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Climatology used to be the orphan of the forecast family - an uninteresting discipline of seasonal averages and far-out probabilities with only remote practical applications. But now, thanks to recent advances in relating climatology to both global and local weather patterns, this branch of atmospheric science shows signs of coming in from the cold. Hi, I'm Dave Thurlow and this is The Weather Notebook.

Climatologists made a major breakthrough when they finally put all the puzzle pieces together to reveal the big picture of what El Niño and La Niña do to weather. El Niño, they realized, signaled not only a change in sea surface temperatures in the tropics, but also a southward shift in the jet stream that amplified storminess in the southern tier of states: more winter rain in California, and significantly higher risk of tornadoes and dangerous thunderstorms in Florida. No, climatologists have not begun issuing tornado watches three months in advance; but they are beginning to forecast for the average number, intensity, and location of severe storms in a given season.

Last fall, with La Niña hanging in for a second year, the climatologists gave forecasters a heads-up for an unusually intense hurricane season - and sure enough, there were 12 named storms, three more than the average, with 5 developing into major hurricanes of category 3 or stronger. For the coming spring and summer, climatologists have taken the unprecedented step of issuing a drought forecast for the South and Midwest - basing the prediction largely on new understanding of how La Niña affects rainfall patterns.

For all its recent refinements climatology remains a science of likelihoods, and this is not likely to change. But judging from current developments, the probability is strong that climatologists will be working more and more closely with forecasters in the years ahead.

Thanks to contributing writer David Lasking and to Subaru.