Heat Waves: Introduction
Summers in Kentucky are warm and humid. Average high temperatures in July approach 90°F. But, high temperatures can drop into the lows 80s, or even the 70s, when a cool front pushes through the state. In some years however, hot weather persists with little or no relief for extended periods. Weather patterns affecting Kentucky during the summer are dominated by the flow of warm, humid air northward from the Gulf of Mexico. This circulation is capable of pushing temperatures well above 90°F or even 100°F. Occasionally, cool, dry continental air from the northwest provides a short reprieve. In some years however, the position and strength of subtropical high pressure off the southeast coast of North America results in extended periods of above normal heat and humidity. An intense heat wave, often accompanying drought, can hold its grip for weeks, and in some cases above normal temperatures persist throughout the summer season. High levels of heat and humidity pose an obvious threat to human health, including the possibility of death. Conditions during a heat wave are typically more severe in urban areas where the heat island effect coupled with limited air circulation intensifies conditions. Because heat waves, if only short ones, are common features of Kentucky's climate, individuals and communities should be prepared for the threats that they bring.
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