22nd Conference on Climate Variability and Change
First Symposium on Planetary Atmospheres
First Environment and Health Symposium
20th Conference on Probability and Statistics in the Atmospheric Sciences
24th Conference on Hydrology
18th Conference on Applied Climatology
First Conference on Weather, Climate, and the New Energy Economy


A common Midwestern question: Where have all our 90F days gone?

David Changnon, Northern Illinois Univ., DeKalb, IL; and V. A. Gensini and J. Prell

A regional study examined the frequency of summer 90F days in the Midwest and found a fairly uniform decrease in frequency since the end of World War II. Summer daily temperature data from NWS cooperative stations were examined at rural and urban locations. A similar long-term decrease in summer daily diurnal ranges was apparent at most stations, especially late in the growing season. These changes in daily temperature characteristics appear to be related to two interrelated regional factors: 1) changing agricultural practices that have increased the amount of water vapor transpired to the lower atmosphere from maturing corn and soybean fields and 2) increased summer Midwestern precipitation amounts. Understanding these changes in the regional climate of the Midwest will assist a wide array of decision makers and forecasters as they monitor summer climate issues.

Recorded presentation

Joint Session 4, Research on extreme weather and climate events and inter-relationships
Tuesday, 19 January 2010, 3:30 PM-5:30 PM, B216

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