The often discussed, sometimes parodied, global weather phenomenon known as El Nino has arrived according to the National Oceanic and Atmospheric Administration. Austrailia's weather service also confirms the warming of the eastern pacific last seen in 2006.

"Even though you see those sea surface temperatures immediately, it actually takes three to four months for the atmosphere to realize the influence of the warmer and colder temperatures," says Steve Naglic, warning coordination meteorologist at Columbia's National Weather Service office. "Since we've just transitioned, we won't see any of the full impacts until this winter."

Most importantly, the event will impact day to day life for the southeastern United States both positively and negatively. Traditionally, El Nino ushers in a more active precipitation pattern for the region. This also includes an increase in severe weather and the chance for snow.  During the fall, severe storms develop as a secondary jet stream over the Gulf of Mexico can develop and interact with colder air masses. On the positive side, increased winter precipitation reduces a wildfire risk during the historically active season.

"Coming into the winter months, hopefully we'll get the precipitation that we need because we've been so dry so far coming into July that we need to make up for the rainfall," says Naglic. "So look for wetter conditions during the late fall into the winter months."

Naglic says that El Nino likely won't have a major impact on current Atlantic hurricane development. Although, El Nino usually means a less active Atlantic basin pattern. The slow Atlantic season is blamed on upper level wind shear and timing. El Nino is expected to have a greater impact on Pacific hurricane development.

According to a NOAA press release, the event is expected to last through winter 2009-2010. That means El Nino will strengthen and peak between October and November. The release goes on to say that El Nino will be discussed further in the Seasonal Hurricane Outlook scheduled for an early August release.

El Nino's counterpart, La Nina, is a result of cooler than normal pacific ocean temperatures.