As El Nino fades, La Nina could have impact on summer weather
El Niño has been the weather word of the past year. Now, there's a new term in town; La Niña. You might call it El Nino's little sister, but they are far from twins.
While El Nino is a warming of the waters of the Equitorial Pacific Ocean, La Nina is just the opposite. During a La Nina phase, water across the equator cools and during extreme years, can often be below average. This can often change weather patterns over the planet.
The Climate Prediction Center issued a La Niña watch for late this spring into the summer. This means confidence is increasing that a La Nina will develop.
Meteorologists at the Climate Prediction Center, a division of NOAA, say the La Niña phase typically follows stronger El Ninos. This year, we may see the influences during the late Summer and into the Fall and Winter.
WHAT COULD LA NINA MEAN FOR US?
While every La Nina year is different, there are certain similarities when it comes to influencing weather patterns.
• Stronger winds along the Equator in the Pacific, which often limits tropical development in the Pacific Ocean.
• Weaker winds in the Atlantic, which are more favorable for hurricanes in the Caribbean and central Atlantic area. Some of the more active tropical seasons took place during La Nina years.
• Above average temperatures in the southeast along the south and Mid Atlantic.
TEMPERATURES: The last time we were in a La Nina phase was the 2011-12 season. While it was considered a weak one, it did bring the typical warmer than average temperatures, with several days topping 100° during the year.
HURRICANE SEASON: The 2012 Atlantic hurricane season was extremely active, tied with 1887, 1995, 2010, and 2011 for having the third-most named storms on record. The strongest of the season was Hurricane Sandy which slammed the northeast with winds topping 100mph.
SEVERE WEATHER: While La Nina is known for being more predictable when it comes to temperatures, predicting how the pattern may influence severe weather is much more tricky. The jet stream is known to keep most of the active weather just to our west during La Nina years, The Ohio Valley would often be much wetter than say, the Mid Atlantic. However, during the hot, dry La Nina year of 2012, the infamous Derecho struck the region on June 29, 2012.
DRY CONDITIONS: Several of the region's droughts started during weak La Nina years. One of those was in 1999. Several area reservoirs began drying up, including Roanoke's Carvins Cove. While the 1999 drought was bad, it was made even worse in 2002 when the reservoir hit its lowest level ever recorded.