(NEXSTAR) – Meteorologists are continuing to warn of the El Niño weather event expected to impact us throughout the winter, with a new climate outlook from the World Meteorological Organization suggesting it "could be unprecedented in strength." In an update Wednesday, the WMO said this year's El Niño weather pattern could be so strong, it could "literally [be] off the monitoring charts that we have used for the past four decades." A main focus of forecasting El Niño comes down to sea surface temperatures.

In the Pacific, an "anomaly of 0.5 [degrees Celsius] above normal" can trigger an El Niño alert from the WMO, according to the United Nations. Between next month and January, WMO has forecast temperatures could rise 3.8 degrees Celsius above average. "This El Niño is a behemoth," the UN’s emergency relief chief, Tom Fletcher, said Wednesday, further describing it as "a wrecking ball," packed with "extreme heat, droughts, and floods."

Its effects are expected to "be felt long after" it peaks at the end of 2026, WMO Secretary-General Celeste Saulo said during a press conference, echoing other recent forecasts. This strong, long-lasting El Niño is expected to have a "pretty substantial impact" on the weather we see over the next several months, Brian James, Nexstar chief meteorologist, previously said. As we head into winter, how El Niño plays out will be very different for the northern half of the country and the southern half.

Broadly speaking, the northern states will be drier and warmer than normal, while southern states will be cooler and wetter. Recent seasonal outlooks follow that pattern. “Based on what I am seeing now, I am officially concerned,” Daniel Swain, a prominent climate scientist at the California Institute for Water Resources, said on social media recently, as reported by Nexstar's KTLA.

"We’ve never seen an event this big before in the context of our rapidly warming climate … The warning lights are flashing." Earlier this month, NOAA's Climate Prediction Center said El Niño "strengthened further" in September, with "a strong-to-very strong El Niño likely" from January through March. "Chances remain high for a historic event that would exceed the strength of previous El Niño events dating back to 1950," the CPC explained. "With an event of this magnitude, the chances of experiencing impacts consistent with El Niño are larger, though not guaranteed."

In late September, Columbia University climate scientist Azhar Ehsan, in a briefing to the media, provided a chart showing the probability of El Niño lasting until spring was "100% to 99%." "I wrote near-certain but it's 100%," he said at the time. As it has been, NOAA's Climate Prediction Center agrees El Niño is 100% sticking around for about six more months, though a La Niña pattern may not be too far away (denoted by the blue bar).

El Niño is on track to reach its peak in December, the WMO's most recent Global Seasonal Climate Update showed. The report suggests sea-surface temperatures are only expected to "increase to record levels" between now and December, according to a press release.

“El Niño doesn't add new heat to the planet. It releases heat the ocean has already been storing beneath the surface - which is why a strong event so often becomes one of the hottest years measured (as with 2024),” Saulo told the Global Heat Forum in Bangkok earlier this month. “The ocean it's drawing from is the warmest we've ever measured it. There is simply more heat available to release."

Ehsan said in a September media briefing that this year's atmospheric evolution looks similar to that of 1997, when one of the strongest-ever El Niños formed. That winter was characterized by broken records and "unusual extremes," climate researchers said in an April 1998 National Climatic Data Center report.

It was the U.S.'s second-warmest and seventh-wettest winter since 1895, and the super-strong El Niño contributed to chaotic weather from coast to coast: the Northeast was hit with ice storms, the Southeast and California were drenched with flooding, deadly tornadoes tore across Florida. There were weeks of storminess, and some cities went days without seeing the sun. As daunting as it sounds, there may be some upsides to the El Niño. KTLA meteorologist Henry DiCarlo said earlier this week that the potential for higher-than-average seasonal rain could help combat the drought conditions California has been battling as of late.

Saulo, however, has warned that regions of the world could face severe drought, flooding, and increased heat. "We cannot stop El Niño," she said. "But we can prevent many of its worst human consequences."