Squall characterization in the Gulf of Mexico

This paper describes a new analysis of meteorological data that improves the understanding and characterization of winds generated by squallsin the Gulf of Mexico. The analysis begins by looking at a particularly strong squall event observed in April 2013 that created gusts that likely approached 40 m/s. Not only was the April squall extremely strong but the wind direction changed rapidly which is often very challenging to dynamically positioned vessels. Indeed one deepwater drilling rig had to make an emergency disconnect during the event. To put the April event into proper historical perspective, the paper produces preliminary estimates of squall gust probability levels based on public domain datasets. This analysis suggests that the April squall was probably close to the 100-yr event and was thus, quite rare. Perhaps more importantly, the analysis shows the 10-yr gusts from squalls exceeds the API 2MET 10-yr estimates for winter storm. This is a significant finding since the 10-yr winter storm is recommended for operating criteria in the Gulf by API recommended practices covering multiple types of offshore facilities. That said, the estimates in this paper are preliminary and further work is needed to remove uncertainty in the n-yr speeds and to quantify rapid wind direction changes before any changes to present operating criteria should be contemplated.