Using an instrument they've named the HOLODEC, for Holographic Detector for Clouds, scientists can now see in fine detail the way air and water droplets mix at a cloud's wispiest edge. iStockphoto hide caption

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A photo from May shows Gino Celli checking his parched crops near his farm near Stockton, Calif. If predictions of a strong El Niño prove true, it could presage a relief from the region's prolonged drought. Rich Pedroncelli/AP hide caption

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The National Hurricane Center introduced a new storm surge forecast map this year. This map, centered on New Orleans, is a prototype. NOAA hide caption

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A lot of the airborne particles in the Earth's atmosphere come from natural sources, such as desert dust (red-orange) and sea salt (blue). But there's also soot from fires (green and yellow) and sulfur emissions (white) from burning fossil fuel. William Putman/ NASA/Goddard hide caption

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A partially frozen American Falls in sub-freezing temperatures is seen in Niagara Falls, Ontario, on Tuesday. Temperature dropped to 6 degrees Fahrenheit on Tuesday. The National Weather Service has issued a wind chill warning for western New York from midnight Wednesday to Friday. Lindsay DeDario/Reuters/Landov hide caption

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Pedestrians brave the cold during their morning commute on Friday in New York. Arctic air and bitterly cold wind is moving across the Northeast, plunging temperatures into record-low single digits, accompanied by subzero wind chills. John Minchillo/AP hide caption

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