Skip to Main Content

AER Winter Forecast Predicts Mild Temperatures in Northern and Eastern U.S., Cold in the Southwest

Lexington, Mass., October 18, 2018 — The Atmospheric and Environmental Research (AER) winter forecast has been made publicly available and can also be found on the website of the National Science Foundation, which funds AER scientist Judah Cohen’s atmospheric and polar research: AER is a Verisk (Nasdaq:VRSK) business.

The 2018–19 winter forecast shows below-normal temperatures for the southwestern United States, the Central Rockies, Northern California, and Southern Oregon, with above-normal temperatures in the remainder of the country, including the northern and eastern U.S. The winter precipitation forecast shows above-normal precipitation across much of the country, especially the Northern Rockies and along the East Coast, and below-normal precipitation across the Pacific Northwest.

The predictors that go into AER’s forecast include El Niño/Southern Oscillation (ENSO), October Eurasian snow cover extent, Arctic sea ice concentration, and an index that measures high-latitude blocking. October Eurasian snow cover extent is currently below normal; Arctic sea ice extent is below normal; and blocking at high latitudes so far this fall has been less active compared with recent years. Below-normal snow cover and a lack of blocking favor a mild winter in the eastern U.S. An El Niño is also happening this winter, which favors a cold winter in the southeastern U.S. However, the signal is weak enough that other predictors are dominating the temperature forecast. This is a preliminary forecast and will be updated next month as more data becomes available.

“The AER winter forecast has been widely acknowledged for its accuracy last winter in predicting cold temperatures with an active storm track. Last winter was one of extremes—with record cold, four consecutive nor’easters, and even record warmth,” said Cohen, director of seasonal forecasting at AER. AER has tried to improve on seasonal forecasts that rely exclusively on ENSO by including information from high latitudes, an area of active research and the subject of many scientific articles at AER.

“Much of last winter’s extreme weather was related to variability in the polar vortex. The climate and forecast communities are realizing the importance of the polar vortex on winter weather; and we believe that snow cover, sea ice, and high-latitude blocking are very good predictors of the behavior of the polar vortex,” continues Cohen. Two of our three indicators suggest that the polar vortex will be relatively strong this winter, potentially bringing extended periods of relatively mild weather to the Northeast this winter. 

About Atmospheric and Environmental Research (AER)
Atmospheric and Environmental Research (AER) provides science-based solutions to global environmental challenges. AER’s internationally renowned scientists and software engineers collaborate to transform state-of-the-art predictive science and analytical tools into practical systems that address both civilian government and defense needs for geophysical understanding, computer simulation, and forecasting. AER customers include government agencies and national laboratories, aerospace and defense contractors, and academia. Areas of expertise comprise atmospheric and environmental science, air quality, remote sensing, meteorology, oceanography, space science, climate change, and software engineering. A Verisk (Nasdaq:VRSK) business, AER was established in 1977 and is headquartered in Lexington, Massachusetts. Visit

Brett Garrison
Edelman (for AER)

You will soon be redirected to the 3E website. If the page has not redirected, please visit the 3E site here. Please visit our newsroom to learn more about this agreement: Verisk Announces Sale of 3E Business to New Mountain Capital.