The Lake Pontchartrain Basin of southeast Louisiana is comprised of many interrelated components forming one of the largest and most diverse estuarine systems in the United States. The Louisiana/Mississippi state line generally defines the northern boundary of the basin's watershed while the southern extent of the basin is formed by the Mississippi River extending from Saint Francisville, Louisiana, south to Pointe A La Hache, Louisiana. The basin is comprised of a variety elements including the 630 square mile Lake Pontchartrain, Lake Maurepas, Lake Borgne, and numerous rivers and bayous including part of the salt waters of the Gulf of Mexico.

Three of the most populated parishes in Louisiana are located within the Lake Pontchartrain Basin with the city of New Orleans located on the southern shore line of Lake Pontchartrain. From extended climatological records of temperature, there are documented differences in maximum and minimum temperatures across the basin defining distinct agriculture zones for locations north of Lake Pontchartrain and those areas located south of Lake Pontchartrain. To expand the understanding and possibly discover additional micro-climates within the basin, a precipitation data set was compiled of daily precipitation records for 17 observing stations across the basin from 1870 to 2000. For each of these individual stations, average rainfall was computed for each month along with a computed variance and standard deviation to describe the variability of the monthly average rainfall throughout the year. To describe the distribution of the 12 monthly averages for the year, the Chi-Square and Shapiro-Wilk Test was employed. From the results of these tests, the monthly averages were considered to be normally distributed at each of the 17 stations. Then an F-test was performed on every combination of two stations to prove the variances between the two stations could be considered to be statistically equivalent. Once the series of F-tests were completed then every two station combination was tested by the Student T-test to see if their means could be considered statistically equivalent. From the Student T-test and the F-test, the only station combinations which did not have statistically equivalent means and/or variances were a few combinations which contained one station located on the north shore of Lake Pontchartrain and one station located on the south shore of Lake Pontchartrain. Due to this finding, the seventeen stations were then grouped into NorthShore (stations located north of Lake Pontchartrain) and SouthShore (stations located south of Lake Pontchartrain) since the station means and variances could be considered statistically equivalent and normally distributed when compared with other stations within their particular group. The Student T-test was then performed on the two groups using computed pooled variances. This Student T-test showed that a statistically significant difference does exist between the monthly mean rainfall of the stations comprising the NorthShore group and those comprising the SouthShore group highlighting the importance of identifying and recognizing mesoscale precipitation patterns along the Mississippi River.