possible for the islands.
Even places not typically in the path of tropical systems are on watch. While California is not typically in the path of tropical systems. forecasters say warmer ocean waters and more favorable storm tracks can increase the risk of tropical moisture reaching the region—raising the odds of heavy rainfall and flash flooding in parts of Southern California. particularly in late-season setups.
AccuWeather also warns of an elevated flood risk across the broader Southwest, including Arizona and New Mexico, where remnants of Pacific storms can interact with monsoon moisture and produce intense rainfall far inland.
Hurricane forecasters are already monitoring the start of the season: the Pacific season began on May 15, and hurricane forecasters are already monitoring two possible tropical storms in the eastern Pacific basin, the National Hurricane Center said in a June 1 advisory.
The Atlantic story looks bleaker for storm counts.
El Niño conditions typically suppress Atlantic hurricane activity. The main driver is increased vertical wind shear—changes in wind speed and direction with height—that can tear apart developing storms before they organize. El Niño also tends to stabilize the atmosphere over parts of the tropical Atlantic. making it harder for thunderstorms to grow into tropical cyclones.
As a result, El Niño years often bring fewer named storms, a lower chance of major hurricanes, and reduced development from African easterly waves moving off the coast of Africa.
While the overall outlook leans below normal, forecasters caution that impact risk remains significant—particularly in seasons where storms form closer to land or undergo rapid intensification.
National Weather Service Director Ken Graham put the message bluntly: “People often suffer from a false sense of lead time.” He added. “Every Category 5 that’s made landfall in this country was a tropical storm or less at three days out. They rapidly intensify and get here quickly. Preparedness early is absolutely key.”.
Hanging over the forecasts is one specific ocean signal that experts say helps explain what might be coming: a Kelvin wave.
At the center of the El Niño development is a Kelvin wave—a large pulse of subsurface warm water now rising toward the ocean surface. NOAA describes it as a slow-moving pulse of warm water traveling eastward just below the ocean surface along the equator in the Pacific Ocean. Unlike surface waves that break at the coast, these are subsurface shifts in ocean heat moving across thousands of miles.
Kelvin waves form when changes in wind patterns—especially weaker trade winds or bursts of westerly wind activity—push warm water built up in the western Pacific toward the central and eastern Pacific.
Severe Weather Europe says it is currently in a downwelling phase, meaning it is actively pushing warm subsurface water eastward across the equatorial Pacific and suppressing cooler water from rising to the surface.
NOAA describes Kelvin waves as having two phases. In the downwelling phase. warm water is pushed eastward and colder water is suppressed from rising to the surface. raising sea surface temperatures in the eastern Pacific and supporting early development of El Niño conditions. In the upwelling phase. after the wave passes. colder water from below can rise closer to the surface. temporarily cooling the ocean in some areas.
A single Kelvin wave can take about two to three months to cross the Pacific. giving forecasters an early signal of how ocean temperatures may evolve. Strong downwelling waves. NOAA says. often are among the earliest signs that the ocean-atmosphere system is shifting toward warmer conditions—even though the wave itself does not guarantee an El Niño will develop.
Behind the jargon, the climate pattern is familiar even when it feels unpredictable in real time.
ENSO—short for El Niño-Southern Oscillation—is the recurring climate pattern involving changes in temperatures in the central and eastern tropical Pacific Ocean. Every three to seven years. water temperatures across the tropical Pacific Ocean warm or cool by anywhere from 1 to 3 degrees Celsius compared to normal. according to the National Weather Service.
La Niña is the cooler phase, when sea surface temperatures in the central and eastern Pacific Ocean are cooler than average, the National Weather Service says. El Niño is the opposite: Pacific Ocean waters in the central and eastern regions are warmer than average, NOAA says.
The timing of hurricane planning also matters. The Atlantic hurricane season runs from June 1 through Nov. 30, and NOAA says ninety-seven percent of tropical cyclone activity occurs during this time period.
For now, the ocean is in motion and the atmosphere is starting to show it. El Niño’s early fingerprints may not deliver instant answers. but they are already changing what forecasters pay attention to—and what families in flood-prone regions. or coastal communities watching the storm tracks. should plan for well before the first warning arrives.
El Niño ENSO Kelvin wave NOAA subtropical jet stream Gulf Coast flooding risk hurricane season 2026 Eastern Pacific hurricanes Atlantic wind shear National Hurricane Center severe weather Europe