EDMOND — Edmond’s extreme weather continues.

A heat wave generating 100 degree-plus highs in the area ended on Monday. In June, flash flooding assaulted the city, in May there was a tornado threat, in December a blizzard. Now, drought is becoming a factor in parts of Oklahoma, a weather official said.

Elsewhere around the world, devastating floods occurred in Pakistan and China. Drought contributed to wildfires in Russia.

What’s it all about? Is global warming, aka climate change, behind the extreme weather? Or is it merely the fact that change happens?

CLIMATE CHANGE 101

Climate change is the long-term average of a region’s weather events lumped together, a change in long-term weather patterns, according to the U.S. Environmental Protection Agency.

Global warming is an average increase in the earth’s temperature, which in turn causes changes in climate, which is always changing.

The Oklahoma Climatological Survey reviewed assessments of climate change research and concluded that earth’s climate has warmed during the last 100 years, that earth’s climate will continue to warm for the foreseeable future, that much of the global average temperature increase during the last 50 years can be attributed to human activities, particularly increasing greenhouse gases in the atmosphere, and that the state will be impacted.

Oklahoma has experienced droughts in the 1910s, 1930s and 1950s, and extended periods of abundant moisture during the 1980s and 1990s, according to the agency, charged by the Legislature with researching the state’s weather.

“Oklahoma has really always been a land of extreme weather,” said Mark Shafer, director of climate services for the Oklahoma Climatological Survey.

KOCO-5 meteorologist Damon Lane said the recent weather has been extreme.

“It certainly has been incredible,” Lane said. “Usually when it rains it pours.”

Is there a link between Edmond’s recent extreme weather and climate change?

Shafer said Edmond’s extreme weather is consistent with projections for climate change. Global climate models, however, are unable to accurately simulate small-scale weather events like thunderstorms or tornadoes, he said.  

By the way, Oklahoma leads the nation in the number of declared disasters — a total of 28 — from Jan. 1, 2000 through July 26, 2010, according to the Federal Emergency Management Agency’s state disaster history data. The events include flooding, ice storms, tornadoes and wildfires.

During the same period, Kansas had 23 declared disasters, Florida and New York had 20, Texas had 16 and California had 13.

The Oklahoma Department of Emergency Management has done a stellar job of preparing information for federal declarations, Shafer said.

Steven Root, president and CEO of WeatherBank, an Edmond-based full-service meteorological consulting company, said his experience has shown that as dramatic climate changes continue away from the long-term mean the likelihood for Edmond weather to be a pattern of extremes will also continue — cold followed by hot followed by cold again, etc.

This flip-flop pattern is quite common during moderately-strong El Niño-La Niña periods very much like the current period, Root said.

Continued warming will create a cascade of climatic shifts which could impact Oklahoma’s climate, but hot years and cold years will continue, as well as wet and dry years, according to the Oklahoma Climatological Survey.

However, little is known of the effects climate change will have on severe weather.



LONG-TERM FORECAST

During coming months, Oklahoma’s weather will be influenced by La Niña, forecasters say. La Niña is characterized by unusually cold ocean temperatures in the equatorial Pacific. El Niño is characterized by unusually warm ocean temperatures in that region.

Lane said during the coming La Niña period Oklahoma likely will experience occasional storms and warmer, drier and windier weather. As a result, the coming fire season could be more active than usual, he said.

Root said not all La Niñas and El Niños are the same.

“Just because we are trending towards a moderately strong La Niña doesn’t automatically mean we’ll see a ‘typical’ La Niña weather pattern,” Root said.

Root said his research has shown that while most patterns have things in common, widely different weather patterns can and do occur between two La Niños and two El Niños.

Regarding the talk about drought, Gary McManus, associate state climatologist with the Oklahoma Climatological Survey, said the state is experiencing a phenomenon known as a “flash drought.”

The latest depiction from the U.S. Drought Monitor indicates that despite recent rains, moderate drought has now gained a foothold in the southeastern half of Oklahoma, McManus said.

Since July 12, much of the southern half of the state received 20 percent to 40 percent of normal rainfall, McManus said. More than 20 Oklahoma Mesonet stations in southwest, central and east central Oklahoma have recorded less than an inch of rainfall during that period, he said.

Oklahoma City has been particularly dry, with a meager .09 inches of rainfall.

The short time it took for the current drought to develop is indicative of a “flash drought” episode, McManus said.

Oklahoma’s secondary “rainy season” of September and early October is approaching, and may provide a much-needed moisture recharge in light of the La Niña conditions, McManus said.

Just in case you’re wondering about the chances for another white Christmas, Lane said the predicted La Niña conditions will make that highly unlikely.



marks@edmondsun.com | 341-2121, ext. 108