Hourly rainfall climatology of Louisiana

This study introduces a climatology of hourly precipitation for four first-order weather stations across Louisiana, investigates possible changes in the hourly precipitation distribution, and links winter (DJF) Gulf of Mexico (GOM) sea surface temperatures (SST) to the frequency of hours with precipitation. Results indicate that it precipitates between 431 and 457h annually, equivalent to roughly 5% of the total annual hours, with distinct seasonal differences. For example, the duration of events is much longer in winter compared to summer, while the number of rainfall events is greater in summer. Using regression techniques, three of the four stations showed a statistically significant increase in 90th percentile hourly events and hourly intensity. At the same time, the frequency of light hourly events (0.254mm, 1.27mm, 2.54mm) decreased. It was also determined that winter GOM SST significantly correlated with the number of hours with precipitation across coastal Louisiana, possibly related to the frequency of synoptic types such as frontal overrunning.