Across America, it’s going to be an El Niño winter — but that means different things in different parts of the country.</p><p>National Weather Service scientists said this week that El Niño, marked by an area of warm water in the Pacific Ocean, “will be the dominant climate factor” affecting U.S. weather this December through February.</p><p>In the Winter Outlook released Thursday, Oct. 15, Mike Halpert, deputy director of the Climate Prediction Center in Maryland, said El Niño shifts tropical rainfall patterns, which changes “the strength and position of the jetstream and storms over the Pacific Ocean and the U.S.”</p><p>El Niño can be a blessing or a curse, depending on your location and weather preference. </p><p>This winter, El Niño will likely make the Midwest warmer than average, the southeast states cooler and wetter and the Pacific Northwest drier, the CPC’s outlook says.</p><p>In the Keys, “It’s pretty typical in an El Niño year to see cooler than average temperatures and rainfall above normal,” David Ross, a meteorologist at the National Weather Service office in Key West, said last Thursday.</p><p>However, the Keys’ weather is moderated by the warm waters surrounding the islands, Ross said, so the effects of cooler temperatures are felt less here than in north and central Florida.</p><p><b>Higher rainfall</b></p><p>El Niño can increase rainfall in the Keys by as much as 50 percent above normal — normal being the average over the last 30 years, Ross said. That could be good news for Key West, which has had less rainfall than normal this year, he added. </p><p>Middle Keys rainfall is about two inches below normal for the year, while rain gauges on Key Largo have been filled by above-average rainfall, as much as 15 inches above the yearly average of about 45 inches.</p><p>Highlights of the CPC Winter Outlook include:</p><p>&bull; Cooler, wetter Florida: Above-average rainfall is expected in the state, with increased chance of tornadoes in the Gulf Coast region. Below-average temperatures are forecast across the Southeast and Mid-Atlantic states and Florida.</p><p>&bull; Warmer: Higher-than-average temperatures are expected in much of the western and central U.S., especially in north-central states from Montana to Wisconsin. But “periodic outbreaks of cold air are still possible.” </p><p>&bull; Drier: Less rainfall than average is expected in the Pacific Northwest and the Ohio and Tennessee River valleys.</p><p>&bull; Toss-up: There’s an equal chance of temperatures and rainfall in the northeast and Alaska being normal, or slightly above or below normal, CPC scientists say.</p><p>Other climate factors also affect winter weather, so there’s more uncertainty in the forecast for the northeast and mid-Atlantic, the CPC said.</p><p>Besides affecting winter weather, El Niño can be good for the Keys during hurricane season.</p><p>The strengthening El Niño seems to have kept a lid on the tropical Atlantic this summer. There have been eight tropical storms and hurricanes this season, and two tropical depressions. Several systems fell apart because of winds high in the atmosphere, which El Niño tends to spur in the Atlantic, according to forecasters.</p><p>The weather service and climate center don’t try to predict specific storms or total winter precipitation amounts far in advance. Snow forecasts depend on winter storms, and those can’t be predicted more than a few days in advance.</p><p>However, it’s safe to expect zero inches of snow accumulation in the Keys this winter.</p><p>The CPC Winter Outlook and other forecast products are available from the CPC at http://www.cpc.noaa .gov.