sCAST - Winter '07 / '08

Met Winter '06 / '07 ------------- Met Winter '07 / '08

AER/s briefing slides (.pdf) about the sCAST model...this year/s forecast...and verification of last winter/s forecast.

Seems odd AER issued a forecast this early since an important model input is October snow cover across Siberia.

From the National Science Foundation (NSF)..."The model uses October Siberian snow cover, sea level pressure anomalies and recent temperature trends in its winter forecast."

AER/s rationale for its Winter '06 / '07 Forecast...
"October 2006 snow cover was observed to be above normal that coupled with a predicted negative winter Arctic Oscillation (a pattern that favors high heights in the Arctic and more cold air intrusions further south) produces the colder than normal temperatures in the East. The above normal snow cover also favors a stratospheric warming event this winter.

"A weak to moderate El Nino is currently predicted for the winter, which we anticipate will not have a strong impact on winter temperatures in the eastern US. However, if the El Nino turns out to be stronger than predicted, in the moderate to strong range, then the predicted temperatures in the East may be too cold. (Also the above normal snow cover in Siberia and observed atmospheric conditions in the North Atlantic during October once again favor a higher probability of a major East Coast snow storm this winter season).

"October is the month where snow cover undergoes its greatest expansion in the Eurasian region. During October, Eurasian snow cover can increase by as much as 10-15 million square kilometers, which is greater than the total land area of the United States, including Alaska. NSF-funded research has shown that variability in the extent of Eurasian snow cover can be used to predict cold or warm winters across the entire mid-latitudes of the Northern Hemisphere."