Transcripts

DAN OLSON: First the good news. As he watches the television monitor showing the prevailing weather conditions, assistant state climatologist Greg Spoden sees what weather forecasters noted late Monday.

GREG SPODEN: The jet stream has apparently moved somewhat to the East and we're no longer under the influence of that very sedentary, high pressure Ridge that extends upward through the atmosphere. And we are now under what's called Southwest flow, where the winds in the upper altitudes are moving from the Southwest to the Northeast.

DAN OLSON: And it is that pattern which, in Greg's Spoden's judgment, means that there is at least a slightly better chance that moisture laden air could reach the Midwest. Outside his office on the St Paul Campus of the University of Minnesota and just out of range of campus lawn sprinklers, state climatologist Jim Zandlo takes a break from the telephone and says it is now clear that extreme drought covers most of the state.

JIM ZANDLO: In fact, that area from East Central Minnesota to West Central Minnesota and Northward up to the Canadian border is all in this category of extreme drought.

DAN OLSON: The damage to small grains caused by drought. Sandler says, is considerable at this point, since the plants are at a critical development stage. Row crops, such as corn and soybeans, the state's two most important cash crops, have a few more days before suffering severe yield loss, Zandlo says, because the moisture use of those plants is not at its highest point. Extreme drought is more than a casual expression. The dryness can be measured, Zandlo says, by computing the use of moisture and comparing it to precipitation to arrive at a specific value on what is called the Palmer Drought index.

JIM ZANDLO: And this index has numerical values that are translated into verbal connotation. At any rate, we're now two or three categories away still from some of the most extreme values that we've seen, such as in 1976 and 1934. So there's a couple of categories in that index that we still haven't experienced yet, but we still have a long summer yet. We don't know what's in store for us.

DAN OLSON: That grim assessment is tempered a bit by an expression Minnesotans have borrowed from New Englanders, who probably borrowed it from residents of the British Isles. If you don't like the weather, wait five minutes and it'll change. Jim Zandlo.

JIM ZANDLO: Well, we do have this characteristic in Minnesota weather of a quick change from a period of dryness to a period of wetness. We've seen extreme drought end in parts of the state in a two or three month period. So it can switch. Again, the question becomes when, and that's more in the realm of being able to predict the forces of the atmosphere. And when you get out beyond three or four days or a week or two at most, the skill there drops off rapidly. And so the physics just can't support it. We don't have enough data.

DAN OLSON: State climatologist Jim Zandlo says the drought may have gotten its start last year, when precipitation was below normal levels. Prior to 1987, Minnesota had a decade of above normal precipitation. Zandlo declines to refer to this drought as part of a cycle. A cycle, he says, implies that the change can be forecast, and Zandlo believes the beginning and end of drought cannot be predicted. I'm Dan Olson.