BOSTON — FOR flood-weary Midwestern Americans, the watchword is "be wary but hopeful."
The atmospheric circulation over North America appears to be shifting back toward the flood-producing pattern of June and July. That could be "worrisome" if it persists, says long-range forecaster James Wagner of the National Weather Service's Climate Analysis Center. But there is no way to know whether or not it will last, let alone cause more flooding.
Meanwhile, Norton Strommen, chief meteorologist for the World Agricultural Outlook Board at the United States Department of Agriculture, says the weather trend "looks like the most optimal situation we could look for" to have a good crop harvest. He notes that the pattern still is one in which storms continue to come through, although they are moving "a bit farther north" than earlier in the summer. Yet, he adds, the pattern also features warmer temperatures, especially along the US-Canada border region where early frost is a concern.
He says a lot of acreage has been lost. Therefore, even though he expects yield per acre to be high, the total harvest will be affected. Nevertheless, he expects it will be a good harvest.
Mr. Wagner explains that the June-July weather was unusual in that it combined summertime moisture and unstable air with a springlike larger-scale circulation. This triggered massive long-lasting Midwestern thunderstorms that fed off moisture pumped in from the Gulf of Mexico. Eventually, there was so much water in the ground that the storms also fed off their own recirculated moisture. This circulation pattern also favored persistent drought in Southeastern states.
The springlike dynamics that drove this weather slacked off during the first two weeks of August. But they appeared to be returning last week. A forecast running through the end of this week "looks like a continuation of a wet pattern," says Wagner's colleague, Anthony Artusa. However, he adds that it's "impossible to say" whether or not this will continue. His forecast also calls for some easing of the drought in Southeastern states as the region of most pronounced dryness shifts somewhat westward.
Some experts have noted that the unusual weather caused hardship because many people were unwisely living and farming in natural flood plains. University of Georgia ecologist J. Whitfield Gibbons, however, sees a larger lesson. He says it's too simplistic just to say people are living where they should not be. Many of these people have no reasonable alternative. The US is overpopulated in relation to its usable land resources, forcing people into environmentally marginal areas, Dr. Gibbons says.
Because of this, he adds, even rare, extreme events such as major flooding or earthquakes now can cause disaster on an unprecedented scale. He says public-policy planners should take this into account.