Impact of the MJO on the Initiation of Mesoscale Convective System over the US Corn Belt

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Wednesday, 7 January 2015: 10:30 AM
224B (Phoenix Convention Center - West and North Buildings)
Elisabeth F. Callen, Iowa State University, Ames, IA; and T. C. Chen
Manuscript (982.6 kB)

Mesoscale Convective Systems (MCSs) are prolific precipitation producers accounting for between 30 and 70 percent of the warm season precipitation in the United States. While this precipitation can be beneficial, it can also be destructive (Doswell et al. 1996, Fritsch et al. 1986). To that end, determining what connections MCSs have to specific atmospheric conditions can make the prediction of time and location of initiation of these MCSs easier to achieve. The MCSs used in this analysis were determined using convective cloud cover and categorical rain in the North American Regional Reanalysis (NARR). The NARR MCSs from 2004 to 2013 were compared to available satellite data to verify initiation. Once the MCSs were verified, Global Forecast System (GFS) data were downloaded to generate the global potential function which is used to depict the Madden-Julian Oscillation (MJO; Madden and Julian 1971). Once the potential function was determined for each day over the warm season, a 30-60 day bandpass filter (Murakami 1979) was applied to determine the 30 and 60 day modes of the MJO and how the MJO affects the weather in the Corn Belt region. In this analysis, the Corn Belt region consists of Kansas, Nebraska, South Dakota, North Dakota, Minnesota, Iowa, Missouri, Illinois, Indiana, and Ohio. The propagation of the MJO was observed through the Corn Belt region. The strength of the MJO when it reached potential initiation locations of MCSs was compared to the initiation times and locations of the satellite verified NARR MCSs and a correlation between MCS initiation in the Corn Belt and the strength of the MJO was determined. This study seeks to examine a possible connection between the MJO and the initiation time and location of MCSs within the Corn Belt region in the warm season (April through September) in the years 2004 to 2013.