Abstract

Summertime droughts and/or heat waves in the Kansas City area and their associated large-scale circulation patterns and land-surface moisture conditions are investigates, using climatological monthly mean surface data, rawinsonde data. Palmer drought severity indices, gridded monthly mean sea-level pressure data, and gridded 500 mb height data. Surface station data include monthly mean surface pressure, maximum/minimum temperature, temperature range, monthly total precipitation, dewpoint and relative humidity.

Anomalies in monthly mean surface air temperature at Kansas City are used as a basis for objectively ranking the 276 months in the 92 summers, 1889–1980. The concentration of drought months in the decades of the 1910s, 1930s, and 1950s is evident. Many of the hot months during these periods exhibited negative anomalies in relative humidity, dewpoint, precipitation and Palmer index.

Not all the hot summer months in the record at Kansas City appear to have been associated with drought (as defined by local soil moisture anomalies). In some cases, anomalous circulation patterns appear to have been instrumental in producing extended periods of hot weather. Hot months at Kansas City are virtually always characterized by upper level anticyclones over the central United States. Namias and Klein have demonstrated that there is also a tendency for hot months to be characterized by enhanced surface anticyclones and upper level ridges over the oceans, a deeper than normal upper level trough along the West Coast of North America, a deeper than normal surface low over the Rockies and low temperature over the Pacific Northwest. These features are also confirmed in our analysis, based on a more extensive dataset, but they are not always present during hot months at Kansas City.s

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