13th Conference on Applied Climatology and the 10th Conference on Aviation, Range, and Aerospace Meteorology

Monday, 13 May 2002: 4:45 PM
Interannual Variability in Storm Structure in the United States
Michael A. Palecki, ISWS, Champaign, IL; and J. R. Angel and S. E. Hollinger
At a given location, the structure of a passing storm can be defined by the high temporal resolution precipitation record of that storm, and the variables that can be derived from these records, such as storm precipitation total, duration, and intensity. The National Climatic Data Center has available in digital form more than 30 years of 15-minute precipitation data, beginning in 1971. While the time series length is brief, there is now sufficient data to begin to assess the storm structure response to large scale modes of interannual variability. This paper examines the response of storm structure variables to Pacific Decadal Oscillation (PDO) state, El Nino/Southern Oscillation (ENSO) state, and the variations of selected mid-tropospheric teleconnections, including the Pacific/North American Pattern (PNA) and North Atlantic Oscillation (NAO). It is hypothesized that previously observed linkages of modes of interannual variability to monthly or seasonal precipitation totals will be modulated by a direct linkage to the nature of individual storms in affected regions of the conterminous United States. For example, work-to-date has shown that individual winter (DJF) storms in the Gulf Coastal Region have greater storm precipitation totals and longer durations during the warm phase of ENSO than during the cold phase. The manner in which precipitation is distributed temporally within storms affects their ability to erode soil, cause flash floods, and have other impacts. Therefore, the results of this research have practical implications for identifying the mechanisms through which these modes of interannual variability impact society. Finally, the limited data of the early and mid-1970s will be compared to later periods to assess the role of the decadal scale variability of the PDO in affecting storm structure.

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