October 15, 2009
Thursday morning, the National Oceanic and Atmospheric Administration or NOAA announced the seasonal outlook for this winter. The outlook shows the regions of the country most likely to experience a warmer or colder winter, and a wetter or drier winter.
Mike Halpert, deputy director of the Climate Prediction Center says, "The outlook favors warmer and drier than average conditions across the northern half of the nation, and wetter and cooler than average conditions across much of the south."
But how does NOAA come up with this outlook? The answer lies in the Pacific Ocean. El Nino is expected to be the dominant climate factor this winter. El Nino is a shift of the warmest waters from the Western to the Central and Eastern Pacific Ocean.
Halpert says, "When we move that heat source, which is what tropical convection does, tropical rainfall transfers heat from the ocean into the atmosphere that impacts the jet stream across the Pacific Ocean, and then downstream over the United States."
Across the Mid-Atlantic, the outlook calls for a cooler than average season, with near average precipitation. But the cooler temperatures may not necessarily translate into more snow.
"It almost seems like the Mid-Atlantic has a feast or famine type of a situation. It doesn't seem like we have average snow that often. It seems like we get a couple of big ones, and a lot, or we end up with virtually nothing." says Halpert.