Otis (2017)

A weak disturbance that originally came from the remnants of Atlantic Hurricane Katia moved westward off the southwestern coast of Mexico and became a tropical depression early on 11 September 2017 about 335 nautical miles southwest of Manzanillo. The system moved generally west to west‑southwest for several days, weakening and strengthening modestly, then turned sharply northward on 16–17 September as environmental conditions briefly became favorable. After peaking, Otis moved into much cooler water and drier, higher‑shear air, rapidly weakened, lost all deep convection by 19 September, and became a remnant low before opening into a trough on 21 September.

Otis did not make landfall. It remained well offshore of Mexico throughout its life, reaching its closest approach and peak intensity over the open eastern Pacific about 1,020 nautical miles west‑southwest of Cabo San Lucas on 18 September. Because it stayed far from land, no tropical‑storm‑force winds were reported at any ships or coastal stations.

The hurricane’s maximum intensity was estimated at 100 knots (115 mph) with a minimum central pressure of 965 mb at 0000 UTC 18 September. That peak corresponds to a Category 3 major hurricane on the Saffir‑Simpson scale. The peak estimate is based on a blend of satellite analyses and has more uncertainty than usual because Otis was a very small storm and its intensity changed rapidly.

There were no reports of storm surge or rainfall impacts related to Otis on land because the cyclone stayed far offshore. Consequently, no coastal surge heights or rainfall totals were recorded for cities or counties in Mexico or the Baja California region.

No deaths or damage were associated with Otis. Forecasters had difficulty predicting its formation—Otis was introduced in the Tropical Weather Outlook only about 18 hours before genesis—and the rapid intensification to major‑hurricane strength was not anticipated by the standard guidance suite. Official track forecasts were generally good at short range but had larger errors at longer lead times due to an unexpected sharp northward turn; intensity forecasts notably underpredicted the rapid strengthening and then overpredicted how long the peak would last.