Cambridge, Massachusetts – A new indicator of climate variability, identified by Dr. Judah Cohen at Cambridge-based Atmospheric and Environmental Research, Inc. (AER), suggests that much of the continental US will experience another warm winter. According to the National Oceanographic and Atmospheric Administration (NOAA), forecasting the upcoming winter season is more challenging due to the ending of the El Niño/La Niña cycle that has guided forecasters for the past three years.

Dr. Cohen has pioneered and recently published research on the effect of autumn Eurasian snow cover on winter temperatures both in Western Europe and North America. Through a teleconnection called the Arctic Oscillation, Dr. Cohen has demonstrated the important influence of the early fall climate in Siberia on much of the Northern Hemisphere in winter. Coupled with the now well-known Pacific Ocean sea-surface temperature oscillations of El Niño and La Niña, this climate signal has correlated well with almost thirty years of US temperature records. In the absence of a strong ocean cycle, Dr. Cohen believes that this Siberian signal could be a critical determining factor in this winter's weather. Although the final snow cover data on which Dr. Cohen's model is based will not be available until November, preliminary evidence indicates that the Midwest and Northeast could see winter average daily temperatures from two to six degrees warmer than the 30-year historical norms.

Among other economic effects, this warmth would depress demand for home heating oil, much of which is used in the Northeast. Currently low petroleum stocks in the United States, due in part to the high crude oil prices throughout the summer, prompted President Clinton's decision last week to release crude oil from the US strategic reserve. Warmer temperatures, however, would offset this potential shortage and could take pressure off prices.

Founded in 1977, Atmospheric and Environmental Research, Inc. is an award-winning environmental research and consulting company with demonstrated expertise in remote sensing, satellite meteorology, numerical weather prediction, climate dynamics and radiation, circulation diagnostics, atmospheric chemistry, air quality and risk assessment, planetary sciences, and systems engineering. AER established a Climate Risk Unit in 1999 to develop and deliver weather and climate products to meet the growing demands of risk managers in insurance, energy, and other weather-sensitive industries. In addition to its Cambridge, MA headquarters, AER has offices in Washington, D.C.; Omaha, NE; and San Francisco and Los Angeles, CA.