Sandra (2015)

A small tropical cyclone formed from a tropical wave that crossed Central America and developed into a tropical depression on 23 November 2015 about 380 nautical miles (n mi) south-southwest of Acapulco, Mexico. The system moved generally west-northwest then northward and lasted until it dissipated offshore of northwestern Mexico on 29 November. Sandra underwent a rapid strengthening phase between 24–26 November, then encountered increasing wind shear and weakened, becoming a remnant low and then a trough just southwest of Culiacán.

Sandra did not make any direct landfalls. The storm weakened to a non-convective remnant low and dissipated just offshore of the northwestern coast of Mexico; no landfalling tropical-storm- or hurricane-force winds were reported onshore.

The hurricane reached a peak intensity of 130 knots (150 mph) at 0600 UTC 26 November with an estimated minimum central pressure of 934 mb, making it a Category 4 hurricane at peak strength. The peak intensity is based on multiple satellite intensity estimates and the pressure–wind relationship.

There were no reports of significant storm surge along the Mexican coast, and no heavy rainfall or flooding reports associated with Sandra on the mainland or Baja California Sur. Rainfall ahead of the system produced generally beneficial totals of about 1 to 3 inches over southwestern Mexico. Socorro Island reported wind gusts to about 35 kt (40 mph) when Sandra passed roughly 100 n mi southeast of the island.

No damage or casualties were reported in association with Sandra. The regions closest to the storm’s final stages were the northwestern Mexican coast near Sinaloa (including areas near Culiacán) and parts of Baja California peninsula that were briefly under tropical-storm watches, but no impacts were confirmed.

Sandra was notable for its timing and behavior: it became the latest-forming major hurricane in the eastern North Pacific in the satellite era (surpassing Hurricane Kenneth in 2011) and was only the second major hurricane in that basin during November on record. The system’s rapid intensification was not well captured in short-term intensity forecasts, though its subsequent rapid weakening was well anticipated; overall track forecasts showed larger-than-average errors because Sandra moved slower and turned less widely than expected.