Miriam (2012)

A tropical depression formed at 0000 UTC on 22 September 2012 about 360 nautical miles south‑southwest of Manzanillo, Mexico. The system moved generally west‑northwest and northwest, becoming Tropical Storm Miriam later on 22 September and a hurricane at 0000 UTC on 24 September. Miriam underwent rapid strengthening on 24 September, reached peak intensity late that day as it approached Clarion Island, then moved over cooler waters and steadily weakened. The cyclone lost its deep convection and became a remnant low by 1800 UTC on 27 September before dissipating a few days later.

Miriam did not make a landfall on the mainland. Its closest approach to land was near Clarion Island (Islas Clarión) well off the southwestern coast of mainland Mexico when the western eyewall passed near the island around 0430 UTC on 25 September. No other coastal landfalls were reported.

The storm’s maximum sustained winds were estimated at 105 knots (121 mph) at 1200 UTC on 24 September, with a minimum central pressure of 959 mb. At peak intensity Miriam was a Category 3 hurricane on the Saffir‑Simpson scale. Wind observations from a Mexican Navy station on Clarion Island reported sustained winds of 58 kt (67 mph) with a gust to 90 kt (104 mph) and a station pressure of 973 mb when the eyewall passed.

There were no reports of storm surge impacts associated with Miriam in the report, and no significant rainfall totals on the mainland were recorded in the NHC summary. The report did note the Clarion Island observations described above; no other specific surge heights or rainfall totals at named cities or counties were provided.

No casualties or damage were reported. The disturbance that became Miriam was identified in the Tropical Weather Outlook about 60 hours before formation, and NHC track forecasts for Miriam were more accurate than their recent 5‑year averages. Official intensity and track forecasts generally outperformed most guidance models for this storm.