El Nino causing major U.S. winter storms?

GREENBELT, Md., Jan. 28 (UPI) -- U.S. space agency scientists said some of intense winter storms occurring this year over parts of the United States might be the result of El Nino.

Siegfried Schubert of the National Aeronautics and Space Administration's Goddard Space Flight Center and colleagues in Greenbelt, Md., studied the impact Nino-Southern Oscillation, or ENSO, events have on the most intense U.S. winter storms.

Schubert said an ENSO episode typically consists of an El Nino phase followed by a La Nina phase. During an El Nino, eastern Pacific temperatures near the equator are warmer than normal, while during the La Nina phase the same waters are colder than normal. Such Pacific Ocean temperature fluctuations are accompanied with fluctuations in air pressure known as the Southern Oscillation.

"By studying the history of individual storms, we've made connections between changes in precipitation in the United States and ENSO events in the Pacific," said Schubert. "We can say that there is an increase in the probability that a severe winter storm will affect regions of the United States if there is an El Nino event."

A related study was published this month in the Journal of Climate.