NOAA is watching for El Nino to develop by this fall

NOAA is watching for El Nino conditions to develop in the central and eastern Pacific Ocean heading into the later half of the year.
Published: Apr. 17, 2023 at 9:32 PM AKDT
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ANCHORAGE, Alaska (KTUU) - As Southcentral Alaska begins to warm up, so too do the waters in the tropical Pacific Ocean.

It’s a change from the past three years as La Nina — the cooling of those same waters — brought a roller coaster ride of temperature and precipitation to the state.

Now, in just over a month, the National Oceanic and Atmospheric Administration is seeing signs that the opposite phase, El Nino, is developing, and quickly. For that reason, NOAA issued an El Nino Watch.

El Nino is the warming of the tropical central and eastern Pacific waters. The heat from those waters helps to fuel thunderstorms tall and strong enough to influence the jetstream pattern around the world.

Climatologist Brian Brettschneider says the likelihood of El Nino occurring by the end of this year is pretty high.

“So if the forecast for an El Nino verifies and the current thinking is there’s an over 80% chance that will happen, we should expect a warm fall and a warm winter moving forward,” Brettschneider said.

Initially, for Alaska, there’s very little impact.

“In the summers, the impacts aren’t felt as strongly — or pretty much anywhere, at least, in the mid and high latitudes — the impacts in the summer are more focused in the tropical latitudes,” Brettschneider said.

Alaska won’t see the major influence of El Nino until later in the year.

“Once we hit the fall, and then the winter, the atmospheric circulation that is impacted by these El Nino conditions ... those do impact high latitudes and they tend to make us much cooler in La Nina periods and much warmer in El Nino periods,” Brettschneider said.

Looking back at climatology, there’s a pretty strong signal, at least for temperatures.

“El Nino winters are all warmer than normal, you know, so it’s is it going to be a little bit warmer than normal, or a lot warmer than normal? Below-normal winters are basically off the table in an El Nino winter.” Brettschneider said.

That means we could see more heavy wet snow events, or cold rain events, or even more freezing rain/ice events during the winter. As for the rest of the spring and summer, Brettschneider says temperature and precipitation are controlled by natural variability in the jetstream. So, there’s a 50% chance of seeing either a warm and dry season, a cool and wet season or a combination of both.