Dense Water Mass Formation and Fate in the Northwestern Gulf of Mexico during the February 2021 Winter Storm Event

During the winter storms of February 2021, the Texas Automated Buoy System (TABS), the regional observing network of the Gulf of Mexico, recorded anomalously cold sea surface temperatures (SST). Observations near Galveston, TX, located in the coastal northwestern Gulf of Mexico (28.98°N,94.9 °W), showed a steep decline in SST of over 4°C (10.73°C), which were also recorded by satellite observations. Two research cruises funded by the NOAA Ocean Acidification Project (conducted in April and August of 2021) collected hydrographic data along a 95°W transect and show a dense and high-salinity "subductive tongue" extending from the coast to the shelf break. Preliminary analysis of this data suggests a connection between the subductive tongue and the formation of a dense surface water mass during the winter outbreak that eventually mixed with ambient seawater as it subducted and moved towards the deep Gulf of Mexico. By August, the subductive tongue was no longer discernible in hydrographic data collected along the same transect, which implies the temporal and spatial scale of the impact of the storm on the coastal environment. Numerical and mathematical methods are used to investigate the hydrographic changes in the northwestern Gulf of Mexico brought about by the winter storms, and the spatial and temporal evolution of these changes in the succeeding months. Long-term implications posed by future climate scenarios include more frequent occurrences of weather extremes such as this event.