1964 Pacific hurricane season

The quietest year since 1953

The archive records five tropical storms, one hurricane and accumulated cyclone energy of 19.2. The current best track counts six storms and two hurricanes, and ranks 1964 second only to 1953 for the fewest storms in the hurricane database. Its six include Silvia, which forecasters named in August but which post-storm analysis kept below tropical storm strength; the archive holds Silvia as a 26 kt depression outside the counts.

A cold phase of the Pacific Decadal Oscillation kept the early 1960s quiet, and no major hurricane was recorded from 1960 to 1966. Satellite coverage was still scarce two years before the geostationary era began in 1966, so some storms may have gone unseen. The Naval Fleet Warning Central in Alameda, California, issued the advisories.

Natalie, Odessa and Prudence in July

The ship California Star found Tropical Storm Natalie on 5 July. Reports told of 80 mph winds near the Tres Marías islands, but the hurricane database keeps Natalie at about 50 mph, and the Naval Fleet Warning Central reported a landfall near Mazatlán on 7 July at that strength. No impact was recorded.

Hurricane Odessa formed about 250 miles south of Socorro Island on 15 July, and warnings went up for the island. The current best track gives a peak of about 100 mph, Category 2, while the archive records 75 kt. Odessa weakened to 40 mph by 18 July, briefly regained 70 mph according to ship reports and dissipated on 19 July.

Tropical Storm Prudence formed near the same area on 20 July and peaked at about 70 mph before cooler water weakened it. It dissipated on 24 July without landfall but sent high surf onto the California coast, especially at Newport Beach.

Tillie's rain over Arizona

Tropical Storm Roslyn formed about 500 miles south-southwest of Cabo San Lucas on 21 August, passed east of Clarion Island and dissipated the next day. Tropical Storm Tillie, the last storm, developed about 150 miles west of Mazatlán on 7 September, passed southwest of Cabo San Lucas and dissipated off the coast early on 9 September.

Tillie's leftover moisture reached southern Arizona, where a cold front set off widespread storms on the evening of 9 September. Amado measured 5.66 inches in 72 hours, Tucson 3.05 inches in 24 hours, and sites in the Catalina foothills and near Sahuarita 6.75 inches. Combined with rain the week before, the Santa Cruz River peaked at 15,900 cubic feet per second near Cortaro.