While factors contributing to bloom initiation and maintenance of the toxic dinoflagellate <em>Karenia brevis</em> in the eastern Gulf of Mexico are well documented, the physical, chemical and biological factors contributing to bloom termination are less known.  We examined the effect of the passage of a meteorological cold front on the 2022-2023 overwintering <em>K. brevis</em> bloom in February 2023.  Located in a large patch just offshore of Sanibel Island in early February 2023, this bloom initiated in October 2022 immediately after the passage of Hurricane Ian.  Pre-front, the water column was well mixed with water temperatures of U+0223D22.5ºC. After the passage of the front, the water column remained well mixed, however, the water temperature decreased to U+0223D20.5ºC. Pre-front, <em>Karenia brevis</em> concentrations ranged from 1.0E+3 to 3.9E+6  cells/L in the patch, while post-front, the concentrations immediately dropped to U+0003C1.5E+6 cells/L_[ch1] . Coincident with changes in cell concentration, changes in cell morphology were observed, with higher percentages of rounded cells indicative of turbulent stress present. Chlorophyll <em>a</em> concentrations dropped in the first 24 hours after the passage of the front by 18.8U+00025.  Results suggest that passage of a single cold front is insufficient to terminate a bloom.  We hypothesize that the rapid passage of several cold fronts over a relatively short time period, such as happened to the fall 2021 bloom, is required for bloom termination.