USA - El Nino to send more wet weather to Asheville?
After the wettest year on record in 2013, the Asheville area has been surprisingly dry since the first of the year.The city received below average rainfall in January and February and is below normal so far this month.But the dry spell may not last long.Thousands of miles from Western North Carolina, a shift in Pacific Ocean temperatures may start a climatic chain reaction that could bring abundant rain and possibly above average snow to Asheville by the end of the year. It’s a prospect some area farmers say the mountains could do without after crop losses last year from excessive rain.Climate scientists around the world are watching weather models that foretell a slight uptick in Pacific Ocean temperatures — a sign that an El Nino pattern may be setting up.El Nino, a periodic warming of tropical Pacific waters, can affect weather around the world, generally bringing cooler, wetter weather to the Southeast.The National Oceanic and Atmospheric Administration’s Climate Prediction Center issued an El Nino watch on March 6, predicting a 50 percent chance of an El Nino forming this summer or fall.“It’s unusually early,” N.C. Climate Office climatologist Ryan Boyles said of the watch issuance. “The models are pretty much in agreement that we’re heading toward an El Nino.”Boyles, however, said El Ninos in the formative stages occasionally fizzle out, so there’s still some uncertainty about what will happen this summer.But if an El Nino does form as forecast models predict, the impact on local weather could be dramatic. In the last El Nino, in 2009-10, Asheville marked one of its snowiest winters on record, with 39.2 inches. And the city in 2009 ended up with 62.13 inches of rain, well above the 45-inch average.“An El Nino doesn’t drive all our weather, but it is the one big impact that we can predict months in advance,” Boyles said.How it worksWhen ocean temperatures warm, more heat rises into the atmosphere to create thunderstorms, which can shift the jet stream south, said meteorologist Pamela McCown, a local weather consultant.“It shifts the main track of the storm systems down over the South and Southeast,” McCown said. “It could bring an end to the drought across the southern U.S.”More rain could be evident in the southern tier of states from coast to coast, especially benefiting states such as California that have been stuck in prolonged drought.Some El Ninos are stronger than others, with more dramatic, predictable weather effects in the stronger versions. It’s difficult to predict the strength of a forming El Nino, McCown said.According to the Climate Prediction Center, three El Ninos were recorded in the past decade. The 2009-10 version was the strongest, though it was considered only moderate in strength. The previous two — in 2004-05 and 2006-07 — were weak, with varied weather impacts.El Ninos typically produce the strongest weather effects in the winter months, McCown said.Dry weather can be good?In the meantime, rainfall in Asheville has fallen way off, starting in January. The city has received below normal precipitation in January, February and so far this month, according to Weather Service records.In many years, that would be a cause for concern heading into the spring growing season, but after a record 75.22 inches of rain in 2013, many area farmers are thankful for the dry spell.“Right now, things look good,” said Glenda Ploeger, who runs Cane Creek Asparagus and Co. in Fairview with her husband, Robert. “I’m happier with less rain than too much. We can irrigate, but if you get 7 feet of rain, what can you do about it?”The Ploegers, who grow about 90 varieties of vegetables at their community-supported agriculture farm off Brush Creek Road, had poor crop yields last year because of all the rain. Too much moisture can cause root rot, mold and mildew on plants and can even kill them, Ploeger said.The farm provides regular boxes of produce to customers during the growing season, but the supply grew scarce last year.“We don’t want a repeat of what we had last year,” Ploeger said. “We did not close down like some CSAs, but some of my families could not get a weekly CSA box. I had to communicate with people week to week on whether they would get a box. We are better off in a dry year than we are in a wet year.”She said young asparagus plants have already been planted, and other early season vegetables such as cabbage, broccoli and turnip greens will be planted this month.The excessive rain had a direct effect on the amount of food the Ploegers donated to area food banks last year — only about 50 pounds, Ploeger said. In a good season, the couple may donate 2,000 pounds of vegetables, she said.Scott Stephens, a meteorologist with NOAA’s National Climatic Data Center in Asheville, said the late winter dryness is partly related to unusually cold temperatures.“Cold winters are typically dry winters,” Stephens said. “If you’re getting arctic air masses, they are typically dry.”Asheville has been blasted by a series of arctic air masses, including one last week. The pattern was particularly evident in January, when the overall average temperature for the month was 30.6 degrees, 6.5 degrees below normal.While an El Nino this summer may get Asheville back into a wet pattern, it’s not a certainty, Stephens said. Despite huge advances in climate science, many mysteries remain, he said.“If it’s a weak El Nino, you could have other overriding atmospheric conditions that could trump the El Nino,” Stephens said. “There’s still a lot about the ocean and atmosphere interactions that we don’t understand and are still learning about. The cautionary note is don’t simplify the atmosphere. It’s very complex. Just when we think we have it figured out, we find there’s something else that could be a big factor.”Source - http://www.citizen-times.com/
