What is National Oceanic and Atmospheric Administration saying? What is the likelihood that the snow will actually be that much better? Where are the ski areas that are expected to be (or historically) most affected?
El Nino is the warm phase of the El Nino Southern Oscillation, which sees a change in surface water temperature in the central and eastern equatorial Pacific Ocean.
Many North American resort operators look to El Nino years for good snow conditions, and some - such as those in the Sierras of California - have good reason. Weather records suggest, however, the impact falls inconsistently across the continent, at least in terms of snowfall. The bad news is that El Nino years tend to be warmer across snow country, potentially impacting snowmaking.
In El Nino years, such as the one under way in 2009-2010, a layer of cold water in the central and eastern Pacific Ocean sinks from 50 meters below the surface to 150 meters, allowing the ocean's surface to become warmer. This in turn has an impact on North American weather, which NOAA has tracked over many years.
NOAA sees a weak El Nino existing in the central and eastern Pacific, which it expects to gain strength through fall and into winter.
A majority of the model forecasts suggest El Niño will reach at least moderate strength during the Northern Hemisphere fall. Many model forecasts even suggest a strong El Niño during the fall and winter, but current observations and trends indicate that El Niño will most likely peak at moderate strength.
That means current conditions, trends, and model forecasts favor the continued development of a weak-to-moderate strength El Niño into the Northern Hemisphere fall 2009, with the likelihood of at least a moderate strength El Niño during the winter, NOAA climatologists predict.
Past El Nino events have brought higher than normal temperatures November through January to the Pacific Northwest, the Midwest, and New England, and colder than normal temperatures to the Sierras, southwestern Wyoming, southern New Mexico and parts of Texas in 1941, 1942, 1958, 1964, 1966, 1973, 1983, 1987, 1988, 1992, and 1995.
El Nino brought drier than normal conditions those same months to the Rockies of Idaho, Montana, andWyoming, and Montana, and wetter than normal across the southern tier of the United States, up into the Midwest, and parts of southern New England.
Jeremy Davis, senior meteorologist with Weather Routing Inc. of New York, said, "Typically, the North Central United States sees milder weather. But weak El Ninos in the first half of this decade here in the Northeast have been generous with snow and slightly cooler-than-normal temps. Weak El Ninos tend to promote East Coast storminess after systems move through the Gulf of Mexico and Florida, then move up the coast, and give the Northeastern United States a good amount of storminess. Strong El Ninos tend to push this track farther west which keeps the East Coast mild."