Winter

To understand how important weather and climate risks are to the economy, watch investors. New research shows that two long-range seasonal weather forecasts in particular can move the stock market in interesting ways. We often think about forecasts as telling us what the weather will bring in coming days, but the National Oceanic and Atmospheric Administration also predicts weather conditions several months out. These seasonal climate outlooks tell us whether the hurricane season is likely to be active, whether the winter is likely to be snowy or cold, and whether an El Niño or La Niña climate pattern is likely to emerge with the potential to influence weather across the U.S. I study the impacts of weather on economic activity as an economist. In a new paper, an atmospheric scientist at NOAA and I analyzed the influence of long-range forecasts by looking at the changing prices of stock options over 10 years and thousands of companies. We found that investors are payin...

Rechargeable batteries are great for storing energy and powering electronics from smartphones to electric vehicles. In cold environments, however, they can be more difficult to charge and may even catch on fire. I’m a mechanical engineering professor who’s been interested in batteries since college. I now lead a battery research group at Drexel University. In just this past decade, I have watched the price of lithium-ion batteries drop as the production market has grown much larger. Future projections predict the market could reach thousands of GWh per year by 2030, a significant increase. But, lithium-ion batteries aren’t perfect – this rise comes with risks, such as their tendency to slow down during cold weather and even catch on fire. Behind the Li-ion battery The electrochemical energy storage within batteries works by storing electricity in the form of ions. Ions are atoms that have a nonzero charge because they have either too many or not eno...

One of the most robust measures of Earth’s changing climate is that winter is warming more quickly than other seasons. The cascade of changes it brings, including ice storms and rain in regions that were once reliably below freezing, are symptoms of what I call “warming winter syndrome.” Wintertime warming represents the global accumulation of heat. During winter, direct heat from the Sun is weak, but storms and shifts in the jet stream bring warm air up from more southern latitudes into the northern U.S. and Canada. As global temperatures and the oceans warm, that stored heat has an influence on both temperature and precipitation. The U.S. has been feeling this warming in the winter of 2023-24, the warmest on record for the Lower 48 states. Snowfall has been below average in much of the country. On the Great Lakes, the ice cover has been at record lows. Late February saw a wave of summerlike temperatures spread up into the central and eastern U.S., along wi...

Meteorologists have been talking for weeks about a snowy season ahead in the southern Rockies and the Sierra Nevada. They anticipate more storms in the U.S. South and Northeast, and warmer, drier conditions across the already dry Pacific Northwest and the upper Midwest. One phrase comes up repeatedly with these projections: a strong El Niño is coming. It sounds ominous. But what does that actually mean? We asked Aaron Levine, an atmospheric scientist at the University of Washington whose research focuses on El Niño. NOAA explains in animations how El Niño forms. What is a strong El Niño? During a normal year, the warmest sea surface temperatures are in the western Pacific and the Indian Ocean, in what’s known as the Indo-Western Pacific warm pool. But every few years, the trade winds that blow from east to west weaken, allowing that warm water to slosh eastward and pile up along the equator. The warm water causes...

The most potent El Niño event in almost a decade is about to exert its peak influence on North American weather. Many parts of the world are affected by El Niño, a periodic one- to two-year warming of the eastern tropical Pacific. In fact, El Niño is the biggest single shaper of Earth’s year-to-year weather variations atop human-induced climate change. And North America is one of the places where El Niño’s influence is most pronounced. Think of El Niño as the boisterous guest around which people gather, or scatter, during the course of a holiday party. For a few months to a year or longer, unusually warm water spreads across a vast area centered on the equator, extending from South America westward. In Spanish, the phenomenon’s name refers to “the Christ child” (literally, the male infant). The name arose because of timing: Anchovy fishers had long noticed that the waters off Peru sometimes warmed,...