Blogs

Few topics capture our readers' interest like the polar vortex. Next Tuesday, December 5, we plan to feed that interest with the launch of a new blog dedicated the winds, climate, and chemistry of the polar stratosphere. Come back next week for our first installment!     Read article

El Niño is currently chugging along, and forecasters expect it to continue for the next several months, with a 62% chance of lasting through April­–June 2024. Since we’re heading into the winter, when El Niño’s effect on Northern Hemisphere temperature and rain/snow is most distinct, today we’ll drive by some of El Niño’s wide-ranging impacts. On rails First stop—this El Niño has now met the threshold for a “strong” event! The August–October Oceanic Niño Index, which measures the three-month-average sea surface temperature in the east-central tropical Pacific (the so-called Niño-3.4 region), was 1.5 °C above the long-term average (long-term is currently 1991–2020). The Oceanic Niño Ind…   Read article

Note: The primary writer of this post is Michelle L’Heureux, but it is inspired by and reviewed by Brian Brettschneider, who is the NWS Climate Service Program manager for the Alaska region. The last several winters have been depressingly bleak for snow lovers in the Washington, D.C. area, where we at the Climate Prediction Center (CPC) are located. Needless to say, when Brian Brettschneider (@Climatologist49) showed me that the D.C. area historically sees above-average snowfall during El Niño winters, I excitedly dusted off our sleds and ordered new mittens because we’re expecting an El Niño this winter 2023–24. With that said, longtime ENSO blog readers will know that I’m wish-casting a…   Read article

El Niño is currently purring along in the tropical Pacific. Forecasters expect El Niño will continue through the spring, with a 75-85% chance it will become a strong event. A stronger El Niño—definition to follow shortly—means it is more likely that we will see El Niño’s expected thumbprint on winter temperature and rain/snow patterns around the world. The tiger’s stripes First, the numbers. Our primary metric for the growth of El Niño is the temperature of the ocean surface in the Niño-3.4 region, a box in the central-eastern equatorial Pacific. Specifically, the anomaly, the difference of this temperature from the long-term average (long-term = 1991–2020). (Why here? Several deca…   Read article

A robust El Niño is developing in the tropical Pacific, and we’re looking ahead to potential impacts on winter weather and climate. For specifics on this upcoming winter, you’ll have to wait for next month, when NOAA CPC will release their winter outlook. Today, I’m going for the big picture—how does the temperature of the surface of the tropical Pacific, thousands of miles away, change rain, snow, and temperature patterns over North America? The short answer: by shifting the location and strength of the jet stream. Let’s back up a bit, though. Any time we talk about the jet stream, we first need to define what we’re talking about, before getting into changes in its behavior and how that …   Read article