July 28, 2008

Drought Circumstances Different for Cleveland, Gaston Counties

By Cherish Wilson, The Shelby Star, N.C.

Jul. 28--Don't let the rain fool you.

It'll take more than a few storms rolling through the area to quench the deficit. Shelby is an astounding 72 inches of rain below normal in almost 12 years. That's more than 6 feet of water missing.

Local meteorologist Robert Gamble explained how drought leads to more drought and why Cleveland and Gaston counties have a different set of drought circumstances.

Q: How do drought conditions set us up for more drought?

A: "You need low-level moisture in the ground to evaporate and form clouds. Until lately, we haven't had much moisture in the ground. It's true, when the wind patterns changed in the late 1990s, our prevailing winds went from southwest to west/northwest.

"I'm not sure why our winds have shifted, but it has to do with ocean temperatures and the locations of high-pressure systems.

"The foothills and western Piedmont have a tendency to stay under high pressure, which means a lack of cloud development and hardly any rain.

"In the summer, when the winds rush down the mountains, that leads to extreme heat waves like we saw August of last year and June of this year. Any rain usually collapses over our area and then re-fires when low level convergence builds up the moisture again. Convergence usually happens in far-eastern Cleveland County, near the Gaston County line, and in the upper sections, near the South Mountains."

In other words, the conditions are just right, Gamble said, for rain skipping the heart of Cleveland County and recovering enough moisture to produce rain just in time to reach Gaston County.

Q: It seems that severe weather is increasing. Do drought conditions brew worse weather?

A: "As far as the spike in severe weather and funnel clouds, it's true that Cleveland County leads the state. We have for about a decade now. The same pattern that gives way to our drought also stirs up low-level convergence around the higher hills, especially in the upper sections of the county, where elevations rise more than 2,000 feet and drop suddenly."

Q: What will it take to break the cycle of drought?

A: "As for hope of getting back into a rainier pattern, well I think it will come but I don't know when. Mother Nature always works in cycles. We have some years of major snows, some years big ice storms, and some years of nothing but heat and dryness.

"You can usually safely expect that when an 'El Nino' weather pattern develops, usually once every few years, then we can get back into at least moderately wet conditions. We're watching a developing 'El Nino' right now, and it may show up by fall or winter.

"The bad thing about drought is that Mother Nature never forgets. You can see that nine out of the last 12 years have been dry, and many years were extremely dry, with double-digit departures. That kind of math plays hard on the deep ground aquifers and water table. No wonder wells, streams and rivers are on the verge of drying up. Even though every shower helps out, we realistically need several years of above normal rains in our watershed to alleviate this drought. Not just one or two rainy months, but years."


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