Forecasting

When tropical meteorologists peer at satellite images, they often catch sight of subtle cloud formations hinting at something more ominous brewing. The first signs of a potential hurricane can be detected days before a storm gains its fierce momentum. Wispy cirrus clouds radiating outward, the appearance of curved banding low-level clouds and a drop in atmospheric pressure are all clues. These early clues are crucial for predicting the onset of what might develop into a catastrophic hurricane. I am a meteorology professor at Penn State, and my research group uses satellites and computer models to improve forecasting of tropical weather systems. With an especially fierce Atlantic storm season forecast for 2024, being able to detect these initial signals and provide early warnings is more important than ever. Here’s what forecasters look for. Hurricane Harvey entered the Gulf of Mexico as a tropical wave before reorganizing into a tropical storm a...

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...

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...

Wildfire smoke from Canada’s extreme fire season has left a lot of people thinking about air quality and wondering what to expect in the days ahead. All air contains gaseous compounds and small particles. But as air quality gets worse, these gases and particles can trigger asthma and exacerbate heart and respiratory problems as they enter the nose, throat and lungs and even circulate in the bloodstream. When wildfire smoke turned New York City’s skies orange in early June 2023, emergency room visits for asthma doubled. In most cities, it’s easy to find a daily air quality index score that tells you when the air is considered unhealthy or even hazardous. However, predicting air quality in the days ahead isn’t so simple. I work on air quality forecasting as a professor of civil and environmental engineering. Artificial intelligence has improved these forecasts, but research shows it’s much more useful when paired with traditional techniques. HereR...

Weather forecasts have gotten quite good over the years, but their temperatures aren’t always spot on – and the result when they underplay extremes can be lethal. Even a 1-degree difference in a forecast’s accuracy can be the difference between life and death, our research shows. As economists, we have studied how people use forecasts to manage weather risks. In a new working paper for the National Bureau of Economic Research, we looked at how human survival depends on the accuracy of temperature forecasts, particularly during heat waves like large parts of the U.S. have been experiencing in recent days. We found that when the forecasts underplayed the risk, even small forecast errors led to more deaths. Our results also show that improving forecasts pays off. They suggest that making forecasts 50% more accurate would save 2,200 lives per year across the country and would have a net value that’s nearly twice the annual budget of the National Weather Ser...