El Niño conditions have started in the Pacific Ocean, and that could be good news for hurricane season here.</p><p>El Niño, also called the Southern Oscillation by scientists, is a warming of ocean surface waters off South America that affects weather patterns across the hemisphere. </p><p>El Niño can help hold down hurricane activity in the Atlantic, according to local weather forecasters and scientists with the National Oceanic and Atmospheric Administration.</p><p>By changing wind patterns, El Niño also can increase rainfall in the U.S. southwest and make winters less wintry in the north. In Florida, the risk of winter wildfires can be reduced by El Niño-driven rain.</p><p>NOAA scientists announced July 9 that ocean temperatures had reached the El Niño range. They predict it will probably last through this winter.</p><p>Matt Strahan, meteorologist in charge of the National Weather Service forecast office in Key West, said El Niño can decrease the total number of hurricanes and their intensity in the Atlantic. But it’s only part of the hurricane puzzle.</p><p>Strahan pointed out that the Atlantic is in an active phase for tropical activity. While more-active and less-active phases last about 30 years, some seasons can be more or less active within those phases. Also, Strahan said, “For us, it takes a pretty strong El Niño to suppress hurricanes in Florida and the Keys.”</p><p><b>Niño appears</b></p><p>The Climate Prediction Center of the National Weather Service reports sea surface temperatures in the El Niño area — off the west coast of South America around the equator — have been 1 C above average since the end of June.</p><p>El Niño is defined by surface temperatures rising 0.5 C or more above average. The last time there was an El Niño episode was 2006, NOAA spokesman Christopher Vaccaro said. </p><p>Climate scientists say the developing El Niño is likely to be weak to moderate in strength in the Northern Hemisphere until fall, when it may get stronger.</p><p>CPC scientists say El Niño suppresses hurricane activity by increasing vertical wind shear — air layers moving at different speeds or directions — over the Caribbean and tropical Atlantic Ocean. The wind pattern can keep hurricanes from forming or from strengthening. </p><p>With El Niño, “It is mostly that upper-level winds blow stronger from west to east, and hurricanes don’t like that,” Strahan explained.</p><p>El Niño doesn’t guarantee a hurricane won’t strike the United States. In fact, the Keys and South Florida have had significant strikes in recent El Niño years.</p><p>At the start of 1992, a strong El Niño was underway, though it had diminished in the June-to-August period. The first named storm of the season didn’t form until mid-August, but it became the catastrophic Category 5 Hurricane Andrew.</p><p>In 1998, a strong El Niño had been underway since the previous spring. By the start of hurricane season, La Niña conditions were starting. That season, Hurricane Georges slammed the Lower Keys, causing extensive storm-surge flooding.</p><p>NOAA forecasters have said it’s most likely that this hurricane season, which runs to December 1, will see an average number of tropical systems. In the Hurricane Season Outlook issued in May, forecasters said there is a 50-percent chance of a “near normal” season. </p><p>Based on several climate factors, NOAA estimated a 70 percent chance of nine to 14 named storms, with four to seven hurricanes and one to three major hurricanes.</p><p>Those ranges have occurred in about two-thirds of past seasons with similar climate conditions to what’s expected this year, the outlook authors said.</p><p>Hurricane seasons from 1995 to 2004 averaged 13.6 named storms, 7.8 hurricanes and 3.8 major hurricanes. The 2005 season set new records for total storms, with 27, and hurricanes, with 15.</p><p>NOAA scientists base their predictions on three main factors: </p><p>— The periods of increased or decreased activity that last for several decades.</p><p>— The effects of El Niño and La Niña on wind patterns and storm formation.</p><p>— Sea surface temperatures in the Atlantic basin, which includes the Caribbean Sea and Gulf of Mexico. </p><p>Temperatures recently have been cooler than average in the eastern tropical Atlantic, which hasn’t happened since 1997. If the cooler temperatures last through the height of the season, scientists expect reduced hurricane activity.</p><p>NOAA will issue an updated forecast for the remainder of the season on Aug. 6.