Ag Weather Forum

Rain Pattern Still Leaves Vacancy

Bryce Anderson
By  Bryce Anderson , Ag Meteorologist Emeritus
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Rainfall through the end of July shows beneficial amounts in many central crop areas, but only light coverage in portions of the western Corn Belt. (DTN graphic)

Dry areas of the U.S. Corn Belt are getting whittled away. The final full weekend of July saw moderate amounts to heavy amounts of rain form in much of the central and north-central Plains and the northern Midwest. Rainfall of more than 7 inches was recorded in northern South Dakota and in south-central Minnesota. Shower and thunderstorm activity was still holding together in Kansas, Missouri, southeastern Iowa and Illinois during the daytime hours Monday.

However, a very dry sector of the western Midwest, comprising the northwestern one-third of Iowa, was largely bypassed by the rain pattern. Even the heavy activity in Minnesota avoided an incursion into the dry areas. In a week that saw many areas to the west and north take in multiple inches of rain, this dry sector of Iowa managed only scattered totals of just over one inch.

Dryness has come on fast in Iowa over the past three months. Three months ago in mid to late April, the entire state of Iowa was classified as drought free by the U.S. Drought Monitor. Now, 54 percent -- more than half the state -- is in some phase of drought. Dryness west of Interstate 35 is the big reason.

For the next week, DTN forecast rainfall brings in only limited additional rain for this sector of the Corn Belt. Seven-day totals for the northwestern third of Iowa are in the range of 0.10 to 0.50 inches -- a tenth to a half inch. In contrast, much of Kansas and Missouri have rainfall of from 1 to 2 inches or more featured in the forecast charts.

Temperatures offer some respite from wholesale withering of crops. Seven-day values are pegged in the range of 5 to 10 degrees Fahrenheit below normal. The benefit to crops from a reduction of evapotranspiration along with a milder trend in overnight temperatures will be important to maintaining crop yield potential -- or at least limiting the yield loss due to dryness. Up to this point, subsoil moisture supplies have also allowed crops to progress; but sooner or later, that profile runs out as well.

Bryce Anderson

Twitter: @BAndersonDTN


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